Jeff Miller
EF5
Operational Models the past few runs on GFS are painting an ominous picture for potential winter precipitation on the pre-thanksgiving holiday driving period. Due to the fact that this will be an extremely busy driving period, the first potential winter storm of the season, and the proximity to Thanksgiving, and within the 7 day forecast period allowed here at Stormtrack, I am starting a forecast thread for a potential significant winter storm event. I emphasize that, as most forecasters and meteorologists know, this is extremely far out, and normally I would wait a day or two longer before beginning a forecast thread. Due to the holiday season, I am starting it now.
The forecast models have caught on to a winter storm scenario for a few days now, however, the past two consecutive runs have painted a major winter storm to blizzard criteria storm over eastern Nebraska, most of Iowa into southern Minnesota to nw Illinois and also into Wisconsin. To note: Ensembles have not caught onto this and are keeping the system open and weaker, and this is a very distinct possibility. The other possibility that experience in early season storms dictates is that the storm will be more intense and pull further north with future runs, impacting more of a central Nebraska South Dakota to central Minnesota line up to the UP of Michigan as often happens in early season storms.
The operational GFS models at the 12z 156 are showing a major snowstorm with a 998 low - with a strong gradient between cold high pressure over the Northwest and the low producing potentially windy conditions with the heavy snow. These operational models deepen to 994 with a very strong and tight gradient as well.
Time will tell what will happen not only with this winter thread but severe threat in the southern plains and gulf coast states. Discussion is open for this potential winter storm situation - and all bets are on if the ensembles will catch on to what GFS portrays or if this winter storm will evaporate like virga on the high plains - leaving this thread dry as a bone and thanksgiving travelers in a much, much better mood.
From OMAHA WFO:
From Des Moines WFO:
http://rap.ucar.edu/weather/model/gfs168hr_sfc_prcp.gif
http://rap.ucar.edu/weather/model/gfs168hr_sfc_mslp.gif
http://rap.ucar.edu/weather/model/gfs168hr_sfc_tmax.gif
The forecast models have caught on to a winter storm scenario for a few days now, however, the past two consecutive runs have painted a major winter storm to blizzard criteria storm over eastern Nebraska, most of Iowa into southern Minnesota to nw Illinois and also into Wisconsin. To note: Ensembles have not caught onto this and are keeping the system open and weaker, and this is a very distinct possibility. The other possibility that experience in early season storms dictates is that the storm will be more intense and pull further north with future runs, impacting more of a central Nebraska South Dakota to central Minnesota line up to the UP of Michigan as often happens in early season storms.
The operational GFS models at the 12z 156 are showing a major snowstorm with a 998 low - with a strong gradient between cold high pressure over the Northwest and the low producing potentially windy conditions with the heavy snow. These operational models deepen to 994 with a very strong and tight gradient as well.
Time will tell what will happen not only with this winter thread but severe threat in the southern plains and gulf coast states. Discussion is open for this potential winter storm situation - and all bets are on if the ensembles will catch on to what GFS portrays or if this winter storm will evaporate like virga on the high plains - leaving this thread dry as a bone and thanksgiving travelers in a much, much better mood.
From OMAHA WFO:
FORECAST BECOMES MUCH MORE UNCERTAIN AS LATEST TWO
CONSECUTIVE RUNS OF THE GFS PAINT A PRE THANKSGIVING DAY BLIZZARD
ACROSS THE AREA. MEANWHILE...THE GFSENSEMBLES KEEP THE SYSTEM
MORE OPEN AND PROGRESSIVE AS DID THE 00Z ECMWF. LATEST 12Z ECMWF
DOES EVENTUALLY CLOSE THIS SYSTEM OFF OVER THE CNTRL PLAINS
SIMILAR TO THE GFS...JUST LATER IN THE PERIOD DURING NEXT WEEKEND
WHICH IS JUST PAST OUR CURRENT FORECAST RANGE. IN A NUTSHELL...WL
NOT BITE ON THE BLIZZARD NEXT WEEK JUST YET AS INDICATED BY THE
OPERATIONAL GFS AS MODEL AND SURROUNDING OFFICES/HPC CONSENSUS
LOOKS TO REMAIN MORE OPEN AND PROGRESSIVE AT THIS TIME. WILL BE A
VERY INTERESTING EVOLUTION TO KEEP OUR EYES ON THOUGH AS WE HEAD
INTO THE HOLIDAY WEEK AHEAD.
From Des Moines WFO:
http://rap.ucar.edu/weather/model/index.php?model=gfsSEEMS THAT OVERALL
TREND IN THE BULK OF THE MODELS IS TO BLEED COOLER AIR SOUTHEAST
ACROSS IOWA THROUGH THE PERIOD...SO ALL RAIN INITIALLY WILL BECOME
RAIN OR SNOW...POSSIBLY EVEN SOME SLEET DURING THE TRANSITION
PERIODS...THEN LIKELY ANY PRECIP BY THANKSGIVING DAY WOULD FALL AS
SNOW. AT THE VERY LEAST...WE COULD BE LOOKING AT 2 TO 3 DAYS OF
UNSETTLED WEATHER...WITH SOME PRECIPITATION TYPE ISSUES DEVELOPING.
AGAIN...THIS IS OUR BEST ATTEMPT TO PROVIDE SOME HOPEFULLY USEFUL
DETAIL AS WE HEAD TOWARD A HOLIDAY TRAVEL PERIOD...BUT WE ARE STILL
SEVERAL DAYS AWAY AND THERE IS MUCH TO BE IRONED OUT.
http://rap.ucar.edu/weather/model/gfs168hr_sfc_prcp.gif
http://rap.ucar.edu/weather/model/gfs168hr_sfc_mslp.gif
http://rap.ucar.edu/weather/model/gfs168hr_sfc_tmax.gif
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