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Oct. 17, 2018
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Glenn Burns weather


Recapping the storm that was Hurricane Florence

This past July in Severe Weather Center 2, we were tracking day after day of torrential tropical showers and storms pretty much every afternoon. The rainfall rates per hour were astounding, sometimes 2-4 inches per hour. The reason we saw that kind of rain were twofold. 
 
First, it was July, our hottest and most humid month. Storms had a lot of “juice” to drop heavy rain. Second, the steering currents this summer were weaker than what I would consider typical for summer. I mentioned to my colleagues that I hoped we did not see any hurricanes move inland toward us or we could end up like Houston and Hurricane Harvey, where a nearly stalled storm dumped historic rainfall.
 
Most of August remained fairly calm as the eastern Atlantic was concerned. The sea surface temperatures off the coast of Africa were downright chilly and not conducive to tropical storm development. All that changed around August 30th when a robust tropical wave moved off the west coast of Africa. Even with the cooler ocean temperatures, the wave began to wind up and soon we had tropical storm Florence with a lot of ocean to continue to grow.
 
Grow it did. At one point the hurricane hunters estimated winds at just below Cat 5 strength, at 155 mph. We were dealing with a monster but where would it go? The initial American model, the GFS, showed it moving toward New England, maybe staying away from the U.S. mainland. The European model, the ECMWF, had a different scenario. It had pegged the storm to hit the U.S. mainland, somewhere in the Southeast.
 
As Florence continued its trek west, models were showed it likely to remain a major hurricane and were coming into alignment as to where it might hit. The Carolinas were in its sights. Prior to landfall, when the storm was still hundreds of miles off the coast, I was watching it here in the Weather Center. Something was happening to the storm. It was becoming lopsided. Strong southwest winds were shearing the storm clouds. Florence could be weakening and indeed it was. The next advisory now predicted it would weaken into a Cat 2, still devastating, but far from Cat 4 devastation. As we all know, it hit near Wilmington as a Cat 1.
 
The European model, prior to landfall, showed it moving inland near Wilmington and then taking a jog to the south toward South Carolina and maybe even impacting Georgia a little. The storm was now slowing to less than a 5 mph forward speed. At that point I knew North Carolina was going to be in trouble. It was not going to be from the wind, it would be from the water. Storm surge and astounding rainfall were going to be the major players. The prolonged inland surge of ocean water was not going to let the rainwater flow back into the ocean.

The rain was predicted accurately; 20-30 inches over 2-3 days, as it turned out, was devastating. The storm was dealing with weak steering currents, like we had in July. Thirty five people lost their lives in Hurricane Florence from the flooding and not from the wind. The name Florence will be retired and never used again.
 
As we move into October, one of the nicest months of the year in north Georgia, we will enjoy the fall color and the cooler temperatures. However, just remember, hurricanes breed in the Gulf of Mexico this month. Rest assured, the GOF will have my undivided attention this month. 
 


Glenn Burns is chief meteorologist for WSB-TV in Atlanta.



  



September 2018 column

Will the rain ever go away?

All summer long, as we all know, we have seen deluge after deluge. We’ve seen so much rain (we have a 13-inch surplus) that many of us now have lakefront property! 
 
I called to get someone to trim some tree branches away from my house and the wait was five weeks!  While many industries that rely on good weather to do business have taken a beating this summer, the tree cutting industry is doing more than very well.
 
Adding to the bizarreness of the weather this summer, we have seen two tornadoes in August. We don’t usually see twisters spin up without a land-falling tropical weather system. However we did have two from afternoon thunderstorms. We had an EF-1 in Walton County and another smaller tornado in Banks County. While it is not unprecedented to see a summer tornado, it is extremely rare.
 
The weather pattern causing this mayhem in the skies has been more like a winter pattern. We are seeing huge low pressure systems cutting across the northern Rocky Mountains and then migrating slowly across to the Great Lakes, exiting the United States from New England. These lows have a counter-clockwise spin and begin tugging up plumes of deep tropical moisture as they move across the nation’s heartland. They basically create atmospheric rivers of tropical air over Georgia.

