Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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708 FXUS63 KARX 220801 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 301 AM CDT Wed May 22 2024 .KEY MESSAGES... - Small shower/storm chances (10-30%) today, highest north of I-94. Severe weather not expected. - Next round of organized showers and storms likely Thursday night/Friday. While a few stronger storms cannot be ruled out, confidence for organized severe storms is low. - Seasonable temperatures with potential for unsettled weather during the latter half of the holiday weekend. && .DISCUSSION... Issued at 300 AM CDT Wed May 22 2024 Today-Thursday: Quieter, small shower/storm chances today The negatively-tilted mid-level trough associated with yesterday`s severe weather continues to slowly pivot across northern MN while the cold front has shifted east of the area. A tight pressure gradient south of the strong surface cyclone and robust low to mid-level wind fields will keep winds gusty today (25 to 35+ mph), slowly diminishing as the low begins to pull farther north through the day. Small (10-30%) chances for showers/storms continues today as a secondary shortwave trough rotates the base of the broader trough within broadly cyclonic flow and steepening lapse rates, highest chances north of I-94. Any showers should diminish by early evening. A dry day is on tap for Thursday beneath shortwave ridging with seasonably warm highs well into the 70s. Thursday night-Friday Night: Shower/storm potential Another shortwave trough will move from the northern Rockies into the northern plains Thursday night into Friday with its associated cold front progressing east with it. Organized showers and storms are expected with this system in response to mid-level warm/moist advection ahead of the front, although the stronger synoptic ascent with the shortwave looks to remain farther north and west. Seasonably strong mid-level flow and increasing low-level moisture would support some risk for strong/severe storms ahead of the front. However, there is uncertainty with the timing of the front and convective evolution. GEFS-based machine learning probabilities indicate low (5-15%) severe weather chances mainly east of the area on Friday, consistent with the past few runs. However, some guidance is a bit slower, and SPC has included parts of northeast IA and southwest WI in a low end (level 1 of 5) risk for severe storms on Friday. Regardless, drying is expected by Friday night behind the front. Saturday-Tuesday: A series of shortwave troughs will eject from the Rockies within quasizonal flow into the Mississippi Valley through the holiday weekend, eventually resulting in broad mid-level troughing over the Great Lakes by Memorial Day. This pattern favors near to slightly below average temps heading into early next week. Given the uncertainty in placement of the troughs, broad-brushed rain chances (20 to 50%) persist later Sunday through Tuesday, but these details will be refined through late week as predictability increases with these systems. Rain chances likely will need to be increased for some of these periods in future updates. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1051 PM CDT Tue May 21 2024 IFR/MVFR ceilings will be seen at the TAF sites overnight. As the surface and upper level low move away from the area late tonight and on Wednesday morning. The low clouds will become more scattered. The low pressure area pulls away, the surface pressure gradient will increase overnight. This will result in west and northwest wind gusts of 25 to 35 knots. && .HYDROLOGY... Issued at 300 AM CDT Wed May 22 2024 MRMS rain estimates and station reports showed a swath of 2 to 4 inches of rain since yesterday from parts of northeast Iowa through central Wisconsin, resulting in rises on some rivers, including the Turkey, Kickapoo, Black, Upper Iowa, and Yellow Rivers. Minor flooding is expected along parts of the Turkey River, and is possible along sections of a few Wisconsin tributaries. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...JM AVIATION...Boyne HYDROLOGY...JM