12:25PM WEDS - Multi-facet system coming in for Thursday.
Latest models continue to trend slowly north/warmer. What looked like a winter storm for northern WI has been reduced to a rain/snow mix - for now. The potential for accumulating snow still there in the north, however rain is expected for most of Wisconsin, and perhaps a thunderstorm south. It doesn't appear that anything significant is in store for Wisconsin however certainly an impactful weather producer for the state.
SNOW - Latest models continue to weaken the snow threat. They are warmer increasing the rain potential across Wisconsin. It seems the cold front will be delayed into Friday. The trend has been for lowered amounts. GFS/EC/NAM keep the heaviest amounts in the snow belt of western Upper Michigan/far N WI so I constrained the higher 5-8" zone there. Will take the risk of locally higher amounts. Felt the NAM was a bit of an outlier at this stage but I'm not willing to rule it out yet. 00EC is was the snowiest...not too confident in it as more recent GFS/NAM runs have been weaker. Best chance for snow on the back end of the system.
RAINFALL - I've kept the 0.5-1.0" zone, shifted it a little north. Potential there for an inch or more in some areas but I'm not confident in the exact location of the heaviest amounts so I broad-brushed the state. Most of the rain will come during the morning hours with the main surge. The afternoon rainfall will be decided by t-storm activity in the south. In a holding pattern regarding the rainfall forecast.
T-STORMS - I included more of southern WI in the strong storm zone but I'm not too concerned at the moment. Models in the worst case scenario suggest that a couple elevated hailers could develop along the elevated warm front across far southern WI. We need to monitor the surface warm front location and whether it sneaks further north with moisture near to the boundary. Still think Iowa is most at risk on Thursday afternoon/evening. NAM might be too far north...typically is. We'll see!
I've updated the maps to reflect latest thoughts.
Thursday will not be windy. Friday will be the windy day so I will separate that out.
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1:48PM TUES - warmer today across all models but not necessarily more intense. Watching southern WI for threat of strong thunderstorms Thursday afternoon/evening(t-storm activity possible during the AM) Wind shear profiles looks pretty strong but worry moisture and thermodynamics might be lacking. In the wash it might just come out to be a strong t-storm or two across northeast IA? Will be watching closely!
10:26PM MON - 18GFS just a touch warmer but not enough to make changes tonight. Next update late AM Tuesday.
8:30AM MON - Watching the evolution of this system on last several runs. Seems to be steering away from a major storm event in favor of a moderate impact/progressive system. Little janky/disorganized at times. The storm looks somewhat mature/even occluded at it's peak over Wisconsin which tends to lead to a narrowing of the main precip band and dry air pockets/issues. Still this system could have a decent impact with several inches of snow north. Rain. Maybe some t-storms south? I'm going to stay away from strong verbiage even if it's bringing late season snow to portions of the state. Confidence is normal today.
06GFS is the furthest north (like usual). GFS ensembles put the heaviest through northern Wisconsin. The last few runs of the EC were slightly colder but. I guess the difference relates to the overall strength of the system where GFS tends to be stronger at this forecast hour thus taking further north. If you compare the EC to the GFS ensembles...not too much difference on the big picture with snow north. The NAM at 84hrs looks similar to the GFS. Regarding amounts... this looks like a 4-9" event for northern WI if models hold. I won't rule out higher amounts somewhere but not drawing attention to that. Will need to better constrain those snow amounts zones later.
RAIN/T-STORMS? - The EC is most aggressive with a thick beefy rain band sliding through southern WI. GFS/CAN not so much which introduces some doubt. There is likely to be dry air narrowing the main W->E precip band through WI and infiltrating the band itself in spots. Still I've gone with a 0.5-1.0" zone to factor in convective precipitation. Perhaps as we get closer I can get more specific. As for thunder...yea, maybe a few embedded rumbles in the far south Thursday afternoon! Not expecting severe weather in Wisconsin right now but it could be a close call. GFS does show a weak pocket of instability slipping through that should be monitored. If models trend warmer then southern WI will need to be reevaluated for severe threat. I've highly the first t-storm zone of the year (see maps). Possibly the first storm chase the season.
In conclusion; trying to approach this carefully. I don't think the verbiage needs to be very strong yet. Will keep an eye on it.
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1:20AM SAT 3/14 - Eyeing up this timeframe for a long time. Models bring a strong low through. Looks to be in fairly significant occlusion/mature phase by the time it arrives which will likely mean dry air issues. Reminds me of Mar 13, 1990 event. Not sure what that event brought for rain or snow but I know it was a severe wx outbreak to the SW of WI. Similarites.
Will attempt an update this weekend. My youngest is sick now joining my oldest and I threw my back out earlier tonight. Fun times!
-JP