Pinwheeling around the lows are ill-defined weather disturbances that work in concert with the tropical air to produce incredible rainfall amounts.  This summer, it’s not been at all unusual to see storms produce rainfall of 2-3 inches per hour! Due to the slow movement of the cyclones, we see endless days of rain and storms. This pattern of above average rainfall will likely persist into September.
 
I know we’d all like to see some cooler temperatures with humidity levels below the tropical rainforest category we’ve been dealing with all summer. We will … eventually.  What I don’t want to see is any landfalling tropical system move into the Southeast. The ground simply cannot tolerate that kind of rainfall. We will be in the peak of the hurricane season this month.  September 10th is the actual peak; thereafter, storms become less frequent, on average.
 
Autumn begins this month and the autumnal equinox is Saturday, September 22nd. The full Harvest Moon is two days later, on September 24th. I for one cannot wait for Ma Nature to crank down the heat and humidity. It won’t be too long until we begin to see hints of fall color. I am guessing, based on the amount of rain we’ve had this summer it will have a major impact on the fall color. The good news is, fall color usually lasts longer with wet summers. The bad news is the fall color is generally muted and dull. Regardless, I will certainly embrace that first nuance of fall in the air.  

August 2018 column

'Anything goes' is the term for this summer's weather 

To say we’ve seen some bizarre weather this summer is an understatement. Every few years we get a very wet summer but this one has been over the top. Deep tropical moisture has smothered the Southeast since June. It used to be,  1-2 inches of rain over a two- or three-day period was a lot. This summer, it’s been very common to see that amount of rain with our heavier showers and storms, in 2-3 hours! Nice to the lake at full summer pool.
 
We are now getting closer to the active part of hurricane season. I think we would all cringe at the prospect of more tropical rainfall.  Just before the 2018 season began, dire predictions came out. An above average season was likely and it could be mayhem. However, a few weeks ago, the National Oceanic and Atmospheric Administration did a complete reversal on its prediction. We had been watching an immense area of cold sea surface temperatures off the west coast of Africa remain in place. In addition to the cold water, large plumes of Sahara dust were blowing off the African coast, across the Atlantic, making their way all the way to Texas. Cold water and the Saharan dust layer are not conducive to hurricane formation. Thus, the reversal in the prediction. I know the residents of eastern Caribbean, especially Puerto Rico, are extremely happy with that as well. As you may recall, Hurricane Maria decimated the island and surrounding islands last season.
 
So here we are in the Dog Days of Summer.  This is the time of year when Sirius, the Dog Star, rises with the sun. In ancient Egypt, this would signal the flooding of the Nile River. So what kind of weather pattern are we expecting this month? Normally I would say smoggy, hot, humid, and temps in the 90s. Normally. However, given what has happened this summer, it is anyone’s guess. Normal summer patterns are not there. 
 
Last month we had a set up like mid spring with powerful tornadoes in Iowa and the Ohio Valley.  We had cooler than average temperatures here in July! I guess anything is possible and as a meteorologist, I can’t wait to see!  
 
For those of you who have emailed me to messaged me on Facebook, asking what kind of weather we might see this Fall and Winter, there are signs of another developing El Nino. Normally, El Nino brings us a cold and wet late fall and winter with freezing rain being the primary form of precipitation in the colder months. We shall see. One thing I can say for now, anything goes!


July 2018 column

July could mean even wetter weather 

Last May a woman emailed me asking me if the cooler and dry weather we saw this winter and spring would continue into the summer. I wrote back and told her one season has no bearing on the other. Soon after, Tropical Storm Alberto brought flooding rain to the Lake Lanier basin. Then the afternoon summer-like thunderstorm machine fired up and with tropical air engulfing north Georgia. The resulting rain has been relentless. This of course, has been good news and bad news. The good news is the lake is full, and then some. The bad news is, people are staying away because of all the rain and stormy weather!
 
July is our wettest month of the year. We average close to six inches of rain for the month. I expect we’ll go well beyond that given the trends I am seeing. The longer-range models show the tropical air remaining and above average rainfall can be expected. July is notorious for bringing locally heavy rain. It is fairly typical to see a pop up afternoon thunderstorm to drop more than an inch and a half of rain per hour.
 
