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Jun. 17, 2019
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Glenn Burns weather


Wondering what kind of summer is ahead

Spring is just about over and summer is just beyond the horizon.The summer solstice is Friday, June 21st at 11:54 a.m. 
 
As far as spring weather, I think we did rather well. We did have several low end tornadoes causing minor damage along with some minor flooding due to heavy rain and run-off. We are heading into summer with a healthy surplus of rain and a full lake. Our long-range models are showing a continuation of above average temperatures. However, there seem to be too many variables in play to determine potential rainfall. 
 
The Climate Prediction Center is giving a 50/50 chance of above or below average rainfall for the summer. Even in this month there are too many variables to give anything else but a 50/50 chance of above or below normal rain. With a prediction of hotter weather, there will be a concern for a lot of evaporation from Lake Lanier if the rains don’t come on a regular basis. 
 
How much evaporation? It’s a tough question given all the variables in play but let’s take a closer look at what happens in a typical swimming pool. Normally pools lose about a quarter to half inch of water per day due evaporation. That would equate to roughly losing 2-4 inches of water per week. For an average size pool, that could be about 30,000 to 50,000 gallons per year. You can imagine how much water we could lose in Lake Lanier, which is 38,000 acres and 59 square miles of water!
 
If it turns out we don’t have our average monthly rainfall for June of 3.94 inches, July usually comes through. July is the wettest month of the year for north Georgia. We average 5.28 inches. Remember the rainfall outlook can’t be determined because of too many variables. We could end of with very little rain or maybe a lot. Since 1996, we’ve seen as little as half inch for the entire month. That was in the year 2008. However, we also seen as much as nine and a half inches of rain, which occurred in 2013. So, we wait and see.
 
As far as temperatures are concerned, the average high in June is 86. With an above average temperature prediction, that means we’ll likely be in the 90s. Might want to get the old A/C tuned up. It may be working overtime this month.
 
June is always a fun month. The water temperatures warm up enough for a comfortable swim. Good times for family, friends, and fun. Enjoy my friends!
 


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



  



May 2019 column

Prodiction for summer; Yep, more rainfall

As many of you know, I have been forecasting the weather here for a very long time. I have been the Chief Meteorologist for WSB since 1983. I have pretty much seen it all. Or so I thought.
 
It began last summer. Enormous amounts of tropical air were billowing into north Georgia. The air was hot on the surface, as we were in the low 90s. The day before I had noticed a minor weather disturbance heading in our direction. A weather disturbance in the summer is basically a pocket of cold air aloft, which causes the air to become “unstable.” Warm air and muggy tropical air will rise quickly when surrounded by cold air. As it rises, it cools, condenses and forms into giant thunderstorm clouds.
 
Our QPF model guidance (quantitative precipitation forecast) showed about an inch to two inches of rain was possible between 12 p.m. and 8 p.m. The afternoon storms did blow up as expected. We were watching the estimated rainfall data coming in on our dual-pol Doppler radar. What we saw buy the end of that afternoon was astounding. Rainfall estimates, along with rain gauges, showed rainfall amounts of 4-7 inches! This has been ongoing since last summer. Astounding rainfall amounts and our climate is changing. I can tell you first hand it is happening.
 
Let’s take a look at last month. You remember that last tornado and severe storm threat we had right as we headed into Easter weekend. Again, QPF rainfall forecast showed 1 to 1.5 inches of rain for the entire event. When it was all said and done, 4-6 inches with isolated 10 inch totals were the rule. Flooding was catastrophic in many areas and flood warnings continue four to five days beyond the rainfall. Many areas saw an entire month’s worth of rain in two to three hours!
 
Lake Lanier is up two feet above full pool as we head into summer. The Chattahoochee continues to flood. We have some serious issues. We may have to lower the lake levels much more than we are doing now to prevent more serious flooding.
 
The outlook for May is calling for above average temperatures and more importantly, above average rainfall! 
 
I think we’re going to see these incredible tropical rains and continued flooding into the summer. Climate change is real and it’s happening.
     

April 2019 column

 

Spring can bring turmoil when it comes to forecasting

Spring is my least favorite season of the year. Aside from the pollen, spring storms are can be extremely violent. We saw that last month with the biggest tornado outbreak in the Southeast in the past five years. More than 23 people, some children, perished in Alabama. It was a horrific Sunday afternoon.  
 
April is a tough forecasting month. It may be difficult to believe, but April is the second driest of the year in north Georgia, behind October. The average rainfall for October is 3.11 inches. Our average rainfall for the month of April is 3.62 inches. We base this on the past 30 years of rainfall.  With fewer days of rain maybe we’ll have fewer days of severe storms. I say maybe because we still have El Nino going and there is just no telling when it will go away. If it weakens, then we’ll get a break in the “atmospheric firehose” of rain we have seen since late summer. If not, then we will continue with the rain train, and likely more severe storms.
 
