Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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715 FXUS63 KARX 031926 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 226 PM CDT Fri May 3 2024 .KEY MESSAGES... - Showers and scattered storms are expected mainly Saturday. Rainfall amounts of up to a half of an inch from the showers or storms. - Active pattern develops next week with periodic showers and storms through much of next week. Timing of convection into region remains an issue and will have impacts on the severe potential across the forecast area. && .DISCUSSION... Issued at 226 PM CDT Fri May 3 2024 Today through Saturday: While quiet weather is in store for the rest of the day, guidance continues to support a shortwave moving through the area on Saturday. Accompanying this wave will be a 30 to 40kt 850mb jet that will help to increase the moisture transport. PWATs will increase into the 1 to 1.3 inch range. Recent guidance continues to show some instability moving further north, as shown by general consensus of 250 to 500J/kg of SBCAPE. The highest instability continues to be in southern Wisconsin. Despite this instability, it is not enough to promote any severe weather, even with the high amounts of shear, 30 to 50kts of 0-6km bulk shear. This means that thunderstorms will be possible as the band of precipitation moves through the morning and early afternoon on Saturday. Sunday into Monday Shortwave ridge builds into the Upper Great Lakes Region Sunday into Monday. Subsidence underneath ridge will allow for mainly dry weather across the forecast area both days. With light winds near the surface...clear skies and an inversion developing over the forecast area Saturday night/Sunday morning. There is the possibility of fog formation across parts of the area...mainly in low lying areas/river valleys. However...if northwest winds stay up enough...fog may not form. At this time...have left mention of fog out of the forecast. Warmer airmass advects into the region Sunday into Monday...as 925mb temperatures warm from around plus 10 degrees celsius Sunday to near plus 14 degrees celsius by 00z Tuesday. High temperatures will be mainly in the 60s Sunday and warming into the upper 60s to middle 70s Monday. Monday night through Friday Main forecast concerns from Monday night through Friday continues to be shower/storm chances through much of the forecast period. Upper level closed low slowly moves over the Northern Plains States and weakens during the forecast period. Latest ensembles/deterministic models continue to show differences in timing of the upper level closed low/impulses rotating around the closed upper level low into the Upper Mississippi River Valley. Confidence in timing of convection and any severe potential with the storms remains low. The latest GFS/ECMWF continue to indicate vertical motion/moisture convergence with the closed upper level low/impulses. This will produce periodic showers/storms through much of the forecast period...Monday night into Friday. Temperatures will remain near or slightly above normal with highs generally in the lower 60s to middle 70s through the forecast period. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1239 PM CDT Fri May 3 2024 Light southwesterly winds expected through the evening, then shifting to southeasterly winds for the overnight period. A line of showers will move through Saturday mid-morning and early afternoon across the area. There is around a 30% chance of thunder to occur within this line, so thunderstorms can not be ruled out. Lower flight categories are expected, especially MVFR conditions. IFR conditions will be possible, as there is between a 20 and 40% chance of IFR CIGS to occur during the morning and afternoon. The wind will shift to the northwest across the area during the afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...DTJ AVIATION...Cecava