Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
421 FXUS63 KMKX 142001 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 301 PM CDT Sat Sep 14 2024 .KEY MESSAGES... - Summer-like warmth continues through the rest of the weekend into the upcoming work week. Daytime highs will range between five and fifteen degrees above normal. - Shower and thunderstorm chances continue to trend down today and tomorrow, with only slight (~15-20%) precip chances forecast near the Wisconsin River. - Dry conditions prevail through the upcoming week, with the next chance for showers and storms not arriving until next weekend. && .SHORT TERM... Issued 301 PM CDT Sat Sep 14 2024 Tonight through Sunday night: Synopsis/Mesoanalysis: Early afternoon surface observations place an area of high pressure near the Quebec-Maine border. Southeasterly flow prevails across southern Wisconsin, which finds itself positioned along the western periphery of the aforementioned surface high. The mild southeasterly flow & mostly sunny skies have allowed for another afternoon of efficient surface heating regionally, with many locations away from the lakeshore currently reporting temps in the low to mid 80s. In the mid-upper portions of the atmosphere, the state finds itself positioned between longwave ridging centered over the Lake Huron vicinity, and upper troughing extending the Canadian Prairie Provinces to the Northern Plains. South-southwest mid-upper winds thus prevail across the region. Several disturbances are progged to pivot through the aforementioned south-southwesterly flow, particularly this afternoon and evening. Lift affiliated with the perturbations will encourage isolated to widely scattered showers and thunderstorms primarily west of the Wisconsin River through early this evening. Above normal temperatures will continue on Sunday, with the afternoon update continuing to trend toward a precip-free final day of the weekend. Rest Of Today & Tonight: An isolated shower/thunderstorm can`t be ruled out through early evening as an upper shortwave migrates from the Mississippi River toward the Upper Peninsula of Michigan. These small chances are currently reflected in regional radar data, which depict a scattering of light echoes from Richland Center toward La Crosse. Given the positioning & track of the responsible perturbation largely to the northwest of the area, have kept slight chance (15-20%) precip probs confined exclusively to the west of the I-39 Corridor. Severe weather is not expected in any showers/thunderstorms that clip our far western counties. Similar to previous overnight periods, patchy ground fog is possible along the Kettle Moraine during the predawn hours. Have accounted for this potential in the afternoon update, though no appreciable impacts are anticipated. Sunday: Well above normal temperatures continue. AM model guidance suggests an entirely dry day across the region, which appears reasonable given an absence of mid-level forcing mechanisms. Have thus favored the consensus of dry solutions and removed all mentionable precip probs from western counties tomorrow afternoon. Quigley && .LONG TERM... Issued 301 PM CDT Sat Sep 14 2024 Monday through Saturday: Synopsis: Upper high pressure will continue to persist across the Great Lakes through at least the middle portions of the upcoming work week. Attendant surface high pressure will continue to linger off the northeastern coast of the CONUS, helping to maintain mild south to southeast surface flow across southern Wisconsin. Well above-normal, summer-like warmth will thus continue through the duration of the long term period. An upper low will eject from the Rockies into the Northern Plains on Wednesday, though its subsequent track into central Canada will keep focused ascent for showers/storms away from the region. A second wave will eject into the south-central Plains during the late week time period, bringing additional chances for showers and storms to central portions of the CONUS. Global guidance suggests that this second trough & its attendant precip footprint could pull closer to the region by next weekend, when mentionable precip chances return to the forecast. Monday Through Thursday: Above-normal temperatures continue. Expect that multiple bouts of showers and storms will occur to our west with an upper trough ejecting into the Northern Plains. Stagnating upper high pressure in place across the Great Lakes, however, appears poised to steer forcing for precip well away from the area & into central Canada. A dry forecast thus prevails through mid-late week. Friday Through Saturday: Above-normal temperatures will continue to persist. Periods of showers and storms will occur over the central CONUS as a second shortwave ejects into the south-central Plains. Current guidance hints that this feature, and the forcing for precip affiliated with it, could pull close enough to the region to support showers/storms by next weekend. Mentionable precip probs thus return to the forecast on Saturday. Quigley && .AVIATION... Issued 301 PM CDT Sat Sep 14 2024 VFR conditions are forecast to persist through the period at all southern Wisconsin terminals. SCT low to mid-level cumulus will continue to develop through peak heating away from the Lake Michigan shoreline. Fair weather cumulus will dissipate this evening as SCT- BKN mid-level clouds gradually thicken from west to east. Patchy ground fog is possible along the Kettle Moraine approaching daybreak Sunday. As observed this morning, said ground fog could bring impacts to SBM and UES early tomorrow morning, though forecast confidence is currently too low to justify any prevailing FG mentions. Trends will be monitored through the overnight period, with FG insertions being made should conditions warrant. Primarily east-southeast winds are expected at all fields, with east-northeast wind shifts anticipated behind the lake breeze this afternoon at ENW, MKE, and SBM. Quigley && .MARINE... Issued 301 PM CDT Sat Sep 14 2024 Winds will remain predominantly south to southeasterly through the duration of the period as 1026 mb high pressure migrates from Quebec into the northeastern United States. 992 mb low pressure will develop over the northern Great Plains by the middle of the week, reinforcing the south-southeasterly flow pattern across the lake. Brief bouts of east to northeasterly winds are possible primarily during the afternoon periods as the lake breezes advance out & away from the open waters. Precip-free conditions are expected through the majority of the week, with rain chances potentially returning by next weekend. Quigley && .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