GaWx

Early maps suggest 12Z GFS will also come in a bit S of prior runs.

I don’t know about NW trend of model consensus stopping as 12Z Icon came in slightly N of its prior. But it may be more that the 12Z CMC trends south because CMC has been N of the others and is correcting itself. Also, Icon has been S of most others and was due to trend N.

Compare 12Z RGEM 84 with 0Z CMC 96: big diff! 12Z RGEM 84 0Z CMC 96 had the low/precip much further N and related to that the low was 4 mb stronger/more amped

The 12Z 84 RGEM is ~150 miles further S with the Gulf low vs the 0Z CMC 96 and precip shield is significantly further south along with it. Thus, I’m expecting the 12Z CMC to come in significantly south of the 0Z CMC with the precip/snow line/540 line, etc.

This means the 12Z CMC should come in a little south of its 0Z with slightly lower thicknesses and a little further S snow line. Also, 12Z RGEM well south of NAM.

Yep. Stronger low. Precip further n

Euro early maps show low/precip will likely be further N than 18z

Also has offshore wave 2 Thu. Complex situation!

0Z Uk further N with qpf vs 12Z

72 hour 0Z Uk vs 84 hour 12Z: similar to CMC…I bet snow line further N than 12Z Uk but keep in mind Pivotal Uk snow maps not accurate on SE side due to counting Ip/ZR as SN

0Z models all show a 2nd wave just offshore the SE that will need to be watched for Thu/Thu nite.

84 hour 0Z RGEM fwiw has not quite as strong Arctic high nearby and 540/546 thicknesses are slightly further N ahead of the low vs 12Z CMC 96. I wonder if this means 0Z CMC will be slightly further north than 12Z with snow line.

Icon: snow furthest N of last 3 runs S of that snow is ZR down to Gainesville to JAX corridor qpf Tue afternoon

EASTERN ALACHUA- INCLUDING THE CITIES OF GAINESVILLE, GAINESVILLE AIRPORT, AND NEWNANS LAKE 841 PM EST FRI JAN 17 2025 MONDAY NIGHT MOSTLY CLOUDY. A CHANCE OF RAIN SHOWERS AFTER MIDNIGHT. COLD WITH LOWS IN THE LOWER 30S. CHANCE OF RAIN 30 PERCENT. WIND CHILL VALUES IN THE MID 20S. TUESDAY MOSTLY CLOUDY. A CHANCE OF RAIN SHOWERS IN THE MORNING, THEN RAIN SHOWERS LIKELY IN THE AFTERNOON. HIGHS IN THE UPPER 40S. CHANCE OF RAIN 60 PERCENT. WIND CHILL VALUES IN THE MID 20S IN THE MORNING. TUESDAY NIGHT RAIN SHOWERS LIKELY. A CHANCE OF FREEZING RAIN AFTER MIDNIGHT. COLD WITH LOWS IN THE UPPER 20S. CHANCE OF PRECIPITATION 60 PERCENT. WIND CHILL VALUES AROUND 20.

