787
FXUS63 KMPX 150455
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1055 PM CST Thu Nov 14 2024

.KEY MESSAGES...

- Warmer temperatures return to open the weekend. Highs warm into
  the upper 50s Saturday. Get outside!

- Unsettled, very active upper-level pattern to bring the return
  of precipitation chances across the Upper Midwest next week.

&&

.DISCUSSION...
Issued at 248 PM CST Thu Nov 14 2024

Call it a classic gray November day across the region thanks to
stubborn stratus that has been slow to clear. For most this has
slowed warming and capped temperatures in the 40s. Interestingly, a
narrow hole in the stratus allowed for some sunshine across western
Wisconsin. Surface observations responded with highs in the low 50s
at Eau Claire. The stratus deck is expected to slowly clear from
west to east tonight. There is a degree of uncertainty in how far
east clearing will take place, however locations that do clear out
have the potential for patchy fog to develop. This scenario is
reflected in the grids across western Minnesota, where the western
extent of the stratus deck has started to show signs of erosion.
There remains some uncertainty in the sky cover forecast Friday, as
various forecast soundings have trended in the pessimistic
direction, thus keeping stratus around through the afternoon. We`ll
hope for some filtered sunshine, but given the seasonality and light
winds would not be entirely surprised if the overcast appearance
wins out across much of the area. Height rises associated with an
approaching thermal ridge will shift over the Upper Midwest to open
the weekend. At the same time, the surface pressure gradient will
tighten heading into Saturday morning as low pressure deepens across
the northern Great Plains. The combination of height rises and
increasing southerly flow will yield a seasonably mild Saturday
(Highs in the mid to upper 50s). The aforementioned surface low is
forecast to track into southern Canada by Sunday and the system`s
trailing cold front will pass through the region in dry form early
Sunday. Westerly flow will knock highs down into the upper 40s/near
50 degrees to close the weekend.

The forecast evolves into a much more active regime next week. It
starts Monday as a vigorous cutoff upper low over the southwestern
CONUS races northeast across the Great Plains. Deep surface low
pressure is forecast to eject east of the Rockies and move towards
the Upper Midwest, in tandem with the approach of the cutoff low. A
broad shield of precipitation will precede the surface low into
Minnesota and Wisconsin. There is a high degree of confidence in a
prolonged period of rainfall Monday into Tuesday, which is reflected
in a significant uptick in NBM`s PoPs (80-90% early Tuesday!). The
forecast becomes more uncertain following the initial round of
widespread soaking rainfall. Large scale phasing of the cutoff low
and incoming upper-level trough is handled differently across the
model suite. This is quite common in the day 6-7 period, in fact it
will probably be a few more days before we can start to lock into a
solution one way or another. Should a solution that efficiently
wraps cold air into the system come to fruition, we will better be
able to address the likelihood of snowfall/amounts for the middle to
end of next week. There is growing consensus that the end of next
week will feel colder, with highs closer to average in the mid to
upper 30s/lows in the upper 20s.

The second half of next week can be summed up in three key pieces:
where and when do the upper level features phase, how efficiently
does cold air wrap into the system, and what is the eventual
residence time of precipition (do we end up with a slow moving
upper low across the upper Midwest through the end of the week
[Euro] or is the departure of the upper level system more
progressive [GFS]). The middle of next week looks wet and windy,
but it`s a little too soon to know if we can throw wintry into
the mix locally. Global guidance has trended in warmer direction
today, with fewer ensemble members producing snow at MSP in the
Wed-Fri timeframe. Stay tuned!

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1052 PM CST Thu Nov 14 2024

The line of stratus has progressed eastwards far more rapidly
than anticipated, and as such the spread of fog has quickly
increased over areas of western MN where the clearing is
focused. Compared to the 00z TAF, increased the onset and
decreased the overall visibility within the fog affected areas,
with RNH/EAU the only sites spared as the stratus remains. Winds
will remain light and variable before turning 150-180 later in
the period increasing to 5-7kts. As the stratus continues to
erode, CIGS should lift leaving us with SCT/BKN250 after around
18z for all locations.

KMSP...A TEMPO group for fog has been included due to the
increased clearing compared to the 00z guidance. We may need to
drop VIS below 4SM, but kept things generally within high IFR to
low MVFR for now as we continue to monitor fog development
tonight.

/OUTLOOK FOR KMSP/
SAT...VFR. Wind SE 15G25-30kts.
SUN...VFR. Wind W 10-15G25kts.
MON...VFR. Wind SE 5-10kts.

&&

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

&&

$$

DISCUSSION...Strus
AVIATION...TDH