Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 290405
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1105 PM CDT Tue Mar 28 2023

.UPDATED for 06Z Aviation Discussion...
Issued at 1102 PM CDT Tue Mar 28 2023

&&

.DISCUSSION...(This evening through Tuesday)
Issued at 340 PM CDT Tue Mar 28 2023

KEY MESSAGES:

- Large storm system on track to impact the central CONUS Thursday
through Friday night. Rain expected Thursday through Thursday night,
with precipitation transitioning to snow on Friday afternoon
and evening.

- A few elevated thunderstorms capable of producing hail along with
localized heavy rainfall possible along the I-90 corridor Thursday
night into early Friday morning.

- Snow accumulations look likely Friday into Friday night, though
spread in potential amounts remains significant.

- First 50 of the year in the Twin Cities likely on Sunday (finally)

- Another potent spring system possible early next week.

Temperatures across southern Minnesota and western Wisconsin are
peaking in the low and mid 30s, with mid to upper 20s across central
and western MN. This initial quick wave of snow will continue to
pass through northeast MN stretching down along I-35 corridor in
east-central MN. A brief burst of snow remains possible across the
northeast Metro and along highway 8 in western Wisconsin. Tonight,
much drier air settles in and forecast soundings show precip
generated with this wave struggling to make it to the ground. Precip
chances have been trimmed to include areas along and south of I-90
corridor in souther Minnesota, which could still be a stretch.

Behind this system, cold and dry sfc high pressure settles in for
Wednesday. Lows Wednesday morning look to be pushing -10F below zero
out toward Morris/Glenwood/Alexandria, with highs struggling to hit
30, even where we`ve been running warmer from southeast MN into
western WI. Temperatures will continue to run 10 to 15F below normal
on Wednesday before we gradually warm into the weekend. Our weather
pattern looks to turn much more active as we end the week, with a
dynamic spring system on track to impact the Upper Midwest beginning
on Thursday through Friday night.

Model spread continues with how strong the system will be, with the
GFS still the most significant outlier on strength for this system.
Rain will begin Thursday as strong isentropic lift spreads eastern
MN and western WI by the afternoon. Thursday night looks promising
for a few thunderstorms as a frontal boundary sharpens up over
northern IA into southeast MN. A very moist and unstable airmass
will move up into IA and southern MN, with showers and thunderstorms
expected to erupt along and to the north of this surface baroclinic
zone and within the confluence zone on the northwest side of a
strengthening LLJ that will be moving from southwest to northeast
IA. There will be plenty of shear in this environment and sufficient
instability to support at least a small threat for some elevated
storms capable of producing larger hail down near the IA border in
southern MN.

On Friday, the system will begin deepening, which means it`ll wrap
in a much colder airmass to its north and west side, which will
start the transition from rain to snow. As for p-types, we kept
things simple by applying a limit of 20 to the wxtype grids for
FZRA. This means the primarily wxtypes will be a rain and snow mix,
with a secondary mention for FZRA. NBM PoWTs spit out a much higher
amount of FZRA, especially in western and central MN, but looking at
forecast soundings from the GFS, you will not see much in the way of
freezing rain, but primarily rain or snow. Freezing rain (and sleet)
become increasingly difficult to achieve in MN and WI the further we
get into Spring compared to the amount the NBM PowT grids contain.
Finally, the transition to snow occurs! It`s a complex setup where a
degree or two difference will end up the difference between rain and
moderate/heavy snowfall. Now for snow totals, it`s looking like a
few inches is a reasonable expectation, though some lower and higher
amounts will be possible depending on any mesoscale banding. I
suspect we won`t really have a great handle on the forecast
p-types until hi-res models enter the picture later this week.

This weekend into early next week, we`ll see heights build in
overhead, with another strong surge of WAA expected on Saturday
night into Sunday. In fact, it is looking to almost be a lock that
MSP will finally see its first 50 of the year on Sunday, with the
NMB 25th-75th high temperature range for Sunday between mid 40s and
upper 50s. This could trend colder if we end up on the snowier side
of the solution for Friday`s snow, but for now it looks like our
first 50 in the Twin Cities. Early next week begins quiet, but by
the Tuesday next week, it`s looking increasingly likely with both the
deterministic models and ensembles that we`ll see another strong
Spring system traverse the central CONUS. However, at this point you
can find anything in the GEFS and EPS that ranges from a null event,
to a really warm system that initiates a rapid snow melt, to yet
another strong Winter storm, so we`ll begin to get a better idea of
how this system may pan out as we get into this weekend.

For now, enjoy the sunshine on Wednesday and then prepare for a more
active pattern to takeover.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1102 PM CDT Tue Mar 28 2023

A few pockets of MVFR clouds at KRNH and KEAU, but overall VFR
conditions throughout the taf sites with some high clouds overnight
and clear skies on Wednesday. Winds will be northwest, and decrease
in speed toward morning. Look for winds to become southeast Wednesday
evening at KAXN and KRWF.

KMSP...

No weather-related aviation concerns. VFR conditions with northwest
winds.

/OUTLOOK FOR KMSP/
THU...VFR AM. PM MVFR/-RA likely and IFR possible. Wind SE 15-25 kts.
FRI...MVFR/IFR/-RA likely, chc SN. Wind NE 25G40 kts.
SAT...VFR with lingering MVFR possible. Wind N 10G20 kts.

&&

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

$$

DISCUSSION...BPH/ETA
AVIATION...JRB


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