Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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176 FXUS63 KGRB 100352 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1052 PM CDT Thu May 9 2024 Updated aviation portion for 06Z TAF issuance .KEY MESSAGES... - A frost or freeze is likely across far northern Wisconsin late tonight. - An unsettled weather pattern will bring intermittent chances of showers and a few thunderstorms through the weekend. Severe weather is not expected with any of these thunderstorms, but we will be watching for the potential for strong storms on Sunday. - Due to the recent rainfall, river levels remain elevated. Some rivers may reach or surpass bankfull. && .DISCUSSION... Issued at 259 PM CDT Thu May 9 2024 Short Term...Tonight and Friday Sprinkles will end and skies will clear as an upper trough exits the region this evening. Low level convergence across central Wisconsin may keep skies from clearing until 09z, which may diminish their frost potential. Decided to issue a freeze warning for Vilas, Oneida, Forest and Florence counties, and a frost advisory for one row of counties to the south. Sunny skies are expected Friday morning, but clouds will increase in the afternoon as an upper trough and surface front approach from the northwest. Showers should arrive in central and north central Wisconsin by late afternoon, and in the evening further east. The upper trough looks quite dynamic, but there is little warm advection or moisture advection ahead of it. Instability should be sufficient for scattered thunderstorms but the severe threat looks low. Highs temperatures will be in the early afternoon near Lake Michigan where a lake breeze will move inland, and across far northcentral WIsconsin where clouds and rain are expected. Long Term...Friday Night Through Thursday Intermittent active weather continues in the extended period. A surge of warmer air will bring the first chance to see the 80s this year. Active weather... Rain will likely be ongoing Friday night as a shortwave works its way across the region. Minor instability, around 100 to 350 J/kg of CAPE, could allow for a few rumbles of thunder early on, but any remaining thunder chances will end fairly quickly overnight. Rain amounts around a tenth to a quarter of precip remain reasonable for this system. Quiet conditions then return by the late overnight hours through Saturday afternoon. Diurnal heating and a passing secondary shortwave will bring the next chance for some rain Saturday afternoon. Instability will be mainly surface based as temperatures get into the middle to upper 60s and low level lapse rates increase, but with little to no instability aloft to work with thunder seems unlikely. In the end, expect an increase in cloud cover with a few isolated to scattered light showers that dissipate as we get past sunset. Sunday will also see a chance for active weather in the afternoon. Southwesterly accompanying a warm front early in the day will bring a surge of warmth and moisture to the region, in particular to the lower levels. That said, mixed layer instability will remain more modest, which will help limit storm strength and shear values will be relatively low, so organized storms seem unlikely. In short, severe weather threat still appears relatively low. However, this environment could produce a few pulse like storms, which would carry the potential for some stronger wind gusts when a storm rains itself out. Scattered rain and storm activity then continues into the evening to early overnight hours. Finally, the next more widespread system will cross into the region sometime in the middle of next week. Temperatures... Temperatures will be warmest on Sunday, thanks to some potentially strong southwesterly flow. This will bring highs in the 70s and could also bring a few to around 80, which would be the first time seeing 80 degrees in northeast Wisconsin so far this spring. Somewhat cooler conditions then follow for the rest of the week, with highs in the upper 60s to lower 70s for the rest of the period. && .AVIATION...for 06Z TAF Issuance Issued at 1052 PM CDT Thu May 9 2024 VFR conditions are expected through at least Friday. Clouds will continue to clear from north to south overnight, with clouds remaining longest over central Wisconsin. A cold front will sweep in from the west, bringing showers to central and north- central Wisconsin Friday afternoon, and to northeast and east- central Wisconsin Friday evening. Conditions could drop to MVFR at times with these showers on Friday afternoon and evening. && .GRB WATCHES/WARNINGS/ADVISORIES... Freeze Warning until 7 AM CDT Friday for WIZ005-010>012. Frost Advisory until 7 AM CDT Friday for WIZ013-018-019-021. && $$ DISCUSSION.....RDM/Uhlmann AVIATION.......Kurimski