Next severe weather event April 26-29

[DaculaWeather]

From Dr. Forbes

-----------------------

In fact, data since 1950 show that there is a tornado mini-alley over north Georgia in a corridor west, north, and northeast of the city. Counties highlighted below have had quite a few more tornadoes than their neighbors. Cobb County, just northwest of Atlanta, has had the most, with 26. It has also had the strongest tornado in the metro area, an F4 in 1992.

Some of this mini-alley may be a consequence of these counties having a higher population than others, giving more people to witness and report tornadoes and their damage. But that may not be the full explanation, as some of the adjacent counties to the east of Atlanta also have high populations.

My theory is that a part of the explanation for the mini-alley may be that warm fronts often tend to stall out over the north suburbs of Atlanta, just south of the mountains of north Georgia. As was the case Saturday, tornado-spawning thunderstorms can get an extra boost of updraft strength and an extra source of rotation from the colliding winds along such fronts.

[audioguy3107]

Ironically (or not), I'm headed downtown tomorrow for CBS Atlanta Weatherfest. Even get a tour of the studios afterwards. I can't wait to get in there and start punching buttons!

If anything happens while you're there, see if they'll let you type up the warning message with a shout out to the forum

[downeastnc]

I am starting to think we might see central and eastern NC bumped to a mod risk for tomorrow, timing has gotten better for severe, this is a snippet from RAH overnight AFD

EXPECT THE TORNADO THREAT TO INCREASE FURTHER EAST AS THE 0-1 KM SHEAR INCREASES BUT GIVEN THE

50+ KNOT LOW-LEVEL JET AND THE STRONG VEERING OF THE WINDS IN THE LOW LEVELS...CAN NOT RULE OUT THE TORNADO THREAT IN THE WEST EITHER.

Now MHX my local office punted to the afternoon crew today so I am waiting for them to see just how big of a threat this is going to turn out to be. The good news is unlike the 16th I dont have to work tomorrow and will be able to chase still this event looks to thankfully pale in comparison to that outbreak. Any of you guys that plan on chasing this way let me know maybe we can get a few carloads going...

[Amos83]

From Dr. Forbes

-----------------------

In fact, data since 1950 show that there is a tornado mini-alley over north Georgia in a corridor west, north, and northeast of the city. Counties highlighted below have had quite a few more tornadoes than their neighbors. Cobb County, just northwest of Atlanta, has had the most, with 26. It has also had the strongest tornado in the metro area, an F4 in 1992.

Some of this mini-alley may be a consequence of these counties having a higher population than others, giving more people to witness and report tornadoes and their damage. But that may not be the full explanation, as some of the adjacent counties to the east of Atlanta also have high populations.

My theory is that a part of the explanation for the mini-alley may be that warm fronts often tend to stall out over the north suburbs of Atlanta, just south of the mountains of north Georgia. As was the case Saturday, tornado-spawning thunderstorms can get an extra boost of updraft strength and an extra source of rotation from the colliding winds along such fronts.

I lived through that 1992 F4.... I was only 10 at the time but remember it very well. The tornado actually jumped directly over my house. It took out 40 trees in my backyard and if I remember correctly had a cone of distruction over a mile or so wide. Remember the lightning was non stop flashes with heavy rain. Then all of a sudden the rain stopped and everything got dead calm. The BOOM roar was something I can still hear today.... crazy, crazy storm. Cobb County for whatever reason is in the sweet spot for tornados.

For months afterward any storm that came through scared the crap out of me.

[Snowless in Carrollton]

Some of this mini-alley may be a consequence of these counties having a higher population than others, giving more people to witness and report tornadoes and their damage. But that may not be the full explanation, as some of the adjacent counties to the east of Atlanta also have high populations.

My theory is that a part of the explanation for the mini-alley may be that warm fronts often tend to stall out over the north suburbs of Atlanta, just south of the mountains of north Georgia. As was the case Saturday, tornado-spawning thunderstorms can get an extra boost of updraft strength and an extra source of rotation from the colliding winds along such fronts

So if the mini-alley is the consequence of a higher population and the fact that warm fronts stall over the northern suburbs, how does that explain so many tornadoes in Carroll County ? A relatively rural county and definitely not in the northern suburbs or anywhere close to mountains.

[OroAeolus]

I am cooped up inside a building at Georgia State University trying to study for finals, so I only can see one part of the sky, but it still looks mostly cloudy here. I don't know much about the technical side of weather, but this storm is coming through at the wrong time. Can. Not. Study. Grr.

