Thursday, December 30, 2010

Forecast for Western/Northwestern WI.

Lots to talk about with the weather in the very near term and middle term which will take us from the rest of today through the weekend… We will talk about rain, freezing rain, sleet, snow…Cold temps….Most of the areas now reporting rain we did have some sleet mixed in from time to time here at the office, however it’s back to all rain once again.


Temps throughout the FA are in the middle 30s with some upper 30s in my Southern areas, along with Ashland….. Light rain is also reported at this hr… Winds are from the South/Southeast from 5 to 15 MPH with a few gusts up to 20 MPH… Still some fog showing up in the SFC OBS..


First off we shall talk about the first storm system.

Using the RUC model we find the first storm system centered over Northwest IA as of 18z…The low pressure is right around the 988 MBS of pressure.. The WV satellite also confirms this rather well…This low is forecasted by the RUC to move into South Central MN by tonight then far Northwestern WI tomorrow morning as it does it will weaken down to around 995 MBS…

Looking at the NAM 12z run…. It has the system centered over KS which does not line up at with the WV satellite imagery….NAM does take the low pressure system into South Central MN then into through Northwestern WI then to the UP of MI as it does it weakens the low to 1000 MBS..

The 12z GFS is in agreement with RUC/NAM models…The 12z ECWMF shows about the same path of said storm.. A tad East though… Still won’t really make that much difference in our weather…..Colder air does work into this system on Friday…. So for today will run with most rain, however there could be areas of mixed precip from time to time….Highs shall remain right where they are middle to upper 30s for the rest of today….There still will be areas of fog from time to time also…. Tonight temps drop into the upper 20s/lower 30s…. Steady rain will becoming to an end at 10 pm or so… We will see freezing drizzle after that throughout the night time, which could lead to some slick spots….

Now lets talk about system number two, much stronger and it has colder air to work with….Looking at the 12z run off the GFS we find a 986 MB low pressure taken shape over Southern CO GFS moves this system do East into the TX panhandle area by later tonight or earlier tomorrow morning..Later in the day GFS tracks this low into Northwest MO, then into Southeastern MN be Friday night/early Saturday morning…Then throughout the day GFS keep said low right on the MN/WI border as it moves to Duluth NM, Then over Western Lake Superior…. The low does deepen to around 994 MBS of pressure as it tracks through far Eastern MN.Far Western WI…GFS shifted the track more Westwards then from it’s 00z run…

Lets look at the 12z run off the ECWMF model…

This model tracks the storm a little more East then GFS has the system a little weaker 998 MBS by time it moves into the UP of MI..There was a shift more East with the track of the storm from the 00z run….

Looking at the 12z NAM it shows about the same as GFS, but much weaker low pressure and colder air throughout the FA….

So as one can see the models still do agree on the second storm system just yet….We will run with more of a wintery mix from Friday afternoon into early Friday evening, then switch whatever moisture that is left into all snow… There still is some concerns about a dry slot pushing into the FA if this does play out we may not see much of anything until we get some wrap around moisture later Friday night into Saturday morning… Then is will be just light snow/flurries….

Friday is looking like this strong cold front pushes into and just to the east of the area so temps from Thursday’s night lows will start to fall by mid morning to around the noon hr.. So we should start the day with some light rain then changing over to freezing rain and sleet before changing over to all snow by Friday night….Friday night temps drop like a rock into the single digits above zero…. Winds will pick up to 10 to 20 MPH with gusts reaching up to around 25 MPH…

Will keep a slight chance of snow going throughout Saturday afternoon as wrap around moisture drops South into the area….. Saturday night is looking to see temps below zero… Right around -5 seems to work out…. Sunday we will be lucky to get to around 10 above…. Monday looks to be warmer with temps back in the lower 20s..Next small chance of snow comes in around the Monday time frame…..

For now we will let the snowfall map stand the way it is… If needed it will be changed tomorrow afternoon….


To start this time frame we still may have some light snow around into early Tuesday morning..Then we settle into a dry period Jan 12…Next storm system could start to effect the area Late Jan 12th through early Jan 13th time frame…This system will have enough cold air in place for an all snow event.. Temps through this time frame Should average out to be around normal to below normal…. Still not seeing any big Arctic dumps…..

The longer term forecast is way out in time so this subject to change…..