490 FXUS63 KMPX 221728 AFDMPXArea Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1228 PM CDT Mon Sep 22 2025
.KEY MESSAGES...
- Ongoing showers and storms exit to the east this morning. Another round of showers and storms is expected along I-90 this afternoon through early Tuesday.
- Quiet weather for the rest of the week with temperatures in the 70s.
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.DISCUSSION... Issued at 254 AM CDT Mon Sep 22 2025
Showers and storms continue primarily in eastern MN and western WI this morning with storm strength having decreased from yesterday evening where we saw some reports of hail up to around 2 inches in diameter in a few locations. The main risk has transitioned to localized flooding tonight as multiple rounds of showers have moved through a few areas, with the highest amount of 3-4 inches over the last 12 hours being observed in portions of northern Dakota and Pierce counties. The upper level low which has been the primary driver behind the last few days of weather is parked over Lake Superior and will weaken further throughout the day today as flow aloft becomes westerly by early Tuesday morning before shifting northerly for the rest of the week. A pseudo stationary boundary and increase low level jet later this evening will set the stage for one final round of showers and storms favoring southern Minnesota along I-90 as the boundary slides southwards into early tomorrow morning, with a few stronger storms possible as SPC has introduced a SWODY1 marginal including 5% hail/wind risks. Storms are expected to be isolated in coverage but keep refiring over the same locations such that localized flooding could also be a concern, however PWATs are somewhat limited around 1.25`` so multiple rounds of training storms will be required to see impacts. As the boundary slides southwards into Iowa overnight, active weather will cease within the bounds of the MPX CWA and will begin a period of quiet weather.
Flow aloft will favor northerly with some wobbles to northwest/northeast over the rest of the week, alongside weak surface high pressure bringing general subsidence across the region. Fair weather cloud cover is still expected as dew points remain in the 50s and we should mix fairly well, which will also mean chances for overnight fog become possible as temperatures fall to dew points with efficient radiation cooling and weak surface winds underneath high pressure. The fog will be the most dense earlier in the week behind the showers, with gradually drying conditions as we head towards next weekend resulting in fog that is overall patchier and less of an issue. Other than the fog chance, there is little in the way of sensible weather expected with a lack of synoptic or mesoscale lifting mechanisms as well as moisture. It looks to be a fairly warm but overall quiet end to September, with predictability lower as we head into October due to a lack of longer scale indicators. For now, enjoy the warm weather while it lasts as October also brings the autumnal equinox, marking the trend of rapidly losing daylight as we slide closer to the winter months.
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.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1213 PM CDT Mon Sep 22 2025
IFR/MVFR stratus has stubbornly persisted this morning. However, obs and satellite imagery do show signs of clouds lifting and breaking apart, such that VFR should return at all terminals by late afternoon. CAMs have trended farther south and east with this afternoon`s precipitation, so have removed the PROB30 mention for -SHRA. VFR expected into tonight before fog and low stratus redevelops for Tuesday morning. IFR to LIFR look most likely for south-central MN into west-central WI as cigs fall to near 500 feet and visibilities reduce in fog. Have gone most aggressive with fog (1/2sm visibilities) at RWF and STC where greatest fog occurred this morning. Conditions should improve to MVFR/VFR by late Tuesday morning. Northeasterly winds become light/calm overnight before increasing to near 5 knots Tuesday morning.
KMSP...Recent obs have shown improvement in cigs with VFR likely quickly into the TAF period. Amendments may be needed to catch up with the trend. Expecting IFR stratus to develop again Tuesday morning before once again improving to VFR by late morning. North-northeasterly winds near 5 knots throughout the period.
/OUTLOOK FOR KMSP/ WED...VFR. Wind NE 5-10 kts. THU...VFR. Wind NW 5-10 kts. FRI...VFR. Wind SW 5-10 kts.
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.MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None.
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DISCUSSION...TDH AVIATION...CTG
NWS MPX Office Area Forecast Discussion