Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 182345
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
645 PM CDT Mon Mar 18 2024

.KEY MESSAGES...

- Elevated fire weather conditions persist through Wednesday,
  continuing into Thursday for eastern MN and western WI.

- Accumulating snow coming Thursday afternoon (western MN) into Thursday
  night (eastern MN and western WI)

- Potential for a larger winter storm continues to exist for
  Sunday through Tuesday next week.

&&

.DISCUSSION...
Issued at 326 PM CDT Mon Mar 18 2024

The combination of morning clouds and continued northwest winds has
resulted in a rather slow temperature increase today, but as high
pressure continues to slide to the south, we`ll continue to see the
winds switch around to the WSW this afternoon. These winds will bring
a thermal ridge in tonight, with temperatures not expected to fall
far from their afternoon highs today. For Tuesday, the thermal ridge
will be shifting into Iowa, with our h85 temperatures cooling
through the day. As a result, we did nudge highs down on Tuesday,
with the biggest downward nudge occurring in the MN River Valley into
south central MN, where a good 5 degrees were taken off the forecast
highs for Tuesday. These cooler temperatures will translate into
higher RHs, which means despite the gusty winds that are expected
(up to 35 mph gusts in western MN), the cooler temps and higher RH
will likely keep us from seeing critical fire weather conditions.
Tuesday night, a secondary cold front comes through with a
reinforcing shot of cold air. Though RHs will be lower on Wednesday,
winds will back off some and with temperatures struggling to reach
the low 30s, that should again keep us at elevated for fire weather
conditions.

For Thursday and Thursday night, it still looks likely that we`ll
see a swath of accumulating snow. The main change we`ve see with the
12z model runs is they slowed down the speed of this system by about
12 hours, pushing the heaviest snow from Thursday afternoon/evening
into Thursday evening/night. Because of this big change in the last
12 hours, the NBM PoPs came in a bit lower than preferred as it
tried to blend between the faster and slower solutions. We did lower
PoPs in the 18-00z window Thursday, then boost them in the 0-6z
Friday window, but tonight`s run of the NBM should have a much
better handle on the PoPs. The large scale pattern is still
supportive of seeing widespread precip, with a strong thermal
gradient existing across MN/WI within the right entrance region of
an upper jet streak. This will support a healthy burst of fgen
induced snow across southern MN. The big source of uncertainty for
this system is the potential for convection on the nose of the LLJ
down along the I-80 corridor. How robust this convection ends up
being will help determine how strong our forcing ends up being (less
convection in Iowa would help our snowfall cause). Still it looks
likely that most of the MPX area will see 2-4" of snow, with a
narrower swath of 4-7" possible within (kind of like the Valentine`s
Day snow).

Over the weekend, a trough will dig into the Rockies, which will
lead to a rather active period of weather Sunday through Tuesday.
The models are coming around on the idea that we`ll see a couple of
waves with this western trough. The first on Sunday, with a second,
stronger wave on Tuesday. EPS mean h5 heights show a nice negative
tilt to the main trough coming up on Tuesday and this should support
a very strong and dynamic weather system across the central CONUS
for early next week. There`s still a good deal of uncertainty with
where the precipitation transition zone will exist with both
systems, but it is looking increasing likely we will see some
significant winter weather impacts to start out the last week of
March within the MPX CWA, so stay tuned as details start coming into
better view.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 623 PM CDT Mon Mar 18 2024

VFR cigs through most of tonight. Broken skies likely to move in
from the northwest during Tuesday morning, resulting in a
period of high end MVFR cigs for most of the morning hours.
Southwesterly winds at 10-15 knots overnight, with a period of
LLWS for a few hours surrounding midnight tonight. It will
generally be westerly between 40-50 knots. During Tuesday
morning, winds will become more northwesterly and increase in
speed with sustained values of 15-20 knots and gusts around 25
knots.

KMSP...Have kept LLWS from 04-08Z tonight with a westerly
direction near 50 knots. High end MVFR cigs look likely after
12Z Tuesday morning. Conditions should return to VFR by noon
Tuesday.

/OUTLOOK FOR KMSP/
WED...VFR. Winds NW 15G25kts.
THU...IFR/-SN likely. Some accumulation likely. Wind E 5-10
kts.
FRI...VFR likely. MVFR ceilings possible. Wind N 5-10 kts.

&&

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

&&

$$

DISCUSSION...MPG
AVIATION...PV


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