Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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532 FXUS63 KGRB 092110 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 310 PM CST Sat Nov 9 2024 Forecast discussion for routine afternoon forecast issuance .KEY MESSAGES... - Widespread light rain likely (70% to 90% chance) this evening into Sunday, with another round of rain likely (50% to 70% chance) Wednesday. - Above-normal temperatures continue into at least next weekend. && .DISCUSSION... Issued at 310 PM CST Sat Nov 9 2024 Short Term...Tonight and Sunday Main focus from this forecast period revolves around precip trends associated with a low pressure system expected to track across the Central Plains to WI through Sunday evening. This afternoon`s water vapor imagery showed the vertically stacked low pressure system over NE, while southerly flow ahead of the system was lifting moisture across the Midwest. Meanwhile, regional radar imagery showed a broken area of rain lifting across southeastern MN, southwestern WI, and eastern IA. These broken/scattered rain showers are expected to gradually lift into the forecast area from southwest to northeast this evening and overnight. A break in the showers is possible Sunday morning as mid-level dry air filters into the area ahead of the low. However, enough low- level moisture will stick around to keep drizzle or mist ongoing before the low pressure system arrives from the west early Sunday afternoon. Rain showers are expected to accompany the low as it tracks east across the state during the afternoon and evening. The rain will end with the departure of the low Sunday evening. Cannot rule out the low chance (up to 20%) for thunderstorms to occur during the afternoon in central and east-central WI, as models indicate mid-level lapse rates around 7C/km and weak elevated instability (MUCAPE up to 200 J/kg). Long Term...Sunday Night Through Saturday Any lingering rain showers will end across northern/eastern WI Sunday evening as the upper low/trough exits the region. A cold front will cross the area on Monday, turning the flow to the northwest. As temps cool, delta Ts will climb into the mid teens, with favorable NW/NNW trajectories for a short time, creating the chance for a few lake effect rain showers, mainly Monday morning. A few flakes may mix in as the boundary layer cools, but no accumulation is expected. Soundings support some drizzle at times as well Sunday night into early Monday. The colder, cyclonic flow will also help keep plenty of clouds in the area Sunday night into Monday, with drier air slowly for clearing skies later Monday into Monday night, especially in/toward central WI. A period of gusty northwest winds is expected behind the front on Monday, gusting to 35 mph. Surface high pressure and mid- upper level ridging builds into the region Tuesday, bringing dry and quiet conditions. A quick moving trough will swing through the Great Lakes on Wednesday, bringing the next round of showers. Limited moisture and the quick nature of the system will limit rain amounts to under a quarter inch. Dry conditions return Thursday and Friday as high pressure builds in. Temperatures will run a little above normal for most of the period, with only a brief shot of colder air behind the front Monday night. && .AVIATION...for 18Z TAF Issuance Issued at 1154 AM CST Sat Nov 9 2024 Besides some SCT/BKN clouds moving inland to the east-central WI TAF sites late this morning, high clouds and VFR conditions prevailed across the region. The system associated with the high clouds will gradually track into WI by Sunday afternoon. As it approaches, anticipate MVFR/IFR cigs/vsbys with periods of rain showers tonight into Sunday. The lowest ceilings are expected to be at the central and north-central WI TAF sites. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kruk/Bersch AVIATION.......Kruk