Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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005 FXUS63 KGRB 081807 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 107 PM CDT Wed May 8 2024 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - An unsettled weather pattern will bring intermittent chances of light rain from today through the weekend. There is a slight chance of thunderstorms over central and north-central Wisconsin this afternoon, but severe weather is not expected. - Low temperatures in the lower to middle 30s will be conducive for a frost and freeze over north-central and far northeast Wisconsin on Thursday night. && .DISCUSSION... Issued at 338 AM CDT Wed May 8 2024 Short Term...Today...Tonight...and Thursday Precipitation trends and temperatures will be the main forecast concerns during the short-term period. An upper level low pressure system and mid-level frontogenetic forcing will gradually shift out of far N/NE WI early this morning, resulting in a gradual decrease in the rain band that lingers there. Patchy dense fog in north central WI should mix out by mid-morning, and a Special Weather Statement has been issued through the commute period. After a short dry period through midday, a few showers and isolated thunderstorms may redevelop over the southwest half of the forecast area, where an inverted surface trough and weak instability (SBCAPE 100-400 j/kg) will reside in the afternoon and early evening. Most of the shower activity should wane after sunset, though isolated showers may linger over the far southern part of the forecast area overnight. Models have trended farther south with the next round of precipitation on Thursday, so have lowered pops to slight chance/chance and shifted precipitation chances a bit farther south. It`s possible that further southward adjustments may be needed, due to dry NE winds. Persistent clouds over northern WI should hold temperatures in the lower to middle 60s over northern WI today, while partly cloudy skies and sunshine boosts highs into the lower to middle 70s farther south. Lows tonight should be in the upper 30s far north to the 40s elsewhere. Mostly cloudy skies and brisk NE winds (especially in the Fox Valley and lakeshore areas) will bring cooler highs in the 50s to around 60 range on Thursday. Long Term...Thursday Night Through Tuesday Weather impacts in this part of the forecast mainly revolve around frost potential and light precip chances. Frost Potential: Clouds will be departing Thursday evening from north to south. As the surface ridge axis arrives overnight, nearly ideal radiational cooling conditions will be in place over central to north-central Wisconsin. Forecast low temperatures remain in the lower to middle 30s over the sandy soil areas of north-central to far northeast WI. These temps will be favorable for frost development. Anyone with cold sensitive plants are advised to take proper precautions. A similar setup could be in store on Saturday night as well, as a weak surface ridge axis is forecast to move into the region late. Forecast temps are few degrees warmer than on Thursday night, but MOS guidance indicates temps in the middle 30s are possible. Light precip chances: A quick hitting clipper system remains on track to bring rainfall to the region on Friday afternoon into Saturday morning. Decent dynamics combined with weak instability up to 100 j/kg could lead to isolated storms and will leave a slight chance of thunder in the forecast. A tenth to a quarter inch of precip appears possible for most locations. Another quick hitting system could generate light rain on Sunday afternoon and evening, but dynamics are not nearly as robust as on Friday night. Precip chances will therefore be lower. && .AVIATION...for 18Z TAF Issuance Issued at 107 PM CDT Wed May 8 2024 VFR flight conditions should dominate the area today, but a few patches of high end MVFR fair weather clouds will be in the area during the afternoon. A few of these clouds could produce brief light rain near the Upper Peninsula border but aren`t expected to have much of an impact over the TAF sites. Tonight, showers lift northwards into southern Wisconsin, but the general trend has kept this rain out of the central to north- central TAF sites as well. This could however, bring some lower cloud cover back to the region by the late morning Thursday, with MVFR ceilings over much of the region. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kieckbusch/MPC AVIATION.......Uhlmann