CHS: LONG TERM /MONDAY NIGHT THROUGH FRIDAY/ THE FORECAST IS STARTING TO NARROW IN ON A WETTER AND COLDER SOLUTION FOR THE UPCOMING MID-WEEK WINTER EVENT AS ARCTIC HIGH PRESSURE SETTLES IN. ALL OF THE OPERATIONAL RUNS OF THE GFS, EC AND CMC ARE STARTING TO ALIGN WITH SUPPORT FROM MANY OF THEIR ACCOMPANYING ENSEMBLE MEMBERS. THIS COUPLED WITH TRENDS NOTED IN THE NBM IS FINALLY ALLOWING FOR SOME INCREASED CONFIDENCE IN HOW THE EVENT WILL UNFOLD AS LOW PRESSURE PASSES BY TO THE SOUTH AND OFFSHORE. THERE REMAINS SOME UNCERTAINTY ON HOW THE P-TYPES WILL EVOLVE AS THE EVENT PROGRESSES, BUT IT IS BECOMING INCREASINGLY FAVORABLE FOR A SNOW/FREEZING RAIN EVENT WHICH COULD BRING IMPACTS, POSSIBLY SIGNIFICANT, TO SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. COMPLICATING MATTERS IS THERE ARE SIGNALS THAT ENHANCED FORCING INDUCED BY BANDS OF MID-LEVEL FRONTOGENESIS COULD YIELD CORRIDORS OF ENHANCED PRECIPITATION RATES, WHICH COULD RESULT IN POCKETS OF MODERATE TO LOCALLY HEAVY PRECIPITATION. HOW MUCH OF THIS ENHANCEMENT WILL OCCUR IS YET TO BE DETERMINED AND CAN NOT BE READILY IDENTIFIED THIS FAR OUT. THIS IS CERTAINLY SOMETHING TO WATCH AS THESE BANDS COULD AUGMENT BOTH P-TYPES, PRECIPITATION RATES AND ACCUMULATIONS. IT IS STILL TOO FAR OUT TO IDENTITY ANY SPECIFIC SNOW/ICE ACCUMULATIONS AND IMPACTS THIS FAR OUT, BUT THE PROBABILITIES FOR BOTH ACCUMULATING SNOW AND ICE ARE INCREASING AND THE FORECAST WILL REFLECT THIS TREND. TIMING FOR THE PERIOD OF GREATEST IMPACTS LOOKS TO CENTER ON THE TUESDAY AFTERNOON TO EARLY WEDNESDAY PERIOD WHEN THE COLDEST AIR WILL ALIGN WITH THE STRONGEST FORCING AND HEAVIEST PRECIPITATION. SOME LIGHT PRECIPITATION COULD REACH PARTS OF THE GEORGIA COAST BEFORE DAYBREAK MONDAY WITH PRECIPITATION ENDING WEDNESDAY MORNING.

From JB regarding the Gulf coast potential: I -10 shut down. This can be historic. Its one thing for one area to get some snow or ice between San Antonia and Jacksonville. but the whole corridor on the gulf coast probably has not happened since 1899 ( and there was no I-10 there, but you get the message). Its hard to believe what can happen here.

Indeed. On the contrary, it is already determined what will happen. It’s just that the models aren’t nearly smart enough to know. They gradually figure it out. And I’m glad they don’t know because otherwise there wouldn’t be these very interesting forecasting discussions! For example, the NW trend is only because the models were too far SE in the first place. The storm didn’t actually trend NW.

No more or less “selfish” than just about anyone here or at any wx bb who wants snow where they live. Totally normal for all. And wishes don’t influence what happens regardless.

Likely. Feb 9-10 of 1973 was huge there and gave ATL nothing!

Well for the 1st one I cheated (traveled) based on models to get to near my old stomping grounds after any chance for here trended NW away from here like usual and after not having seen a flake in 7 years. And we all know this one is far from certain. I had actually been considering going back to ATL to get their 2nd round (small chance I’d reconsider) and get out of the big ZR danger zone. But at least now I have 2 small power backups coming just in case and will check into dry ice as was recommended by Tony although that may be hard to deal with from what I’ve read.

Even after reducing members somewhat for it being 10:1 instead of Kuchera, ~1/3 of the 12Z EPS members give just about the entire TLH to AYS to SAV corridor and surrounding areas the heaviest snow on modern records (back to at least late 1800s to early 1900s)! And this mean isn’t including sleet or ZR. Just over 50% give JAX and between 1/4 and 1/3 even give @pcbjrmeasurable snow! This is still a crucial 4.5 days out and the NW trend threat is still there.

12Z EPS snow: once in generation snow in much of coastal far S SC/SE GA/N FL if this were to verify well: hasn’t occurred since at the very least 1989 for most of those areas, which was years before the WWWeb even got going and many here not even born yet! I’m trying to keep my excitement in check because it could easily verify way differently since it’s still 4.5 days from this initialization, the 12Z models have huge disagreements, and this would be an exceedingly rare event! @metalicwx367 @Awesomesauce81 @gtg947h

Sorry, but I don’t know.

3.8” combined SN/IP would be biggest on record at AYS 12Z UKMET has essentially no wintry precip except tiny bit of sleet AYS Tue night

12Z Euro: ZR 0.67” @pcbjr, 1.34” JAX IP 1.0” AYS, 1.3” SVN Snow: 2.8” AYS, 3.2” SVN, 0.1” JAX