Glenn Burns weather
Formula is right for fall color
Can you believe it’s already October? I think fall is, by far, most everyone’s favorite season of the year. After that long and very hot summer, most people are enjoying the respite from the heat. However, according to the Climate Prediction Center forecast, October will be warmer than average. For you cool weather lovers, don’t panic! With the lower sun angle and fewer light hours, I don’t think we’ll see any 90 degree heat.
What I love most about the fall is the fall color. Last autumn the leaf color was little dull and did not last very long. So what do we need for descent fall color? According to the United States National Arboretum, the process that starts the cascade of events that result in fall color is actually a growth process.
In late summer or early autumn, the days begin to get shorter, and nights are longer. Like most plants, deciduous trees and shrubs are rather sensitive to length of the dark period each day. When nights reach a threshold value and are long enough, the cells near the juncture of the leaf and the stem divide rapidly, but they do not expand. This abscission layer is a corky layer of cells that slowly begins to block transport of materials such as carbohydrates from the leaf to the branch. It also blocks the flow of minerals from the roots into the leaves.
Because the starting time of the whole process is dependent on night length, fall colors appear at about the same time each year in a given location, whether temperatures are cooler or warmer than normal. So, while you may have heard that frost or cold weather causes the leaves to change color, it is only one of many environmental factors that play a part. Temperature does however, play a role with the color and its intensity of fall foliage.
So what will this autumn’s fall foliage be like? You know we had a very hot and a very wet summer. The best weather for brilliant fall foliage is summer with a lot of rain followed by a dry, cool and sunny autumn with warm days and cool but frostless nights. So we did have a wet and warming growing season. We can put that into the plus column. When we have cool nights with a lot of sunshine during the day the red and purple pigments become brilliant. So, we can put that into the plus column.
What we don’t want to see are freezing temperatures, highs winds, or heavy rain. With the prediction of seeing near average or slightly above average rain this month, we can put that into the plus column too. October is usually one of the driest months of the year. So, based on all of this, I would say we are going to have an excellent fall color season this autumn. Only time will tell.
Have a great October and don’t worry about setting your clock back one hour to Eastern Standard Time until November 1st.
See you again next month when I expect El Nino to begin kicking into gear.
Glenn Burns is chief meteorologist for WSB-TV in Atlanta.
September 2015 column
An explanation of the upcoming 'Godzilla El Nino'
August began pretty much like it should have. It was dry and it was hot. Then in the middle of the month tropical rains began to fall for about a week. It was certainly great for those brown lawns and wilting gardens. Then the headline hit the news and social media. “Godzilla El Nino.”
The emails began coming and my social media pages on Facebook and Twitter were filled to capacity with questions from frantic people wanting to know what they needed to do to prepare. Obviously this was some type of scare tactic and media hype introduced to the public. So, let me set the record straight on this “Godzilla El Nino.” Back in 1997 through 1998, the ocean waters off the west coast of South America in the equatorial Pacific Ocean became abnormally warm. This is a natural cycle that occurs every 4-7 years. It can, and does, change global wind patterns and can change what we would consider “normal weather.”
During a typical El Nino winter we can expect mild temperatures across the northern Rocky Mountains, a very snowy Northeast, a brutally cold Great Lakes area, extremely wet conditions for central and southern California, and a very wet Southeast, including Atlanta south, into south Georgia. Northern Georgia, from a Rome to Gainesville line, tends to be drier. El Nino is also responsible for reducing Atlantic hurricanes by creating an environment of wind shear over the ocean, an environment that shuts down hurricane formation. It can also create intense rain-making storms for California, which would not be a bad thing, considering the severe drought conditions that state has been in place for the past three years.
I remember the strongest El Nino in my 33 years forecasting the weather for north Georgia. That 1997-98 fall and winter brought us a whopping half inch of snow for the entire winter. It also brought more than eight inches of rain above our winter average! There was considerable flooding most of that winter. The trees were dormant, no longer taking in the rainwater as they did in the warmer months. Run-off of the rain into creeks and streams was off the charts. Since that winter, the building across north Georgia has tripled non-porous surfaces. So many more parking lots, malls, driveways, and roads have been constructed that there will likely be tremendous flooding if this El Nino mimics 1997-98. Granted, no two El Nino years are ever the same so we will have to wait and see how this all evolves. There is one other “wrench in the works.” Off the West Coast of the United States there is an extremely warm eastern Pacific Ocean. No one really knows how this warm water will interact with all that is going on. This is new territory for us meteorologists.
So, with the impending “Godzilla El Nino,” let’s just remain calm and maybe Mothra will come to our rescue! I will have an update on what we have learned next month. Stay tuned!
August 2015 column
That was one tough month of July
I am so glad July is over! That was one of the hottest in years across most of north Georgia with daily highs in the low to mid 90s most every day. Those pop up afternoon storms were extremely fierce with that high heat too. We sure saw some impressive lightning displays almost every single day. I do believe temperatures will remain slightly above our average high of 88 through most of the upcoming month. August is also a fairly dry month and I expect to see an average of four inches of rain.
The only thing that could change that would be a tropical storm or hurricane. At this time of year, we begin to see huge waves of thunderstorms roll off the west coast of Africa. The storm waves will move out into the open Atlantic. Most will fade away. Others will develop into the strongest tropical systems of the season. The reason: they have a large open expanse of warm water to cross. By the time they cross the Atlantic into the Caribbean, they can become monsters.
I know we’ve all heard it will be a quiet hurricane season. While I tend to agree, it only takes one big storm, like Hurricane Andrew, to wreak havoc on the U.S. Coast. There are a couple of reasons why we will have a quieter than average hurricane season. First and foremost, is El Nino. This eastern equatorial sea surface warming causes global wind patterns to change. During El Nino, strong westerly winds in the upper atmosphere are very strong. This wind shear tends to dissipate tropical systems before they can gain too much strength.
