Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
773 FXUS63 KMKX 050928 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 428 AM CDT Sun May 5 2024 .KEY MESSAGES... - Patchy fog possible this morning in the Wisconsin River Valley. - Quiet and dry weather expected for Sunday into early next week. - Additional showers and thunderstorms are expected during the middle portions of next week. Uncertainty remains regarding the potential for severe weather. && .SHORT TERM... Issued 318 AM CDT Sun May 5 2024 Today through Monday: Some fog remains possible this morning in patchy spots owing the wetting rains from yesterday evening, building subsidence, and light winds. The Wisconsin River Valley will be the most favored region for fog development. Otherwise today, high pressure will continue to shift east and settle over the Upper Great Lakes by tonight. Clear skies and full solar insolation should lead to a well mixed boundary layer and fairly low dew points in the upper 30s to low 40s. Winds will be light out of the north, becoming more light and variable this afternoon. Highs should reach the upper 60s to near 70, generally west of Waukesha, Washington, Racine, and Kenosha counties, as the weak pressure gradient will allow a lake breeze to start fairly early in the afternoon and push inland, keeping highs in the mid 60s closer to the lakeshore. Temperatures will cool into the 40s tonight under mostly clear skies and continuing subsidence. Another round of fog in the Wisconsin River Valley may occur. Monday will be another beautiful day, with slightly warmer daytime highs inland in the low to mid 70s as ridging aloft amplifies. Prevailing winds will be off of the lake from the east as high pressure moves toward Lake Huron, keeping conditions cooler again in lakeshore counties and their westward neighbors. CMiller && .LONG TERM... Issued 428 AM CDT Sun May 5 2024 Monday night through Saturday: WAA and an occluded front are expected to approach Wisconsin Monday night as a low deepens over Eastern Montana/Western North Dakota. Showers and thunderstorms are expected to spread southwest to northeast into the state early Tuesday morning into the post dawn hours. There are two camps of solutions for Tuesday and Wednesday as the NAM and 00z ECMWF favor precipitation coming through as a solid line along the occluded front through the daytime hours on Tuesday, while the GFS favors a dying line in the morning with more redevelopment in the afternoon. This in turn then influences the storm potential on Wednesday. If the ECMWF/NAM solution verifies, much of Tuesday afternoon could be dry following the passage of the occluded front and its precipitation by the early afternoon. Without a blow- up of precipitation Tuesday afternoon, favorable dew points may be pushed into central IL, then return north on Wednesday behind a warm front as a surface low deepens over the middle Mississippi Valley. EPS ensembles show a strong wave aloft and more favorable flow on Wednesay, and the ECMWF shows convection blowing up along the warm front just south of the WI/IL border Wednesday afternoon. The GFS has the precipitation lifting north Tuesday morning/afternoon with redevelopment during the mid to late afternoon over southern WI. Shear looks like it would be marginal, but the GFS supports steep mid level lapse rates, hinting toward a severe hail threat, provided a storm establishes itself. This convection Tuesday afternoon would then give a reinforcing push to dew points southward down to the Ohio River Valley. The GFS then also forms a low Wednesday, but the warm front only rises as far north as central Illinois, and Wednesday storm chances stay well south. With all of these confounding factors, it remains too early to put a definitive label on the storm threat for Tuesday and Wednesday, but trends will be monitored for better confidence with each successive model run. A weak sfc trough may then linger for Thursday providing additional rain chances. Beyond, slight chances for rain linger into the weekend as a weak upper trough passes over the Upper Great Lakes. CMiller && .AVIATION... Issued 326 AM CDT Sun May 5 2024 Before dawn some patchy ground fog may form with fog more favored to form in the Wisconsin River Valley. Otherwise, light northerly winds are anticpated today, with winds becoming light and easterly over the area as a lake breeze works inland. This lake breeze circulation is anticipated to work inland starting at 17z and making it as far inland as KMSN by 00z. Winds should then become light and variable overnight. Barring areas of patchy fog, VFR conditions are expected today into Monday with mostly clear to partly cloudy skies anticipated. CMiller && .MARINE... Issued 324 AM CDT Sun May 5 2024 High pressure will spread into the Upper Great Lakes Region and linger through Monday. This high pressure will bring light northerlies to the lake this morning, with winds growing light and variable over the lake this afternoon into tonight. Monday, winds look to become easterly at times, but lack of a strong pressure gradient over the area will mean that the east winds will be interspersed with boughts of light and variable conditions. Monday night, winds will grow southeasterly and breezy to 20 knots over the southern half of Lake Michigan by Tuesday morning. Winds then come around to westerly after a front lifts north over the area Tuesday night into early Wednesday morning. A brief period of Small Craft Advisory criteria waves may occur Tuesday morning. CMiller && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ 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