[FoothillsNC]

Sun has been in and out here too. Temperature up to 78 now with a dew point of 70. Storms now firing over the foothills and upstate. Just the tip of the iceberg of what should be an extremely active day and night for us.

that line is here, and its pouring. Huge drops , and it sounds great. Must be a quarter inch already. I had about 900 pounds of mulch on my truck and just shoveled it off in time. I'd hate to think how much it weighs with water in it.

I am starting to think we might see central and eastern NC bumped to a mod risk for tomorrow, timing has gotten better for severe, this is a snippet from RAH overnight AFD

EXPECT THE TORNADO THREAT TO INCREASE FURTHER EAST AS THE 0-1 KM SHEAR INCREASES BUT GIVEN THE

50+ KNOT LOW-LEVEL JET AND THE STRONG VEERING OF THE WINDS IN THE LOW LEVELS...CAN NOT RULE OUT THE TORNADO THREAT IN THE WEST EITHER.

Now MHX my local office punted to the afternoon crew today so I am waiting for them to see just how big of a threat this is going to turn out to be. The good news is unlike the 16th I dont have to work tomorrow and will be able to chase still this event looks to thankfully pale in comparison to that outbreak. Any of you guys that plan on chasing this way let me know maybe we can get a few carloads going...

I agree. The actual front is probably going to slow down tomorrow once its east of the foothills in the morning, so that will give it time to re-develop by shortly afternoon again, by then it could be strong again in eastern NC.

[GaStorm]

Yea there is like a small tornado alley from Carrol county NE into Cherokee county. This is old, but from 1950-2009 Cobb county had the third most tornadoes than any other county in Georgia, Hall county also gets a lot of tornadoes.

It's interesting as soon as you get E of the 285 perimeter how tornadoes nearly cut in half, except for Hall.

Interesting. I think Hall county has had some of the strongest tornadoes in the state from what I remember.

[DaculaWeather]

I agree Snowstorm, Gwinnett County has less than half the tornadoes the counties to the west have, and we have a TON of people here.

Study while you can, the bad stuff will be later, you can take a break then and watch the weather!

[jrips27]

I'm at school so don't have much time to type. Currently about 71^oF with intermittent sun. Looks like the SPC shifted the high risk a tad closer to the ATL area. Will check back in around 12:45

[Snowless in Carrollton]

I could be wrong but I believe Hall County has had 2 of the 20 deadliest tornadoes in U.S. history. In 1936, 203 people died in Gainesville and in 1903, 98 people died in Gainesville.

[EmersonGA]

I agree Snowstorm, Gwinnett County has less than half the tornadoes the counties to the west have, and we have a TON of people here.

Study while you can, the bad stuff will be later, you can take a break then and watch the weather!

We had a discussion on here awhile back. I personally feel like it is a combination of the wedge fronts and terrain. Storms tend to pop up on the edge of the wedge fronts. The 2008 downtown Atlanta tornado is a perfect example of this. Also the foothills of the Apps come to a point right at high tornado area NW of Atlanta. I can go 2 miles west of Emerson and be in perfectly flat plains. The land quickly rises up to the Allatoona mountains. Keep going NE and you get higher and higher. I think it funnels the storms along the south of this area and up to the NE.

[burkecountync]

GSP has interesting discussion at midday:

LATER THIS AFTERNOON...SBCAPE VALUES WILL LIKELY RANGE AROUND 1500 J/KG. FORECAST SOUNDINGS INDICATE THAT A LONG AND CURVED HODOGRAPHS WILL DEVELOP THIS AFTERNOON...HELICITY VALUES BETWEEN 0-3KM BETWEEN 200 TO 300. TRIGGER FOR AFTERNOON STORMS SHOULD REMAIN TIED TO COOL POOL BOUNDARIES AND ADDITIONAL S/W. I WILL FORECAST LIKELY TO HIGH CHC COVERAGE. THESE STORMS WILL LIKELY HAVE GREATER POTENTIAL FOR SVR WEATHER. ESPECIALLY...IT STORMS DEVELOP INTO WELL ORGANIZED MULTICELL OR SUPERCELLS. THIS EVENING AND OVERNIGHT CONTINUES TO LOOK FAVORABLE FOR THE PASSAGE OF VERY STRONG TO SEVERE TSRA. SFC LOW PRESSURE WILL TRACK NORTHEAST ACROSS THE OHIO RIVER VALLEY. THE COLD FRONT ASSOCIATED WITH THE LOW WILL SWING ACROSS THE SOUTHERN APPALACHIAN REGION LATE THIS EVENING...PUSHING EAST OF THE MTNS EARLY THURSDAY MORNING...AND EAST OF THE CWA AROUND SUNRISE. THE ENVIRONMENT AHEAD OF THE COLD FRONT WILL FEATURE VERY STRONG LLVL VEERING WIND PROFILES. IN FACT...WINDS AROUND 2 KFT MAY EXCEED 50 KTS AS EARLY AS 3Z AND CONTINUE UNTIL 9Z. HELICITY WILL LIKELY PEAK MORE THAN 400 M2/S2 AHEAD OF THE LINE...WITH SWEAT VALUES BETWEEN 400-450. CAPE VALUES WILL RANGE BETWEEN 1000 TO 2000 J/KG. THIS ENVIRONMENT WILL CERTAIN SUPPORT THE FORMATION OF A SQUALL LINE...PRODUCING DAMAGING WINDS...LARGE HAIL...AND POSSIBLY TORNADOES. IT IS INTERESTING TO SEE THE HIGH RESOLUTION MESOSCALE MODELS DEVELOP DISCRETE SUPERCELLS ALONG AND AHEAD OF THE SQUALL. IF THE SUPERCELLS DEVELOP...THEN THE POTENTIAL OF TORNADOES WILL INCREASE. CURRENT THE AXIS OF THE SQUALL IS EXPECTED TO CROSS THE SOUTHERN APPALACHIANS LATE THIS EVENING THROUGH MIDNIGHT...ACROSS THE FOOTHILLS DURING THE EARLY MORNING HOURS...THEN THE PIEDMONT BETWEEN THE LATE NIGHT HOURS UNTIL THE PRE DAWN HOURS.