Second is the widespread African dust that is currently blowing across the Atlantic. I was fishing in south Florida last month and it looked like the smog capital of the world. It was extremely hazy every single day due to the African dust. Meteorologists and hurricane specialists analyzing satellite data from the past 25 years found that during years when the dust storms rose up, fewer hurricanes swept across the Atlantic, while periods of low dust storm activity were followed by more intense hurricane activity. Hurricanes are fueled by heat and moisture, and it’s theorized the dust storms help muffle the storms before they fully develop by cooling the Atlantic Ocean. I am waiting to see if the pattern of increased African dust storms will continue to have an effect on our tropical season.
I also wanted to mention this has been a horrible year for lightning fatalities across the country. So far, we have had 20 fatalities. With above average temperatures continuing this month, that means storms can be huge, creating intense lightning. These summer storms, as you well know, can fire up in a very short period of time. Lightning is going to be your main threat. Please monitor radar on your mobile device. So far, none of the lightning fatalities this year have been in north Georgia. Let’s keep it that way.
July 2015 column
So what will July bring, weather-wise?
July is here and I know everyone has been asking me if it will be as hot as June. July is of course, the hottest month of the year with an average high of 90. However, I am seeing some really crazy weather patterns as a result of the summer El Nino. (El Nino in its simplistic definition is above normal sea surface temperatures off the coast of Ecuador and Peru. It usually occurs in December.)
I remember Texas and Oklahoma last year. Several years of drought left the ground parched and dry. Crops were dead. Cattle ranchers were selling all their livestock because they could not feed them. The experts said it would take years to recover from a drought of that magnitude.
As it turned out, it took only five weeks. El Nino has disrupted the “normal” global wind patterns bringing Texas an enormous amount of rain. Then in mid-June, Tropical Storm Bill formed in the northwest Gulf of Mexico and brought another 6-10 inches of rain in just 36 hours. The ground in parts of northern Texas and Oklahoma just can’t hold any more water.
While Texas was getting slammed with flooding rains, our weather in the Southeast turned brutally hot. We never really had much of a spring, as you well know. We went from highs in the upper 70s to low 80 straight into the mid-90s.
I don’t believe in my 33 years forecasting the weather for north Georgia, I have ever seen Lake Lanier warm so quickly. One week the water temperature was 79 degrees and the next week it was 85. It takes a tremendous amount of energy to warm water like that.
So, let’s get back to the question everyone is asking. Will July be as hot as June? El Nino makes long-range forecast extremely challenging. From what I can see, I do believe we may begin the month with temperatures at or slightly below average. I say this because I am seeing the pattern of drier than average weather changing this month. I think with above average rainfall, we would likely see nothing too drastic early this month. By late July, we will likely see temperatures get really hot again. As always, time will tell.
Enjoy the lake and its warm temperatures and be safe. Always be on alert for those pop-up afternoon storms. You know how much lightning they can produce and how quickly they can form. Carry along our weather app on your mobile device and we’ll be here, always keeping you ahead of the storms.
June 2015 column
Get read for a 'fickle' month
June is here, and although we have seen extremely warm temperatures throughout much of May, Summer officially begins late this month: Sunday, June 21st at 12:39 p.m. So what exactly is the Summer Solstice? A solstice happens when the sun’s zenith (highest point) is at its farthest point from the equator. On the June 21st solstice it reaches its northernmost point and the Earth’s North Pole tilts directly toward the sun, at about 23.5 degrees. It’s also known as the northern solstice because it occurs when the sun is directly over the Tropic of Cancer in the Northern Hemisphere.
June can be a very “fickle” month when it comes to rainfall. In looking over the data from the past 15 years, we’ve seen as little as inch of rain in June of 2000. In 2013, we had almost 10 inches of rain for the month. From the weather patterns that have been setting up the last two months, and with El Nino going strong in the eastern equatorial Pacific Ocean, I am looking for above average rainfall for the month. Since summer storms are very tropical in nature, tropical downpours are very likely. These are called “Pulse Thunderstorms” because they develop quickly, become fierce with hail, strong winds, and intense lightning, and then die quickly. They “pulse up” and then quickly fade.
I know everyone likes to be on the lake this time of year. In preparation, I would really like to suggest getting our WSB Weather App. It has some great new features. Not only can you see our live radar, it now has the capability to detect approaching lightning and will warn you when it becomes close enough to be dangerous. Think how valuable that would be on your next family outing. The “Pulse Storms” produce an incredible amount of lightning. I have seen nearly 300 strikes every 15 minutes from a storm. Most of these produce negative lightning strikes, coming from the bottom of the cloud to the ground. However, about five percent of lightning strikes are positive strikes. These bolts originate from the top of the storm cloud. Because they have to travel a greater distance to reach the ground, they are much more powerful. A typical negative charged bolt is about 300,000,000 volts and 30,000 amps of power. Your typical household lighting bulb is about 120 volts and 12 amps. The positive lightning bolt can reach 1 billion volts and 300,000 amps! The stronger voltage and longer lasting bolt is the reason they cause so much damage and cause so many deaths. Positive strikes are usually the cause of forest fires, house fires and damage to planes and power grids. What makes them even more dangerous than that? A positive lightning bolt can travel 10 miles from its parent thunderstorm!
So, please be safe this summer. Take along our weather app. Summer storms can pop up quicker than you think.
May 2015 column
We've been lucky with severe storm season - so far
Our March-April severe storm season has been severe storm season “light.” We sure escaped what others around tornado alley have not this spring. It has been extremely active from Texas to Minnesota and east toward the Ohio Valley. We are now entering the month of May and the peak of the tornado season is under way.
With the peak of Georgia’s severe weather season now behind us, we get to enjoy one of the most beautiful months of the year. I absolutely look forward to the month of May. The pollen is gone and the temperatures are not too hot and not too cold. That being said, we can still get severe storms but they will be few and far between.
