Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
393 FXUS63 KMKX 071427 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 927 AM CDT Sat Jun 7 2025 .KEY MESSAGES... - Small shower chances (10-15%) return this afternoon and evening. - Better chances (60-90%) for rain and storms with the passage of a cold front for storms Sunday into Monday. Some storms may be strong Sunday and Monday. - Temperatures will remain within a few degrees of normal through early next week. && .UPDATE... Issued 925 AM CDT Sat Jun 7 2025 Some weak echoes of reflectivity south of the La Crosse WI Radar are evident, likely creating some virga in southwestern WI through this morning, beneath the broken altocumulus clouds overspreading the region. Though 5-15% chances for showers remain in the forecast this afternoon and evening, the stabilizing influence of easterly / southeasterly winds off of Lake Michigan and an extremely deep (and plenty dry) mixed layer are expected to keep showers / weak storms away for today. Looks like pleasant weather with highs in the 70s inland, 60s by the shoreline. 06z Model runs for Sunday`s cold front still remain dispersed / incongruent on the arrival timing, hence will need to wait for this morning`s 12z guidance before providing an update on the marginal potential for strong storms. Sheppard && .SHORT TERM... Issued 358 AM CDT Sat Jun 7 2025 Today through Sunday night: Zonal flow remains at 500mb across the central and eastern CONUS. Under this zonal flow there are multiple shortwaves and little wiggles moving through, which will again create sporadic/nebulous upper level lift today. There is one shortwave trough in particular thats a bit more organized and stronger than the rest that should pass just to the south of the state line this afternoon/evening. With sfc high pressure off to the northeast, dry air at the surface will remain through much of the morning keeping conditions dry. Any radar returns are likely to be virga with the stronger showers maybe producing some drizzle across mainly central and west central Wisconsin (where there is more low and mid level moisture). As the surface high pressure begins to move east into the New England states later today, there will be a slight increase in moisture especially for areas along the WI/IL border. Increased moisture and upper level lift has lead to some low chance POPs around 20% this afternoon and evening. Any rain that makes it to the ground is likely (80%) to be drizzle/light rain. The best chance for any rainfall is likely to remain to our south where the better upper level support (shortwave) will reside. As the high pressure moves out, low pressure in Manitoba will deepen and begin to occlude. As this low pressure system slowly moves eastward, an associated cold front is expected to move through the Great Lakes Region. There are still little differences in timing as this cold front phases with/interacts with the same shortwave that is expected to bring light rain today. By and large tho, rain is expected (60 to 80% chance) to move in from the west Sunday afternoon and exit to the east Sunday evening. Given the slight differences due to the two phases systems, an upper level trough and associated sfc cold front with a shortwave trough to the south of the state. There are two potential scenarios which will impact the strength and coverage of any thunderstorms. The earlier and quicker the front moves through the weaker the CAPE is and we maybe get an isolated stronger storm. The slower and therefore later the cold front moves through the better primed the environment will become and the greater the CAPE will be. This could lead to a few more marginally severe storms. With the current set up the models with the slower cold front movement are the ones that do not have the upper level trough and shortwave phasing. This difference is on the order of a couple hours and because of that opted for a middle ground for POPs since not matter what there is high confidence for rain and thunderstorms. The main concerns for any stronger storms will be some brief gusty winds and hail. Patterson && .LONG TERM... Issued 358 AM CDT Sat Jun 7 2025 Monday through Friday: The main upper low is anticipated to swing through the area on Monday, bringing another round of showers and storms to southern Wisconsin. Though it will be a bit drier overall on Monday than Sunday, colder temps aloft and steeper mid-level lapse rates will lead to some moderate instability. There should be plenty of forcing with this wave as well, so higher end precip chances (50-80%) still look warranted. This is supported by 90%+ probabilities for 24 hour measurable precip in the latest ECMWF and GFS ensembles. Could see a stronger storm or two, with gusty winds and small hail possible. Temps will likely be a few degrees below normal Monday given the cooler airmass and expected clouds/precip. Mainly dry weather is expected for Tuesday and Wednesday as high pressure builds into the area. Not out of the question for isolated showers and maybe a storm on Tuesday as a weak waves pushes through, but most places will likely be dry. Temperatures will recover into mid-week as upper level ridging builds in from the west, with highs up to around 80 by Wednesday. Could see a few showers/storms Thursday over the top of the ridge, but confidence in this activity is on the lower end at this point. Shower and storm chances will then increase late week as shortwave lifts through the area. Warm temps and increasing moisture are expected through the end of the week as well. DDV && .AVIATION... Issued 925 AM CDT Sat Jun 7 2025 Broken altocumulus clouds will create periods of VFR ceilings over 8,000 ft today, with some additional thin cirrostratus around 25,000 ft at times. Inland areas may observe diurnal cumulus between 4,000 and 7,000 ft (still VFR) this afternoon. Some virga in southwestern WI with the altocumulus this morning, then just a 5-15% chance for a shower in the region this afternoon / evening (most likely for showers / weak thunderstorms to remain confined to Illinois today given our lack of instability and dry mixed layer in Wisconsin). Light east to southeast winds. A cold front is expected to move eastward across the region Sunday, with south to southwest winds ahead of the front and due west or northwest winds behind it. Numerous showers and thunderstorms expected along the front. Models remain uncertain on the arrival time and propagation speed of the front, hence our forecast calls for a wide window (10am-7pm) for the storm potential, though the progressive nature of the front ought to limit storm activity / coverage to just a 1-3 hour timeframe within said window (for any given airport). A strong storm or two cannot be ruled out. Sheppard && .MARINE... Issued 358 AM CDT Sat Jun 7 2025 High pressure over Lake Superior this morning will move east out of the Great Lakes Region this weekend. As this high moves east, an area of low pressure will approach the state from the Northern Plains. Light and variable winds are expected until the high pressure has moved into the New England States. Winds will shift to southwesterly Sunday morning and increase, leading to some moderately breezy winds. Winds will stay well below Gale Force. Showers and storms are expected Sunday and Monday. Southwest winds will remain through mid to late Monday then become westerly. Patterson && .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