Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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791 FXUS63 KMPX 030858 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 358 AM CDT Wed Jul 3 2024 .KEY MESSAGES... - Thunderstorms and locally heavy rainfall likely for Thursday and Thursday night. - Chances for showers and a few thunderstorms will linger into next week with temperatures remaining below normal. && .DISCUSSION... Issued at 358 AM CDT Wed Jul 3 2024 Aside from some low stratus lingering in parts of western WI, skies are clear across the Upper Midwest this morning. Water vapor imagery shows several weak disturbances across the northern Plains. These will continue eastward today and could spark a few showers or storms across the northern half of MN, but rising mid level heights and a dry atmosphere should limit coverage of these to less than 20 percent. The rest of the area could have some fair wx CU this afternoon with highs in the low to mid 80s. The trough over the northern Rockies will dig southeast tonight and begin to reach the Upper Mississippi Valley late tonight and early Thursday. Showers and a few storms will overspread western MN after midnight and begin reaching eastern MN/WI by midday Thursday. As the upper low continues across the northern Plains and reaches MN late Thursday, it will continue digging and become neutrally tilted. Forcing will become more focused and a broad surface low will develop and track across southern MN. Scattered to numerous thunderstorms are expected by afternoon, which will continue Thursday night along and north of the low track. Mid level lapse rates will remain poor and the prospects of significant surface heating appear limited given the extensive cloud cover, so instability will be lacking. However, there is some potential for a few stronger storms with several hundred joules of CAPE given moist surface conditions. Some non-supercell tornadoes can`t be ruled out near the surface low. This system is beginning to reach the window of the CAMs and many of the members seem too sparse with precipitation - possibly as a result of low instability. From a synoptic standpoint, one would expect more widespread activity than the CAMs would currently indicate. Nevertheless, even the less bullish CAM output does generate some impressive totals locally due to a combination of the location of the deformation zone across central MN and WI and slow storm motions. Some localized totals could exceed 2 or 3 inches, with some model output indicating the potential for even higher values than that. Kept PoPs in the 70s to 80s, but it doesn`t appear rain will be continuous for many hours at a time in any given location. Problem for Thursday evening will be determining where and when specific locations will be impacted as activity could remain more scattered than with other events recently. The showers will linger into Friday across eastern MN/WI, but some activity could redevelop farther west in the afternoon with breaks in the clouds and some instability developing within the cyclonic flow. Multiple waves within a broad north central U.S. trough will keep precip chances going for much of the remainder of the period. Nothing looks particularly widespread or heavy, but it will continue the gloomy and un-Julylike weather for the region. Temperatures will remain below normal until if/when the western Ridge builds east. Some of the extended guidance is hinting at that possibility toward mid-July. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1029 PM CDT Tue Jul 2 2024 For EAU, IFR cigs and patchy mist will linger for the next couple of hours before clouds finally clear to our east. Elsewhere, VFR expected at all terminals with only high clouds during tomorrow, though more clouds will start to arrive from the west Wednesday evening. West-southwesterly winds will be around 5 knots overnight, becoming westerly at around 10 knots during Wednesday. Some gusts to 20 knots are possible during the afternoon. Winds will slow to calm/variable Wednesday evening. KMSP...Westerly winds could gust to above 20 knots during Wednesday afternoon. /OUTLOOK FOR KMSP/ THU...MVFR/IFR SHRA/TSRA, mainly PM. Wind SE 5-10 kts. FRI...MVFR SHRA/TSRA likely. Wind N 10G20 kts. SAT...Chance MVFR/SHRA/TSRA, mainly PM. Wind W 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...Borghoff AVIATION...CTG