


Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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301 FXUS63 KGRB 092359 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 659 PM CDT Wed Jul 9 2025 Updated aviation portion for 00Z TAF 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 00Z TAF Issuance Issued at 658 PM CDT Wed Jul 9 2025 Finally we were able to get rid of the lower MVFR stratus. Clouds have been slowly scattering out early this evening. Eventually skies will clear later this evening into the overnight hours. The clear skies and light winds, along with lingering moisture from recent storms, will result in patchy fog overnight. At this point, seems greatest risk of fog is at GRB, ATW, MTW where min temps are expected to fall below the crossover temps. Have continued to cover this with TEMPO groups for MVFR VSBY. Mid clouds will gradually increase by afternoon at the TAF sites with potential for showers and storms moving into central WI on Thursday evening. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kruk AVIATION.......JLA