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FXUS63 KARX 092046 CCA

Area Forecast Discussion
National Weather Service La Crosse WI...Correction
220 PM CST Mon Dec 9 2019

.SHORT TERM...(This evening through Tuesday)
Issued at 220 PM CST Mon Dec 9 2019

As this system continues to move out, lingering light snow showers
will continue to move east and out of the region by tonight. 
Cold air advects in behind the cold front and high pressure builds
into the region. Gusty northwesterly winds will diminish into the
teens overnight and last through tomorrow afternoon. Temperatures
combined with wind will create wind chills into the -10 to -20 
range by Tuesday morning.

After midnight, there is a chance for flurries through
tomorrow afternoon. The further north and east into Wisconsin, 
the greater the chance for flurries as soundings show decent lapse
rates and better low level saturation than areas to the south and
west. High temperatures will be in the single digits to teens.

.LONG TERM...(Tuesday night through Monday) 
Issued at 220 PM CST Mon Dec 9 2019

Surface ridge builds into the Upper Great Lakes quickly Wednesday 
and forecast area will be dry. Arctic airmass will allow 
temperatures to be well below normal...with highs rising to around 
zero to the teens. 

Focus turns to Wednesday night into Thursday...vigorous shortwave 
trough quickly tracks across the Northern Plains/Upper Midwest. The 
09.12z GFS/NAM are in good agreement with decent forcing/isentropic 
lift in association with the shortwave trough. Hence...the 
deterministic models are suggesting slightly higher qpf amounts than 
previous runs. With temperatures through atmosphere column below 
freezing...precipitation type should be all snow and the higher qpf 
will result in slightly higher snowfall amounts. Have increased qpf 
and snowfall amounts slightly...based on the stronger forcing/lift 
with the shortwave trough.

Main forecast concerns are precipitation chances Thursday night into 
Monday. The 09.12z deterministic models are in good agreement with 
overall west to northwest upper level flow pattern through the 
period. Biggest issue during the period is timing the pieces of 
energy embedded in the upper level flow across the northern tier 
states/Upper Midwest. Depending on temperatures...precipitation 
types will be an the deterministic models suggest a 
couple of days temperatures are expected to be near or above 


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1134 AM CST Mon Dec 9 2019

LIFR conditions will continue as band of snow along cold front
continues to impact the area. In addition expecting northwest
winds to increase significantly as peak cold air advection kicks 
in this evening. Snow will be relatively short lived so conditions
should gradually improve to IFR and possibly MVFR later this 
evening, but eventually some drier air in highly subsident flow 
takes over and clear things out. VFR will return overnight, but 
ceilings could come back in later Tuesday as cold air advection 


WI...Winter Weather Advisory until 6 PM CST this evening for WIZ017- 




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