With a Spring El Nino, I still see above average rainfall on the docket this month. I have been seeing a consistent pattern developing over the course of the last month. We have a huge high pressure center that seems to have found a home and currently resides in the northern part of the Gulf of Mexico. The high pressure center seems to oscillate north and south but remains semi-permanent in the gulf. When it moves north, we turn dry and hot, just as we did with the record high of 86 in Atlanta last month and a record 89 in Athens. When it shifts just 50 to 100 miles south, the flood gates open and Gulf of Mexico moisture pours in with tropical-like rains.
I think we will find abundant rainfall going into summer. This is certainly much better news that what we were facing just 10 years ago when we were in the middle of that extreme drought. I think we can all sympathize with the folks out west who are enduring yet another extremely dry year with massive water shortages.
At this time of the year, everyone wants to know if it’s going to be a really hot summer. My answer is probably not. With abundant rainfall, temperatures should be fairly typical. There will be days when that high pressure in the gulf nudges northward and nudges the rain pattern north. When this happens I am sure we will see some 90-plus degree heat. Overall, I do think we’ll have temperatures for the most part, in the mid to upper 80s on average.
This will all hinge on how long El Nino lasts and how strong or weak it gets. The bottom line is likely going to be above average rainfall and typically warm temperatures this month. Can’t wait to get to the lake! See you next month.
April 2015 column
It's time to put up the jackets, maybe
Well, another winter is in the books and spring has officially arrived … or has it?
This past winter was the 61st coldest on record for our area. December was the warmest month of winter with temperatures averaging nearly five degrees above normal. January was fairly typical with temperatures only .2 degrees below normal. February was a different story. We were nearly seven degrees below normal.
The official snow total at Atlanta’s Hartsfield Jackson International Airport was only a trace, which was 2.1 inches below the 30 year average. However, we all know the ice and snow in our northern counties was substantial, especially the ice storm in February.
From the data I have been seeing, we may have several chances for freezing or near freezing temperatures this month with above average rainfall. In fact, I see cooler than average temperatures continuing until June. I know everyone is cringing about that. Let’s face it, we all want to enjoy the lake on sunny warm days.
Let me explain what is happening. We have a massive area of high pressure in the eastern Pacific Ocean that is now moving. This is causing warm and extremely dry conditions in the western states. In fact, many areas out west only saw about 15 percent of their usual snowfall this past winter. There are some very serious drought concerns. That same high pressure is causing the upper level winds, the steering currents, to go up over that high pressure into western Canada and then blast down into the southern states, bringing us the cooler than average weather.
While we may not want to see cooler temps, they do have a silver lining. First and foremost, cooler temperatures inhibit severe storms. Our spring storms are most violent when we have sharp contrasts between cooler weather to the north and warmer temperatures here. If the cool pattern continues, there are no “weather wars” between air masses. I am not saying we won’t see severe weather this month, just less of a chance. In addition, the pollen season will be more progressive than explosive. I don’t think we’re going to see those 11,000 pollen counts this season.
Based on the past 30 years of weather records, April is the driest month of the year. We average 3.36 inches of rain. However, this year we have a spring El Nino. This throws yet another wrench in the works. The above average sea surface temperatures in the equatorial Pacific Ocean change the global wind patterns. We will likely be dealing with two branches of the jet stream, the cold northern branch and the southern branch coming in across the eastern Pacific, then over Mexico, into the southeast. This southern branch is likely to transport an enormous amount of moisture our way. So, while April is usually the driest month, it may not be the case this go-around.
In any event, spring is here and I personally, am looking forward to a kinder and gentler severe storm season. As always, my team of five meteorologists and I will always keep you informed.
March 2015 column
This month ushers in severe storm season
As I said in last month’s column, I thought February would be the coldest month of the winter. As it turned out, it indeed was. We even set a record low on February 20th of 16 degrees in Atlanta. On that same night, Blairsville, up in the northeast Georgia mountains, dropped to -2 degrees.
The biggest story from last month was the devastating ice storm centered around Lake Lanier and to the north. The set up included a strong area of arctic high pressure that brought in a very shallow later of cold air (below 1800 feet). This cold air wedged itself down the east side of the mountains and “pooled” across northeast Georgia. Temperatures remained just below freezing and never moved. Above ground, at an altitude of 5,000 feet, the temperature was in the mid-40s.
When I saw this setting up, I just cringed. As the snow from the higher clouds fell into the warm layer, the snow melted into rain drops. The rain then fell on to the sub-freezing ground, where it formed a layer of ice on roads and trees. Between a quarter to half inch of ice accumulation was very common. The sheer weight of the ice was just too much for the trees to handle and one by one, they came crashing down on homes and power lines. Many residents were without power for nearly a week.
So now we head into my least favorite season of the year. Aside from the pollen, it’s severe storm season. I do expect a very active season. All winter long we have been dealing with two jet streams over the United States. The cold polar branch has been bringing us the cold arctic air. The southern branch, which has been cruising over the Pacific Ocean, and Mexico, brought us the moisture and our ice storm. It is this southern branch I am most concerned about. When spring storms erupt, these strong upper level winds over the top of the storm bring the storms a tremendous amount of energy. As winds increase from the surface to the top of the storm, this wind shear can cause the air to begin to rotate horizontally. As storm updrafts become stronger, they will tilt that rotating wind into the horizontal. This is the beginning of a tornado.
I don’t see much change in this upper level wind pattern so let’s get ready this month. There are so many ways to receive alerts, and one of the best, is our WSBTV Weather App, available for a free download in the iTunes store. It is also available for Android. We will also have our team of five meteorologists here every day, keeping you ahead of the weather.
February 2015 column
February could bring coldest temps this winter
The dire predictions from some about this winter being cold and harsh have yet to materialize. In December, the average temperature for the month was two degrees above the 30-year norm. Although we had a couple of bouts of cold weather in January, those mid-60 degree days in the middle of the month balanced that out. At press time, we did not yet have the average for January.
