Thursday, December 2, 2010

The forecast for Western/Northwestern WI.

Forecast concerns…. Last night was our coldest night of the session, temps dropped in the lows single digits to below zero…Here at the office we recorded a low of -2° meanwhile Siren came in with -1° so far those have been the coldest readings I have seen in the SFC OBS……Next on the list is the significant snowfall possible for my far Southern two Counties…The a shot of more Arctic air on its way… So lets get right into this all of this….

Not really much time for current conditions ATTM...


Looking at the SFC charts this morning we find a short-wave centered over Northwest IA/Northeastern NE… This has been the cause for some light snow/flurries out over Southwestern MN…. This feature is forecasted to fill/washout…. Also we find a rather large ridge of High pressure 1028 MBS centered just North of Central ND…. Meantime we find forming low pressure over South Central Alberta Canada…. This will turn into our next system of interest… More on that if a few….Looking at the upper levels we still find a rather large trough of low pressure digging into the eastern part of the CONUS… Keeping my FA under Northwesterly flow….This is forecasted to slowly work East/Northeast… NAM and ECWMF in rather good agreement on the weather features…. GFS does seem a little on the fast side with the clipper system….So for now will leave GFS out in the back 40….. Today high pressure builds into the area this will allow for a partly cloudy day ,there still will be slight chance at some flurries as we are still close enough to the 500 MB low pressure…. Satellite does show more clouds lurking to our North/Northwest see no reason why that won’t drift in from time to time… Temps today should only hit the upper teens throughout a good chunk of the FA… Some lower 20s will be possible over my Southern Counties… Tonight 1028 MB high pressure is forecasted to be centered over Western MN this will allow skies to once again clear off… Winds will become calm this should allow for another cold night with temps falling back into the single digits to below zero once again…Looking at the RH charts we should see clouds start to increase tomorrow morning as the system starts it trek to the Southeast…. So time to talk about this clipper……For the most part NAM and ECWMF are in rather good agreement… Still the placement of snow is still a little in the air yet… GFS would have the heavier snows more South then ECWMF, NAM would place the whole FA in the heavier snows…. So have decide to blend all three models as I like parts of each one…. So the low pressure is forecasted to move Southeast into Northeast WY then track to about East Central NE then over to down to Northeast MO.. This would put my far Southern Counties is area to pick up 6 to 8 inches of snow, while the rest of the FA will see from 1 to 6 inches of snow…. See our snowfall map below…. Behind this system the Arctic flood gates open up as Northwesterly winds funnel down more cold air… Temps should be below norms throughout much of next week… Should also remain dry…. More on the long range forecast after we are done dealing with this system……