NWS Forecast Discussion
222
FXUS63 KMPX 210121
AFDMPX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
721 PM CST Mon Jan 20 2025
.KEY MESSAGES...
- One more night of dangerous wind chills between -30 to -40
degrees.
- Very light snow Tuesday night into Wednesday & again on
Friday.
&&
.UPDATE...
Issued at 652 PM CST Mon Jan 20 2025
Have opted to include our entire coverage area in an Extreme
Cold Warning, starting at current time and ending at 10am (thus
moving the end time up by two hours from noon to 10am).
The reasoning: wind speeds will be slightly higher overnight,
with fairly frequent gusts, thus there will be plenty of
variance around the -35 threshold overnight through sunrise just
enough such that those values will likely be realized over all
counties within our coverage area. The lowest wind chills,
around -40F, are expected over west central to central MN and
over portions of western WI, while values which will flutter
between -33 to -36 will occur near the MN River and in far
southern MN (near the I-90) corridor, along with in and around
the Twin Cities metro.
The timing of the back end has been moved up as the forecast
wind chills improve appreciably late morning back to between
-20F and -30F, then over -20F starting in the afternoon. No
additional wind chill hazards are expected beyond late Tuesday
morning. Though there may be a 1-2 hour period of wind chills
rising through the bracket of a Cold Weather Advisory late
Tuesday morning, that duration will be short enough and
understood to continue rising out of that threshold, thus no
additional products beyond the Extreme Cold Warning are
expected.
&&
.DISCUSSION...
Issued at 212 PM CST Mon Jan 20 2025
Our coldest air of this Arctic outbreak has arrived, as the
base of the deep trough covering all of North America has become
centered over the upper midwest. 850 temperatures will drop to
around -35 C by this evening within the core of this trough,
which are in the 99.5th percentile for cold airmasses. Air
temperatures are already around 5 degrees colder than prior days
with afternoon temperatures in the negative teens across
central Minnesota & between -5 to -10 elsewhere, & expect these
trends to continue tonight. Thus, we`re looking at our coldest
night of this outbreak with widespread temperatures below -20
across central Minnesota & between -15 to -20 elsewhere. While
winds will be decreasing tonight with the core of the Arctic
high sliding just off to our southwest, there will be just
enough wind at these temperatures to again lower wind chills to
-30 to -40 degrees. Unlike prior days, temperatures will begin
to rebound late tomorrow morning as warmer southwesterly winds
develop on the back side of the departing high. Temperatures
will warm into the single digits across most of the area by
mid- afternoon, while wind chills will be warmer but still
below zero. Temperatures generally rebound back to seasonable
values Wednesday into the weekend, other than a brief cool down
behind a clipper on Thursday.
Flurries have become widespread this afternoon with banded
stratocumulus developing along with the increasing cold
advection. Other chances for light snow are expected later this
week, as a number of clippers pass through the region in the
wake of our departing Arctic high pressure. The first of these
comes Tuesday night into Wednesday, although our area of
Minnesota & Wisconsin looks to be split between two lobes of
vorticity & better forcing to our north and south. This means we
probably can`t expect more than flurries to a light during of
snow given the meager moisture in place behind our cold airmass.
A more put-together clipper looks possible during the Friday-
Saturday timeframe, but again moisture will be lacking with this
system. Chances look a little higher for more widespread snow
with the end of the week system, but accumulations will still be
below one inch. Chances for any appreciable accumulating
snowfall continue to look low through the end of January.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 652 PM CST Mon Jan 20 2025
VFR conditions expected throughout this duration. There is the
possibility of some MVFR ceilings with very light flurries
continuing into the evening but those instances will be few and
far between. Then, pronounced scattering out of clouds and
rising decks will help promote the very cold VFR conditions
expected overnight into Tuesday. Breezy NW winds will gradually
back to SW and S over the next 24-30 hours, with speeds
increasing to near 15G25kts late Tuesday afternoon into Tuesday
evening.
KMSP...No additional concerns.
/OUTLOOK FOR KMSP/
WED...Chc MVFR/IFR with -SN. Wind SW bcmg W 5-10 kts.
THU...Chc MVFR/IFR with -SN early. Wind NW 5-10 kts.
FRI...VFR. Wind SW 5-15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Extreme Cold Warning until noon CST Tuesday for Anoka-Benton-
Blue Earth-Brown-Carver-Chippewa-Chisago-Dakota-Douglas-
Faribault-Freeborn-Goodhue-Hennepin-Isanti-Kanabec-
Kandiyohi-Lac Qui Parle-Le Sueur-Martin-McLeod-Meeker-
Mille Lacs-Morrison-Nicollet-Pope-Ramsey-Redwood-Renville-
Rice-Scott-Sherburne-Sibley-Stearns-Steele-Stevens-Swift-
Todd-Waseca-Washington-Watonwan-Wright-Yellow Medicine.
WI...Extreme Cold Warning until noon CST Tuesday for Barron-
Chippewa-Dunn-Eau Claire-Pepin-Pierce-Polk-Rusk-St. Croix.
&&
$$
UPDATE...JPC
DISCUSSION...ETA
AVIATION...JPC
NWS MPX Office Area Forecast Discussion