[downeastnc]

that line is here, and its pouring. Huge drops , and it sounds great. Must be a quarter inch already. I had about 900 pounds of mulch on my truck and just shoveled it off in time. I'd hate to think how much it weighs with water in it.

I agree. The actual front is probably going to slow down tomorrow once its east of the foothills in the morning, so that will give it time to re-develop by shortly afternoon again, by then it could be strong again in eastern NC.

LOL glad you got done with your mulch, can you imagine how long it would have took to dry out had it gotten soaked in the back of your truck, trying to get it out soaked with a shovel=heart attack.....

I still think you guys miight repeat the early Apr event tomorrow morning and this afternoon could really go off out there, heck all of NC could see lots of severe cells fire this afternoon as a precursor to the main event Thurs.

I am glad I got lots of sleep last night cause its gonna be a long night and even longer day tomorrow.

Gotta love this from GSP

THE ENVIRONMENT AHEAD OF THE COLD

FRONT WILL FEATURE VERY STRONG LLVL VEERING WIND PROFILES. IN

FACT...WINDS AROUND 2 KFT MAY EXCEED 50 KTS AS EARLY AS 3Z AND

CONTINUE UNTIL 9Z. HELICITY WILL LIKELY PEAK MORE THAN 400 M2/S2

AHEAD OF THE LINE...WITH SWEAT VALUES BETWEEN 400-450. CAPE VALUES

WILL RANGE BETWEEN 1000 TO 2000 J/KG. THIS ENVIRONMENT WILL CERTAIN

SUPPORT THE FORMATION OF A SQUALL LINE...PRODUCING DAMAGING

WINDS...LARGE HAIL...AND POSSIBLY TORNADOES. IT IS INTERESTING TO SEE THE

HIGH RESOLUTION MESOSCALE MODELS DEVELOP DISCRETE SUPERCELLS ALONG

AND AHEAD OF THE SQUALL. IF THE SUPERCELLS DEVELOP...THEN THE

POTENTIAL OF TORNADOES WILL INCREASE.

[ATL_Militarypolice]

Interesting. I think Hall county has had some of the strongest tornadoes in the state from what I remember.

Yes, one that really stands out was the Gainesville tornado in 1936. Rated EF4 with 1600 injuries, and 203 deaths. That tornado is ranked 4th out of the top 10 deadliest tornadoes documented. One thing I find interesting is Georgia has never had an EF-5/F5 tornado dating back to 1950 so far from what I can find.

[MotoWeatherman]

I could be wrong but I believe Hall County has had 2 of the 20 deadliest tornadoes in U.S. history. In 1936, 203 people died in Gainesville and in 1903, 98 people died in Gainesville.

Could you imagine living back in that time without any sort of radar to give any sort of warning? You might as well walk around blind.

[DaculaWeather]

Up to 75/69 now and the temps are now rising at a faster rate, more than 4 degrees/hr. We'll have DP's in the 70's before this gets here, it doesn't bode well for us at all. I'm starting to get a little more concerned.

Watching more rotation from the Huntsville radar http://www.daculaweather.com/grlevel3/storm_mode_3.php

[Snowless in Carrollton]

Yes, one that really stands out was the Gainesville tornado in 1936. Rated EF4 with 1600 injuries, and 203 deaths. That tornado is ranked 4th out of the top 10 deadliest tornadoes documented. One thing I find interesting is Georgia has never had an EF-5 tornado dating back to 1950 so far from what I can find.

