Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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
43
44
45
46
649 FXUS63 KMPX 011744 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1244 PM CDT Sat Jun 1 2024 .KEY MESSAGES... - Showers and clouds will gradually clear from west to east today. - Severe thunderstorms & localized heavy rain possible Sunday evening, especially across western and southern Minnesota. - Another chance for widespread rain and thunderstorms is likely Tuesday. && .UPDATE... Issued at 922 AM CDT Sat Jun 1 2024 Cold front this morning is starting to become a little better defined from roughly New Ulm up through the Twin Cities. As convergence increases along the front with dewpoints around 60, we`re seeing enough forcing with this moisture to start forcing some showers/drizzle along the boundary. This boundary will push east some, but will wash out this afternoon over western WI. An isolated shower will be possible through the afternoon along this boundary, but limited instability will keep the severe threat with any of this activity very low. Tonight, we`re seeing increasing agreement among the CAMs of some isolated/scattered showers developing over central MN. Basically, as the cold front washes out over southeast MN/central WI, a warm front starts to sharpen over central MN this evening, and it`s north of this feature we see the CAMs trying to spit out some weak showers. For Sunday, a slower trend in the timing of the shortwave/front that will force convection in the afternoon in the Dakotas continues to be noted. So the same concerns about the severe risk for the MPX area due to limited instability mentioned in the overnight AFD continues. The consensus we`re seeing from the 12z guidance coming in is that we`ll see storms develop along the boundary in Dakotas (more so in the northern version) quickly line out, with that line approaching western MN in the evening. How far north that line will be is a bit in question, with the HRRR taking it across northern MN, while the NAMnest would have it moving through our western CWA. The current Day 2 outlook still looks reasonable, though may have a bit more of eastern buffer in the severe probabilities than needed, so it seems unlikely that we`ll see an eastward expansion of probabilities with the afternoon update. && .DISCUSSION... Issued at 326 AM CDT Sat Jun 1 2024 Today through Monday...Showers continue to diminish in coverage and intensity early this morning along and east of a line from roughly Fairmont to Mankato to the eastern Twin Cities metro up through Taylors Falls. An additional tenth to two tenths of an inch of rainfall is possible through sunrise as the showers continue to progress to the northeast. Hi-res models indicate that some redevelopment of showers in this same general area and western Wisconsin is possible later this morning as a weak 700mb wave moves through. Otherwise, skies will become mostly sunny with highs in the mid to upper 70s. Attention then turns to Sunday afternoon and the threat of additional rain and severe thunderstorms. While the SPC SWODY2 Slight Risk was expanded eastward to include the western half of Minnesota and the Marginal Risk encompassing the remainder of the MPX forecast area, there are a few factors that may impact how much severe weather we end up seeing. First and most notably, forecast CAPE values have decreased from run to run over the last 24 hours or so. This may be in part to some Sunday morning convection that CAMs are highlighting across western and southern Minnesota associated with a LLJ/WAA. This cloud cover would prevent afternoon highs from reaching the low 80s from previous forecasts and limit instability. Another factor is the timing of the cold front moving from the Dakotas into Minnesota, which seems to have slowed down from previous forecasts. Storms coming from the Dakotas are expected to grow upscale into an MCS as it crosses into Minnesota Sunday evening with the main threat being damaging winds and heavy rain. The system would weaken as it continues eastward into Wisconsin around sunrise Monday with showers ending by mid afternoon. Tuesday through Friday...After a brief break from active weather Monday afternoon, rain and thunderstorm chances return Tuesday. A negatively tilted 500mb trough is forecast to move across southern Canada and the Dakotas through early Wednesday morning. There are still timing differences between the guidance as well as slight differences in placement and strength, but another round of heavy rain and some strong thunderstorms appears likely. There will be plenty of Gulf moisture advected northward with PW values above the 90th percentile of climatological norms and high temperatures in the low to mid 80s. As of right now, this system looks to be stronger than Sunday`s and definitely bears watching over the next couple of days. Behind this system, we get back into northwest flow aloft with the 500mb low lingering across northeastern Minnesota. Additional shower chances are possible through the second half of the week with highs in the low to mid 70s. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1231 PM CDT Sat Jun 1 2024 A rather diffuse front now stretches from about AEL to RNH. This front will wash out this afternoon near its current location, with enough moisture remaining east of this boundary to keep occasional showers going in the EAU area over the next few hours. Tonight, this boundary will wash out, with a warm front taking shape over central MN. We could see a few showers try to form on this boundary for AXN/STC, but those probabilities are low enough at the moment to keep those TAFs dry. Over in WI, skies will clear out with winds going calm as the front washes out. This setup is looking increasingly likely to create some dense fog for EAU in the morning, with a possibility at RNH as well, though the fog probabilities look much better to the east of the them. Sunday will see increasing southeasterly winds during the day. Southerly h85 winds will be increasing through the day as well, which could produce scattered shra/tsra, but CAMs are pretty muted at that potential right now, so the dry TAFs continue through this period. KMSP...With increasing southerly wind at 850mb Sunday afternoon, you can`t completely rule out scattered shra/tsra activity developing, but at this point, the next rain chances look to be tied to the remnants of a line of storms that will be coming out of NoDak Sunday afternoon, reaching MSP closer to 6z Monday. /OUTLOOK FOR KMSP/ MON...MVFR/-RA early chc TS, then VFR. Wind W 5-10 kts. TUE...VFR early, then MVFR/SHRA/-TSRA. Wind S bcmg W 10-20 kts. WED...VFR. Wind W 15-20G30-35 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ UPDATE...MPG DISCUSSION...Dye AVIATION...MPG