This brings us to February. The Climate Prediction Center gives us a 50/50 chance of having above or below average temperatures and precipitation. There may be too many variables to nail it down one way or another. Nevertheless, I have been looking through the coldest winter temperatures ever recorded in the Atlanta and north Georgia areas. Eight of the coldest temperatures ever recorded were during the month of January, as you might expect. The coldest during that month occurred on January 21st, 1985. On that day the temperature dropped to minus 8 degrees. On the list of the coldest Atlanta temperatures was the day we dropped to zero. That was Christmas Day, 1983.
Do you know when the coldest temperature to ever be recorded in Atlanta was? It was in February. On February 13th, 1899 the temperature fell to 9 degrees below zero! In the north Georgia mountains, both Blue Ridge and Blairsville saw the temperature drop to 18 degrees below zero. Both records stand to this day. I am telling you this because I do see signs that we could be in store for a very cold first half of the month. I don’t see anything close to those long standing records so don’t worry!
So, with my humble opinion that we are going to see what may be the coldest weather of the winter this month, it won’t be as cold as it could be. The reason is the lack of snow cover on the ground to our north. Unlike last year, we have just not seen the kind of systems that produce a lot of snow. With the lack of snow to our north, the cold air moving south may get a chance to warm up a little before reaching us. Air warms by conduction. The sun heats the ground and then the ground heats the air above it. Let’s hope this less-snowy winter holds this month.
I know what you’re thinking. If it’s going to be cold, what would be our chances for snow? That’s the question of the day and a little more difficult to nail down. Pretty much all winter we’ve had a split jet stream. The colder polar jet has remained to our north for the most part, occasionally bringing down shots of cold arctic air to the south. Traveling from west to east we have the sub-tropical branch of the jet stream. This southern branch can sometimes promote storm growth in the Gulf of Mexico. That’s where the “big boys” come from, the ones that can bring us accumulating snows. Needless to say, we will be watching intently this month for the gulf storm and a dip in the polar jet stream. When they meet, it can be very interesting. Stay tuned!
January 2015 column
A plan for winter weather is now in place
As we enter a new year, my thoughts have immediately turned to last year, specifically January of last year. I am hoping we never see anything like that again in north Georgia. We knew the snow was coming. We knew it was going to be around two inches or less in most areas. We also knew cold arctic air would be blasting in as the snow began tapering off. Unfortunately, many people across north Georgia either did not believe the forecast or misunderstood it. Regardless, we all know that minor winter storm created an epic disaster.
In the months following, I was asked to be on the governor’s Winter Weather Task Force, along with leaders from GEMA, GDOT, and the National Weather Service. We looked at the issues involved with this winter weather disaster, made recommendations, and came up with a plan to make sure what happened in January of 2014 does not happen again.
On Monday, January 27th, 2014 we knew winter precipitation was going to move in. It was not an especially big storm and we only expected modest snowfall (most areas would receive 2” or less). The National Weather Service issued a “winter storm watch” that included the metro area. That same night, the NWS canceled the winter storm watch and replaced it with a “winter weather advisory.”
Normally when you go from any type of watch, the next step would be to a warning. So county emergency managers, school superintendents, and most others thought the NWS had downgraded us. That was NOT the case. The advisory was actually an upgrade from a watch because there would be some travel issues. Before school began the NWS and I could see things coming together so that 3:39 in the morning, the advisory was replaced with a “winter storm warning.”
However, that morning, there was no snow falling so people just went about their business. About 11 a.m. the snow began and the arctic air moved in. People began leaving work and school in droves and it did not take long for roads and freeways to become parking lots. Truckers began sliding into cars and blocking freeways. It was mayhem.
From the governor’s task force, new policies have been set. We now have a state meteorologist (my former producer) and will have weather briefings from the NWS that will include all partners so everyone is aware and on the same page. Truckers will be stopped at checkpoints before entering our area and will be told to park until the danger is over. Last winter was a learning process. This year a plan is in place.
I expect winter weather this month and hopefully the problems last year will never be seen again. Stay tuned!
December 2014 column
Blame Nuri for the early cold weather
It began as an area of low pressure southeast of Guam in the western Pacific Ocean. There was little wind shear and a very warm ocean and this area of low pressure began to grow and get much stronger. In less than a week, it became a Super Typhoon named Nuri. And that is the name of the storm that brought us brutal cold in the middle of last month.
Super Typhoon Nuri was powerful and massive, spanning some 800 miles. Winds were sustained, sustained mind you, at 180 miles per hour with higher gusts when it moved just southeast of Japan. As the storm moved northeast into the northern Pacific, it started to tangle with the jet stream and was drawn toward the Bering Sea. As it did so, it began to feed on cold Canadian air and became a massive extra-tropical cyclone. As it headed for the Bering Sea and Alaska it mushroomed into the most powerful storm in recorded history for the region. Ships and crab boats encountered 100 mph winds and waves, get this, over 50 feet high!
As the storm began riding the jet stream into the northwestern United States, it began pulling up so much warm air from the south, and so much cold air from the north, it caused the jet stream to buckle. When that happened, it opened the flood gates to the North Pole and sent the jet stream all the way down to Texas and Gulf Coast. Bitterly cold arctic air sank far south, blanketing areas from the Rocky Mountains to the eastern seaboard with record cold temperatures. While we did not see any record lows here in north Georgia, our temperatures last month, as many of you know, were more typical of mid-January.
As we enter the month of December, I know everyone wants cold weather, and of course, a white Christmas. From what I have seen, now that we don’t have any more typhoons to disrupt the normal weather patterns, we can pretty much look forward to typical December weather. So what is typical December weather? We can and do see thunderstorms and 70s in December. We see sleet and snow too. I think we’ll see the usual progression of warm ups and cool downs with bands of showers along each cold front. I am not seeing anything really extreme.