While El Nino may be troublesome for us at this time of year, if it continues into summer, then we can actually benefit from it. El Nino creates a lot of wind shear.  When the shear extends out over the ocean, then tropical systems have a very tough time developing. Most will meet an abrupt demise.
This time of year many of us like to begin planting and do a little gardening. In addition to El Nino making rainfall unpredictable, it also makes temperature forecasting a bit of a challenge. I can see some late season freezes, what we sometimes call “Dogwood Winter” or Blackberry Winter.”  Many area farmers got hit hard last spring with some seriously cold weather that caused quite a bit of damage to the strawberry and peach crops. My best advice to avoid this is to plant after Easter, or at least wait until after tax day.  
 
In conclusion, in my 37 years of forecasting weather for Atlanta and north Georgia, I have seen the majority of weather in April to be rather calm. That was not the case in 2017. On April 3rd, we had a major outbreak of tornadoes.  Twenty-seven twisters touched down in Georgia and damage was extensive. Two days later, as people were trying to clean up and make some sense of what had just happened, another squall line brought another seven tornadoes to the state. It was one the most horrific outbreaks of tornadoes I have ever covered. 
 
This month, we will all hope for the best but let’s continue to prepare for the worst. Be vigilant this month and don’t let your guard down.


March 201 19 column

'Firehose' of moisture likely to continue

El Nino is in full gear and the atmospheric “firehose” of moisture from the eastern Pacific Ocean continues to bring us a seemingly endless supply of rain. The ground moisture is running between the 70th and 90th percentiles. Lake Lanier remains above full summer and the Chattahoochee River continues to spill out of its banks every time it rains. Could the weather get any worse? Absolutely! 
 
We are now entering the rainiest month of the year! Based on the past 30 years, we average 5.38” of rain in the month of March. If the trend in heavier rain continues, and I firmly believe it will, we could get double that. If that happens, by the end of this month, we will have more than half of our average ANNUAL rainfall, which is 49.71”.
 
Yes, it’s a pretty grim outlook. Are you ready for some good news? Maybe I should say some slightly less bad news? In addition to March being the wettest month of the year, it’s also the time when we see more tornadoes and severe thunderstorms. You are probably asking about that “less bad news” right about now. The same atmospheric conditions brought about by El Nino MAY also reduce the severe weather threat. Please remember, I did not say we won’t have tornadoes or severe storms. Just to be clear, there SHOULD BE fewer.
 
I have looked back over the past 20 El Nino years and have found fewer severe storms in March. In fact, there have also been fewer Atlantic hurricanes. El Nino is making all of our lives miserable with the frequent flood-producing rain but it can also reduce the number of days of severe weather. Temperatures during El Nino times can also fluctuate wildly. Don’t do any planting until after Easter.

Although I do expect warmer than average temperatures this month, I do think we will see several days with morning lows at or below freezing. With the persistent “Cold Air Wedge” pattern, I would also say the areas around Lake Lanier may have some really cold days this month.
 
All things considered, we are still headed in the right direction. Warmer and warmer days give us something to look forward to … boating and fishing adventures on our favorite lake.
   

February 2019 column

Mother Nature was even confused about winter

Last October, the Climate Prediction Center issued its highly anticipated “Winter Weather Outlook.” I was anxious to see what it had to say about our upcoming winter.  I was so disappointed when it finally arrived. It showed warmer than average temperatures for much of the western United States.

For much of the east, including north Georgia, it showed us as having equal chances of above or below average temperatures. The precipitation outlook showed above average precipitation, which as it turned out, was right on target.  However, I was so disappointed not to see a definitive temperature outlook.
 
Everyone on my social media pages was equally disappointed. I knew there must be too many variables in play to make an accurate projection. Nevertheless, people wanted a prediction. Then I got an idea. I would let Mother Nature make the prediction. I then challenged everyone on my Facebook and Twitter pages to observe what was going on in nature. 
 
I was overwhelmed with observations. I received hundreds of pictures of woolly bear caterpillars, all with wide brown bands, indicating a mild winter. I received hundreds of pictures of “spoons” inside persimmon seeds, indicating a lot of winter snow. I received pictures from cattle farmers and horse ranchers, showing cows and horses with little or no winter coats.  Another indication of a mild winter. Squirrels were building their nests high up in the trees and bees and hornets were swarming late into fall, another warm winter prediction.
 
As it turned out, Ma Nature did not have a clue about the upcoming winter and the extreme cold we have been enduring since before Thanksgiving, when temperatures dropped into the mid 20s. The breaking apart of the Polar Vortex sent below zero temperatures far south into the U.S. We certainly had a taste of that when temperatures last month dropped into the teens and 20s for many, many days.
 
