Saturday, November 20, 2010

Forecast for Western & Northwestern WI

Weather headlines… Main story is the cold air that pushed into the area yesterday afternoon…Skies did remain clear for longer, so a thought temps took a hit last night…. Temps here at the office bottomed out at a only 7°… Problem number two…. Is the wintery mix and freezing rain, then snow on Monday, then snow again for Wednesday and Thanksgiving day… Things have changed over the last few computer runs once again… Now where back to a possible winter storm…. As models have slower and now deeper system moving through…Will talk about that in awhile…. Last but will be talked about is the Arctic blast that is set to move in after the departing storm system….


At this 7 AM hour temps are ranging from the lower to middle teens, a few calls and texts to some of our weather observers also show a few temps in the upper single digits….Skies are partly to mostly cloudy… Winds for the most part are out of the North/Northwest….. Windchills range from a lonely 2 here at the office to 10 in EAU….


Looking at the SFC charts off the NAM we find a 1036 MB high pressure system that is centered over Southern Canada just North of Central ND….This high has allowed for skies to remain clear long last night as talked about above… Said high is forecasted to move along the border of the USA and Canada today, should be centered just North of Central Northern MN by midday…As it pushes off to the East WAA slowly begins to kick back in… Clouds should start to thicken up more as we fly through the day…. However don’t see any precip as dry air still holding strong through the day….. Profiles aloft still show warmer temps, however down at the SFC temps still remain rather cold until Sunday afternoon when SFC temps do climb into the middle 30s…. What does this mean to us here at the SFC? Well I will tell you…. We shall see a wintery mix later tonight changing over to all freezing rain by Sunday morning…. This should change over to plain old rain in the early afternoon hrs.. By Sunday night the profiles show cooling taken place aloft this will allow for the rain to change back over to a wintery mix before changing over to all snow, after the cold front pushes through.. Little or no ice and snow accumulation… Though some roads could be on the slick side……Monday we see a little stronger system forming on the Southern part of the cold front.. This 1004 MB low pressure is forecasted to move into WI… System should have enough cold air to play with at the mid to upper levels and down at the SFC for an all snow event… 1 to 2 inches of snow will be possible… However most of the heaver snowfall amount should be up in Douglas County, and into Northwestern Bayfield County… Here we could see 2 to maybe as much as 4 inches….Then we get a break in the action for Tuesday/Tuesday night

So the forecast for today… Clouds thicken up highs will remain cool middle 20s, North winds becoming Northeast around 5 to 10 MPH… Tonight… Cloudy with a wintery mix, lows should remain in the middle 20s,winds From the East becoming South/Southeast 10 to 15 MPH…. Sunday… Freezing rain in the morning, turning to rain in the afternoon.. Highs in the lower to middle 30s South winds around 3 to 6 MPH….. Sunday night….. Rain chaging over to a wintery mix, then changing over to all snow… Lows in the middle 20s…. Monday… Cloudy with snow 1 to 2 inches possible… Higher amounts up in my far Northwestern FAs…. Tuesday and Tuesday night dry highs in the lower 20s with lows in the lower teens.


This forecast cycle still remains to be a pain, as forecast models are now singing a new song the last few runs, unlike most of the week….. There is some problems showing up for Wednesday through Thursday, main problem is the placement of the storm system and how deep to run with it…. Timing is not as bad on the past two runs…..Lets break it all down since this is a high travel period…

Looking at old reliable ECMWF model…. Late Tuesday night we see a 1001 MB low pressure taking shape over Northwestern CO… This low is forecasted to move into Southwestern IA/Northwestern MO by late Wednesday evening…Low deepens to around 994 MBS… The low is then forecasted to push through Central WI up into the UP of MI by late Thursday night, still we see more deepen… Down to around 990 MBS…It does appear this system will have enough cold air in place at all levels to be an all snow event…..I won’t get carried away just yet on putting out a snowfall map, however if things do play out we could be looking at 6 to 10 inches of snow high higher amounts closer to Lake Superior…. Will put out a snowfall map either tomorrow or Monday….

Ok let look at the GFS model… This model does track the storm system more East and is much weaker with it…. Timing however seems to line up rather well with the ECMWF model….So for now am going to disregard GFS as it does not do so well this far out in time…. However we will shall if it comes on board with ECMWF over the next few runs….If GFS is right this would put the heavier snows well to the East and South of the area…. Like discussed in earlier forecast…… So as of right now confidence levels are still rather low……. One thing both models do agree on… Is an Arctic dump that is setting up for the middle to the end of next week…. Still feel we will see our lows drop well below zero, if we do get a deep snow pack the lows could fall as cold as the teens below…. Highs will barley climb out of the single digits…. This cold trend is forecasted to last right through the end of the forecast cycle….

Also, this possible winter storm looks to be a wind jammer on the model…. Gales could return to Lake Superior!