Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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482 FXUS63 KGRB 250316 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1016 PM CDT Fri May 24 2024 Updated aviation portion for 06Z TAF issuance .KEY MESSAGES... - Occasional showers and thunderstorms are expected into the evening hours. Brief gusty winds and heavy downpours are expected. - Memorial Day weekend starts off dry for Saturday, but rain chances increase by Sunday afternoon and continue into Memorial Day. A soaking rain could occur during this time. - A few rivers over central and eastern Wisconsin could surpass minor flood stage early next week. && .DISCUSSION... Issued at 319 PM CDT Fri May 24 2024 Short Term...Tonight and Saturday A negatively tilted upper trough and attendant surface front will produce a broken line of thunderstorms as it moves across the area into the evening hours. Showers and thunderstorms that moved across the region earlier today and cloud cover have kept the lower atmosphere stable through mid afternoon, but increasing moisture convergence and and warm advection ahead of the front should create enough instability to get things going by 22z or 23z. Strong winds and hail are the main threats from this system. The activity will end by late evening, and cLearing skies and drier air will arrive overnight. Low temperatures should be a few degrees below normal. Saturday should be mostly sunny and a bit breezy with seasonable temperatures. There could be a stray shower in far northcentral Wisconsin. Long Term...Saturday Night Through Friday A 500mb trough will swing into the area late Saturday night into Sunday morning, then move across the western Great Lakes Sunday into Memorial Day. Beyond Memorial Day, ridging is expected across the plains which will result in the western Great Lakes being in a north/northwest flow pattern. The ridge should then shift east into the western Great Lakes by Friday of next week. Temperatures through the middle of next week will run at or slightly below normal, then would likely trend warmer than normal late next week. For Saturday night, a weak surface boundary will be lurking across the far north. Per coordination with Marquette and Duluth, will have a small chance of showers and thunderstorms across the far north for a few hours into the evening. Dry conditions will prevail overnight. The next system approaches from the south Sunday morning. By noon, there will be chances of rain across much of the area west of an Eagle River to Algoma line, with a widespread rain event expected Sunday afternoon and evening. There are some difference in the track of the low that could impact rainfall amounts and also the possibility of some stronger storms across eastern Wisconsin. Rainfall totals over an inch are possible across much of the area Sunday afternoon and Sunday night. This will cause rivers to rise again with several reaching bankfull stage and at least a few rivers could reach flood stage early next week. On Memorial Day, the northwest flow pattern will result in more convection developing during the day with a cool air aloft. Some of these storms could produce gusty winds and possibly some small hail. Confidence is not high enough to add to the Hazardous Weather Outlook. The cool cyclonic flow combined with daytime heating may trigger some more showers and perhaps a few storms on Tuesday. Dry conditions are expected Wednesday and Thursday with the next chance of rain on Friday. Frost may be possible across the north Thursday morning as the latest guidance would suggest lows in the middle to upper 30s. && .AVIATION...for 06Z TAF Issuance Issued at 1005 PM CDT Fri May 24 2024 Showers were tapering off over eastern WI, and scattered showers were noted along a cold front in NC WI. The threat of storms should be about over by issuance time, so won`t carry any mention in the TAFs. MVFR/IFR ceilings will improve from west to east as the cold front shifts through late this evening into the early overnight hours, followed by clearing skies (except over far NC WI). Winds will become gusty from the west after the frontal passage, then turn S-SW in the mid to late afternoon on Saturday. A period of LLWS is expected to impact the northwest half of the forecast area overnight into early Saturday morning, and also possibly for a brief period in NC WI Saturday evening. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....RDM/Eckberg AVIATION.......Kieckbusch