El Nino will likely continue well into the spring. That means the above average rainfall will continue. It also means with more cloudy days than sunny days, our temperatures will remain below average through April. I would not plan on doing any spring planting until May. I would expect some significant late season spring freezes, like we had last year. 
 
Braves pitchers and catchers report to spring training in the middle of the month. Spring may be around the corner but you’ll never know it from the temperatures we will see this month. Stay warm!


January 2019 column

We may have some 'interesting' weather this month

As I mentioned last month, there was a good chance we would see some ice and snow early in December. As it turned out, parts of Rabun County tallied 6 to 8 inches of snow. Temperatures around Lake Lanier were going to be borderline from the wedge. The approaching winter storm was certainly going to bring enough moisture in to north Georgia. The National Weather Service issued Winter Storm Warnings and Winter Weather Advisories but temps stayed just warm enough for a cold rain instead of ice. Now we are about to enter another cycle of winter.
 
You may have heard about the polar vortex. In the media, it has been likened to a Godzilla-like cold air monster invading states with incredible cold and gobbling up cities in blinding snow. The polar vortex is an area of low pressure that is “parked” over the North Pole. It can cause some pretty wild weather and even bring single digit temperatures to the mountains and teens into the metro area.

Sometimes this low-pressure system can weaken. When that happens, part of it can break off and migrate southward, bringing frigid air with it. Normally, when the vortex is strong and healthy, it helps keep the river of air known as the jet stream traveling around the globe in a pretty circular path. This current keeps the cold air up north and the warm air down south. However, without that strong low-pressure system, the jet stream doesn’t have much to keep it in line. It becomes wavy and rambling, conducive to storm formation and cold air being funneled into the deep south. 
 
I have been paying close attention to trends and signals in the atmosphere. I believe this month we will see the polar vortex weaken, especially after mid-month. I think late January and February we are going to have some VERY cold days. All we need is an approaching winter storm to supply the moisture, and if the timing is right, we will have a huge snow, perhaps several.  
 
Not all cold snaps are the result of the polar vortex. We always see cold arctic outbreaks in January.  However, the ones that brings the coldest air, are usually the result of the weakening vortex. You might want to stock up on that firewood this month.  
 
While we all know we can have some winter weather issues this month, please remember, it is also a very active tornado month.  During January 2017, we had 23 tornadoes. It is not the Arctic cold fronts that bring tornadoes. They are usually benign and may bring some rain. Fronts coming in from the Pacific or Southern Canada are the ones responsible for the powerful tornado-producing storms.  We’ll be on the lookout.  
 
I hope you and yours had a wonderful Christmas and I want to wish you all a healthy and prosperous New Year.


December 2018 column

A long, cold, wet winter on the horizon

As we moved into mid-October and temperatures across north Georgia were still in the 80s and 90s, my colleagues and I were wondering if autumn temperatures would ever arrive. In November, all that changed as we went directly from summer heat to winter cold, just like last year.
 
Something else has also been occurring, pretty much on a weekly basis as we moved through November. We have seen a “wedge” of cold air about every four to five days blast into Georgia. If you are not familiar with a “cold air wedge,” let me explain. The official terminology is a CAD, or Cold Air Damming. When cold high pressure moves out of Canada and then temporarily stalls in the mid-Atlantic or near New England, it will send down a very cold, shallow, and dense layer of cold air.

Since it is shallow, the northeast wind drives it south with the southern spine of the Appalachian Mountains acting like a dam, funneling it in to Northeast Georgia. The cold air gets trapped and is “wedged” in place. At the same time, above the wedge, around 5,000 feet, we have a southwest wind coming in right off the Gulf of Mexico. This results in clouds, rain, mist, and drizzle. In the winter, it will often result in ice! You’ll recall on November 13-15, we had three straight days of rain, totaling more than 5-6 inches in some areas. With temperatures in the 40s we had no issues other than flooding. Imagine if it was winter and we had freezing temperatures! We would have a major ice storm that would be nothing short of catastrophic.
 
I am sure you have seen the NOAA Winter Weather Outlook. If not, NOAA gives us a 50/50 shot at above or below average temperatures. I am not buying that. I have seen many signals that are telling me we are going to have another brutal and long winter. What do I mean by a long winter? Remember last winter and how cold it stayed through much of spring? Area farmers really got hit hard with several freezes going into the growing season. I think the same thing might happen this winter. We may actually see the coldest temperatures of the winter in February or even March! Would not be at all surprised if freezing temperatures last well into April.
 
