STORM2K

We're sitting at 35 degrees here at our house...rain is pouring down at 1/4-1/2 inch an hour...and we've got thunder and lightning. Interesting.

39 here. We just had a pretty VIOLENT thunderstorm come through. Several close strikes/loud rumbles. I was shocked when the first one hit about 8:40pm. It was torrential rain for a few minutes but now it's over. VERY VERY strange.

I don't recall ever having a storm like this in our area under these conditions. Strange indeed. 35F w/thunder and lightning--in FEB.

Also, to the south of Atlanta (Coweta and Fayette Counties), they're getting HAIL.

JenyEliza wrote:I don't recall ever having a storm like this in our area under these conditions. Strange indeed. 35F w/thunder and lightning--in FEB.

Also, to the south of Atlanta (Coweta and Fayette Counties), they're getting HAIL.

I can't recall either. The only time I've ever heard of thunder here below about 45 degrees(and even that might be too low) was during the Blizzard of 1993.

Brent wrote:

JenyEliza wrote:I don't recall ever having a storm like this in our area under these conditions. Strange indeed. 35F w/thunder and lightning--in FEB.

Also, to the south of Atlanta (Coweta and Fayette Counties), they're getting HAIL.

I can't recall either. The only time I've ever heard of thunder here below about 45 degrees(and even that might be too low) was during the Blizzard of 1993.

You're absolutely right. I'd forgotten about the thundersnow in 1993. That is the ONLY other time I can recall a storm like this in the Atlanta area...and I"ve lived here since '68.

Jen

Nice! The two hour lightning strike count increased 58.82%, from 91 to 221, in the last half hour.

Convection around a mid and upper low with temperatures in the 30's is quite impressive. This already shows us that there is a bit of a lapse rate issue (with the elevated convection w/out soundings).

Definitely a potent little MLL we're dealing with.

One of the things that's actually hurting somewhat (and helping to keep things borderline) is the stable wedge along the SFC, where the colder air aloft will probably have a little harder time mixing down. Deformation zone magic may be achieved as this thing tries to crank up, and convection/T-storms around the MLL is a sign that it's doing so ...

I haven't checked the soundings from anywhere, but again, the warm nose is offsetting more dramatic falloffs in temperatures ... first, you have to bring that down (of attempt to), and the colder air aloft is drawn down, and the wedge only complicates things that much more ...

Larger scale convective outbreaks tend to rob moisture further upstream but there are no absolutes. Convection on this scale (yes, there's a convective line forming and may take some moisture, but dynamics, stronger lift, especially INVOF the deformation zone can just wring out all the available moisture both efficiently and effectively (which tends to be along the NW side of a MLL) ...

FWIW, people around the ATL area are reporting intense CG strikes and very loud thunder around the area. HIGHLY HIGHLY unusual with temperatures in the 30's. Let me say, I'm glad this isn't occurring with strong WAA, and w/out a wedge ...

the dynamics alone are already producing a lot of hail and this w/out daytime heating (insolation), and frankly, it isn't exactly warm at the SFC, but the lapse rates above the warm nose are quite impressive. They have to be to get stronger convection, and during an event without a wedge, even MORE SFC instability would be thrown into the mix. Remember that cold air damming and wedges are very stable boundary layers of air at the SFC ... instead, imagine a strong WAA (warm air advective SFC regime), and you have all the ingredients for some hellacious thunderstorms (SVR a damn good bet) ...

SF

We had some thunder and lightning around my way too. Very strange with the temp that low! The last time we had storms in December there were snow showers the following week. It will be interesting to see if that happens again.

GAStorm wrote:We had some thunder and lightning around my way too. Very strange with the temp that low! The last time we had storms in December there were snow showers the following week. It will be interesting to see if that happens again.

2000? Yeah... but it was 70 degrees outside when the storms hit. An F4 tornado hit Tuscaloosa, Alabama that day. It snowed the very next MORNING and then again 2 days later(1 inch snowfall both times)

We did not have any lightning here as far as I could tell. But it did rain pretty heavily before the system was done.

JenyEliza wrote:I don't recall ever having a storm like this in our area under these conditions. Strange indeed. 35F w/thunder and lightning--in FEB.

Also, to the south of Atlanta (Coweta and Fayette Counties), they're getting HAIL.

I've actually observed thunderstorms in temps below 40° on several occasions in my memory....including once in 1982 with severe flooding occurring (over 6" of rain fell here with heavy thunder for hours with a temp in the upper 30's).

I've also observed thunder and lightning a couple times with freezing rain falling and trees covered in ice. If the atmosphere is unstable enough, cold temperature doesn't stop thunderstorms from occurring. What it does...or usually does is limit their intensity. While I've seen damaging thunderstorm winds with temps in the lower 50's and small hail in the low 40's, I've never seen a tornado occur in north or central Georgia with a surface temp below 60° (and rarely with surface dewpoints below 60°).

PW

Last year or the year before, Lincoln, IL, NWS issued SEVERE THUNDERSTORM WARNING with snow. Talk about INTERESTING!!

Brent wrote:2000? Yeah... but it was 70 degrees outside when the storms hit. An F4 tornado hit Tuscaloosa, Alabama that day. It snowed the very next MORNING and then again 2 days later(1 inch snowfall both times)

GAStorm wrote:We had some thunder and lightning around my way too. Very strange with the temp that low! The last time we had storms in December there were snow showers the following week. It will be interesting to see if that happens again.

I work with someone who mentioned that storm not too long ago. He lived in Alabama and said it was quite an experience. It doesn't get any more extreme than that!