July thunderstorms are amazing to watch as they form. They are called “Pulse-Type” thunderstorms. They “pulse up” and then wind down in an hour or less. However, they can wreak havoc in that hour. As the sun heats the ground, the air over the ground gets hot. Just like a hot air balloon, the air rises. The colder the surrounding air, the faster it rises, many times to heights over 50,000 feet! 
 
When the National Weather Service launches its weather balloon in the morning, we get a great deal of valuable information. We can get a good handle on the severity of the storms. One of the parameters we look at is the freezing level. The height at which temperatures will be at or below freezing is usually about 13,000 to 14,000 feet. Above that is the hail growth zone. Updrafts drive rain drops up into the hail growth zone. The stronger the updraft, the longer the hail can grow. Large and damaging hail, in excess of an inch in diameter, can cause damage.
 
As hail, super-cooled water droplets than can remain liquid even in a freezing environment, and rain drops bump into each other in the cold dry air in the higher realms of the storm, the friction generates an electrical charge. Intense lightning is the end result. When I track summer storms with our StormTracker 2 HD Radar, the hail cores show up as magenta. More often than not, intense lightning surrounds the hail core.
 
As I mentioned, a pulse-type afternoon thunderstorm generally lasts for about an hour. It goes from a “bubbling” cumulus cloud, into a mature thunderstorm. As the rain and hail continue to fall they will ultimately overwhelm the updraft of warm air that gave birth to the storm. Whew. The storm is dying and now it’s safe. Well, not so fast. July storms can be more dangerous when they are dying, even more so then when they are going full bore as a mature storm. The falling rain and hail can collapse the storm. That collapsing air can come crashing down to the ground and will fan out in all directions at speeds of 60 to 90 miles per hour. It’s called a downburst and it can cause as much damage as a weak tornado.
 
Before you head out on the lake, make sure you know the forecast. Torrential rain, gusty winds to 60 mph, intense lightning, large hail, and downburst winds are all part of July storms.


June 2018 column

Being thankful for a quiet spring 

I was not sure what to expect this severe weather season across north Georgia. As it turned out, we had one of the quietest in recent memory with one tornado day in north Georgia. As we approached late April into May, when the majority of the country’s severe storms are likely across the nation’s heartland, again, there was nothing much to see. Tornado season across the plains was very quiet compared to what we have seen over the past several years. I think we can attribute that to all the cold stable air that covered much of the country through much of April and May. From 1991 through 2015, the average number of tornadoes for Georgia each year is 29.  We had eight statewide. You will get no complaints from me. From here on out, we deal with pop-up afternoon thunderstorms with an occasional squall line.
 
Late last April through the first couple of weeks of May, the weather, as you know, was gorgeous. We had lots of sunshine, little rain, and pleasant temperatures, except for a few 90 degree days in early May. Then when the school year was winding down and the kids were scheduled for outdoor activities and field days, a huge surge of tropical air poured into the Southeast with torrential rains and an occasional lightning strike. I just could not believe the timing. Area teachers emailing me all day long for the forecasts could not believe the timing either.
 
Here we are in June. Meteorological summer begins June 1st and runs through August 31st. Officially, summer begins Thursday, June 21st at 6:07 am.  June 1st is also the beginning of hurricane season. There are many predictions that we will have an above average number of named storms this year. There are also some who believe El Nino, along with an increased area of Sahara dust coming off the coast of Africa, may inhibit hurricane formation in the Atlantic. We really don’t have to worry much this month about Atlantic hurricanes. This time of year, the Gulf of Mexico is the breeding ground for tropical systems. All area lakes are in great shape, thanks to our late spring rains.

My concern is that with the so much tropical air in place to early in the summer, will we see a potential major flood event where lake levels cannot be drawn down quickly enough prior to a storm?  Through much of late May it has felt like July. Moisture coming from deep in the tropics seems to be relentless, much more so than I have seen in a number of years. It is concerning, to say the least. My hope is that El Nino will kick in early and we see the wind shear associated with this Eastern Pacific ocean cooling take its toll on developing storms. Time will tell, as it always does.
 
