Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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220 FXUS63 KARX 160937 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 437 AM CDT Thu May 16 2024 .KEY MESSAGES... - Showers and storms continue to push through the area this morning. Additional storms may develop east of the Mississippi River this early afternoon with some strong to marginally severe storms possible. - Additional shower and storm chances spot the forecast through the weekend into early next week. Stay up to date with the latest forecast as detail continue to be refined. - Temperatures increase into the weekend with highs in the 70s to low/mid 80s. && .DISCUSSION... Issued at 437 AM CDT Thu May 16 2024 Today - Tonight: Current radar mosaic shows showers and thunderstorms moving across the forecast area ahead of a surface boundary and approaching upper level shortwave trough. By 3 AM local observations showed a few locations picked up around 0.25 to 0.50". These showers and storms will continue to push northeast/east through the area slowly clearing west of the Mississippi River through the morning. However, will be monitoring conditions through the day as hi-res guidance shows some additional development east of the Mississippi River in the early afternoon with the aforementioned shortwave and a trailing piece of energy along with increasing moisture. As was mentioned with the previous forecast, there will be some dependency on timing and how much instability we can build through the day. Short term guidance would suggest potential for SBCAPE to increase to around 1000-1500 J/kg, though there is some question on how quickly the moisture axis may be displaced eastward. SPC has maintained a marginal risk (1 of 5) for severe weather for portions of far southwest into central Wisconsin where there may be a short window this early afternoon for strong to marginally severe storms (main threats hail 1-2", gusty winds with any storm) to develop before pushing eastward by late afternoon. Friday - Next Week: Drier conditions look to follow for Friday before another system moves through the region over the weekend. Warmer air moving in the region ahead of this system will allow highs to increase into the mid 70s to low/mid 80s Friday into the weekend. An upper level shortwave trough is forecast to track across southern Canada/Northern Plains Saturday with an associated surface front swinging across the region. Ensemble solutions suggest a few showers and perhaps storms developing late Saturday along the front, though there appear to be some differences between individual ensemble members on how much and even how far south showers and storms develop. Model guidance appears to be in good agreement in an upper level trough across the western U.S. by the start the week. Multiple rounds of shortwave energy look to eject from the mean trough through the early start of the week. However, there remains lower predictability in narrowing down details such as timing and location of these waves and in turn developing surface features with the extended forecast range. This is reflected with quite a bit of variability in GEFS and ECMWF ens solutions through the period. With this said, the current forecast would point towards Sunday night into early Monday for the next chance for increasing shower and storm chances. Will maintain blended model guidance until further details can be refined, but a more active period looks to be possible into early next week. Will note that with these uncertainties temperature spread begins to increase into the week as well. However, current signals in guidance would suggest highs remain generally around and slightly above the seasonable normals to start the week. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1058 PM CDT Wed May 15 2024 A mix of VFR and MVFR conditions are expected through the TAF period as showers and isolated storms (~15% chance) progress through the region overnight and into the early morning Thursday. As this disturbance, passes through the region cigs will begin to drop to MVFR with visbys of 4-5SM possible in more robust showers. There is some signal (20-30% chance) for IFR cigs to get into KRST into the morning hours however this appears unlikely at this time. Otherwise, as the disturbance begins to exit the region conditions will return to VFR by the afternoon with diurnal mixing. Depending on how fast sky cover clears, will have to watch for some redeveloping showers and storms (Roughly 20% chance at KLSE) east of the Mississippi River later into the afternoon. Winds will remain fairly light at 5- 10 kts through the TAF period and will shift from the southeast to west/northwest during the day on Thursday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...EMS AVIATION...Naylor