486
FXUS63 KMPX 092036
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
336 PM CDT Wed Jul 9 2025

.KEY MESSAGES...

- Dry and mild tonight, with the chance of showers and
  thunderstorms across southwestern Minnesota overnight.

- Marginal Risk (Level 1 of 5) for strong to severe
  thunderstorms Thursday afternoon into early Friday.

- Widespread soaking rain and storms Friday through Friday
  Night.

- Warm and mainly dry Saturday-Monday, then the next system to
  bring organized rain/storms arrives Tuesday-Wednesday.

&&

.DISCUSSION...
Issued at 334 PM CDT Wed Jul 9 2025

Surface analysis this afternoon shows high pressure centered
over the western Great Lakes, encompassing MN/WI, while a
surface low over eastern Saskatchewan province has an associated
warm front extending south across the Dakotas and into the mid-
Mississippi River Valley. Multiple surface lows dot southwest
Canada, linked by weak frontal boundaries, while high pressure
generally prevails over the Rockies to west coast. Aloft, a deep
high pressure ridge sits centered over the Four Corners region
with a ridge axis extending NE over the Northern Plains into
Manitoba province. In addition, a deep upper level low sits over
northern Alberta province with a couple notable shortwave
trough axes rotating around the main low. These shortwaves will
become the focus for our more active weather Thursday-Friday.

The area of surface high pressure will slowly shift to the east
over the next 24 hours, owing to the ridge axis from the
desert southwest nudging it to the east while the over
southwestern ridge flattens. Increasing isentropic lift in
advance of the warm front will spark off a few
showers/thunderstorms in western MN late tonight into Thursday
morning, nothing of consequence but a few heavier dumping
showers are possible given the moist environment across the
region (PWAT 1.00"-1.25"). This will be in conjunction with
minor buckling in the H5 flow, creating weak shortwave troughs
which will drift through the Dakotas into MN/WI late tonight
through tomorrow. Have kept PoPs in the 20-30% range due to the
expected isolated to scattered nature of the distribution of
precipitation.

The bigger issue becomes the deep western CONUS low for Thursday
night as it thrusts a potent shortwave trough axis southeast
through the PacNW during the day Thursday, moving through the
Northern Rockies Thursday night into Friday morning. At the
surface, the cold front associated with the Saskatchewan low
(which will move into southwest Ontario province by Friday
morning, will shift southeast and extend from northern MN
southwestward through the Dakotas. Along this front, a secondary
low pressure center will develop over eastern NE into western
IA, essentially helping advect moisture of Pacific/Gulf origins
and low level convergence into the Upper Midwest. The confluence
of these synoptic features aloft and at the surface along with
the plentiful moisture will spell fairly persistent rainfall
early morning Friday through Friday evening. Rainfall totals
will likely exceed 1" from southern-eastern MN into western WI.
The shortwave trough aloft which will swing across the area
Friday night into Saturday will take on a more negative tilt
during the night, which may not only aid heavy rain potential
but potentially also severe weather development. There is a
broadly- spread Marginal (Level 1 of 5) Risk of severe
thunderstorms for mainly late Thursday through Friday. Still too
much uncertainty to determine the placement with such broad
moisture and lift mechanisms across the region, but the
placement of the LLJ will determine if/where an MCS may develop
and progress across the area. Those details will still be hashed
out over the next 24-36 hours by SPC.

Once past this relatively heavier rain event, dry weather is
expected for the Saturday-Monday timeframe as surface high
pressure of western Canadian origin along with a broad ridge
axis glides across the region. The next system of consequence
will arrive Tuesday as another western Canadian upper level low
takes a similar progression, drops a potent upper level trough
axis southeast through the PacNW region, but this next system
becomes much more wound-up aloft. A deep H5 low looks to develop
over south-central Canada to aid in cyclogenesis of a low off
WY/SD, potentially bringing another round of widespread rain
Tuesday into Tuesday night.

As for temperatures, highs look to generally remain in the upper
70s to mid 80s for the end of this week through the start of
next week, but it`s not until after the passage of the system
for the middle of next week that a cooling trend may well be
upon us. Models indicate that starting next week Wednesday,
highs will hold in the 70s area- wide while lows drop to the 50s
area-wide.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1235 PM CDT Wed Jul 9 2025

Southeasterly winds AOB 10 kts through the afternoon, with
diurnal CU field developing around ~5kt feet. It`s possible the
western MN will need -SHRA/TS mention late tonight in
association with storms that are forecast to develop over the
Plains. For now, have included PROB30s at AXN, MKT, and RWF for
the morning convection. Confidence in impact to terminals is
currently too low to go prevailing.

KMSP...Slight chance, not even PROB30 worthy, for a shower in
the morning hours at MSP. Did not include this in the TAF for
confidence is low in impacts. For afternoon showers and storms,
went the PROB30 route due to low confidence in where storms
will bubble up and if they will impact the terminal.

/OUTLOOK FOR KMSP/
THU...VFR. SHRA/TSRA likely late night. Wind S 10-15kts.
FRI...SHRA/TSRA likely. Wind SW 5-10kts bcmg WNW 10-15kts.
SAT...VFR. Wind NW 10-15 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.

&&

$$

DISCUSSION...JPC
AVIATION...PV