If you are wondering about the names of the storms for the 2018 season, here they are: Alberto, Beryl, Chris, Debby, Ernesto, Florence, Gordon, Helene, Isaac, Joyce, Kirk, Leslie, Michael, Nadine, Oscar, Patty, Rafael, Sara, Tony, Valerie, William.

Let’s hope Alberto does give us an encore performance of what happened back in 1994! That kind of flooding was horrific and it was only a tropical storm!

May 2018 column

Don't let recent rains fool you 

In March, colder than average temperatures prevailed across north Georgia, as they did in April.  What will May and the rest of the summer be like? According to the Climate Prediction Center, north Georgia will likely see warmer than average temperatures.  Rainfall predictions have too many variables apparently, therefore there are equal chances of above or below average rainfall. After a dry April, I was hoping to see increased rainfall as we head into summer.  
 
Beginning this month and continuing into August, rainfall is usually in the form of scattered afternoon and evening showers and thunderstorms. Widespread rain, even dispersed across the area like we see in the winter, will be a rare event. Lake Lanier, like most of our area lakes, is in fairly good shape and can withstand some dry weather. Our lakes levels are not only affected by rainfall and run-off from that rain, they are also affected by the temperature.
 
With warmer than average temperatures likely, we will see more evaporation. You would be amazed how much water is evaporated by Lake Lanier in just one day! On a really hot summer day, the lake will evaporate between 50 million and 100 million gallons of water!  With continued hot and dry weather, you can see how quickly lake levels can drop with that kind of evaporation. That’s why I was hoping to see above average rainfall predictions.
 
The average rainfall for April is 3.35 inches. April is our driest month of the year. The average May rainfall is not much better with 3.66 inches. In June, we increase to a monthly average of 3.94 inches. Rainfall will ramp up in July, with an average of 5.28 inches. However, showers and storms will be hit or miss.
 
Also, a meteorologist I heard speak at the last American Meteorological Society conference last June in Austin, Texas make an astounding prediction. He explained he has come up with a formula to do extremely accurate long-range weather predictions. I am very skeptical. Here’s what he predicted. He said if there was a tropical weather system in the Gulf of Mexico on July 1st, shortly thereafter there would be a major hurricane in the Gulf. I have it on my calendar to watch.
 
In the meantime, I am dusting off the fishing poles and am looking forward to getting out on the lake for some of the best fishing of the year. I am sure we will have another brief shot of cooler temperatures this month. However, all in all, I love the weather in May. It’s most of the time not too hot … most of the time not too cool …. and the humidity is rarely oppressive. Enjoy the weather because the heat may be on this summer!


April 2018 column

Rethinking 'April showers' 

April in north Georgia. What stands out in north Georgia this month? Easter? The Dogwood trees in bloom? The pine pollen that covers everything in a film of yellow dust? For me, April is the driest month of the year. I know what you’re thinking. It’s spring and what about all the April showers? Based on the last 30 years of climatology, the average rainfall for the month is 3.36 inches, making it the driest month of the year.  If you are now wondering what the wettest month of the year is, you would have to look at July. We average 5.27 inches of rain in July.
 
If you are a golfer, then you know April means the Masters.  Augusta National is always a spectacle of color with the azalea’s and blooming trees. Even though April is the driest month of the year, there is a tendency to see stormy weather and even freezing cold temperatures, like last year. You may also remember April 3rd, of last year. Eight tornadoes hit north Georgia and caused widespread destruction. Then much of our peach crop was wiped out by the cold that followed.
 
What I am trying to point out is that even though April is the driest month, it is not necessarily the calmest month. We had supercell thunderstorms last month with three devastating tornadoes in metro Atlanta. It can and does happen in April too. We are still dealing with “weather wars” being waged in the atmosphere when cold air meets warm air. There is so much spin in the atmosphere in the spring from changing wind speeds to changing wind direction with height. I have seen just showers, without lightning, rotate and spin up small tornadoes. We all need to be weather aware, even during the driest month of the year.
 
I know we are all looking forward to the warmer temperatures this month. With the higher sun angle and more hours of daylight, our warming will surely continue.  However, I do see a pattern where we might see several more blasts of cold air. And don’t think it still can’t snow this time of year. Many of you may remember the six inches of snow that fell in our northern suburbs back in 1985. I am not saying we’re going to have a snowstorm this month but there have been years when some heavy April snows have occurred.  
 
