Weather

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fxus63 kunr 060910 
afdunr 


Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota 
310 am MDT Monday Oct 6 2008 


Discussion...water vapor imagery shows the broad upper trough 
continuing to push eastward this morning with subsidence approaching 
along the backside. Radar shows a cluster of showers across 
northeast Wyoming heading into the Black Hills...and a separate band 
moving through south central. Northwest flow will continue across 
the area today as high pressure builds from the west. The showers 
across the area this morning will decrease through the afternoon as 
drier air quickly moves in...and be completely gone by evening. 
There was some concern with advisory criteria winds this 
afternoon...particularly across the northwest South Dakota plains. However the 
latest model runs have been trending weaker with winds at 20 to 30 
miles per hour. K2wx may reach minimal advisory criteria for a couple 
hours...but dont think its Worth any headlines. 


Drier weather will return to the area Tuesday with mostly sunny 
skies and temperatures back to near to slightly above seasonable 
values. The next cold front will cross the area Wednesday bringing 
cooler temperatures across northeast Wyoming/northwest South Dakota. It doesnt look like 
there will be enough moisture present for any precipitation to develop with 
this front. A deepening trough will approach from the west Wednesday 
night with low pressure developing somewhere near or just south of 
the County Warning Area. This will bring southerly flow across the now-stalled 
frontal boundary resulting in some isentropic lift/overrunning. Have 
introduced probability of precipitation for the northern half of the County Warning Area...though confidence 
in this specific area remains low at this time depending on where 
the low sets up. Precipitation will continue into the extended. 


Extended...GFS/ECMWF continue to show precipitation somewhere across 
the forecast area on Thursday and Friday but differ in the location 
due to model differences in the low track. 06z European model (ecmwf) has come more 
into line with previous GFS runs so have more closely followed the 
GFS idea with highest probability of precipitation over northeastern Wyoming and 
northwestern South Dakota on Thursday...then have generally broad 
brushed the probability of precipitation until models come into better and more consistent 
agreement through the rest of the extended forecast period. It still 
looks cold enough for the first snow of the season at some locations. 


&& 


Aviation...VFR conditions will continue today and tonight. A few 
showers are expected today...mainly this morning. 


&& 


Unr watches/warnings/advisories... 
South Dakota...none. 
Wyoming...none. 


&& 


$$ 


Calderon/Richards