Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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459 FXUS63 KGRB 302037 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 337 PM CDT Thu May 30 2024 Forecast discussion for routine afternoon forecast issuance .KEY MESSAGES... - 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 strong thunderstorms and heavier rainfall. && .DISCUSSION... Issued at 336 PM CDT Thu May 30 2024 Short Term...Tonight and Friday Dry and quiet conditions are expected to continue through at least early Friday morning before the next chances for rain return, mainly in north-central WI. Main forecast challenges are timing out the shower chances and how far east they will track throughout the day on Friday. This evening through tonight...Departing upper-level ridging and a surface high will keep dry conditions across the forecast area during this forecast period. However, high and mid-level clouds will sneak into central and north-central WI overnight. As a result, have low temperatures a couple degrees warmer in these areas, in the middle 40s to low 50s, compared to east-central and far northeast WI with values ranging from the low 40s to mid 40s. Friday...A decaying line of showers associated with a weak shortwave moving from the west will attempt to bring showers into north- central WI Friday morning. The evolution of these showers and their progression eastward throughout the rest of Friday is uncertain due to the amount of lingering dry air from the departing high. CAMs support the dry air factor as they show the showers becoming scattered and even dissipating as they continue eastward. However, by the afternoon, models suggest a low-level southerly jet increasing across western WI ahead of an approaching cold front. This may allow the scattered showers to redevelop during the afternoon and move into central and north-central WI. A few rumbles of thunder will also be possible during the afternoon as enough instability will be present. Meanwhile, conditions in east-central and far northeast WI will remain dry on Friday. Therefore, have slightly cooler high temperatures in central and north-central WI, in the upper 60s to mid 70s, with values ranging from the mid to upper 70s in east-central and far northeast WI. Highs along the lakeshore will be the coolest with values ranging from the mid 60s to upper 60s. Long Term...Friday Night Through Thursday A transition back to a more unsettled is expected to begin the extended period and will likely continue through at least the middle of next week. Friday night through Sunday morning...As a ridge continues to push toward the eastern Great Lakes and out of the region Friday night an axis of deeper moisture (PWATs of 1-1.2") will move over central and north-central WI out ahead of an upper-level shortwave. Isolated to scattered showers and weak storms are expected to spread northwest to southeast Friday night through Saturday afternoon. Weak instability during this period will limit the potential for any stronger storms, but isolated weak thunderstorms will be possible, mainly Saturday late morning and afternoon across central and north- central WI. A weak low-level ridge will bring a brief end to the precipitation chances Saturday night through Sunday morning. Sunday Afternoon through Monday night...A more widespread chance for showers and thunderstorms is expected across the region beginning Sunday afternoon with an initial northward surge of warm moist air (PWATs 1.4-1.7") ahead of surface low developing over the Northern Plains. Ensemble cluster analysis shows considerable uncertainty with the timing and location of showers and storm during this period , however, the better chance for severe thunderstorms Sunday appears to be west of the region where instability with be greater. The better chance for severe weather in the CWA appears to come Monday late morning/afternoon with the passage of the attendant cold front. Key factor in the severe weather chances will be if and to what degree instability recovers after the first wave of showers and storms Sunday afternoon and evening. Still need to iron out the finer details during this period, but if you have outdoor plans Sunday afternoon and/or Monday you`ll want to keep an eye on the forecast. Rest of the Extended...Another brief lull in the precipitation is expected for most of Tuesday before the next system pushes into the region next Wednesday. Temperatures...Near to or just slightly above normal temperatures are expected across the area during the extended period. Highs each day are forecast to range from the low 70s to around 80 degrees away from Lake Michigan, while locations on the immediate shoreline will likely see highs in the mid to upper 60s. && .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.....Kruk/GK AVIATION.......Kruk