You may remember the Climate Prediction Center Winter Weather Outlook I wrote about last fall.  With the cooler central Pacific Ocean temperatures firmly in place, (La Nina) the outlook called for our winter to be warm and dry.  Of course, as we all know, it turned out to be brutally cold with above average rainfall and two incredible snow storms. I was getting a little concerned through the early part of winter when it was so dry and then the heavens opened up and we’re in great shape. The lake is in beautiful shape and as we head into the driest month of the year, we can say, no worries!

March 2018 column

Recalling recent super storms 

On the night of March 14th, 2008, I was watching the radar.  There was a strong storm in Floyd County but that was about it. The storm continued moving to the southeast but showed no signs of weakening after 30 minutes.  
 
It was not your ordinary thunderstorm. It was a Supercell thunderstorm but there were no signs of any rotation just yet. In its 9 p.m. outlook, the Storm Prediction Center issued a slight risk of severe weather across portions of the southern United States from Oklahoma to Georgia, with a two percent risk area for tornadoes in north Georgia, including the Atlanta area. 
 
Around 9:20 I saw a little rotation on our radar and then a tornado warning was issued for Atlanta at 9:26 p.m. when the thunderstorm that caused the tornado was around five to six miles northwest of downtown area. No watches were in effect for the area due to the low probability and unusual isolated nature. Again, this was the only storm on radar at the time. The tornado moved to the southeast, which is also unusual, as most supercells generally move to the northeast along a cold front. As it continued move toward the downtown area, around 9:30 p.m., you could begin to see signs of rotation very well.
 
The NWS then issued a tornado warning. There was a lot going on in the city that night. The SEC basketball tournament at the Georgia Dome and the Hawks at Philips Arena. We had immediate reports.  A tornado was on the ground in the downtown area. It was causing widespread damage across downtown Atlanta, including to the CNN Center and to the Georgia Dome and the Omni Hotel, which was evacuated after many windows were blown out. The Westin Peachtree Plaza suffered major window damage. Centennial Olympic Park, SunTrust Plaza and historic Oakland Cemetery were also damaged.  
 
I can remember the video of all the gravestones that were blown over. One man was killed near downtown Atlanta and 30 others were injured. Two other deaths occurred on March 15 when larger round of severe weather and tornadoes ravaged the north Atlanta suburbs. In total, 45 tornadoes were confirmed over the 24-hour period from eastern Alabama to the Carolina coast, with most of the activity concentrated in the Metropolitan Atlanta area, the Central Savannah River Area and the Midlands of South Carolina.
 
In 2011, there was a “Super Outbreak of tornadoes. It was one of the costliest and deadliest in U.S. history. The hardest hit of our southern states were Alabama and Mississippi but it also produced destructive tornadoes in Arkansas, Georgia, Tennessee and Virginia, and affected many other areas throughout the Southern and Eastern United States. In Alabama alone, 238 tornado-related deaths were confirmed by the Storm Prediction Center and the state’s Emergency Management Agency. In total, 362 tornadoes were confirmed by the National Weather Service. That was an astounding number.
 
What did the tornado outbreaks of 2008 and 2011 have in common? Both were La Nina years, like this year. Am I predicting more super outbreaks like those years?  There is no way to predict such events. All I am saying is that this would be a year when I would be extra weather-aware. As we have seen in 2008, it only takes a single storm to wreak havoc. What I will be watching for is to see if the February warm pattern continues this month. If it does, then we could have some trouble as strong cold fronts move into the Southeast and wage their “weather wars.”  The Climate Prediction Center thinks it will stay warm.

February 2018 column

It's called forecasting for a reason 

I hope all of you are surviving this winter. The Climate Prediction Center Winter Outlook was for above average temperatures and below average precipitation. As you well know, it’s turning out to be one of the coldest and snowiest winters on record for north Georgia.
 
What has also been remarkable is that Atlanta has been consistently cooler than Anchorage, Alaska most of last month. When we had our second snow on January 16th and our temperature hovered in the mid 20s, Fairbanks was in the mid 30s! We have actually had more snow than Chicago this winter!  Yes, things are just a little out of whack.
 
