GaWx

1055 PM EDT SAT MAR 15 2025 THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... PAULDING COUNTY IN NORTHWESTERN GEORGIA... HARALSON COUNTY IN NORTHWESTERN GEORGIA... CARROLL COUNTY IN NORTHWESTERN GEORGIA... NORTHWESTERN COBB COUNTY IN NORTH CENTRAL GEORGIA... DOUGLAS COUNTY IN NORTH CENTRAL GEORGIA... SOUTHEASTERN FLOYD COUNTY IN NORTHWESTERN GEORGIA... NORTHERN HEARD COUNTY IN WEST CENTRAL GEORGIA... NORTHWESTERN COWETA COUNTY IN WEST CENTRAL GEORGIA... SOUTHWESTERN FULTON COUNTY IN NORTH CENTRAL GEORGIA... SOUTHEASTERN GORDON COUNTY IN NORTHWESTERN GEORGIA... POLK COUNTY IN NORTHWESTERN GEORGIA... BARTOW COUNTY IN NORTHWESTERN GEORGIA... * UNTIL MIDNIGHT EDT. * AT 1054 PM EDT, SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE EXTENDING FROM ESOM HILL TO CORINTH, MOVING NORTHEAST AT 70 MPH.

The damaging wind threat cannot be understated. They’ll almost definitely affect many more folks than the number hit by tornadoes. Winds not far above the surface are 70 mph+. ATL being up at 1K Ft elevation increases that risk.

Here is the new tornado watch:

Thanks, Chuck. Check out the lagging OHC’s impressively steep warmup during the same period:

This is relevant for the Atlanta area, for which a tornado watch is likely to be issued by 9PM. The highest risk looks doesn’t look likely to reach the NW/W burbs til ~11PM+ and downtown til midnight or later per model consensus. It’s possible that the worst for downtown and nearby won’t be til ~2AM:

How does it look for the ATL area tonight?

The EPS/GEFS both still have 2 more strong reversals to go this month, 3/19 and 3/28-9, with both at new records vs current lows of -16 to -17:

It’s not all cc as the strat. warming is in play among other things.

For what area and when is the SPC mentioning 60-100 mph gusts?

I haven’t yet because I’m following up prior posts ITT (continuity), including the current strat. reversal along with any potential after effects and also mid-March is still early to completely move on to 2025-6. After all, some like to get through March as the end of the cold season before completely moving on. I don’t see any harm in having two active threads for the next few weeks or so, which has already been the case for a number of weeks.

Charlie, Your global temp graph contrasts quite a bit to the Arctic (80N+) that I posted just above this, which shows it flat 1970-94 vs yours for global having ~0.35C of warming 1970-94. *Corrected

I sure hope you’re right!

Related to the above, here are the means for the Arctic by season 1958-2025: Winter, summer, and annual: bulk of winter/annual warming just since 2005 while summer hasn’t warmed at all Spring, autumn, and annual: autumn has warmed 2nd most of the 4 seasons but bulk also just since 2005 while spring’s more modest warming mainly only since 2010:

Interestingly, the Arctic (80N to the pole) is on the verge of having the coldest mean temp of the entire season so far (see image below). This is as of Mar 12. If it drops any more it will become the coldest of the season. There have been a good number of seasons with the coldest in Mar since 2017-8: 2017-8, 2018-9, 2019-20, 2020-1, and 2022-3. And 2023-4 only barely missed! Before that one has to go all the way back to 2008-9, 2005-6, 2004-5, 2002-3, 1995-6, 1985-6, 1984-5, 1983-4, 1975-6, 1969-70, and 1968-9 (going back to 1957-8) for the coldest in March. So, for the 60 year period 1957-8 through 2016-7 there were only 11 (18%) with coldest in March. In contrast, 5 of the subsequent 7 (excluding 2024-5) or 71% have had that. Yes, I’m cherry picking to an extent due to 7 seasons being a pretty short period. However, it does beat the prior highest of 4 of 7 (57%) seasons that covered 2002-3 through 2008-9. Also, it may rise to 6 of the last 8 (75%) if today shows a further drop. If so, that would compare to the previous highest 4 of 8 (50%) from the decade of the 2000s Coldest daily mean is Feb 25. Mar 12th anomaly (about at normal) is the coldest daily anomaly since way back in August:

What’s your current feel for the threat level and timing for the Atlanta area? A friend of mine there is in semi-panic mode.

Tonight’s walk resembled a midwinter version with 47-48 and a stiff breeze making it feel like 30s. It felt great! The upper low has given us very little rain this evening.

This is wild! Despite only a marginal tornado risk, a tornado (EF2!) hit the studio in Seminole County, FL, a little NE of Orlando along I-4 this morning while the TV met was on the air!!

I was reading elsewhere that Greer, SC (elevation ~1,000 feet) has been having sleet mixing in with the rain (unofficial report).

As predicted this area has been inundated the last 24 hours with a very beneficial heavy rainfall, with the bulk of it falling last night: this Cocorahs map for the 24 hours ending ~7AM shows 2.4-3.5” over much of the E half of Chatham County into N Bryan County! Plus some more fell after 7AM and more is expected later today with the upper low. The last time the area had anywhere near this much was 11/7-8/2024. Prior to this, the heaviest since 11/7-8 was 1/21-2/2025:

26FEB2025 27.5 1.1 27.0 0.3 26.7-0.2 27.5-0.6 05MAR2025 28.1 1.6 27.4 0.5 27.0 0.0 27.8-0.3 So, the latest week being reported (last calendar week) shows all regions warmed with Nino 3.4 up to 0.0 and Nino 1+2 up to a whopping +1.6. But keep in mind that these aren’t taking into account the relatively warm surrounding tropical/global waters like RONI does. So, one may want to subtract ~0.5 to 0.6 to get a better picture of the situation. Regardless, the trends have been clearly warmer and Nino 1+2, itself, would still be in moderate Nino territory and Nino 3 would be up to neutral. https://www.cpc.ncep.noaa.gov/data/indices/wksst9120.for

Sunday was, indeed, an off and on soaking rainy day and evening with very chilly NE winds. Temps were only in the upper 40s to low 50s much of the daytime! We even had some rumbling thunder for a few minutes. All very beneficial for the relatively dry soil but not beneficial for going for a walk. Rain has been near continuous the last few hours and should continue through much of the night. There looks to be a break after dawn, but another (final) batch of showers is progged for later in the day into the evening due to the upper level low.

Nino 3.4 has continued to warm overall with the latest being +0.187 per OISST and -0.059 per CDAS. Also, though still lagging, OHC has been rapidly warming and is ~-0.45 as of the latest:

He’s still forecasting BN temp. domination 3/20-4/15. We shall see. Todays Euro Weeklies have mainly NN to AN most weeks but check out 3/31-4/6: Run from 3/5: Run from 3/8 (latest): pretty big change 3/8 run at H5: there’s a moderate -NAO/-AO signal then

Much of tomorrow afternoon here is forecasted to be 10-15 BN due to chilly flow behind a cold front in combo with clouds and widespread rain due to a surface low forming along the Gulf coast and moving ENE to near or just south of this area. Rainfall of 2-3” will be quite possible over the next 48 hours, which would be very beneficial due to the winter having BN rainfall. The last significant rainfall event was actually with the big winter storm 1/21-2. If KSAV gets 1.34”+, it would become the wettest event since Nov 7th.

Of course it’s the infamous Happy Hour run, when the GFS has an excuse to get drunk and be happy! Enjoy tonight’s 0Z runs. They’ll be an hour later starting tomorrow for almost the next 8 months.