Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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706 FXUS63 KGRB 301803 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 103 PM CDT Thu May 30 2024 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - A Frost Advisory remains in effect through 9 AM for locations generally north of a Merrill to Antigo to Wausaukee line. - Due to recent rainfall, a few rivers will remain at bankfull but below minor flood stage through the weekend. - A more unsettled pattern is forecast to return this weekend through at least the middle of next week. Currently, Sunday night through Monday has the best chance for thunderstorms and heavier rainfall. && .DISCUSSION... Issued at 323 AM CDT Thu May 30 2024 Short Term...Today...Tonight...and Friday Arrival and extent of rain showers on Friday is the primary focus as high pressure dominates the weather today and tonight. Sharp ridging aloft is present from the central CONUS to Hudson Bay. Similar at the sfc as high pressure ridge stretches from northern Quebec across James Bay and into the western Great Lakes. Other than a few mid clouds over southwest WI, skies are clear to start the day over the region. Edge of high clouds ahead of cold front and some showers and thunderstorms over the Dakotas is drifting across Minnesota and Iowa. These clouds will be over Wisconsin tonight. In the meantime, it is a chilly start over northern WI where temperatures have fallen into the mid 30s and Frost Advisory is in effect until 9 AM this morning generally north of a Merrill to Antigo to Wausaukee line. Readings are in the 40s elsewhere. Moving forward today, other than some fair weather cumulus clouds later this morning into the afternoon, skies will be mostly sunny. Gradient east wind enhanced by lake breeze will keep the immediate Lake Michigan shore cooler in the lower 60s this afternoon, but readings just inland will reach the 71-74 range. Increasing mid and high clouds will keep readings tonight warmer over north- central WI. Portions of northeast to east-central WI that remain clear longer tonight could see readings drop to near 40 where winds go calm. Most locations will see lows tonight in the mid 40s. Friday will feature increasing and thickening mid clouds from west to east as upper trough over the northern Plains slowly smashes down the sharp upper ridge over our region today. Surface cold front over the northern Plains will shift across Minnesota through the day and reach western Wisconsin by Friday evening. Increasing theta-e advection ahead of the front will combine with weak instability to result in small chances of showers and maybe a rumble of thunder moving into especially central Wisconsin to north-central Wisconsin in the afternoon. That said, forecast soundings show a lot of dry air around in wake of the departing ridge and the forcing is hardly robust. Thus, think showers on Friday will be scattered at best and it is likely northeast and east-central WI likely remain dry through the day. Highs on Friday could reach the mid-upper 70s, but it will be cooler in the upper 60s/around 70 from Wausau to Eagle River due to thicker clouds and better chances of showers, and also near the immediate Lake Michigan shore with a southerly flow. Long Term...Friday Night Through Wednesday The dry stretch will come to an end for the extended period as active weather returns for the weekend and early next week. Friday night and Saturday... Upper ridging will slide into the eastern Great Lakes Friday evening, allowing the axis of warmer air and active weather to move into the region overnight through Saturday morning. Scattered on and off showers are expected to be in the region but any precipitation will likely remain light as the main moisture remains blocked off with a more southerly system. A rumble of thunder or two will also be possible by the afternoon, but overall the storm chance will be relatively small. Sunday into Monday... The next period to watch for a more widespread rainfall event will be Sunday and Monday. A strong shortwave will cross the Northern Plains Sunday, helping in the development of a surface low that will come towards the region sometime late Sunday through Monday. The timing and path of this system remain uncertain at this time. A more northerly track would likely keep our area out of the warm sector for Sunday, keeping the area dry; but a more southerly track would bring a round of showers and storms at least into central Wisconsin already late Sunday evening. In either case, the main event will likely be associated with the attendant cold front that should come through the region sometime Monday. Although its a bit early to assess severe potential, moisture will be plentiful with PWATs pushing up to around 1.4-1.6 inches so heavy rainfall will again be in the works. Depending on the track and timing of the initial precipitation, some of the mid-range models also bring some additional storm development Monday evening, which may support some stronger storms if we can get instability to increase across the region during this timeframe. Rest of the forecast... Finally, most long range models bring another fast moving shortwave into the region around the middle of next week, which would likely bring another round of showers and storms through the region. Temperatures... High temperatures will warm over the weekend with highs in the upper 70s to lower 80s by Sunday. From there, high temperatures will remain fairly steadily in the upper 70s to lower 80s through the middle of next week. && .AVIATION...for 18Z TAF Issuance Issued at 103 PM CDT Thu May 30 2024 Good flying conditions are expected at all TAF sites through early Friday morning. However, some models are showing signs of LLWS developing in north-central WI overnight. But confidence is not high enough at this time to include this at the RHI TAF site. Conditions will begin to change in north-central WI at the end of this TAF period with the arrival of light showers and possibly a rumble of thunder. Anticipate the showers and possible rumbles of thunder to pair with brief MVFR conditions around midday Friday in north-central WI. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....JLA/Uhlmann AVIATION.......Kruk