However, I do see the possibility of an extremely cold January and February. A white Christmas is certainly possible this year but the odds are certainly not in our favor, based on the past 30 years of climatology. We shall see.
I would like to take this time to wish you all a very Merry Christmas and a wonderful, happy, and prosperous New Year. See you again in 2015!
November 2014 column
What El Nino will bring us this winter
El Nino continues to develop in the equatorial Pacific Ocean this month. We continue to see significant warming of the sea surface temperatures. It is likely to be a weak El Nino even for the late fall and winter. That being said, it is still likely to disrupt and change the global wind patterns. So what does that mean for Georgia and the Southeast?
If it behaves like a typical El Nino, our winter is likely to the colder than normal. The Climate Prediction Center is giving north Georgia a 33 percent chance of below average temperatures from December through February. Precipitation however, is a little more uncertain. During a weak or moderate El Nino, central and south Georgia tends to receive much more rain than north Georgia.
Here in north Georgia, we can be divided even further. The mountains would receive less precipitation than counties to the south. There appears to be much uncertainty about this. To that end, the Climate Prediction Center has placed the area north of Macon in the “Equal Chance” category, meaning we have too many variables to make an accurate prediction. In my 30 years of seeing the effects of El Nino, which occurs about every three to five years, I have seen winters where it has been drier than normal and wetter than normal with nearly identical situations.
Above average winter precipitation during an El Nino is highly dependent on the position of the southern branch of the jet stream. It will travel from the Pacific Ocean, through California, the southern states, and into Georgia. It could waver only 50 miles north or south and completely change our weather. It is definitely a fine line of variability.
While we all wait for winter weather, I must remind you November is a “transition month.” As we transition from autumn to winter, we can and often do, face devastating severe storms, like we did last month. Six tornadoes touched down on October 14th. Insured losses were more than $6 million.
The tornadoes were spawned along the leading edge of a squall line called a QLCS (quasi-linear convective system). They are extremely difficult to detect on radar. We did spot them and we did track them and because of the technology we have, no one was hurt. That is and always will be our goal. I would expect to see several more systems like the October outbreak this month, especially with the changing southern branch of the jet stream over us.
So, with that in mind, take a little time to enjoy the remaining fall color. The holiday season is upon us and winter is looming. November is a month of transition so get ready for stronger cold fronts, stronger storms ahead of those cold fronts, and the freezing temperatures that will no doubt follow.
October 2014 column
Remembering the hurricane that hit Atlanta
At the beginning of the month, we were looking at the long-range models for this October. The patterns are showing a warmer than average month with about equal chances of above or below average rainfall. As we were pondering the rainfall, one of our meteorologists reminded me of the night of October 4th and 5th, 1995.
I remember that night all too well. Category 4 Hurricane Opal was spinning in the Gulf of Mexico. Although satellite observations showed some weakening, it was still a very formidable tropical cyclone. What bothered me the most was its fast forward speed. Opal was moving at nearly 30 miles per hour and aiming for the Florida Panhandle, heading almost due north.
When tropical systems move inland they are usually moving about 5-10 miles per hour. As they move over land they no longer have the energy from the ocean to maintain their strength. That is the way things are supposed to work. This was not the case with Opal. The hurricane was maintaining its heading and speed. It would only take eight hours at that speed to move from the panhandle into the Atlanta metro area. This would not be enough time for the storm to substantially weaken. It was going to be a very long night.
I watched the eye move inland and make a bee line up the Georgia-Alabama state line. Squalls in the outer bands were already producing torrents of heavy rain and spinning up many tornadoes. When Opal moved into the western part of the metro area, we clocked winds at 79 miles per hour. Opal was still a hurricane!
As the outer bands continued to swirl, warnings for winds and tornadoes were coming in fast and furiously. Damage reports flooded our newsroom. Thousands of trees were down. Power was out for many. At the height of the storm, nearly 400,000 people had no power. However, Opal was not quite finished. Winds on the ground are slowed by friction. The higher up in the storm, the stronger the winds. When those winds hit the north Georgia Mountains, it was mayhem. Thousands upon thousands of trees, some more than 100 years old, snapped like twigs. It wasn’t until Opal reached Tennessee that it was downgraded to a tropical storm. When it was all said and done, 43 counties in Georgia were under a state of emergency. There were several deaths from tornadoes and fallen trees. All totaled, there was $5.1 billion in damage in the Southeast. It was one of the scariest nights I have ever had forecasting the weather.
When our fall cold fronts move south of Georgia they will tend to stall in the Gulf of Mexico during the month of October. So far, the giant Sahara dust cloud has kept the Atlantic quiet. I hope never to see another storm like Opal. Rest assured we will be watching the Gulf intently this month. Aside from possible tropical development this month, October is my favorite month of the year. I hope the blue sky, low humidity, cool morning lows and warm daytime highs will prevail. Expect the fall color to peak around the third week of the month and continue through early November.
September 2014 column
A strange summer comes to close this month
Summer ends this month. Fall officially begins on September 22 at 10:29 p.m. I have to say, this has been one of the strangest summers I have ever seen. It seemed to be a season of extremes. Rainfall was certainly not a problem. We had pop-up afternoon storms somewhere in Georgia just about every day. The storms this summer produced some of the most intense lightning we have seen in Severe Weather Center 2. Trees would get struck and would crash onto houses. People in their living rooms were hit. There were numerous attic fires from lightning every time a storm popped up.
On the other end of the spectrum were the temperatures. This summer our temperatures were below average by 2-3 degrees. There were several major cold fronts that moved through in July and August. When we track a summer cold front, we usually just see a shift in the wind from the south to the northwest. The northwest wind will tend to bring in some slightly drier air. However, the cold fronts this summer were actually cold fronts. We set low temperature records on several occasions in July! 59 degrees in Atlanta was the coolest low temperature record. Many mountain communities saw low temperatures in the upper 40s in July. I have never observed that in my 32 years here at WSB.
