Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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126 FXUS63 KARX 142019 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 319 PM CDT Wed Aug 14 2024 .KEY MESSAGES... - From Tonight into Thursday morning, there will be a round of showers and storms. Some of these could produce heavy rain. - From Thursday afternoon into Thursday evening there will be an additional round of showers and thunderstorms. While rain rates look to be less, there could be some strong to severe storms. This is highly dependent upon afternoon cloud cover. && .DISCUSSION... Issued at 319 PM CDT Wed Aug 14 2024 Tonight through Thursday night... The 14.12z models continue to show that a low pressure system will move slowly east northeast through the area and gradually deepen. Even though it will be deepening, the 0-6 km shear is rather messy. This is especially the case in the 3-6 km shear. The 0-3 km shear look a bit better, but its shear is in the 20 to 30 knot range. Unlike yesterday, there appears to be a bit more instability in the wake of the morning convection. Many of the models are suggesting 1-2K J/kg 0-1 km CAPES. There are even a few models up to 2500 J/kg. This will all depend on the cloud cover during the afternoon. In addition, there will be some moderate to steep mid-level lapse rates. This could result in some pulse severe storms, so the marginal Day 2 SPC outlook looks reasonable. With precipitable water values increasing to around 2 inches and warm cloud depths of 3.5 to 4 km, these showers and storms will be highly efficient rain producers. WPC has the area under marginal risk for excessive rain. It continues to look like most areas will see anywhere from 0.75 to 1.5 inches of rain. The 24-hour HREF QPF ensemble localized probability matched mean has an area of 2-3 inches from northeast Iowa northeast into north-central Wisconsin. Friday... The 14.12z models continue to show that surface low will continue to move east northeast into the northern Great Lakes. This will keep scattered showers and maybe a few storms as shortwaves rotate around this low. With limited instability and the best moisture to our east, rainfall totals still look to be on the lighter side. Days 8 to 14 (August 22-28)... Unlike the past several days, it looks like there will be a far less amplified 500 mb pattern across the northern United States and the Canadian Prairies. As a result, it is looking like the omega high in the 6 to 10 day period will quickly flatten as a series of shortwave troughs move through this region. Northwesterly flow aloft will bring unseasonably cool air south into the region. As a result, the chances for below-normal temperatures have increased across the Upper Mississippi River Valley east into the Great Lakes. While the temperatures look a bit cooler, there continues to be enhanced chances for drier than normal. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1243 PM CDT Wed Aug 14 2024 Based on radar trends and CAMS delayed the onset of the rain for this afternoon at KRST and evening at KLSE. As the rain moves into the area, soundings show a gradual drop in ceilings to IFR/MVFR tonight. Even added some MVFR visibilities due to fog for KRST from late tonight into mid-morning Thursday. Winds will be sustained around 10 knots with some gusts up to 20 knots from tonight into Thursday morning. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Boyne AVIATION...Boyne