Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
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514 FXUS63 KMKX 222021 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 321 PM CDT Wed May 22 2024 .KEY MESSAGES... - Gusty westerly winds up to 30 mph continue this afternoon, then decelerate gradually this evening. - Isolated showers and weak thunderstorms may develop later this afternoon into this evening (20% chance). - Next round of showers and thunderstorms will be Friday morning through Friday night. No severe storms are expected, but gusty winds and small hail are possible. && .SHORT TERM... Issued 315 PM CDT Wed May 22 2024 Tonight and Thursday: Radar and GOES satellite depict isolated weak thunderstorm development over far southeastern MN, drifting east- southeastward towards our western CWA. The current 15% PoPs for later this afternoon / evening are likely to be increased towards 30% (perhaps locally higher) for areas west of a Madison to Fond Du Lac line now that convective initiation is confirmed. Severe weather is not expected from these storms at this time, given limited instability. With CAPE around 500 to 750 joules and effective shear around 30 kts, and if storm clusters become more organized, small hail and sub-severe wind gusts cannot be ruled out. Skies clear out and winds decelerate tonight, leaving dry / pleasant weather for Thursday. A light southwest breeze is expected to partially abate the lake-breeze on Thursday, with inland areas reaching the upper 70s. Sheppard && .LONG TERM... Issued 315 PM CDT Wed May 22 2024 Thursday night through Wednesday: Medium-amplitude perturbations in the polar jet continue to rotate through the upper air pattern, continuing the trend of off and on shower and thunderstorm chances through the end of the forecast period. For Friday, a low pressure trough passes through WI, pulling roughly 1000 joules of CAPE into the CWA, co-located with 30 to 50 kts of deep shear. Storms are not currently expected to be severe, but small hail and localized sub-severe wind gusts may occur. As the trough progresses east, storms clear out late Friday night, leaving quiet weather and daytime highs around 70 for Saturday. The next chance for showers and thunderstorms would be Sunday morning through Sunday night (60% chance). Rain may continue at times into Monday (50% chance) in the cold sector of the passing low pressure system, but ensembles indicate limited instability and hence much lower chances for thunder into Monday. Sheppard && .AVIATION... Issued 315 PM CDT Wed May 22 2024 Clouds have scattered and lifted to VFR levels as expected, and should remain so this evening before completely clearing out tonight. Gusty west winds decelerate this evening, with slower southwest winds continuing tonight into Thursday. There is a window for isolated showers and weak thunderstorms to develop later this afternoon into this evening (20% chance of rain and thunder by Lone Rock WI), but confidence remains too low for inclusion in TAFs at this time. Highest chances would be further west towards KMSN. Clear skies and dry weather expected late tonight into Thursday. Sheppard && .MARINE... Issued 315 PM CDT Wed May 22 2024 Low pressure around 29.1 inches will continue northeastward across Ontario, weakening to 29.3 inches tonight. Gusty southwest winds up to 30 kt will continue through this afternoon, especially over the northern half of the lake. Light to modest southwest winds will then prevail over the entire lake for tonight and Thursday. Winds will become east-southeast on Friday as a low pressure trough around 29.5 inches approaches from Wisconsin. Winds will shift to the west in the wake of the trough Friday night. High pressure around 29.9 inches will overspread the Lake Michigan on Saturday. Low pressure around 29.3 inches will slide across the Midwest Sunday and across Lower Michigan Monday. Sheppard && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643-LMZ644 until 7 PM Wednesday. Small Craft Advisory...LMZ645-LMZ646 until 5 PM Wednesday. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSMilwaukee www.twitter.com/NWSMilwaukee www.youtube.com/NWSMilwaukee