U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 100522 
Storm Prediction Center ac 100521 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1121 PM CST Mon Dec 09 2019 

Valid 101200z - 111200z 

..no severe thunderstorm areas forecast... 

severe thunderstorms are not expected Tuesday across the contiguous 
United States. 


Well-defined upper vort/low, centered just south of the 
international border west of elp, is forecast to deamplify and shift 
east across Texas during the day1 period. With large-scale high-level 
confluence expected to focus over the mid-south, surface cold front 
will be forced off the Gulf/southeast coasts as high pressure builds 
across lower latitudes. This flow regime should prevent true 
maritime tropical air mass from advancing inland ahead of the front 
and subsequent moisture/instability is expected to remain rather 
weak through the period. As a result, majority of convection will 
likely be somewhat elevated and likely Post frontal in nature. 
Additionally, thunderstorms should remain mostly isolated and the 
threat for severe is low given the weak buoyancy. 

.Darrow/squitieri.. 12/10/2019 


Mesoscale Discussion

acus11 kwns 091719 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 091718 

Mesoscale discussion 2191 
National Weather Service Storm Prediction Center Norman OK 
1118 am CST Mon Dec 09 2019 

Areas affected...northeast Iowa/southeast Minnesota into much of 

Concerning...heavy snow 

Valid 091718z - 092115z 

Summary...a quick onset of moderate to heavy snow is expected to 
persist for a few hours as it moves out of Iowa and Minnesota and 
into Wisconsin. 

Discussion...a band of snow coincident with a cold front and 
supported by deep frontogenetical lift is quickly progressing east 
across the upper Mississippi Valley, producing brief periods of 
heavy snow along with gusty winds. The heaviest part of the band 
currently stretches from far southeast Minnesota and northeast Iowa 
into west-central Wisconsin, and will likely maintain intensity for 
a few hours. With time, the band is likely to dissipate from south 
to north as the greatest ascent lifts north. 

.Jewell.. 12/09/2019 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 42619216 43389186 44109143 44889099 45599058 46178970 
46128914 45768817 44628798 44168822 43099012 42679086 
42399128 42289210 42619216