Before our winter season began, broadcast meteorologists, national weather meteorologists, county emergency managers, GDOT officials, and school superintendents met at Georgia Tech to discuss the upcoming winter.  Meteorologically, we all saw the colder ocean temperatures in the eastern equatorial Pacific Ocean, signaling the developing La Nina.  Without going into a bunch of meteorological jargon, the bottom line was a warm and dry winter.  However, our NWS meteorologists did say that, from time to time, we could see some severe ice storms.  That is what we all prepared for and we happily went on our way.
 
An epic early December snow storm gave us pause. Then the temperatures got cold and stayed cold through January. This is not our typical La Nina weather, to say the least. So, what is going on? There is a feature over the north pole called the Polar Vortex. You might have seen media reports like “Godzilla Polar Vortex to attack the Northeast.” That’s not entirely true!   The polar vortex is a prevailing wind pattern that circles the Arctic, flowing from west to east all the way around the Earth. It normally keeps extremely cold air bottled up toward the North Pole. Sometimes however, the  Polar Vortex weakens, allowing the cold air to pour down across Canada into the U.S., all the way down into Georgia. In addition to bringing cold, the air mass can push the jet stream, a river of wind that flows from the Pacific Ocean across the U.S., much farther south as well. If we get even a small weather disturbance, bringing Gulf moisture, it can fall as heavy snow, which is what happened here in December.
 
Why does the vortex weaken?  Some climatologists believe it’s because more Arctic sea ice is melting during summer months. The more ice that melts, the more the Arctic Ocean warms. The ocean radiates much of that excess heat back to the atmosphere in winter, which disrupts the polar vortex. Data taken over the past decade indicate that when a lot of Arctic sea ice disappears in the summer, the vortex has a tendency to weaken during the following winter.  Although the extent of summer sea ice in the Arctic varies year to year, overall it has been disappearing more and more over the past decade. Climate change scientists are forecasting the sea ice to continue to vanish even more in the years ahead. That could mean more trouble for the polar vortex, and more frigid outbreaks here in Georgia.
 
We have a nice tool that shows us when the polar vortex is set to unleash arctic air. It’s called the Arctic Oscillation Index and has been performing quite well this winter. I can actually see when cold arctic air will move in as much as a week in advance. 
 
The one thing I don’t want to see this month is my heating bill from January! I bet it will look like a second mortgage. Hopefully the weather will settle down a bit this month and no more thrills … chills … and higher heating bills.
 
Now we begin to move into severe storm season. We will chat about what to expect next time.  Stay warm!

January 2018 column

Ah, the joys of forecasting snow in Georiga


We have one month behind us in the meteorological winter and two months to go. If the first month is any indication of what we can expect this La Nina winter, we are going to have our work cut out for us!
 
December’s snowstorm was without a doubt, one of the most challenging forecasts in my 36 years forecasting the weather for north Georgia. When I was looking at the various models a few days before that Friday the 8th snow, the majority showed modest snow amounts of one, maybe two inches.  However, there was one model that was showing 6-10 inches! I thought that was just ridiculous. I also know we don’t really know what is going to happen when forecasting snow in north Georgia until the night before or the day of, the event.  
 
The night before the National Weather Service issued a “Winter Weather Advisory” for up to one inch of snow. That is what we went with during the 11 p.m. newscast on December 7th. I said again, it might not be until the morning until we actually had a good handle on things. Sure enough, models began to indicate more than an inch of snow. It now looked like we could get two to three inches of snow, possibly isolated higher amounts. So, the NWS then issued a “Winter Storm Warning” for the western metro counties. The fun and games began that morning and the snow came down at such a rate that 2-4 inch accumulations were being observed in less than an hour. When it was all said and done, snowfall, mainly along and west of I-85, measured six to 13 inches! 
 
I remember the Blizzard of ’93 very well. I made a perfect forecast on that storm, basically using stone knives and bear skin rugs, compared to the technology we have today. That was the most snow I have ever seen fall in north Georgia. However, this month’s storm result at my house: nearly 13 inches. I knew it was more than 1993. Sure enough, our December 18th, 2017 shattered snowfall records in some areas. For Cobb County and Carroll County, the 12-13 inches was the most snow since the NWS began keeping snow records in 1928!  
 