I am not trying to spread gloom and doom but I certainly want you to be prepared. Ice is going to be a major concern for us in the normally colder locations around the Lake Lanier basin. Gainesville along with Athens are the areas that can bear the full wrath of ice storms. If you are wondering about snow, I believe it would not be out of the question to see frequent flurries and possibly several measurable snows between December and April. Although there are some signs of a warmer early December. What makes me think we will see frequent snows?
 
How many storms have we seen evolve in the Gulf of Mexico this fall? One after the other. All have been underestimated as far as amounts and impacts. Our 1-2 inches of rain from the mid-November storm eventually became 5-6 inches. That same storm that gave us the rain became a nor’easter and clobbered New York City. Less than 2 inches of snow, followed by a cold rain was the forecast. What actually happened was quite different. Six inches of snow and freezing rain shut the city down with numerous accidents and hundreds of trees falling on homes, cars, and powerlines. It was their version of “Snowmageddon.”
 
I am hoping our computer models do a little better this winter. I will tell you something I hope you remember. A week before any potential snow the internet and social media will light up with amateur meteorologists forecasting a snow apocalypse. There will be people from everywhere saying they saw 20 inches of snow or 10 inches of ice was going to happen. Don’t pay attention to any of that. After forecasting winter weather over the past 36 years for north Georgia, I know for a fact we cannot be certain of exact locations, the time of arrival, or how much wintry precipitation we will get until the day before or the morning of, the actual arrival of the storm.
 
I hope you all have a wonderful Christmas and if you are looking for a family present this year, may I suggest a sled?

November 2018 column

Hurricane Michael causes catastrophic damage

As I ended my article last month, I said we would be watching the Gulf of Mexico intently during October for any tropical development. I was especially curious to see what would evolve as far as tropical weather systems.
 
Last month, the Gulf of Mexico was VERY warm. In looking at the average temperature over the past 30 years, I noticed the water temperatures were running about 2-3 degrees warmer than they would typically be at this time of year. Down in the Caribbean, there was a weather disturbance that caught my eye around October 1st. There was no wind shear anywhere in the Gulf of Mexico. The water was extremely warm. I knew, if it moved from its proximity to land, all it could do was get stronger and more powerful.
 
On October 7th, after a week of simmering over the warm water, it became a tropical depression. The National Hurricane Center gave it an 80 percent chance of becoming a tropical storm at that point. Everything I saw pointed to strengthening. There was nothing to stop it.
 
It took a day to become Tropical Storm Michael and a day later, it was Hurricane Michael. The development was quick. Now we had to figure out where it was going to go and what the conditions would be like in the atmosphere ahead of the storm. That job went to the Hurricane Hunters. The Air Force sent up its P3 Gulfstream IV jet to sample the air and atmospheric conditions in the environment ahead of the storm. There was nothing but bad news coming back with the telemetry. There was no meteorological reason to stop it from becoming a monster.
 
When the first advisory came out, the projected path took it through the eastern part of the Gulf of Mexico, crossing the very warm Loop Current. In addition, there were several warm water eddies, with surface water temperatures in the upper 80s to near 90 degrees. The warmer the water, the more “octane” for a tropical system to develop. And develop it did.
 
By October 9th, we had a major Category 3 hurricane and it was getting even stronger. By the 10th, when it made landfall, it was a CAT 4 with sustained winds of 155 miles per hour and wind gusts of 175 miles per hour! It was a beast that was 400 miles wide and looked like a buzz saw on the satellite pictures as it cut a direct path through the Gulf of Mexico, toward the Florida Panhandle.
 
As it was about to make landfall, I told my colleagues here in Severe Weather Center 2, I was seeing something I had not seen since Hurricane Andrew hit Miami in 1992. There were little perturbations rotating around the eye wall of the storm. I knew I had seen them before. They were vortices of powerful winds rotating around the eye. I knew the devastation was happening at ground zero, in this case Mexico Beach, Fl.
 
When the first surveys were done two days later, trees were snapped in half, damage to homes and businesses was catastrophic. There was a 50 mile swath of damage that looked like a tornado hit. The vortices I saw on the satellite did exactly what they did in Miami after Andrew, flattened everything.
 
It was the 3rd CAT 4 hurricane to hit the U.S. mainland in two years. In just a few hours, peoples’ lives were turned upside down. People that chose to stay say they will never do that again. Most thought they would lose their lives.
 
If there was a bright spot, it was that Michael was a quick mover and did not linger for days like Hurricane Florence did in the Carolinas. Rainfall was not a problem with Michael, it was the storm surge of up to 13 feet in some spots and those CAT 4 155 mph winds. Each hurricane or tropical system is unique with its own set of perils. It will all be over by the end of this month, when hurricane season ends.


October 2018 column

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. 
 


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.


 
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