Tuesday, July 13, 2010

Forecast discussion for Western/Northwest WI

Main focus of this discussion will be on the severe weather outbreak that is looking us right in the face for Wednesday...


*** CURRENT CONDITIONS ***

Temps this morning are in the lower 60s with some upper 50s to found in my Northern FA... dewpoints in the middle to upper 50s... Winds from the East/Southeast ranging from calm to around 6 MPH...Skies for the most part are mostly sunny....

*** FORECAST DISCUSSION ***

SFC analysis shows a 1010 MB high pressure over Lake Superior this morning... Wind have backed to the East/Southeast through out the night between said high and a 993 MB low pressure system over Southeastern MT/Northeast WY.. The high pressure system is forecasted to move of into the OH valley, meanwhile the low pressure system will be working towards Northeast SD.... This will start the WAA into the area today along with moisture flowing back Northwards.... Tonight models are showing an MCS forming over ND into SD, along with parts of Western MN... There is no second guessing on the cloud cover that will blow off from the complex to make into the FA overnight... Don't think we will have to worry about any showers or storms during the overnight hrs, that should remain out over Western MN into maybe Central MN.... Wednesday... LLJ increases from the South/Southeast to 30to 40 KNTS.. Lapse rates do increase to around 7 C/KM.... Cape is forecasted to range from 2500 J/KG to 3000 J/KG... Looking at the 700 MB temps we do find temps increasing to around -10c.. So some cap does appear which will help hold the wannabe severe thunderstorms at bay.... Dewpoints soar into the upper 60 to lower to middle 70s... So deep level moisture shall be in place..... We also have very good wind shear setting up over the area... Cold front is forecasted to move towards the area showers and thunderstorms are forecasted to be ongoing over in MN.. This may die off before reforming as the frontal boundary pushes East... Thunderstorms should start to form over the FA after 1 PM or so... Some of these thunderstorms should have no problem becoming severe as we work through the afternoon and into the late evening hrs... See HWD above for info on this.... Temps today shall be right around 80s into the middle 80s for Wednesday.. Rest of the work week looks to be on the warm side with temps in the middle 80s to upper 80s... May be flirting with the 90 degree mark Friday and Saturday... Saturday night another system could be another round of showers and thunderstorms to the FA...This is forecasted to last into Sunday...