Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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830 FXUS63 KMPX 132051 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 351 PM CDT Thu Jun 13 2024 .KEY MESSAGES... - Drying out this evening with a beautiful Friday forecast. - More widespread showers and thunderstorms likely Saturday with locally heavy rainfall possible. - An intense heat wave will build across the eastern third of the country next week with the Upper Midwest on its western periphery. This will mean periods of hot and humid conditions and multiple rounds of thunderstorms with heavy rainfall. && .DISCUSSION... Issued at 345 PM CDT Thu Jun 13 2024 Within the most recent radar scans, the shower activity as well as the more abundant cloud cover has finally reached Iowa and will continue to make its way southeast. Dry and quiet conditions will prevail for the next 36 hours or so as upper-level ridging and surface high pressure fill in from our west. This evening will be a good one to go out and enjoy with lows tonight reaching low to mid 50s under mostly clear skies. Friday will be a beautiful day despite a few afternoon clouds and highs nearing the low 80s. By Friday night, a shortwave over the CO Rockies will eject towards the northern plains. Showers and thunderstorms will begin to develop over southwestern MN around sunrise and then extend north and eastward in coverage by Saturday afternoon/evening. PWATs exceeding 1.75" as well as a +40kt LLJ will allow for some potentially heavy rainfall across central and southern Minnesota and parts of western WI. The forecasted QPF validates the slight risk for excessive rainfall in those areas issued by the WPC. Saturday`s disturbance will quickly vacate to the east by Sunday. Ridging will intensify over the eastern CONUS and an h85 thermal ridge over the west-central CONUS will shift east. This will make conditions feel rather soupy with high temperatures in the upper 80/low 90s, dew points in the 70s, and heat indices in the mid to upper 90s. Another shortwave enters western MN Sunday afternoon and tries to create some modest elevated instability of 2000 J/kg of MUCAPE as well as steep lapse rates of 8 deg C/km. However the caveat here is forecast soundings showing at least 5kt deep capping inversion. So in the off chance that the shortwave does find a miracle to break the cap, maintained the inclusion of chc PoPs through Sunday night. Monday into next week features an elongating troughing pattern upstream over the western CONUS. This will cause multiple shortwaves to eject over the northern plains with several additional chances of precip. At the same time, ridging will continue its grasp over the eastern CONUS and place MN/WI on the western periphery of the thermal ridge with a strong LLJ continuing to advect warm moist air from the south. Therefore warm and humid conditions will last at least through Wednesday before some relief returns Thursday with cold front reduces temps to the low 80s. As for rainfall amounts, there are still some inconsistencies in QPF totals due to frontal placement within the guidance. But with noticeable high PWATs and a mainted moisture rich LLJ, any rainfall that does occurs will have an increased likelihood of being heavy which increases the concern with flooding through the period. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1230 PM CDT Thu Jun 13 2024 VFR conditions are expected for the TAF period with elevated showers over south-central Minnesota departing by 21Z today. Northwest winds of 10-15G20kts this afternoon--strongest in central/western MN--decrease after sunset to around 5kts or less. Winds will be light and variable for Friday with a SCT CU deck for the afternoon. KMSP...VFR conditions expected for the TAF period with northwest winds around 10kts this afternoon decreasing to 5kts or less overnight. CU develop by midday tomorrow with VFR bases. /OUTLOOK FOR KMSP/ FRI...VFR. Wind N at 5 kts. SAT...RA/TSRA/MVFR likely, IFR possible. Wind SE 10-15G25kts. SUN...Mainly VFR. Slight chc TSRA/MVFR. Wind S 10-15 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...Borghoff/Dunleavy AVIATION...CTG