730 
fxus63 kmpx 172337 
afdmpx 


Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota 
637 PM CDT Wednesday Mar 17 2010 


Discussion... 
surface high pressure over the County Warning Area this afternoon. Leftover low level 
moisture was deep enough to generate/lift to some cumulus 
under/near the ridge. This will gradually dissipate by sunset over 
the area with perhaps a few middle level clouds later tonight over 
the west. Middle level clouds will increase over the region 
Thursday...perhaps giving way to a bit of middle level echo or 
sprinkle possible late Thursday afternoon. Weak cold front/surface trough 
move south over the area Thursday with the middle clouds. Should see 
decent mix develop...especially east Thursday afternoon...and we 
should warm to the lower 60s once again over the eastern County Warning Area. 


Weak forcing/lift into the southern portion of the County Warning Area Thursday 
night...continuing the light rain/sprinkle threat. Upper trough 
moves across the area Friday into Friday evening...and all models 
now converging on system affecting mainly SC Minnesota during the period. 
Will mention slight chance southern metropolitan to move to collaboration with 
surrounding area. Will hold onto high probability of precipitation over far south. Again 
thickness and 925mb temperatures suggest rain to snow scenario 
where precipitation does occur. 


This system exits the area Friday night with weak ridging 
developing for Saturday. Should see sunshine...but initial cold air 
shot drops over the region with high temperatures remaining in the 
30s. Next stronger wave drops southeast Saturday night/Sunday with 
gusty northwest winds and perhaps a few snow showers over wc 
Wisconsin with the frontal passage. 


Longer term...upper flow is progressive and warmer air tries to 
lift north and east over the region later Tuesday and Wednesday. 
12z GFS and European model (ecmwf) not in very good agreement with system 
development. Will hold onto low probability of precipitation Tuesday and follow HPC with 
chance probability of precipitation for Wednesday. Temperatures on a warm up during 
this...so there will likely be a period of at least a rain snow 
mix...most likely Tuesday. 


&& 


Aviation.../00z taf issuance/ 


A Pacific high pressure ridge extends from the Southern Plains 
northeast through Minnesota early this evening. Southerly winds to 
prevail tonight and at a pace to extinguish any returning fog 
threat. There will be some stratus across south central Minnesota this 
evening but that should advect east southeast away from the area. A 
warm front aloft will move over the area tonight...bringing with 
it 30-40 knots west-southwest winds between 1500 and 3000 feet. At this time have 
not mentioned low level wind shear given that the speed increase 
in height should be gradual as opposed to abrupt. With the 
passage of a surface trough...the surface winds will turn westerly 
Thursday morning at Minnesota taf sites and by afternoon in WI. These 
will increase in speed due to deep projected mixing. Even higher 
speeds may be realized at kaxn...kstc...and krwf depending on if 
more sun is realized. High and middle level clouds are all that is 
expected for the area taf sites through the period. 


Kmsp...winds will back by middle-evening and decrease slightly before 
holding steady in speed. These are expected to reach 230 degrees 
and last through daybreak before quickly turning around to the 
west northwest. 


&& 


Mpx watches/warnings/advisories... 
Minnesota...none. 
WI...none. 
&& 


$$ 


Dwe/mtf