383
FXUS63 KMPX 212330
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
530 PM CST Thu Nov 21 2024

.KEY MESSAGES...

- Patchy freezing fog possible tonight and Friday night.

- One last chance to get some outdoor work done on Sunday with
  highs in the 40s.

- Turning much colder next week, with our first taste of arctic
  air looking increasingly likely for Thanksgiving weekend.

- No significant winter systems expected to impact the region
  over the next week.

&&

.DISCUSSION...
Issued at 401 PM CST Thu Nov 21 2024

A surface low as been tracking south across Lake Michigan through
the day, with high pressure over the Dakotas keeping the ceaseless
northwest winds going through this afternoon. The good news is that
through Saturday morning, the Dakotas high will be slowly working
across the MPX area. This means we finally lose the winds on Friday,
but the big uncertainty is what happens with the cloud cover.
Looking at RAP soundings, we look to have a scenario where we have a
thin moisture layer that gets trapped beneath an inversion. This
time of year, that translates into very stubborn stratus layers that
are poorly resolved by the models. As the high pressure moves in on
Friday, the loss of cyclonic flow should start to clear out the low
clouds, but those low clouds look to be replaced by mid and upper
level clouds. The biggest issue with cloud cover will come during
the overnight periods the next two nights. Winds will become light
and variable overnight in western MN and then across the entire area
Friday night as the surface ridge axis moves through. With this
setup, anywhere that sees clear skies tonight in western MN will
likely have that clearing filled in with freezing fog, with that
freezing fog threat spreading across pretty much the entire area
Friday night. Again, the big uncertainty is what cloud coverage will
look like the next two nights. Given the uncertainty with cloud
cover, we don`t have much fog mention, but anyone that manages to
get light winds and clear skies over the next two night will have
the threat of freezing fog.

For the weekend, models continue to show a shortwave working across
the international border Sunday night/Monday. This shortwave will
drag an inverted surface trough across the area Sunday into Monday
morning. The best forcing and signal for precipitation continues to
be across the international border and Lake Superior, though we
could see some light rain/snow across central MN and northwest WI
late Sunday into Monday. The main impact locally of this inverted
trough will be the WAA out ahead of it. This WAA will send highs
into the 40s for much of the MPX area on Sunday, giving us one last
chance to get some outdoor work done before some real winter cold
comes slamming in for the end of November.

As for next week, the mean 200mb flow from the EPS shows the primary
jet being a southern stream feature that will be well to our south.
This means the primary storm track will be to our south. However,
there will be a northern stream jet of the northwest variety coming
down from northwest Canada into the Dakotas. This northwest jet is
what will open us up to getting our first real shot of arctic air of
the season over the extended Thanksgiving holiday weekend. This is a
cold a dry pattern, so it looks unlikely we`ll see any significant
weather systems up this far north, but given the multiple streams of
flow near us, we will have to potential for seeing some quick
hitting waves capable of producing some light precip. Given the
temperatures we will have next week, any precipitation we see will
come in the form of snow. At this point though, deterministic and
ensemble systems would favor any snow we see next week being more of
the cosmetic/nuisance variety as opposed to a big dump of snow.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 521 PM CST Thu Nov 21 2024

High end MVFR is expected to drop into low MVFR/IFR territory over
the next few hours. Once again, models have not been handling
cigs well today. Generally kept things a little more optimistic
than guidance, which had more IFR than MVFR. Ceilings will rise
by early Friday afternoon, with VFR expected for all except KEAU
by the end of the period.

Winds will remain elevated for a few more hours before trending
down. A surface high is expected to move overhead tomorrow,
leading to winds 5kts or less.

KMSP...No additional concerns

/OUTLOOK FOR KMSP/
SAT...Chc MVFR cigs. Wind NW 5-10 kts.
SUN...VFR. Wind SE 5-10 kts.
MON...VFR/MVFR w/ chc -SHSN. Wind NW 10-15G20kts.

&&

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

&&

$$

DISCUSSION...MPG
AVIATION...Dye