Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 121707
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1207 PM CDT Tue Mar 12 2024

.KEY MESSAGES...

- Elevated fire weather conditions today and Wednesday.

- Chances for a soaking rain Wednesday night into Thursday
  continue to look best across southern MN.

- Temperatures head to below normal levels Sunday.

&&

.DISCUSSION...
Issued at 258 AM CDT Tue Mar 12 2024

At 2am, a surface low was near St. Cloud, with a cold front trailing
to the southwest across southwest MN. An impressive warm nose moved
in ahead of this cold front, with the 230am temperature at MSP
having warmed back up to 60 degrees. One thing is for sure, the low
for the day in the Twin Cities will be coming at the end of the
calendar day. That cold front mentioned will continue to push east
through the morning, taking the thermal ridge with it, but it will
still be a very mild day, with highs in the 60s for most of the MPX
area, with EAU making another run at a record high (current forecast
is 68 with the record at 67 from 2016). Behind this cold front, the
airmass will remain very dry, with afternoon RHs again expected to
bottom out in the 15% to 25% range. Like yesterday the limiting
factor for seeing critical fire weather conditions will be the
lighter winds. Still given the expected RHs, there will be enough to
wind to continue to support keeping the SPS issued last night for
elevated fire weather conditions today in place. Only change to the
weather for Wednesday is slightly cooler temperatures, especially
across central MN (where it will stay in the 50s). These cooler
temepratures will keep RHs from falling quite as far as we`ll see
today, but RH values falling to between 20% and 30% will keep the
increased wildfire risk going for one more day.

Wednesday night through Thursday continues to hold out our best hope
for rain, but how far north rain makes it remains at question. The
h7 wave helping do drive this wave will be coming out of Nebraska
and shearing out over Iowa or southern MN. The NAM/Canadian are the
most aggressive with bringing the h7 trough into southern MN, with
the heaviest precip axis coming all the way up through the Twin
Cities. The ECMWF is at the southern end of the spectrum, with the
north edge of the rain shield barely making it up into southern MN,
with the GFS in between. We have seen a deepening of the surface low
over the last few model runs, but with that forecast to go somewhere
between central Iowa and the MO/IA border, we`re going to have to
deal with dry northeast winds undercutting this forcing/moisture
heading north, so we`re definitely not ready to jump on the wetter
solutions for southern MN yet. To go along with the precip chances,
steep enough mid-level lapse rates show up to keep the TS mention
the NBM has for Thursday over south central MN. As for precipitation
amounts, within the core of the deformation band, we`ll likely see
convection help aid in rainfall amounts of 1" to 1.5", but we will
see a very sharp gradient to the north of this band and of course
that gradient will be somewhere in the MPX cwa.

For the weekend, a pattern shift is still expected as a ridge builds
up the west coast of Canada and a trough digs into the Great Lakes.
This trough and associated pools of colder air and vorticity aloft
will drive a risk of showery activity starting Saturday afternoon
and lasting through Sunday, with the best chances for precip across
eastern MN/western WI. That precip will start as rain Saturday, but
transition to snow Saturday night into Sunday for anything still
lingering around. Given this pattern, temperatures will take a nose-
dive for Sunday and Monday, with highs only expected in the 30s, our
first foray into below normal temperature territory since the
aggressive one-day cold snap back on February 28th. How long these
colder temperatures last into next week is uncertain as ensemble
spread starts to increase quite a bit with how far east the western
NOAM ridge will make it next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1202 PM CDT Tue Mar 12 2024

Only high clouds are expected through the period becoming SCT-
BKN overnight for most. Northwest winds will turn to the
northeast/east through early tomorrow morning with speeds 10 kts
or less.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/
THU...MVFR/VFR, chc IFR/RA. Wind NE 10-15G20-25kts.
FRI...VFR. Wind W 10-15G20kts.
SAT...VFR chc MVFR/SHRA. Wind NW 15-20G30kts.

&&

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

&&

$$

DISCUSSION...Dunleavy
AVIATION...Dye


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