Area Forecast Discussion
Issued by NWS Twin Cities, MN

Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
589 FXUS63 KMPX 170458 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1158 PM CDT Mon Sep 16 2024 .KEY MESSAGES... - Highs in the 80s continue through Thursday. - A more active pattern is expected for the second half of next week into next weekend with the best chance for rain right now is Wednesday night through Thursday evening with lots of spread continuing on when a weekend round arrives. - Heavy rain is currently the greatest potential hazard, though a severe potential is slowly starting to emerge for the two active periods as well. && .DISCUSSION... Issued at 318 PM CDT Mon Sep 16 2024 It`s another day of summer thanks to the blocking high that remains entrenched over the Great Lakes. MSP has been knocking on the door of 90 this afternoon. We have 150 years in our record book for September 16th, and we`ve only gone into the 90s 5 times, so although this heat is not unprecedented, it is pretty uncommon. Like yesterday, mlCAPE is over 1000 j/kg and we have a cu field out there as a result, but we lack the forcing (like they`re seeing up near the Canadian border) to get thunderstorms going. We look to be stuck in this pattern through Wednesday where we look to remain dry, but we`ll be in this southerly, warm advective flow where you can`t rule out seeing some isolated showers during the afternoons with peak heating and again during the late night/early morning hours with LLJ activity. There`s little agreement in the models on when/where any of this activity may develop through Wednesday, so we stuck with the NBM through Wednesday, which is a mainly dry forecast for the MPX area, though we may be playing a bit of whack-a-mole if activity tries to develop. Wednesday night through Thursday night. This is what looks to be our first period of active weather during the next 7 days. Models have shifted a bit with this system, as what had been looking like Thursday night for being our most likely period for rain is now more up at the Wednesday night/Thursday time frame. What hasn`t changed is that we`ll have a cold front coming at us Thursday that will be becoming increasingly displaced from its surface low and upper forcing. Given the weakly forced nature of the front, it`s no surprise to see the variability in the models we continue to see with QPF generation, but as mentioned yesterday, along the cold front Thursday afternoon, there will be sufficient shear and instability to support an at least small severe risk, it`s just a question of where that front will be during peak heating. Friday through next weekend. The one period where we are seeing increased agreement is that high pressure will result in dry weather to end the week on Friday. In addition, the west winds that we`ll see that day will also finally break our run of highs in the 80s as we start to see temperatures trend back toward our normal mid- September levels. For next weekend, there`s basically a 40% chance of rain the whole time, but that reflects the large spread we continue to see with how, and more importantly when, our next system will unfold. The idea of an h5 low coming out of the 4-corners at the end of the week, going into the Great Lakes early next week remains, but spread remains large with the track the h5 low will take into the Great Lakes and with how long it will take to get there. But, the potential remains for a good soaking rain to the north/east of the eventual low track. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
-- Changed Discussion --
Issued at 1157 PM CDT Mon Sep 16 2024 VFR. Southerly winds will continue to remain elevated in speed through the pre-dawn hours and then increase gusts to 20-25kts after 16z. Diurnal Cu is expected to develop this afternoon once again and could develop a stray isolated shower. However, given the lack of confidence within the CAMs, was reluctant to include any mentions of precip during this TAF period. KMSP...No additional concerns. /OUTLOOK FOR KMSP/ WED...VFR, chc MVFR/-TSRA late. Wind SE 10-20 kts. THU...VFR. Evening SHRA/TSRA. Wind S 15G25 kts. FRI...VFR. Chc -SHRA/-TSRA. Wind S 5-10kts.
-- End Changed Discussion --
&& .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...MPG AVIATION...BPH/Dunleavy