FCST: 12/23-24/09 Snow NW MO and NE KS

EDIT 0530Z/23: The 0Z runs of the NAM and GFS are in and they are much more impressive and bullish with their snow totals.  Steve and I have been looking at the models all evening trying to figure out our best forecast to put up on the blog.  We are going to stick with 3" to 6" right now, with the heaviest falling late Thursday evening into the overnight hours.  We could locally see some 8" amounts if the ULL tracks as the models suggest.  If the ULL tracks further S and E and the secondary low takes over as the dominant low we could see A LOT more snow locally.  The secondary low that forms over AR intensifies as it moves up along the MO and IL borders.  The pressure gradient also increases dramatically as the ULL's pull off to the north and east.  This pressure gradient tightness will bring strong, gusty winds into the local area which COULD produce near whiteout or blizzard conditions Thursday night!  Please keep abreast of the latest NWS forecasts for watches and warnings as this is a significant storm system!  Currently KEAX has no watches issued, but I anticipate some sort of headline by tomorrow morning as long as the model runs stay consistent and surface/upper air obs are supporting snow/ice crystal formation! ~ CS


WOW, what a storm to watch and try to amateur forecast...this has been a learning experience to say the least....I still see the probability of at least two ULL and a shortwave from the NW impacting our weather over the Christmas holiday.....I do think we will have a dominant low that the others will interact with to give us a winter weather event here locally.......

Forecasted Low Surface Tracks

The storm system has entered the sounding network and the models have had a couple of runs with "real" data to work with"  My current thinking is the ULL is going to track a bit further south and east, which has been my concern all along.  During the winter months it is very difficult to get a low to track as far north as the models have been predicting.  This is due to cold air intrusion and the position of the southern jet stream.  There is some consistency to the models now and they are coming into better agreement.

This being said I believe the heavier snow totals are going to be pulled further south and east than previously forecasted.  I do believe NC KS, SC NE and NW IA are going to see the heaviest snow totals from this storm, some areas may see up to 18" of snow.  My current thought around here is quite a bit less...maybe in the 3" to 6" range.  However, if the QPF is not being overdone by the models we could get quite a bit more.  It all depends on the track of the ULL, the speed of the ULL and if the low intensifies. 

Here are my forecast reasonings:
1000-500 and 850-700 mb freezing line is east of us now earlier than anticipated,
1000-500 mb RH greater than 90% and dry air intrusion remains east of the local area,
Warmest Vertical Temp and 850 mb freeze line is also east of us now,
ULL is tracking to our south and east (not sure how far right now though),
ULL slows down and intensifies as it moves off to the northeast,
Heaviest snow to fall north and west of the track of the ULL,
Long duration snow event is in store.

Timing of the precip:
A cold rain will rapidly change to snow during the late afternoon hours on Thursday.  Snow will continue, moderate at times, during the overnight hours into Friday morning. Heaviest snow should fall between 9 p.m. and midnight.  Strong winds will accompany the snow and we could have whiteout to near blizzard conditions making travel nearly impossible during the overnight hours on Thursday.

More later this evening as I get a chance to look at this evenings model data. ~ CS