It is about this time of year when I begin to receive inquiries about our winter weather. As we all remember, last winter was brutally cold and we had two major winter weather events. Winter patterns don’t usually set up until late October or November. However, if I were to make a prediction now, I would make that prediction on persistence. What I saw last winter, to some extent, actually continued into the summer. I am not seeing a major pattern change as we head into September. That being said, I would think our upcoming winter might be another cold one. I cannot comment on whether or not there will be any snow or ice, as they are random events.
Temperatures this month should still be warm with plenty of time to enjoy more time on the lake. If you are out on the lake on the night of September 8th, you’ll be in store for a real treat. The full Harvest moon will rise in the east at around 9:30 pm. It is a little early this year.
I hope you’ve enjoyed your summer. Seasons are changing this month and I will be here, as always, to get you through the transition. Enjoy!
August 2014 column
An explanation of 'dog days'
All last winter, all I heard was how cold it was. Everyone was wishing for an early summer. Guess what’s happening now? You got it! Everyone is now asking when it is going to cool down! I can assure you, it won’t be in the month of August. We are in the Dog Days of Summer.
I have heard many north Georgia residents say it is the time of year that drives dogs mad because it is so hot and miserable. This is NOT the case. You might have heard of a constellation named Orion. Often referred to as “The Hunter,” Orion is a prominent constellation visible throughout the world. Nearby is the constellation Canis Major, which is Latin for “greater dog.” According to constellation lore, Canis Major is one of Orion’s hunting dogs.
Located in Canis Major is a star named Sirius, also called the “Dog Star.” With the exception of our sun, Sirius is the brightest star visible from Earth. The brilliant, blue-white star’s name comes from the Greek word for “searing” because Sirius is so bright. It was easy to track even for early astronomers. During April and early May, Sirius was visible in the southwest after sunset. But by the time mid-summer would come along, Sirius would rise and fall with the sun and get lost in the daytime light.
However, the ancients knew that the “Dog Star” was still there, up in the sky with the sun during the hottest time of the year. They reasoned that since Sirius was so bright and up there with the sun, it must be adding to the heat to produce the hottest time of the year. Of course we all know Sirius is still there, it just does not produce any heat. So that is the true story of how the Dog Days got its name.
While we all simmer through the Dog Days, we have a real treat coming this month. If you happened to miss the Super Moon in July, don’t worry. The best is yet to come! The August Super Moon will be the closest the moon comes to earth all year, and should be the best of the five Super Moons of 2014 as it passes within 221,765 miles of us. The next Super Moon is on August 10th. September 9th is the last Super moon. The “Super Moon” is a relatively new term to refer to the “perigee full moon” or new moon, basically, when the moon comes to the closest point in its orbit to earth. (The moon’s orbit is an ellipse, not circular) “Super Moon” usually refers to any of a number of times the moon orbits earth that fall within the closest 10 percent of orbits. I don’t think there is anything quite as beautiful as a full moon rising over Lake Lanier on a warm, Dog Days of Summer night. Enjoy!
July 2014 column
When sunglasses fog up, it's one of those days
It is early morning and the sun has been up for about an hour. When you walk out the door to get into your car, your sunglasses immediately fog up. You know it’s going to be one of those days you wish you could hang out by the pool. It’s already stiflingly hot.
Far above the ground, where you see the jets flying, it is very cold. As the sun continues to bake the ground, the air over the ground begins to heat up, becoming lighter and very buoyant. A column of warm, sticky, tropical air begins to rise. With the air around this column being very cold, it begins to rise faster and faster until the water vapor in the air condenses to form a cloud. Our cloud stops rising as it encounters a layer of warm air. Overnight, the heat we absorbed all day escapes and rises. It forms what we call a “cap.” Our little cumulus cloud tries to climb higher but there is no longer any cold air around it to help push it upward. By early afternoon a weakness forms in the cap and the air rushes upward at tremendous velocity. The cloud continues to grow with huge towering branches of cumulus clouds. Trillions of water droplets begin to get super-cooled, remaining liquid below 32 degrees. Some water droplets begin to freeze into small hailstones.
Gravity begins tugging at the hail pulling it toward the ground. On their way, they collide with the super-cooled water droplets and grow larger. But the updrafts coming from the ground are relentless. They bring the hailstones back up, high into the cloud, coalescing into even larger and larger hailstones. The rain and the hail begin to collide in the stronger upper level winds. And then it begins with the first crack of lightning.
A summer storm is born and it’s a big one. In the middle of this storm the updraft of warm and humid air continues to supply the storm with energy. It continues to grow larger. Looking down from space, our satellite imagery shows what looks like a large cotton ball, towering over surrounding clouds. Our radar shows a large core of hail and very heavy rainfall. As we switch modes on the radar to show wind velocities, we can see straight-line winds on the edge of the thunderstorm at 60 mph. We are also detecting hail the size of quarters. The National Weather Service radar operator issues a Severe Thunderstorm Warning. Our storm is now reaching its mature stage. All hell is breaking loose on the ground. Rain, hail, high winds and severe lightning, as many as 100 strikes in 10 minutes are occurring.
As the rain and hail continue to fall, the air below the storm begins to cool. The updraft of hot humid air that was once feeding the storm with energy is being overwhelmed by the rain and hail-cooled air. It is scrounging for energy but there is none. When the storm can no longer continue there is a last downward rush of cold air. The air rushes toward the ground at nearly 80 miles per hour. As it hits the ground it fans out in all directions, causing roof shingles to peel away, lawn furniture is scattered everywhere and several trees are blown down in this wet microburst. From the time the storm first formed to its last death throws, 45 minutes have passed! This was a typical “pulse type” thunderstorm frequently found during the month of July. This is why you need to pay particular attention to the weather forecasts and have a weather app or weather alert radio when you want to spend a day on the lake.
Be safe this July my friends. Summer storms can be deadly.
