Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
645 FXUS63 KMKX 020255 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 955 PM CDT Mon Jul 1 2024 .KEY MESSAGES... - River flooding and high water levels continue this week. Additional rises will be possible with any heavier rainfall that occurs later tonight through Tuesday night. - Rain and thunderstorms are expected at times later tonight into Tuesday morning, and again later Tuesday into early Wednesday morning. Primary concern is heavy rainfall, especially for Tuesday night. - Shower and thunderstorm chances return for Independence Day and Friday. && .UPDATE... Issued 955 PM CDT Mon Jul 1 2024 An area of showers and a few storms are trying to move eastward into the western parts of the area, aided by differential CVA and some warm air advection. This will be fighting very dry low levels per area forecast soundings, and ceilings are generally above 8000 feet AGL. Think that some very light showers or sprinkles may make it into the far western parts of the area over the next few hours, and may need further adjustments to PoPs in that area. The main area of rain and thunderstorms with heavy rainfall is likely to focus from northern Iowa across southwest to north central Wisconsin overnight into Tuesday morning, aligned with the southwesterly low level jet nose and focused warm air advection. The northwestern parts of the area should get in on this activity, though again the heaviest rainfall should remain to the northwest. There should be a lull in the activity later Tuesday morning into the afternoon, before more rain and storms moves into mainly southern Wisconsin by later Tuesday afternoon, continuing into Tuesday night/early Wednesday morning. This second round would be more impactful for heavy rainfall, as the low level jet nose focuses over the region with high precipitable water values over 2.00 inches. The right entrance region of the upper jet also helps with upward vertical motion, and the slow moving cold front moves slowly east and parallel to the upper flow. Thus, may see more training of convection and heavy rainfall over the area. Areas southwest of Madison will have the best chances for greater then 2.00 inches of rainfall per ensembles. May need to consider a Flood Watch for flash flooding in later forecasts, depending on how much we get in northwest parts of the area with the first round of rainfall. High swim risk/Beach Hazards Statement continues for Tuesday for all Lake Michigan beaches, for high waves causing dangerous rip currents. This will linger into Tuesday night for beaches in Sheboygan and Ozaukee County, with south winds continuing to bring high waves to those areas. Stay out of the water during this period. Wood && .SHORT TERM... Issued 310 PM CDT Mon Jul 1 2024 Tonight through Tuesday night: Dry and pleasant weather continues until late tonight (after midnight). A surface pressure trough extending south from low pressure in Manitoba (connecting to a satellite low in KS) works with the departing high pressure system to generate strong 850-700mb WAA late tonight, leading to a gradual increase in rain shower coverage early Tuesday morning, with a chance for a few weak elevated thunderstorms amongst the showers (though HREF Mean MUCAPE is < 500 joules). One or two lulls in shower / weak thunderstorm activity may occur mid Tuesday. In the late afternoon / evening, the LLJ strengthens overhead (40-45 kts, PWAT climbs to around 2.0 inches), potentially fueling showers and weak thunderstorms capable of higher rainfall rates. Shower and thunderstorm activity gradually decrease late Tuesday night as a cold front crosses the region, moving clear of the CWA by around 7 AM CDT Wednesday. Sheppard && .LONG TERM... Issued 310 PM CDT Mon Jul 1 2024 Wednesday through Monday: The passage of a weak high pressure system will lead to a lull in active weather on Wednesday. West winds 10 to 20 mph behind the cold front will only briefly provide CAA. The subsidence of the approaching high will clear the skies out gradually, sending Wednesday`s daytime high temps into the mid 80s. West winds abate the lake breeze and allow areas east of the Kettle Moraine to soar into the upper 80s. The active weather pattern returns Thursday into Friday as low pressure develops in the northern Plains and tracks eastward. A semi persistent trough axis over the northern plains may allow additional low pressure systems to follow a similar track, leading to occasional shower / storm chances through the end of the forecast period. Sheppard && .AVIATION... Issued 955 PM CDT Mon Jul 1 2024 May see a few showers approach Madison and Janesville over the next few hours, though they should be very light or just sprinkles. Southeast winds will linger overnight into Tuesday morning, with some gusts to 15 to 20 knots at times. Low level wind shear conditions are possible overnight, though will leave out of TAFs for now, with 2000 foot AGL south winds around 40 knots. More rain and thunderstorms should move into areas northwest of a Monroe to Sheboygan line overnight into Tuesday morning, with more scattered showers and a few storms elsewhere. May see MVFR to IFR visibility values in any heavier rain or storms, with VFR conditions expected otherwise. South to southeast winds are expected Tuesday. A lull in the showers and storms is anticipated from later Tuesday morning into the afternoon, before more rain and storms moves into southern Wisconsin later Tuesday afternoon into Tuesday night and linger into early Wednesday morning. This period may see heavy rainfall and more widespread MVFR to IFR visibility values, as well as some MVFR ceilings developing by Wednesday morning. South to southwest winds should weaken Tuesday night into early Wednesday morning. May see some low level wind shear conditions during this time, with southwest winds around 35 knots at 2000 feet AGL. Wood && .MARINE... Issued 310 PM CDT Mon Jul 1 2024 With high pressure around 30.3 inches lingering over Lake Michigan, winds will be light and variable for the rest of today, predominantly westerly over the northern edge and easterly over the southern edge. High pressure will continue moving east, exiting the western Great Lakes Region tonight. Winds will become southeasterly and increase tonight as low pressure around 29.4 inches moves northeast from Saskatchewan toward James Bay. Winds will remain south to southeasterly until Tuesday night when a cold front crosses the lake. Rain and thunderstorms are expected with the frontal passage. Southwest to west winds are expected behind the front. Weak high pressure returns to the region Wednesday night into Thursday bringing a return of light and variable winds. Sheppard && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Beach Hazards Statement...WIZ052-WIZ060...6 AM Tuesday to 1 AM Wednesday. Beach Hazards Statement...WIZ066-WIZ071-WIZ072...6 AM Tuesday to 7 PM Tuesday. LM...Small Craft Advisory...LMZ643...6 AM Tuesday to 1 AM Wednesday. Small Craft Advisory...LMZ644-LMZ645-LMZ646...6 AM Tuesday to 7 PM Tuesday. && $$ 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