914 
fxus63 kfsd 211534 
afdfsd 


Area forecast discussion for southeast South Dakota/southwest Minnesota/northwest Iowa 
National Weather Service Sioux Falls South Dakota 
1030 am CDT sun Mar 21 2010 


Discussion... 


Quiet morning across the area with high pressure in control. 
Forecast on track with only very minor edits for real time trends. 
New pfm out. /Jm 


&& 


Aviation... 


VFR conditions through tonight. 


&& 


Previous discussion... 


Ridge of clear...dry and cool high pressure moving southeastward through County Warning Area this 
morning...flwd by increasing south-southwesterly flow of gradually warmer air this afternoon 
through Monday. Warmer air aloft should translate to surface fairly well in 
western County Warning Area this afternoon...and most of County Warning Area for Monday...and went on warm side 
of guidance. NAM guidance way too cold for highs today and Monday with no snow 
cover and late March sun. Southeastern County Warning Area looks to be the least mixed out 
on backside of Cool Ridge...so was not quite as optimistic there. 
Clear skies today with increasing high clouds from northwest to southeast over County Warning Area through 
Monday. Should get windy on Monday especially southeastern two thirds County Warning Area with strong south-southwesterly 
winds of 30 kts plus...mixing down to surface by afternoon...ushering in the 
warmer air. For Monday night...approaching northern stream trough and height 
falls bring some middle level saturation eastward into the County Warning Area. Still mild dry 
air in the lower levels...but put in a slight chance -shra as less chance of 
evaporation to the ground at night. Wave seems to pass by Tuesday morning 
as cold front moves southeastward through area...and knocked back highs some more. 
Did leave in isolated -shra for Tuesday with continued cold advection and 
passage of upper trough...but middle levels really drying out behind fnt. 
Did add isolated -shra to southern County Warning Area Tuesday night as boundary sags south and 
another middle level wave seems to approach area from Central Plains. Raised 
highs some both Wednesday and Thursday as air mass behind fnt modifies with 
less clouds. However...new cold front moves southward into northern County Warning Area Thursday dropping 
the temperatures there. All models show a decent upper trough moving over area 
by Sat implying a decent chance of rain changing to snow. But since this is 
the 6 to 7 day forecast and models can change...will obviously leave for 
dayshift to think about. /Ryrholm 


&& 




Fsd watches/warnings/advisories... 


South Dakota...none. 
Minnesota...none. 
Iowa...none. 
NE...none. 


&& 


$$