Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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005 FXUS63 KMPX 300631 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 131 AM CDT Thu May 30 2024 .KEY MESSAGES... - Rain and thunderstorms will move into western Minnesota starting Thursday and will slowly push into eastern Minnesota/western Wisconsin into Friday morning. - Marginal Risk (Level 1/5) for damaging wind and large hail in place across SW Minnesota Thursday. - Isolated shower chances continue this weekend. Best potential appears to be Saturday night into Sunday morning. - Another round of widespread rain and thunderstorms is forecast across the Upper Midwest Sunday evening into Monday, with the chance that a few storms could be strong. && .DISCUSSION... Issued at 227 PM CDT Wed May 29 2024 Talk about a great day of weather! Hopefully folks got the chance to get outside today or will be able to salvage some of the gorgeous late-May weather this evening. Afternoon highs in the low 70s will gradually fall through the 60s this evening, with only a light southeasterly breeze at times. Diurnal Cu will decrease in coverage and set the stage for a clear night ahead, thanks to quiet weather beneath a well defined upper-level ridge. Lows will generally dip into the mid-50s for most of Minnesota, but will run a bit cooler in the mid to upper 40s across western Wisconsin. On Thursday, the ridge axis will shift east thanks to a "push" from the next upper-level trough that is progged to become negatively tilted over the northern Great Plains. The relationship between the eastward advancing ridge (and expansive surface high) and the incoming trough will allow for moisture return out of the Gulf to advect north through the Plains. A region of broad ascent should promote the development of rain and thunderstorms across Nebraska and the Dakotas late tonight. This activity will push east towards western Minnesota in the first few hours after daybreak. Forecast soundings indicate low-level dry air present through mid to late morning across western Minnesota, which will likely work to delay the onset of some of the earlier chances as depicted on the CAMs. However, the eastward advance of the upper-level features in tandem with continued moisture flow into the region will work to produce scattered to likely rain/storm chances across western Minnesota tomorrow afternoon and evening. A more defined band/clusters of convection are expected to develop ahead of a cold front in the eastern Dakotas tomorrow afternoon and will progress eastward overnight, weakening with time. SPC has introduced a Marginal Risk for severe weather across southwest Minnesota, generally along and southwest of the Minnesota River. The environment across southwest Minnesota is forecast to support an isolated instance of damaging wind/large hail given MLCAPEs upwards of 500-1000 J/kg and roughly 30 knots of shear. Stable lapse rates aloft and the loss of daytime heating will work against a more substantial threat. The highest PoPs along and ahead of the cold front will translate east towards the Twin Cities by daybreak Friday and will arrive in western Wisconsin by mid-morning. Rainfall projections from WPC are between 0.25-0.5" for most locations, with the potential for higher amounts beneath stronger convective cells in southern/western Minnesota. We`ve maintained chance PoPs through Friday evening, as a secondary wave is forecast to swing around the base of the trough over the Upper Midwest. This has resulted in variance throughout the model suite, however there are plenty of wet solutions to satisfy keeping chance PoPs in play through the period. The weekend forecast features quite a bit of dry time, however we`ll keep isolated to scattered shower chances around the area. Models have focused in on late Saturday/early Sunday as a window for showery activity given a few quick hitting "ripples" in the zonal flow aloft. A better defined "dip" in the upper-level flow and associated mid- level shortwave trough will bring better chances for rain and thunderstorms across the Upper Midwest Sunday into Monday. Indications are that warm air advection ahead of this system will warm temperatures into the low 80s, which will combine with more appreciable moisture return to fuel strong storms. It`s too soon to evaluate the potential for specific hazard types, but it`s fair to say that any convection that moves through would likely pose a heavy rain threat given PWATs pushing 1.5" per the blended global ensemble suite. The unsettled pattern will swing another chance for showers and storms with the passage of a cold front in the Tuesday/Wednesday timeframe. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 128 AM CDT Thu May 30 2024 VFR conditions overnight and most of Thursday, with rain showers and possibly a thunderstorm moving in from west to east later in the day and overnight. Winds will become more southerly, with gusts near 20 kts possible around mid-morning. Did introduce a prob30 group for thunder at the western TAF sites. KMSP... VFR conditions throughout the TAF period, with gusty southerly winds near 20 kts on Thursday. Rain will move in from the west Thursday evening/night. There is a chance for thunder, but for now did not include the mention of thunder in the TAFs. /OUTLOOK FOR KMSP/ FRI...VFR/MVFR, chc IFR/-TSRA early. Wind S 10-15kts. SAT...VFR/MVFR, chc -TSRA. Wind SW 10-15kts. SUN...VFR, chc MVFR/-TSRA. Wind S 10-15kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...Strus AVIATION...JRB