Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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989 FXUS63 KGRB 151148 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 648 AM CDT Sun Sep 15 2024 Updated aviation portion for 12Z TAF issuance .KEY MESSAGES... - Isolated showers and a few storms will continue in central and north-central WI through early this afternoon. Severe weather is not expected. - Dry weather and summer-like temperatures are expected this week. Highs will range from the upper 70s to middle 80s. The next chance of rain will not arrive until late this week or next weekend. && .DISCUSSION... Issued at 359 AM CDT Sun Sep 15 2024 Short Term...Today...Tonight...and Monday Minor precip chances and above normal temperatures are the main focus from this forecast period. Lingering moisture from the remnants of Francine was producing isolated showers over portions of central and north-central WI this morning. Meanwhile, patchy ground fog was being reported across portions of far eastern WI, where winds were calm and little cloud cover prevailed. This fog will burn off soon after sunrise. Today...Anticipate the isolated showers to continue in central and north-central WI for the remainder of the morning, and possibly into the early afternoon, until dry air from high pressure to the east retrogrades into the area this afternoon. Cannot rule out a few rumbles of thunder before the precip ends, with MLCAPE of 400-700 J/kg in the area. By the afternoon, clouds will be on the decrease across the region due to the dry air. The prevailing warmer airmass, in addition to the extra sunshine this afternoon, will result in warmer temperatures over the area compared to Saturday, with highs ranging from the low to mid 80s. Tonight and Monday...The dry air from the high pressure system to the east will keep dry conditions in place overnight under mostly clear skies with lows ranging from the mid 50s to low 60s. Dry conditions are also anticipated for Monday. The only exception may be across far north-central WI, where some guidance is indicating isolated diurnal, pop-up showers and storms developing during the afternoon. Decided to add a low chance (15%) PoP during this time, but confidence is still quite low in this occurrence due to the amount of dry air in the area. Another day of above normal temps is expected on Monday with highs mainly in the mid 80s. Long Term...Monday Night Through Saturday The main themes of the long term are seasonably warm and dry. Pattern is amplified, yet changeable, through the week. The rex block that has impacted our region this weekend gives way as organizing low off the southeast coast, which could become tropical in nature, eventually shifts across the southeast this week while heights build again from the plains to the Great Lakes. Meanwhile deep troughing will reload multiple times over western North America, but will make little progress farther east. Eventually by late this week the pattern transitions to more of a omega block with troughing out west, sharp ridging from the southern plains to the western Great Lakes and the remnants of the southeast low easing across the Appalachians toward the mid Atlantic. All that said, the net result for sensible weather over northeast WI is similar to what we have had for the last week, warm and mainly dry. The next chance for some rain does not arrive until late this week. Though looking at trends in models and ensembles, it probably won`t reach our area until next weekend. Temps will be seasonably warm, though not hot, as highs persist in the lower to perhaps mid 80s (70s lakeside) while lows drop mainly into the 50s. After the more humid weather this weekend due to the plume of moisture from the remnants of Francine, most of the coming week will be characterized by more comfortable humidity as dewpoints will be centered in the 50s with even some upper 40s over the north as high pressure over the northeast extends sfc ridging westward across the Great Lakes. Hazardous weather looks minimal with no real chance of thunderstorms until next weekend and light winds on the waters. Does look like many nights will continue to feature shallow ground fog which will lead to localized reduced visibility in the pre-dawn hours. && .AVIATION...for 12Z TAF Issuance Issued at 648 AM CDT Sun Sep 15 2024 Middle and high clouds prevailed across the region this morning, as light isolated showers moved northeast over the central and north-central WI TAF sites. The exception has been a small cluster of showers and isolated thunder that developed near the AUW and CWA TAF sites. Anticipate the southern end of this cluster to reach the AUW TAF site within the first hour or two of this TAF period, while CWA should remain dry. The trajectory of the cluster`s center looks to remain just south of the RHI TAF site this morning, however, some of the isolated showers surrounding it may reach RHI. Reflected this with VCSH at RHI for now, but an amendment may be needed. Any showers or storms will come to an end by mid-morning. VFR conditions will prevail for the remainder of this TAF period, with southerly winds of 5 to 10 kts, gusts to 15 kts, this afternoon. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kruk/JLA AVIATION.......Kruk