109
FXUS63 KMPX 141747
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1247 PM CDT Sat Sep 14 2024

.KEY MESSAGES...

- Scattered showers expected in eastern Minnesota & western
Wisconsin today. A few thunderstorms are possible, especially if
showers arrive later than sunrise.

- Warmer and generally unsettled weather to continue on and off next
week. The best overall chance for showers looks to be Friday into
Saturday.

&&

.DISCUSSION...
Issued at 310 AM CDT Sat Sep 14 2024

A rather interesting view from GOES satellite imagery this morning
with a narrow line of showers with rumbles of thunder extending from
western Minnesota through the Canadian border. There is then another
narrow gap with a lack of cloud cover from where the showers are
located to the western edge of the Twin Cities metro, at which point
you have widespread cloud cover associated with what will eventually
be our showers stretching all the way through half of Wisconsin. The
low level jet which was expected to be the locus for showers this
morning has yet to fully strengthen, with a 6 degree C dewpoint
gradient stretching into southern Minnesota with our showers more
likely as dew points increase over the next several hours. CAMs have
generally performed poorly in resolving not only the showers off to
the west but also what limited activity thus far in northern Iowa,
with the closest CAM thus far being the HRRR which doesn`t bring
showers into eastern Minnesota until after 18z. For now, the
expectation should still be isolated to scattered showers developing
around sunrise and continuing through much of the day before
dissipating tonight as the forcing and moisture exit to the east.
Those that see showers could see enough intensity for a tenth of an
inch or two, however most will likely remain within a few hundredths
overall which continues our relatively dry stretch for September as
a whole. There is the possibility of a few thunderstorms especially
if the HRRR wins out with mainly afternoon showers, which will
mainly be a nuisance for outdoor activities with little chance for
severe weather with a lack of shear to maintain and instability on
the lower side. Temperatures will remain in the upper 70s to low 80s
with what is our coolest high temperatures forecast over the next
several days with our next likely 70s being next weekend.

After the showers depart later today and overnight, Sunday looks
quiet before we see relatively unsettled weather throughout the week
with on and off chances for showers. This is due to the ridge
overhead weakening with an occluded upper level trough over the
western CONUS dragging a weak area of CVA and brief height rises and
falls with little organization. The position of the occluded system
should keep the greater moisture and lift over the Dakotas with
showers more isolated and weaker as we rely on weaker pockets of
lift within shortwave energy. Unless we see an MCS type feature
moving out of the Dakotas, which is not evident within any of the
guidance right now, we likely miss out on the majority of the
legitimate rain chances that remain off to the west. Our reward will
be continued warmer weather with weak surface high pressure and a
lack of any kind of changes to the airmass until the very end of the
period when temperatures finally drop back to the 70s for highs.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1234 PM CDT Sat Sep 14 2024

Outside of some passing patches of drizzle, precip over eastern
MN and western WI has been pretty underwhelming. Given the cloud
cover and cooler temperatures, expecting the underwhelming trend
to continue the rest of the day, so really backed off on any
additional precip mention outside of MSP, which has one of those
drizzle patches incoming. Biggest question tonight is what do we
see for potential stratus expansion. Right now, HREF shows the
greatest potential for stratus in northeast MN, though this
could dip down into central MN and STC.

KMSP...There is a batch of drizzle incoming to start this
period. So far today, drizzle patches have produced 2-4sm vis
with cigs 015-025. Have a TEMPO group for the first two hours of
the TAF to cover the DZ threat. After that, looks like a pretty
quiet weather period with the biggest area of uncertainty being
the extent of stratus we see develop late tonight. If we do see
stratus going into Sunday morning, it looks to be based between
3k and 5k feet.

/OUTLOOK FOR KMSP/
MON...VFR. S Chc MVFR/SHRA. Wind S 10-15 kts.
TUE...VFR. Wind SE 10-20 kts.
WED...VFR. Chc -SHRA/TS/MVFR. Wind SE 10-15 kts.

&&

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

&&

$$

DISCUSSION...TDH
AVIATION...MPG