Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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219 FXUS63 KARX 091949 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 249 PM CDT Sun Jun 9 2024 .KEY MESSAGES... - Cooler tonight with below normal lows generally in the upper 30s to 40s. - Showers/storm chances increase on Tuesday with periodic storm chances into the weekend. Details on the severe weather potential or any heavy rain chances will need to be worked out in the coming days. - Below normal for Monday/Tuesday, but a warming trend into the weekend with temperatures trending normal to above normal with highs in the 80s. && .DISCUSSION... Issued at 245 PM CDT Sun Jun 9 2024 Tonight - Monday: A nice Sunday so far with plenty of sunshine for most to start the day. However, current satellite imagery shows clouds increasing across parts of the area this afternoon with a shortwave dropping down across the region. Model guidance has continued to keep a dry forecast for most with some very light echos/accumulations mainly north of the forecast area. Perhaps some sprinkles could be squeaked out further south, but overall have maintained the dry forecast for most across the forecast area today. Otherwise, observations so far this early afternoon show quite breezy conditions with winds gusting generally 25 to 45 mph. These increased northwest winds will continue through the afternoon before relaxing into the evening/overnight hours. Surface high pressure will begin to build in towards the region with skies forecast to begin clearing a bit and winds becoming lighter tonight. With this, overnight lows look to be cooler than normal for this time of the year, with lows forecast to drop into the upper 30s to lower 40s across portions of central/north-central WI and upper 40s to 50 elsewhere. Drier conditions look to follow into the day on Monday with highs rising into the low to mid 70s for most. Off and on precipitation chances into the weekend. Details on the severe weather potential or any heavy rain chances will need to be worked out in the coming days: Monday night, surface high pressure remains over the local area with a ridge aloft. This ridging is broken down by a 500mb trough tracking across Canada into the Northern Plains and eventually the Upper Mississippi Valley/the forecast area Tuesday. Moisture transport increases with temperatures warming through the 70s. There is pooling of 850mb moisture ahead of the 850mb warm front and ahead of the 850mb cold front. Through 12Z Tuesday, the HRRR has scattered showers/thunderstorms to the west of the forecast area with MUCAPE and some shear over western MN. Surface dewpoints are progged to be quite dry, in the 40s with pooled 60s dewpoints over western MN into southeast SD. The NAEFs precipitable watter values have negative anomalies until 18Z Tuesday. During the day, the vertical motion appears to lead with the trough, so there is limited/a more gradual wind shift with less convergence during the afternoon when there is more instability and more shear to work with. Forecast soundings show some steep lapse rates to work with. Hodographs show good low level shear, but some weakness above that layer, then stronger winds/straightline hodograph aloft. So...severe weather ingredients are not aligned. Even so,with it being June and a warm front/cold front moving through have kept chance pops in and will need to monitor how these factors come together as we get closer to Tuesday. Return flow sets up quickly for Wednesday across the Plains with a couple of shortwave troughs embedded in the flow across southern Canada affecting the forecast area through potentially Thursday or Friday. Scattered thunderstorms are forecast to develop with these features Wednesday. The current theta-e axis is forecast across parts of western MN/western IA with steeper lapse rates and stronger deep layer shear in this area. This area to our west is currently highlighted for a 15% risk of severe weather. The embedded trough for Wednesday into Thursday appears to have deeper moisture with with precipitable water values near 2 inches with potentially a stalled frontal boundary. Should the boundary get pushed south, more of the severe weather/heavy rain potential would push farther south across the southern half of Iowa, but could also clip parts of our Iowa/southern Wisconsin counties. Ridging builds in for Friday, however a closed low over the Southwest U.S. late in the week is forecast to head through the Four- Corners region and lead trough energy also moves out of the Pacific Northwest, moving through the Upper Midwest Saturday night and Sunday. Needless to say...this storm system will bear watching as well. Seasonal high temperatures are in the lower 80s, thus still below normal for Tuesday, but 80s are forecast for the rest of the week. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 111 PM CDT Sun Jun 9 2024 VFR conditions are forecast to continue through the TAF period, with some increase in clouds across parts of the area this afternoon/evening. The main TAF concern though looks to revolve around increased northwest winds with wind gusts 20 to 35+ kts this afternoon. Winds are forecast to decrease into the evening and overnight hours with winds turning generally more north tonight into early Monday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...EMS/Zapotocny AVIATION...EMS