Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
334 FXUS63 KMKX 230910 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 410 AM CDT Mon Sep 23 2024 .KEY MESSAGES... - Areas of fog are possible over northwestern counties later tonight. - Cooler/near normal temps are expected through the start of the week with daily highs in the upper 60s and lower 70s. - High uncertainty in timing and placement for precipitation next weekend (15 to 30 percent chance). && .SHORT TERM... Issued 410 AM CDT Mon Sep 23 2024 Today and Tonight: Cooler temperatures, drier air and mostly clear skies are in store for much of southern Wisconsin today. With the cold front to our east in Michigan and Indiana, a drier air mass will move into the state bringing dewpoint temperatures in to the mid 40s to low 50s. With the light winds away from lake Michigan and the clear skies, there is a small chance for some fog to develop early this morning prior to sunrise. The best chances for fog to develop will be in the northwestern corner of our forecast area, particularly in the low lying areas. The window for this fog to develop will be small as were looking for the dew point depression to be at or near zero before the drier air mass begins to move in. Outside of this, the beach hazard statement and high swim risk remains in effect for southern Wisconsin beaches through this afternoon (into this evening for far southeastern Wisconsin). This is due to the north to northeast gusty winds and building waves. The tighter pressure gradient over the Lake will eventually shift and weaken, which will cause the waves to diminish later today. The chance for rain returns to southern and eastern Wisconsin tonight into Tuesday. A low pressure system will move from the mid Mississippi valley and is expected to pass near the southern portion of Lake Michigan. There is still a bit of uncertainty on the track of this low pressure system. The difference in track is how far to the south will this low pass. Keep POP chances low with the with 40% chance being the max across far southeastern Wisconsin during the early morning hours Tuesday. There will be a brief period of east winds expected, which should help with some moisture advection that wraps around the low. Otherwise the better chances for rain and thunderstorms is expected to stay to the south. Patterson && .LONG TERM... Issued 410 AM CDT Mon Sep 23 2024 Tuesday through Sunday: As the low pressure system moves out of the southern Great Lakes Region, guidance has it interacting with a Canadian surface high. This would likely slow down the forward progression of the low pressure system causing it to linger a bit over Lake Michigan and far eastern Wisconsin. So low chance POPs around 15% are expected to persist into Tuesday evening. After this low pressure system exits, the Rex Blocking Pattern is expected to set up across the Central CONUS. This pattern will then dominate through much of the week. This pattern would keep Wisconsin dry and slightly warmer with highs slightly above normal in the mid to upper 70s. Uncertainty returns for the weekend as long term guidance suggests a tropical system advecting northward out of the gulf and interacting with the center low pressure system of the Rex Blocking Pattern. If these two low pressure systems due interact, its likely that the Fujiwara effect would take over and cause them to rotate around the center point (kind of looks likes its rotating around each other for those who are less familiar with this effect). This brings in a lot of uncertainty on the track and how this would break down the blocking pattern. Especially when the strength of the system coming out of the gulf would be a key factor. Kept to the average among guidance which introduces some low chance POPs around 30% or less for the weekend. Patterson && .AVIATION... Issued 410 AM CDT Mon Sep 23 2024 Predominately VFR conditions are expected across southern Wisconsin. Western terminals will have a small chance to seem some fog develop early this morning under the clear skies, and light winds. Drier air will be moving from the north which should limit its development. Not expecting dense fog at this time, but the best chances for fog or some low stratus would be low lying areas in the west. Expect visibilites to remain 3 SM or greater. Otherwise dry conditions with mostly clear skies are expected through this evening. Clouds return tonight ahead of an approaching low pressure system. This low is expected to pass to our south across northern Illinois into southwestern Michigan. Some showers will be possible on the northern side of the low overnight into Tuesday afternoon before the low pressure system exits. North to northeast winds today will become easterly for a short time Tuesday before returning to northerly. Patterson && .MARINE... Issued 410 AM CDT Mon Sep 23 2024 Gusty north to northeast winds will persist through this afternoon as low pressure around 29.9 inches continues east toward the New England States. High pressure around 30.0 inches will build into the northern Great Plains as the low moves east keep the pressure gradient tighter over Lake Michigan during this time. Gusts will taper late this afternoon into tonight as the high pressure moves over the northern half of the lake before moving toward James Bay. The next chance for rain arrives Tuesday morning ahead of an upper level disturbance, with only slight chances (around 40 % or less) for thunderstorms over the far southern portion of the lake. Winds will briefly become easterly as this disturbance moves through before returning to north to northeasterly. A broad area of 30.0 inch high pressure will be dominant surface feature regionally through mid to late week, helping to maintain north- northeast breezes. Additional rain chances arrive by next weekend. Patterson && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066 until 1 PM Monday. Beach Hazards Statement...WIZ071-WIZ072 until 4 PM Monday. LM...Small Craft Advisory...LMZ643-LMZ644 until 1 PM Monday. Small Craft Advisory...LMZ645-LMZ646 until 4 PM Monday. && $$ 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