June 2014 column
Summer could bring interesting weather
At 6:51 a.m. on Saturday June 21st, summer officially begins. Summer 2014, from what I have seen, could be a very interesting summer.
If you will recall, last summer was absolutely miserable. We had showers and thunderstorms pretty much every single day and consequently, cooler than average temperatures. While the above average rainfall was certainly great at keeping the lake level up, it was not so great for those of us wanting to enjoy the lake. So, the question of the day is, are we going to see a re-peat performance.
Hurricane season begins June 1st and continues to the last day of November. During June, the most likely area for tropical development is in the Gulf of Mexico. By July, the favored area is the Caribbean, and in August and September, that area shifts to the Atlantic, where the major hurricanes are likely to form.
Since 1970, according to the U.S. Geological Survey, there has been an increase in the amount of Sahara dust streaming across the Atlantic Ocean. Last hurricane season, the dust clouds were especially thick as storms in Africa tossed the dust high into the atmosphere. We saw it as high as 15,000 feet! Sahara dust clouds have a chilling effect on the ocean, preventing the formation of the tropical waves that push off the west coast of Africa. Normally, these waves will evolve into tropical depressions or tropical storms. However the Sahara dust clouds prevent incoming sunlight for warming the ocean to the levels that would support tropical system formation. Hurricane experts believe that will happen again this season so a much fewer number of systems will likely develop.
Another reason this tropical season will be below average has to do with what is happening on the other side of the world, in the equatorial Pacific Ocean. It appears we may have a very strong El Nino developing, the likes of which we have not seen since 1997. El Nino is a warming of the sea surface temperatures in the Pacific that will result in a changing of the jet stream and wind patterns across the globe. The effects of El Nino in the winter months for north Georgia are more pronounced, with cooler temps and above average precipitation. However, in the summer months, it will also have a major impact.
Scientists studying El Nino development believe we just might have a cooler than average temperatures this summer as a result. Last summer, because of the rain, we only had a handful of days where temperatures reached 90 degrees. It may be the same this summer because the jet stream will be at a much lower latitude, supplying us will little shots of cooler air. Will we see above average rainfall? It will all depend on how quickly El Nino forms. I can say from past experience, summer storms will likely be stronger because of the increased wind shear.
My summer forecast then, will be for cooler than average temperatures. I cannot definitively say much about increased rainfall yet. We will be watching as things continue to evolve.
May 2014 column
Last month was quiet on the storm front
April was an incredibly quiet severe weather month across the country. The number of tornadoes was 46 percent of normal. Here in Georgia, we average four tornadoes statewide in April. We only had one tornado and it actually occurred from a heavy shower and not a thunderstorm. There were several minor injuries and damage to two homes just to the northwest of Griffin in Spalding County.
In the month of May, the average number of tornadoes in Georgia is three. This is based on the past 30 years of weather records. From what I have seen in the long-range models, rainfall in May should be below our 3.67 inch average. Maybe the below average severe storm season will continue. Beyond that, the Climate Prediction Center is giving us equal chances of above or below average rainfall. That prediction was made before signs of a developing El Niño.
It appears that an El Niño is in the works right now and it might be a big one. El Niño can boost the odds of extreme weather (droughts, typhoons, heat waves) across much of the planet. If current forecasts stay on track, El Niño might end up being the biggest global weather story of 2014. The most commonly accepted definition of an El Niño is a warming of the tropical Pacific Ocean south of Hawaii, lasting for at least five consecutive three-month “seasons.” A recent reversal in the direction of the Pacific trade winds appears to have kicked off a warming trend during the last month or two. That was enough to prompt U.S. government forecasters to issue an El Niño watch last month.
Forecasters are increasingly confident in a particularly big El Niño this time around because, deep below the Pacific Ocean’s surface, off-the-charts warm water is lurking. Currently there is a huge sub-surface wave of very warm water that currently spans the tropical Pacific Ocean – big enough to cover the United States 300 feet deep. That’s a lot of warm water. As that blob of warm water moves eastward, propelled by the trade winds, it’s also getting closer to the ocean’s surface. Once that happens, it will begin to interact with the atmosphere, boosting temperatures and changing weather patterns.
In the United States, this could bring welcome rains to our western states suffering from severe drought. While residents there might be very happy about this, these rains may be so heavy as to cause more flooding and mudslides. In Georgia, we may see a benefit. In fact, this may be good news for eastern coastal states. An El Nino will create strong easterly winds across the Atlantic. With so much wind shear, Atlantic hurricanes will have a VERY tough time developing. Colorado State University hurricane forecasters, including Dr. Bill Gray, is prediction only three hurricanes to form this season, one of which will be a major hurricane. Certainly good news!
April 2014 column
Spring is like a split personality
April is a month I like to call a Jekyll and Hyde month. For the most part, the weather this month is mostly tranquil and serene. In fact, it is the driest month of the year in north Georgia. We have abundant sunshine, the plants and trees are still in bloom, and temperatures continue to warm. However, things can frequently turn ugly in a heartbeat.
I remember back in 1987 when temperatures were warming and we were on a fast track to warmer spring weather. Then I noticed this huge area of cold arctic high pressure barreling out of Canada. At the same time, there was a stalled out cold front in the Gulf of Mexico. A low pressure area was forming along the front. It looked like a typical winter storm scenario. As new computer model data continued to stream in, it was now apparent the moisture and the cold were about to meet up at the same time, and right over Georgia. Even though we were well into the 70s, I had to make a prediction. Within 48 hours, we had 4-6 inches of snow from the mountains in to the northern suburbs of Atlanta. Two days later, we were back in the 70s! The latest I believe it ever snowed in our area was April 25 when 1.5 inches fell in 1910, also the heaviest for the month, and the latest-ever freeze.
