Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
104 FXUS63 KMKX 271546 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 1046 AM CDT Fri Jun 27 2025 .KEY MESSAGES... - Heat index vales in the 95 to 100 degree range are possible on Sunday. - Thunderstorms are possible Sunday afternoon and evening, along and ahead of a cold front. Gusty winds and hail are possible with the strongest storms. && .UPDATE... Issued 1046 AM CDT Fri Jun 27 2025 Clouds will gradually decrease through the afternoon, though at what pace is still in question. Besides a stray sprinkle over far southeastern Wisconsin through noon, dry conditions are expected. Fog will be a concern tonight as high pressure brings calm winds and mostly clear skies. Boxell && .SHORT TERM... Issued 415 AM CDT Fri Jun 27 2025 Today through Saturday: The cold front is expected to move east across the area this morning, and to the east this afternoon. A few showers may still occur into this morning, until the front exits the area. Otherwise, low clouds from the west may push into the area and linger through this morning, before scattering out this afternoon with daytime heating. Some uncertainty with how far east and how long the low clouds may linger. Northern and western portions of the area have the better chances to see the low clouds this morning. South to southwest winds will shift west behind the front, with gusty west winds expected into this afternoon. Highs today should reach into the middle to upper 70s northwest half of the area, to the lower to middle 80s in the southeast half. Weak high pressure will move into the region tonight and into Saturday morning, before shifting off to the east. Winds will weaken as a result, with skies becoming mostly clear by later tonight. Dewpoints close to the temperatures with these conditions may allow for some fog and/or low stratus cloud development. For now, uncertain with if and how much fog and low stratus clouds may develop, so left mention out of the forecast for now. Lows in the upper 50s north to the lower 60s south are expected. Wood && .LONG TERM... Issued 415 AM CDT Fri Jun 27 2025 Saturday night through Thursday: Ridging firmly builds into Wisconsin Saturday night into Sunday. Low level jet dynamics indicate the best chances for thunderstorm development are angled into central and northern Wisconsin overnight Saturday. Kept NBM PoPs (20 to 30 percent chances) in the northern parts of the area for this timeframe, due to uncertainty in ridge placement and therefore in the northern extent of the nose of the nocturnal low level jet. Sunday, ridging reaches its farthest north peak, with expectations for temperatures around 90 degrees or in the lower 90s across southern Wisconsin. Southwesterly winds will allow for these temperatures to reach all the way to Lake Michigan. In addition, these southwesterly winds will bring in dewpoint temperatures in the upper 60s to lower 70s, allowing for heat index values of 95 to 100 degrees. As heat and humidity build, a low pressure system slides across central Ontario, dragging a cold front through Wisconsin and setting off a line of convection moving southeastward during the afternoon to evening hours. Due to high instability (ensembles showing 70 to 80 percent chance of CAPE greater than 2500 J/kg) and moisture content, strong to severe storms are possible as this front pushes southeastward. Bulk shear remains modest at 20 to 30 knots, with locally stronger shear in the vicinity of the remaining cold pool from the previous night`s convection. Gusty winds and hail are possible, and will continue to refine the forecast as additional model runs come in. Low pressure occludes into the Hudson Bay by Monday, bringing cooler air from the northwest into southern Wisconsin. Still, expect temperatures to be mild in the middle 80s. With northwesterly flow and the occluded low, a few shortwaves may produce isolated to scattered thunderstorms Monday. Occluded low pushes eastward into Quebec Tuesday into Wednesday, allowing for ridging to slowly build back into southern Wisconsin. Surface low pressure develops in the lee of the central Rockies during this time, bringing summertime temperatures and eventually additional thunderstorm chances toward the middle to later parts of the week. MH && .AVIATION... Issued 1046 AM CDT Fri Jun 27 2025 MVFR ceilings will gradually scatter and lift to VFR this afternoon, though just how fast is still in question. VFR will prevail from later this afternoon into the evening hours. Fog will then become a concern late tonight. The most dense fog will likely occur west of the terminals, but some visibility reductions are expected at most locations by early Saturday morning. Boxell && .MARINE... Issued 415 AM CDT Fri Jun 27 2025 Low pressure around 29.7 inches will move from north central Wisconsin into Lower Michigan and Lake Huron today. Showers and a few thunderstorms may linger into this morning, along a cold front. South winds will become southwest today ahead of the front, with west winds behind the front by later this afternoon into tonight. Weak high pressure around 30.1 inches will move into the region later tonight into Saturday, which will allow winds to weaken. Winds will become south and increase Saturday night into Sunday, as the high moves east of the region. Showers and thunderstorms are possible with the front Sunday afternoon and night. Winds then shift west by early next week. Wood && .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