


Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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199 FXUS63 KGRB 091918 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 218 PM CDT Wed Jul 9 2025 Forecast discussion for routine afternoon forecast issuance .KEY MESSAGES... - Next chances for widespread active weather from Thursday through Saturday. Heavy rainfall and a few strong storms will be possible on Friday. - Another round of active weather is possible during the middle of next week. && .DISCUSSION... Issued at 214 PM CDT Wed Jul 9 2025 Tonight into Thursday...Conditions to remain dry through the first half of Thursday. This afternoon`s clouds stuck around longer than previously forecast, but should gradually decrease into the evening as the sun sets. Mostly clear skies and light winds are expected overnight, which may lead to patchy fog development in some spots by early Thursday morning. Any fog would burn off soon after sunrise. End of Week Precip...Models continue to indicate the next opportunities for precipitation occurring between Thursday and Saturday as a couple of mid-level shortwaves move through the area. The first of the shortwaves looks to track over the area on Thursday. The associated moisture axis will likely struggle to make eastward progress due to dry air sitting over the eastern half of the state. But, portions of central and north-central WI could still see some afternoon/early evening showers and non-severe storms. A few showers and storms may linger overnight Thursday in central and east-central WI, but the loss of daytime heating and the weakening of the shortwave will limit the coverage. The next mid-level shortwave will begin to move into the area Friday morning and strengthen with time through Friday night as an upper- level trough digs over the Northern Plains. This will leave the forecast area under a southwest flow, lifting an abnormal amount of moisture into the area with PWATs between 1.75-2.10 inches (150-200% of normal). There are still discrepancies in the track and timing of the shortwave and where the axis of heaviest rainfall will occur, but the overall signal continues to suggest the potential for localized heavy rainfall somewhere across the forecast area (probability of exceeding an inch at any one location is 20-30%) Friday evening/night. The severe potential continues to appear low given the timing and placement discrepancies and the possibility of clouds during Friday morning. If anything, forecast soundings would suggest a heavy rain event (tall, skinny CAPE) with marginal potential for isolated strong wind gusts (small inverted-Vs). Precipitation chances look to continue into Saturday as the aforementioned upper-level trough and associated surface cold front moves across the Upper Mississippi Valley. Rest of the extended...Dry conditions are anticipated through the remainder of the weekend and into early next week. The next chance for precipitation then looks to occur sometime in the middle of next week. Temperatures...While temperatures are expected to remain slightly above normal throughout the entire forecast period in the 80s, humidity levels will be the main feature in flux. The late week system will bring dew points into the upper 60s to low 70s on Friday and Saturday, leading to the return of humid conditions. However, heat indices will remain well below any heat headline criteria. && .AVIATION...for 18Z TAF Issuance Issued at 1221 PM CDT Wed Jul 9 2025 A lingering low stratus deck and the development of afternoon cu has left MVFR cigs at all TAF sites except MTW at the start of the 18z TAF issuance. Anticipate the cigs to gradually rise to VFR and/or clouds dissipating over the next couple of hours. However, clouds will linger the longest across the far north due to lake enhanced clouds dropping south from Upper MI. Clearing skies and calm winds should occur by this evening and continue overnight. If enough clearing occurs, could see some patchy fog development across some of the TAF sites by early Thursday morning. Decided to include TEMPO groups with MVFR vsbys at all TAF sites except GRB and MTW. VFR clouds will begin to increase from the west by the end of this TAF period. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kruk AVIATION.......Kruk