Just a quick update. I won’t be drawing a snow map this evening for a couple of reasons: One, it’s Christmas Eve, two, the Euro won’t be out for another hour+, and three, the amount of inconsistency and volatility regarding this storm is something I’ve heard people with years of forecasting experience beyond my own, say they have never ever witnessed. In other words: You’re looking at one of the most complex storm systems we’ve ever seen…moreso because of the location it may or may not impact rather than because of the storm itself.
But I will provide you with a couple of major teases. The two maps I place at the end of this entry are raw snowfall forecasts from the GFS and NAM computer models from this evening. Now, don’t go shouting from the rooftops. I STILL am not behind this storm. I still see flaws. I still think the models are suffering problems (given their wild swings and disagreements over the last 2-4 days or so, this may seem obvious). And I still think we’re in for changes here in the final 36-48 hours before gametime. The Hydrometeorological Prediction Center’s model discussion this evening is once again hinting at the potential that the models are erring, and that could be leading to solutions later in their runs that are, well, incorrect.
CONSOLIDATING UPPER LOW OVER THE EAST... LOW PRESSURE FORMING UP THE EAST COAST...PREFERENCE FOR A 00Z NAM/15Z SREF MEAN COMPROMISE THERE ARE SMALL SCALE DETAILS THE NAM/GFS/ECWMF ARE SHOWING ISSUES WITH WHICH MAY IMPACT ITS FORECAST LATER ON. THEIR SOUTHERN STREAM SHORTWAVE IN TEXAS ARE 30-40 METERS TOO WEAK AT THE 500 HPA LEVEL BASED ON RAOB REPORTS FROM TEXAS. THE NAM DOES NOT CAPTURE THE ONGOING CONVECTION IN EASTERN TEXAS. THE 18Z AND 00Z GFS RUNS ARE SHOWING SIGNS OF CONVECTIVE/GRIDSCALE FEEDBACK AS THE SYSTEM MOVES ALONG THE GULF COAST WHICH COULD BE MAKING ITS SOLUTION AT THE SURFACE AND ALOFT TOO STRONG. THERE ARE HINTS THAT THE RIDGE INITIALLY ALONG THE EAST COAST IS MORE AMPLIFIED THAN THE NAM...WHICH WOULD BE CLOSEST TO THE 12Z ECMWF/12Z ECMWF ENSEMBLE MEAN FORECASTS FOR 00Z. ANY OF THESE DETAILS COULD DEGRADE/NEGATIVELY AFFECT THE SHORT RANGE FORECAST.
So there’s still much uncertainty. I mean, honestly, there’s NO forecast out there now that stands much chance of being right on, including my own. This is simply one of those storms where you sit back, roll the dice, and pray you come close.
Consider a compromise of the maps below as the potential for the maximum impact of this storm. Click on either map to enlarge it. Consider my forecast map from earlier this morning the potential for minimum impact of this storm. So enjoy the tease, because tomorrow is going to tell us that either a hefty dose of reality is going to kick in, or you really will believe in miracles. Merry Christmas!