12/3/2011 Weekend Weather Thread

cloneluke80

Well-Known Member
Apr 11, 2006
1,772
52
48
West Des Moines, IA
Looks like the first major winter storm brewing coming out of the 4 corners.. which is where most big ones come from..

National Weather Service Text Product Display

Earl's GIS Radar Site Overlays Page

Earl's GIS Radar Site Overlays Page

keeping an eye on these model runs..

from NOAA discussion:

RECENT 12Z RUNS ARE NOW STARTING TO CONVERGE ON A CONSENSUS HOWEVER...TRENDING TOWARD EACH OTHER...AND RESULTING IN INCREASED CONFIDENCE OF A WIDESPREAD PRECIP EVENT ACROSS OUR FORECAST AREA SO HAVE RAISED POPS INTO LIKELIES FOR MANY LOCATIONS SAT AND SAT NIGHT. THIS IS ALSO SUGGESTED BY OFFSITE WRF RUNS PRODUCED BY LOCAL TV STATIONS. THERE IS STILL LOW CONFIDENCE IN SENSIBLE WEATHER HOWEVER WITH 6C DIFFERENCE BETWEEN ECMWF AND GFS WARM LAYER TEMPS...ECMWF ON THE WARMER END STILL SUGGESTING THE MORE NWRN TRACK. THUS HAVE SNOW NW...BUT RAIN AND SNOW CHANGING TO SNOW BY SAT NIGHT CENTRAL AND SE. ECMWF/GFS STORM TOTAL QPF AMOUNTS RANGE FROM A HALF INCH TO AN INCH SO THERE WILL LIKELY BE A SIGNIFICANT SW-NE SWATH OF WHAT MAY BE HEAVY SNOW IN CENTRAL IA WITH MODERATE RAINS TO THE SOUTH BUT LOCATIONS DIFFICULT TO PINDOWN RIGHT NOW.
 
00z runs of GFS and NAM are even more ominous. Latest GFS putting down heavy snow right across central Iowa from southwest to northeast. Northern stream system has seemed to slow down considerably from previous GFS runs, it is very close to ECMWF runs now but just slightly further east.
 
00z runs of GFS and NAM are even more ominous. Latest GFS putting down heavy snow right across central Iowa from southwest to northeast. Northern stream system has seemed to slow down considerably from previous GFS runs, it is very close to ECMWF runs now but just slightly further east.

In English?
 
Basically as of right now models are trending toward a heavy snow event somewhere across Iowa, with NCEP (National Center for Environmental Prediction) models placing this band across central Iowa, while the European model is a little further northwest. It is still a long ways out, and far from set in stone as it will be a pretty dynamic setup (with interaction between northern and southern stream) with many pieces needing to line up.
 
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With the way it looks, if central Iowa is where the band of snow sets up, it will likely stretch back towards Manhattan as well. There's still a few days for this to change.
 
Yay...looks like the time has come to start hitting up schnacks blog and iowachase for GIS models. :yes:
 
Basically as of right now models are trending toward a heavy snow event somewhere across Iowa, with NCEP (National Center for Environmental Prediction) models placing this band across central Iowa, while the European models is a little further northwest. It is still a long ways out, and far from set in stone as it will be a pretty dynamic setup (with interaction between northern and southern stream) with many pieces needing to line up.


What exactly does heavy snow mean?
 
clarkbutterfingers @aggieville
8 inches or more with gusto winds in a 100 mile wide band smoking DSM.
 
I will admit weather is no where near an area of expertise for me. Can anyone that understands models and forecasts give an update (Note: I understand we're still a few days out, but its still interesting to hear)
 
I will admit weather is no where near an area of expertise for me. Can anyone that understands models and forecasts give an update (Note: I understand we're still a few days out, but its still interesting to hear)

There was a bit of a shift north and west on the most recent model runs(barring the GEM which is an outlier at this point) also precip totals are up some. NAM(I don't have any proof, but it seems like the NAM has not done well this fall)/Euro favor NW Iowa for best snowfall, GFS is paints the best swath a bit further south. Each of the models are handling the stream interaction and trough tilt a bit differently leading to a fair amount of uncertainty.
 

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