So here we are in January. It’s usually the coldest month of the year and presents its fair share of winter weather surprises. I will throw this out there. The last 10 out of 15 years when we have had a December snow, it never snowed again for the entire winter.  However, it is not the snow I am concerned with this month. It’s ice.
 
A La Nina weather pattern is notorious for bringing us ice storms. La Nina winters have brought catastrophic ice storms where power can be out for a week or more. This is the month it will most likely happen, according to climatology. I am not forecasting an ice storm but I will certainly be keeping my eye out for even a minor chance. This would be something you need a lot of lead time on. I would want everyone well prepared for long duration event. I will do my best to keep you informed. Maybe, just maybe, it will be one of those 10 out of 15 years where we don’t get any more frozen precipitation after a December snow. Prepare for the worst and we’ll hope for the best.
 
Happy New Year to you and your families and I hope 2018 is a wonderful year for you.

December 2017 column

Forecast calls for La Nina making a visit this winter

It’s pretty hard to believe that another year has come and gone, but here we are in December! We have certainly had another “interesting” year of weather, capped off by that insane hurricane season. After a fairly warm and benign October, November held few surprises as above average temperatures continued with a fairly dry pattern. We did have that nice cool blast just in time for Thanksgiving.  I think it felt a little more festive this Thanksgiving than last.
 
From what I have seen, we should be looking at yet another pattern change this month. I am seeing above average temperatures returning. However, we are in a pattern where we could see cold air damming. La Niña will frequently bring a shallow layer of cold air into northeast Georgia with Hall County the “bullseye.” It makes temperature forecasting much more challenging. While Atlanta could see temps near 70 in the so-called “cold air wedge,” Gainesville may be in the 50s.
 
Anyone who is involved with Lake Lanier is also tuned in to rainfall. We are all aware of the lack of rainfall we have seen in October and November. It now appears La Niña will keep us in below average rainfall this month too. Even my longer-range models taking us into spring, keep us drier than average. 
 
During the late fall and winter, we always see the Corps of Engineers draw the lake level down. This year was no exception, despite all the predictions of a drier winter. This is very concerning since we rely on the winter rain to replenish the lake. Going from a dry winter into an expected drier than average spring could result in the lake level remaining very low.  Summer is always hit and miss with rainfall so we could be facing drought conditions by June. Nothing is etched in stone but these are the trends I am seeing and these are the trends we have seen with past La Niña events.
 
As we head into winter, which officially begins on December 21st, everyone always wants to know if I think we will see snow. There is always that chance but my bet this winter is for ice. As I have explained, we’re in a La Niña, favorable for the cold air wedge. With a classic wedge, warm moist air is coming in with with southwest winds, over the top of the shallow cold air coming in with northeast winds. This gives us, more often than not, drizzle and mist. If the ground, or bridges and overpasses, are below 32 degrees, we will have ice. Downed trees and power lines will be the rule. You might want to prepare now and stock up on supplies, as power outages might last for days. 
 
We’ll keep an eye on the weather and I will have an update on any changes in our winter weather outlook next month.



November 2017 column

 

Winter prediction: Warmer and drier than normal

After the record high temperatures last month and the air that came from the tropical rainforests of Central America, courtesy of Hurricane Nate, I bet you thought we would never see any cool weather last month. We did of course and now everyone is asking what the weather will be like this winter. NOAA (National Oceanic and Atmospheric Administration) issued its winter weather outlook and it looks like we’re going to see a very typical La Nina pattern. We are currently in a La Nina Watch.  In the simplest of explanations, La Nina is part of a cyclical pattern of ocean warming (El Nino) and ocean cooling (La Nina) in the eastern or central equatorial Pacific Ocean. If you’re asking what ocean temperatures in the Pacific Ocean has to do with our winter weather, the answer is: A lot! This pocket of cooler sea-surface temperatures off the west coast of South America along the equator disrupts global wind patterns. It forces the polar branch of the jet stream to stay farther north.  This will mean the southern states will generally warmer and drier than average. That being said, we will still see blasts of cold arctic air plunge into the Southeast from time to time. However, the overall average temperatures will be much warmer for us.
 
