Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
499 FXUS63 KMKX 040248 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 948 PM CDT Wed Jul 3 2024 .KEY MESSAGES... - Independence Day Afternoon: Isolated to scattered showers and thunderstorms are expected during the afternoon. Best chances for showers and thunder in central and southwestern Wisconsin (25 to 45 percent chance). A few later afternoon storms could produce gusty winds. - Independence Day Evening: Areas along and west of I-39 have the greatest chances (50-80%) to see showers/storms between 5 PM CDT and 11 PM CDT, while areas east of I-39 have lower (15-45%) potential. Early evening storms could produce gusty winds and small hail. - The greatest window for showers and thunderstorm chances (>65%) will be after 10 PM CDT tonight through Friday with medium (45-65%) potential for rainfall to exceed one inch northwest of HWY-151. Widespread accumulations up to 0.25 inch are expected. - Elevated water levels continue on area rivers and streams through the end of the week. Flood Warnings remain in effect in several locations. && .UPDATE... Issued 947 PM CDT Wed Jul 3 2024 The forecast remains on track for tonight and Thursday. Fog still seems possible this evening across southwestern Wisconsin, especially in low lying areas and areas near the Wisconsin River. However, cirrus associated with the ongoing convection in Missouri streaming across southern Wisconsin combined with drier air currently in the boundary layer will help inhibit widespread fog development, especially if additional cirrus from the ongoing convection across the Plains is able to advect over Wisconsin before an adequate inversion is able to set up via radiational cooling. All this is to say that fog remains in the forecast for southwestern Wisconsin, but is not expected to be widespread. Heading into Thursday, a quiet morning is still expected as weak high pressure influences the region. CAMs still depict some shower and thunderstorm development tomorrow afternoon ahead of the main frontal boundary. Currently no changes to the expected timing or hazards of the expected convection Thursday evening associated with the front, but we will continue to monitor trends over the next few model runs, especially as we head into the Independence Day festivities. Falkinham && .SHORT TERM... Issued 321 PM CDT Wed Jul 3 2024 Tonight through Thursday night: Mostly sunny skies and light westerly winds continue through this evening, with winds becoming light and variable overnight. Low temperatures in the mid-60s are expected. A few areas of patchy fog are possible in the low lying areas of southwestern Wisconsin as moist soils remain after recent rainfall. Currently expecting drier air in the remainder of the boundary layer to prevent widespread fog production. Temperatures increase quickly under a mostly clear sky and light southerly winds Thursday morning (Independence Day), with highs in the low to mid-80s expected. A lake breeze is expected to develop in the midday hours and reduce temperatures in lakeshore counties through the afternoon. During the afternoon hours, MUCAPE upwards of 1000 J/kg and a few shortwave ripples ahead of a deepening upper low may assist with scattered shower and thunderstorm development. Generally expecting these showers and thunderstorms to be short-lived as pop-up variety thunderstorms due to a lack of environmental shear. However, a few storms may grow enough to produce gusty winds or small hail after 4 PM CDT. Lake breeze component looks to keep those areas stable without pop-up thunderstorm potential during the afternoon and evening hours. A frontal boundary looks to begin to push eastward through southwestern Wisconsin around 7 PM CDT, although there remain differences in timing by a few hours on CAMs. These storms move eastward through the I-39 corridor by 11 PM CDT, and into, but UES may as well depending on the lake breeze. southeastern Wisconsin thereafter. Concerns remain for gusty wind and small hail through the evening hours, diminishing overnight. However, thunderstorms continue throughout the overnight hours, with a reinforcing cold front during the late overnight hours bringing additional storm chances. Storms continue through the overnight hours as low pressure deepens and propagates eastward. Storms look to remain progressive and not tap into the full potential of PWATs around 1.5 inch, but potential remains (45 to 65 percent) for greater than an inch of precipitation north and west of HWY-151. Localized river flooding is expected to continue. MH && .LONG TERM... Issued 321 PM CDT Wed Jul 3 2024 Friday through Wednesday: Showers and thunderstorms continue through much of Friday on the back side of departing low pressure. Generally expecting precipitation rates to be lower with this activity, with accumulations less than a half inch expected. Still, river flooding concerns continue into the weekend. Northwesterly breezes and overcast skies will keep temperatures in the 70s. Dry and clear conditions Saturday will bring temperatures back to near 80 degrees, with light northwesterly winds as high pressure builds back into the central Plains. A 500 mb trough is then expected to affect the Upper Midwest Sunday into Monday, bringing additional thunderstorm chances. As the trough departs on Tuesday, additional showers and thunderstorms are possible as southern Wisconsin remains on the northern edge of the central Plains ridging. Due to uncertainty of convective evolution, kept NBM PoPs through the long term. Seasonable temperatures near 80 degrees remain through Wednesday. MH && .AVIATION... Issued 947 PM CDT Wed Jul 3 2024 VFR conditions are expected throughout the TAF period. Winds will be light and variable tonight as weak high pressure influences the area, and will become southerly by Thursday afternoon. There is the potential for some shower and thunderstorm development Thursday afternoon, although some disagreement amongst the CAMs bring down confidence of timing and location and have left mentions out of the TAFs. However, MSN, JVL, and UES currently look to be the most likely to see precipitation. More widespread storms along a frontal boundary are then expected Thursday night as it moves across the state. Falkinham && .MARINE... Issued 321 PM CDT Wed Jul 3 2024 Breezy south winds across Lake Michigan this afternoon will diminish and become westerly overnight as weak high pressure moves east across the lower Great Lakes region. Light westerly winds will be in place to start the day on Thursday, but are expected to turn easterly and accelerate by Thursday afternoon as low pressure deepens over Wisconsin Thursday night into Friday. As the low pressure system moves across Wisconsin on Friday, winds across the southern half of the lake will generally be from a south to southwesterly direction whereas winds across the northern half of the lake will be from an east to northeasterly direction. Gusts across the lake will be around 20 kt on Friday. Showers and thunderstorms are also possible across the lake on Friday associated with the low. As the low moves across central Lake Michigan Friday night, winds will become more variable, but will become northwesterly for the start of the weekend as the low lifts northeastward into eastern Canada. Falkinham && .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