I also heard that Arkansas has never had an EF5 tornado, which is interesting considering how many tornadoes they get.

[downeastnc]

cell headed for the west side of Charlotte near Gastonia could be about to get severe warned.....30k 40% 1" hail

[DaculaWeather]

And LOTS of sunshine coming this way...

[audioguy3107]

Yes, one that really stands out was the Gainesville tornado in 1936. Rated EF4 with 1600 injuries, and 203 deaths. That tornado is ranked 4th out of the top 10 deadliest tornadoes documented. One thing I find interesting is Georgia has never had an EF-5 tornado dating back to 1950 so far from what I can find.

That is true, no F(EF) 5 in the state of Georgia, which is pretty remarkable considering that we're not somewhere where severe weather is a rarity (i.e. the Pacific NW or Maine for example). Let's hope today is not the day. (unless of course it's in a rural non populated stretch!!!)

[Snowless in Carrollton]

Could you imagine living back in that time without any sort of radar to give any sort of warning? You might as well walk around blind.

Yeah, and some of the buildings probably weren't built as well as they are now, or maybe they were i'm not sure.

[Brick Tamland]

GSP has interesting discussion at midday:

And the really bad thing is it will come through overnight when people are asleep.

[audioguy3107]

Here we go.

[ATL_Militarypolice]

FFC update...already 2000+ cape. Not good...

FIRST ROUND OF SEVERE WEATHER MOVED THROUGH THIS MORNING AND HAS

SUBSIDED. STORMS DIED FAIRLY QUICKLY THIS MORNING AND SHOULD HAVE

TIME FOR THE ATMOSPHERE TO RECOVER BEFORE ANOTHER ROUND OF SEVERE

WEATHER THIS AFTERNOON/EVENING. 12Z FFC SOUNDING ALREADY SHOWS

2300 J/KG CAPE ACROSS THE AREA AND A GOOD AMOUNT OF SHEAR. HIGH

SHEAR AND CAPE PROGGED THROUGH TONIGHT AND WITH THESE HIGH

PARAMETERS THE POTENTIAL FOR A SEVERE WEATHER OUTBREAK THIS

EVENING CONTINUES. BEST CHANCE OF SEVERE WEATHER STILL REMAINS

ACROSS NORTH GEORGIA...ALTHOUGH ALL OF NORTH AND CENTRAL GEORGIA

HAS A CHANCE TO SEE SEVERE WEATHER TODAY.

THIS NEXT ROUND OF SEVERE STORMS SHOULD BE APPROACHING THE

NORTHWEST BORDER AROUND 6PM AND SHOULD GENERALLY CLEAR OUT CENTRAL

GEORGIA BY 8AM THURSDAY.

QUICK UPDATE TO THE GRIDS TO CUT BACK ON SEVERE WEATHER WORDING

FOR THIS MORNING...BUT INCREASE WORDING FOR THIS EVENING.

[downeastnc]

I also heard that Arkansas has never had an EF5 tornado, which is interesting considering how many tornadoes they get.

Not really EF5 are extremely rare only 52 tornados EVER have been given a F5 and so far there have been I think 2-3 EF5's, remember in order to get the old F5 winds had to exceed 261 mph and thats just flat out rare. I imagine there will be more EF5's handed out since it lowers the winds to 200+.

Offically NC has never had a F5 since the 1984 monster F4 only had winds of 200 mph however had that same tornado occured today it would be a EF5 on the new scale.

[Snowless in Carrollton]

My underground storm shelter might come in handy on a day like today. I don't know what i'd do without one.

[GaStorm]

Yes, one that really stands out was the Gainesville tornado in 1936. Rated EF4 with 1600 injuries, and 203 deaths. That tornado is ranked 4th out of the top 10 deadliest tornadoes documented. One thing I find interesting is Georgia has never had an EF-5/F5 tornado dating back to 1950 so far from what I can find.

You would think that the western part of GA would have the strongest tornadoes being so close to AL. I remember hearing about another strong one in Hall county but don't remember the year it hit. I think it was an EF3 possibly.

[burkecountync]

And the really bad thing is it will come through overnight when people are asleep.

Exactly what I am most worried about. Storms more often than not seem to hold together as they move over the mountains in the nighttime hours when you have these dynamics. Nighttime may not be the blessing like it typically is. Nighttime may be a curse this time.

[mikepie]

You would think that the western part of GA would have the strongest tornadoes being so close to AL. I remember hearing about another strong one in Hall county but don't remember the year it hit. I think it was an EF3 possibly.

I remember there was a strong one in Hall county in either 1997 or 1998. It struck early in the morning (maybe about 4:30-5:00AM). Did significant damage.