If you are wondering about snow, I think we should all be more concerned about ice. I have been forecasting the weather for north Georgia for the better part of 36 years. I have seen a thing or two. It has been my experience that we will see many more “Wedge” type weather events with a La Nina. The technical name for the wedge is CAD or Cold Air Damming. When an arctic high pressure systems breaks loose and drive across Canada into the northeast part of the country, the clock-wise wind circulation around the high drives a shallow layer of cold air south. The air is cold and dense and behaves much like water. The Appalachian Mountains act like a dam, funneling the shallow layer of cold air into north Georgia. The air is frequently coldest around Hall County. 
 
In a typical CAD event, winds above ground are coming in from the southwest at about 3,000 to 5,000 feet. This southwest wind is transporting moisture in from the Gulf of Mexico. The result is drizzle or light rain falling into the shallow layer of cold dry air. As the precipitation falls, some will evaporate. As we all know, evaporation is a cooling process. So the rain falling will make the surface air even colder. Now the problems will begin. We have the beginning of an ice storm. Accumulating ice will cause extremely hazardous driving, especially on bridges, overpasses, and elevated roads, not to mention massive power outages from the ice accumulating on power lines. Each La Nina is different but they all pretty much have the same basic characteristics. The good news is, we have the technology and experience to very reliably predict when they will occur, many days in advance.  
 
So, fasten your seatbelts, be ready for a warmer and drier winter and be on guard for those times we ice and cold arrive in northeast Georgia.
         
    

October 2017 column

My concern for hurricanes came true last month

I hope you read my column from last month. Now you know why I was so concerned about the ramping up of hurricanes in September. What an incredible month of storms! People have been asking me if it’s global warming making the storms more powerful. My answer has been 100 percent, “No.” In the Atlantic last month we had no wind shear from El Nino. We had no Sahara dust. We had very warm ocean temperatures but nothing extraordinary. When the tropical waves rolled off the west coast of Africa, they entered a perfect environment to become massive and dangerous hurricanes.

Hurricane Harvey was pushed farther west into the Gulf of Mexico. It was not an overly impressive hurricane but when we saw the environment over Texas, we began to worry. There were two massive high pressure areas over the country. One was in the West and the other in the East. Harvey was going to move in between them. We knew it was going to stall with nowhere to go. Indeed it did and more than 48 inches of rain caused flooding to 20 percent of the Houston metro area. Ten percent of the buildings and homes in the Houston metro had water damage. Gas prices still remain high but they are no doubt artificially inflated now.
 
After Harvey, along came Irma.  Another Atlantic crossing from West Africa into ideal conditions brought Irma to a strength rarely seen. The European computer models, the most reliable, was bringing the storm through the Caribbean, hitting just about every island possible. We knew it would eventually turn north but we did not know exactly when or where. That turn prediction was extremely important in determining the impacts on our local weather. With each model run that came in the center was being pushed farther and farther west.  North Georgia would now be on the northeast quadrant, the most powerful side of the storm, as the center moved into Alabama.
  
As wind and rain began to increase here, trees began to fall.  Hundreds and hundreds of them crashing onto buildings and homes.  During the height of the storm most of us were seeing winds of 30-40 mph sustained. However, the gusts were in the 50 mph range.  The two strongest wind gusts were 64 mph at Hartsfield Jackson International Airport and a 55 mph gust in Habersham County. Many people were without power for almost a week.
 
Then, along came Maria.  Winds sustained at 175 mph with gusts to 215 mph. It looked like a buzz saw cruising into the Caribbean. Puerto Rico took the brunt of the storm, knocking out power to the entire island of more than 3.5 million. Many nearby islands had catastrophic damage and nine people lost their lives.  This was the worst hurricane season since 2005.
 
We are not out of the woods just yet. Hurricane formation is now shifting from the Atlantic to the Gulf of Mexico. You may remember hurricane Opal in 1995. That was a storm that really intensified in the Gulf of Mexico. As we head into October, maybe my favorite month of the year, the leaves will be changing and hopefully the temperatures will be getting a little cooler. Our long-range outlooks continue to hint at warmer than average temperatures through November.


 



 
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