While April can be very pleasant, and on rare occasions even snowy, it is a month that has spawned violent weather. The Dunwoody Tornado was a significant tornado that tore across the northern suburbs of metro Atlanta on April 9, 1998. It struck parts of the four most populous counties in Georgia: Cobb, Fulton, DeKalb, and Gwinnett. The most severe damage was in the Dunwoody area, where the storm reached a high-end F2 on the Fujita scale, making it one of the strongest and most damaging recorded to have hit that area.
The thunderstorm was part of a major outbreak that started in the south-central United States on April 6. The particular supercell which produced it also spawned the tornado that ripped through western suburbs of Birmingham just a few hours prior, on the evening of April 8. That storm was rated F5 and killed 32 people.
March is usually the time we see the most severe storm activity and tornadoes. However, the abnormally cool air we had, severe storms never materialized. I don’t believe I have ever seen a March go by without a single severe storm. I am hoping severe storm season just isn’t getting a late start. We shall see in the Jekyll and Hyde month of April. Be prepared.
March 2014 column
Residents need to take warnings seriously
February 2014 may go down as one of the most bizarre weather months I have ever seen. After “Snowpocolypse” in late January, an even stronger winter storm developed in the Gulf of Mexico and ran right into a wedge of cold arctic air. It was amazing to see the different types of precipitation we endured over that 36-hour period.
We were a lot more prepared for the second one. Our 1-2 inch snowfall on January 28th turned into the worse traffic nightmare since “Snowjam” 1982. People were stuck on the roads and in schools for up to 24 hours. Most everybody blamed the government for its lack of preparedness. I beg to differ. We all knew we were going to see 1-2 inches of snow followed by an arctic cold front. We knew it was going to develop in the late morning and continue into the evening. However, people chose to go to work. Schools chose to have class. Then it began to snow and everyone left work and school at the same time. All the traffic on the roads caused a massive snow melt which abruptly turned into ice with the cold arctic air moving in. Trucks to treat the roads could not get to their destinations and then the public said the government should have been more prepared. It was actually the residents of north Georgia that were not prepared and did not take our forecasts seriously and caused the chaos.
When we were forecasting the snow, sleet, and ice again two weeks later, people heeded the warnings and we avoided a repeat performance. Gov. Nathan Deal in the days after the January 28th storm, appointed a task force, of which I am a member. We have met several times and have made some excellent suggestions on how to address future winter storms. I am also doing a lot of the forecasting too. Although winter is just about over, I have reminded the task force about March 13, 1993! While seeing another “Storm of the Century” is not likely, you never know, especially with this weather pattern we are in.
Speaking of weather patterns, it is likely we are going to see the strong southern branch of the jet stream continue to traverse the southern United States through the spring. It wasn’t a week after our snow, sleet, and ice that we were under a tornado watch with violent overnight storms causing trees to crash into homes. I suspect we are going to have a very active tornado and severe storm season if the pattern holds. I cannot emphasize enough that we all need to be prepared. You need an app that has a warning alert for your smart phone. We have a great weather app that I think is the best in the country. It is free on iTunes. If you don’t have a tablet or smart phone, you need to get a weather alert radio. Whenever there is a severe storm threat, you will have critical weather information when you need it, even if the power goes out. Take for example our first round of severe storms back in February. They moved in during the middle of the night when most of us were asleep. Getting a warning from your smart phone, tablet, or weather alert radio can and does save lives.
February 2014 column
So just what is a 'polar vortex'?
As we move out of a record setting cold January for much of the eastern two thirds of the country, our long-range models show we can expect a nice warming this month.
Last month we all heard ridiculous headlines like “the polar vortex is set to devour the Midwest and Northeast.” I think a little explainer about the polar vortex is in order. I believe we all know or have at least heard of, the Bermuda High. In the summer, it’s a semi-permanent area of high pressure centered near Bermuda. It’s what keeps us warm and muggy during the warm months. It’s also a guide for hurricane movement. In the winter, the Bermuda High migrates eastward across the Atlantic and sets up near the Azores. It then becomes known as the Azores High. It’s pretty much the same thing with the Polar Vortex. It’s a semi-permanent area of low pressure centered near Baffin Island. The polar vortex, as it sounds, is circulation of strong, upper-level winds that normally surround the north pole in a counterclockwise direction – a polar low-pressure system.
These winds tend to keep the bitter cold air locked in the Arctic regions of the Northern Hemisphere. It is not a single storm. On occasion, this vortex can become very weak and can become distorted and dip much farther south. When this weakening occurs (called a negative north Atlantic Oscillation) frigid arctic air is allowed to plunge much farther to the south than normal. This is why we saw the record cold across much of the country, including a 6 degree record low here in Atlanta earlier last month.
The north Atlantic Oscillation models show it going into the positive range this month and therefore, we can expect a nice warming trend, at least for the first week or two. That is as far as the model data goes out. The Climate Prediction Center is a little more confident, indicating above average temps for the entire month. So, if you like warm temperatures, this is certainly good news for you.
On the other hand, this may not be such good news for those of us in the meteorological community. When we see a rapid thaw after harsh cold, we tend to see above average severe weather. Climatologically, severe storm season begins this month along the southern gulf coast states, from Louisiana to the Florida Panhandle. The reason being is this geographic area tends to get warmer first. That being said, we have certainly seen our fair share of violent storms and tornadoes in Georgia in February. With temperatures warming, and it could be a significant warming, the battle zone between cold air and warm air could be accelerated northward. There has also been another weather feature we have taken great note of this winter. Our jet stream is split over the continental United States. The cold polar branch wavers across the country like a snake bringing down the cold arctic air. The southern branch of the jet stream is riding hell-bent across the Mexican Baja into the southeast. This river of air running at nearly 80 miles per hour churns through the atmosphere at around 18,000 feet. When these strong upper level winds cruise over thunderstorms, they add a tremendous amount of energy and wind shear. Tornadoes and severe thunderstorm winds will now be our focus of attention. After such an active winter, we will have to wait to see how weather patterns continue to evolve.
My best advice, be prepared. Severe storm season is almost here.