Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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290 FXUS63 KMPX 301156 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 656 AM CDT Thu May 30 2024 .KEY MESSAGES... - Today and Tonight...Rain and thunderstorms will move into western Minnesota later today and slowly push eastward into Friday morning. The risk for damaging wind, hail, and heavy rain is low, but non- zero. - Friday...A narrow area of thunderstorms with heavy rain is possible Friday afternoon/evening, mainly along and east of I-35. - Next Week...Two stronger systems will bring widespread thunderstorm chances on 1) Sunday evening/night, and 2) Tuesday/Night. These are several days away, but will need to be monitored for severe weather and heavy rain potential. && .DISCUSSION... Issued at 246 AM CDT Thu May 30 2024 Today and Tonight...Early morning satellite and radar showed an area of showers and thunderstorms across the Dakotas slowly moving east. A few high clouds were spreading out ahead of these, and this will lead to filtered sunshine today. Areas in western Minnesota will see some scattered showers and thunderstorms develop later today as warm air advection moves across the region. A more widespread area of precipitation will arrive when the aforementioned convection in the Dakotas makes its way east this evening and overnight. This will be a slow- moving system, and most locations should see some rainfall. For that reason, did increase the hourly precip chances above the blended guidance where confidence was highest in rain. The timing may be off a bit, as alluded too in the previous discussion, but wanted to advertise the higher likelihood of seeing some rain as this system slowly passes across the region later today and into Friday morning. There are marginal risks for both wind/hail across southwest MN, and also excessive rain across central and western MN. However the lack of instability, together with the steady eastward advancement of the storms, should limit concerns for severe weather or flooding. On Friday...this boundary will eventually stall out across the region, and then slowly shift northward a couple counties as a warm front. This stall, and then change in direction could lead to heavy rain threat from training thunderstorms over a narrow area. WPC has issued a marginal risk of heavy rain across central/eastern MN and western WI. Although the risk outlooks are the same, the synoptic set up is more favorable for heavy rain on Friday afternoon/evening as compared to today/tonight. While confidence is higher in the heavy rain potential tomorrow, there is more uncertainty on where the storms will track. Some of the guidance has the boundary hanging up across the Twin Cities, while others have it making it down to near I-90. Given the lack of heavy convection with a cold pool from tonight`s storms, the northern solution seems more likely, but can`t rule out the southern solution (as shown in the 06Z HRRR) either. On Saturday, most locations should be dry. But, there could be a boundary in place, and weak warm air advection will linger across the region. While your location likely won`t see any rain, there is a small chance (20 to 30%) that it could catch a stray shower or thunderstorm, so did increase pops above the blended guidance to at least represent this potential. Sunday through Thursday...Confidence continues to increase in the chance for storms late Sunday into Sunday night, and also again Tuesday into Tuesday night. On Sunday, the thermodynamic set up is about the best we`ve had all year, with mid level lapse rates forecast to be near 8C/km, and surface temps in the low 80s with dewpoints in the lower 60s. MUCAPE values near 2000 J/kg are possible, with a favorable shear profile of southerly 925 winds of 20 to 30 kts, and due westerly winds above 500 mb. While the shortwave trough does have a lower amplitude, it will be moving pretty quickly, and becoming more amplified. If things come together just right, that could lead to organized convection with severe weather potential late Sunday and Sunday night. A second system, will follow quickly for Tuesday. There is more uncertainty in the timing and placement of this upper level shortwave. The deep layer shear profile does appear favorable for severe weather, but the CAPE potential is still variable. At the very least, both these systems will be monitored over the next few days. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 651 AM CDT Thu May 30 2024 VFR conditions for most of the day. Showers and thunderstorms are still expected to move eastward later today and tonight, but the timing has slowed a bit. Winds will be south/southeast today with gusts near 20 kts. The gusts will decrease toward sunset. KMSP...VFR conditions through 00Z tonight. Showers with a few embedded thunderstorms should be knocking on the door this evening, and impact KMSP overnight. Due to uncertainty in timing and coverage, did not include mention of thunder in the TAFs. /OUTLOOK FOR KMSP/ FRI...VFR/MVFR/-RA likely, 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...JRB AVIATION...JRB