UPDATE MONDAY 12/18 1:30PM -
Small southward shift in model simulations over the last 24 hours. Big differences between forecast models, both long range and initial short range models. The general consensus is to track a low pressure system across northeast Illinois (Chicago) with snow across central, lesser snow and light mixed precip and/or rain for the southern third of Wisconsin. Slightly weaker today. The Canadian is an interesting wrinkle and an outlier. Obviously the forecast for late this week is highly prone to change. This is still a good starting point. There will be more to talk about tomorrow once we build some consistency. Here is a way-too-early snow accumulation estimate to think about:
POSTED SUNDAY 12/17 1:30PM -
Thru the first few weeks of winter Wisconsin has been lucky to avoid the statewide snowstorm we are known for. That could easily change by the end of this week (Dec 18-24).
It's Too Early
Forecast models have been consistent in bringing a moderate or greater impact snowstorm to Wisconsin during the Thursday(12/21) - Friday(12/22) period. Honestly there hasn't been a run in awhile that didn't bring the storm to Wisconsin. The exact location, track, strength, timing and precipitation types continue to change significantly run to run, therefore it is too early to do or say much else. We will keep an eye on it and updated you during the week. For the latest information keep it here at WISCONSINWX.COM.
TOO EARLY GUESTIMATES? - 8-12" for central and/or northern. Snow, freezing rain, mix, or rain for southern Wisconsin. The 12Z 12/17 GFS run was pretty solid. Could turn out much differently.
Temperaturs will be near or slightly above average this week. High temperatures at or above freezing will go to work on existing snow cover. Following the system for late next week, an arctic airmass will uncork for Christmas.
Much colder, perhaps subzero high temperatures for those with a fresh snow cover at some point between Sunday and Tuesday. This is pretty common following a snowstorm in late December.