272 FXUS63 KMPX 050357 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1057 PM CDT Tue May 4 2021 .SHORT TERM...(This evening through Wednesday night) Issued at 240 PM CDT Tue May 4 2021 Diurnal CU have been numerous along and east of the Mississippi River today, but clear skies have prevailed to the west. As daytime heating diminishes after 7-8 PM, the cloud cover will dissipate rather quickly leading to a clear night. A surface high pressure ridge axis will shift east across the region and result in decoupling winds across most of the CWA, but especially eastern MN and WI. Good radiational cooling and relatively moist RH should result in at least a few hours of areas or widespread frost across WI. Areas of frost should also occur farther west, but perhaps just before sunrise. For now, highlighted the areas most at risk for plant damage with a Frost Advisory. Locations north of Madison, MN, to the northern Twin Cities Suburbs, to Chippewa Falls, WI have not yet really jump started the growing season yet, so advisories are not being issued for them at the moment. A clipper system will track southeast from the western Dakotas to western Iowa Wednesday and Wednesday evening. An area of rain to the north of the track will move into western MN by late morning, then spread southeast to portions of western WI by evening. The best chances are west of the Mississippi River, where likelies and categorical PoPs continue. Amounts are expected to be light and less than 1/4 inch. Another high pressure builds in Wednesday night and skies should clear around midnight. Frost will become an issue again early Thursday and additional headlines are likely. .LONG TERM...(Thursday through Tuesday) Issued at 240 PM CDT Tue May 4 2021 The temperature forecast has remained consistent over the last 2 or 3 forecast cycles and nothing is changing on that regard, with high temperatures generally in the mid 50s to low 60s and lows in the mid 30s to low 40s. As noted in the previous long term discussion from the midnight shift, elevated fire weather conditions still look possible on Thursday due to a combination of low RH dropping into the mid to upper 20s and winds gusting to 20-25mph out of the northwest. Right now skies look partly cloudy which could limit mixing, but with any pockets of clearing that could change rather quickly so not counting out the potential for increased gusts during the afternoon. There is still also that hint of some thunder with a few rain showers mainly in our northeastern CWA Thursday evening, however forcing is not the greatest with high pressure nearby underneath the incoming ridge. Friday looks to be the most pleasant day overall with mostly sunny skies underneath the incoming ridge and 5-10mph winds with an occasional 20mph gust as the pattern quickly changes as the ridge pushes eastwards later in the day. A broad upper level trough forming in the western CONUS will push eastwards, with a surface based low pressure system appearing in different locations between GFS/ECMWF producing two very different forecasts. The ECMWF is farther south with the low, centered over KS/OK, with the precipitation shield north of the warm front reaching only as far as central Iowa leaving MN/WI dry. The GFS meanwhile produces a much stronger upper level trough and closed low, which produces a broader area of synoptically driven precipitation. The GFS is also keeping the better chances south of our area, however it does scrape the western part of the state with some scattered precipitation Saturday evening into Sunday morning as it rotates through the region. Depending on how this system ends up evolving, with the GFS showing further precip chances as the closed low moves through while the ECMWF remains dry and transitions to split flow, going into the middle of May looks to be largely transitional with no significant weather systems moving through. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1057 PM CDT Tue May 4 2021 Trend with latest model runs for precip Wednesday is to nudge it a little south. This nudge was enough to keep any precip mention out of AXN/STC/RNH/EAU. Otherwise, timing from the previous TAFs still looks good. In addition, with the surface low going to the south of FSD, it still looks good to keep any MVFR cigs confined to MKT/RWF. KMSP...Not many changes needed from going TAF with very light rain looking to move in around 19/20z. If anything, confidence has increased in MSP remaining VFR this period. /OUTLOOK FOR KMSP/ Thu...VFR. Chc -SHRA. Wind NW at 10-20kts. Fri...VFR. Wind NW at 5-15 kts. Sat...VFR. Wind SE 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...Frost Advisory from 2 AM to 8 AM CDT Wednesday for Goodhue. WI...Frost Advisory from 2 AM to 8 AM CDT Wednesday for Chippewa-Dunn- Eau Claire-Pepin-Pierce-St. Croix. && $$ SHORT TERM...Borghoff LONG TERM...TDH AVIATION...MPG