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000
FXUS63 KMPX 170656
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
156 AM CDT Wed Apr 17 2024

.KEY MESSAGES...

- Ongoing rain with a chance for a few strong thunderstorms
  along I-90 later this afternoon and evening. Rain continues
  through tomorrow evening.

- A few small chances for showers beyond the short term, with
  southern MN on Thursday and along and east of I-94 on Monday
  into Tuesday next week.

- Temperatures remain in the 50s and 60s for highs, with lows in
  the 30s and 40s with frost/freeze probable on Saturday &
  Sunday morning.

&&

.DISCUSSION...
Issued at 211 PM CDT Tue Apr 16 2024

Regional radar imagery shows a broad swath of precipitation ranging
from Nebraska up through Minnesota and down through portions of Iowa
and Missouri. There is a break within the cloud cover and
precipitation over western Iowa, and this area of clearing is the
location to watch for development which could scrape southern
Minnesota later this afternoon and evening. RAP soundings and
analysis shows the potential for a bit of instability to build
within this area of clearing, resulting in little CIN and MUCAPE of
500-1000 J/KG. This couples with a broad area of wind shear
associated with a pair of frontal boundaries stretching across the
area, with a warm front draped over central to north-central Iowa
and a cold front southwest through eastern Nebraska. The warm front
will be the key feature to watch as it would provide the wind shear
needed for a few storms to maintain strength, should they form
within the area of clearing in western Iowa. Right now, the
expectation is for a couple storms to move through the periphery of
the MPX CWA, with most of the stronger storms remaining southeast of
the area along the area more favorable within the warm region south
of the warm front and east of the cold front, giving us a marginal
severe weather threat for the I-90 corridor which includes a small
hail, wind, and tornado chance. Rain showers will continue to churn
across the area north of the warm front which is where most of the
CWA ends up, with a healthy amount of rain already having fallen and
another half to full inch expected before it exits later on
Wednesday. Rumbles of thunder are likely to continue through the
duration of the system even after the severe weather threat ends
later this evening. Aside from the rain, the strong surface pressure
gradient resulting in strong sustained winds will continue through
this evening with winds at 20-30mph primarily out of the east, with
gusts from 40-50mph remaining possible. A few stronger gusts up to
55mph could mix down from any of the stronger showers which develop
due to the momentum enhancement from precipitation, however this
will be on an isolated basis. Winds will begin to shift
northwesterly by tomorrow morning as the surface low slides
eastwards, with speeds briefly weakening overnight before increasing
to 15-20mph gusting to 30-35mph tomorrow.

As the upper level system occludes and begins to weaken as it heads
towards the Great Lakes, the surface low will follow with weakened
frontal boundaries, resulting in a downwards trend in rainfall
intensity with little in the way of storms overnight and through
much of tomorrow, with dry conditions by tomorrow evening. This
system will quickly push eastwards, followed by another shot of
light rain moving northeast across the plains which could give
southern Minnesota and perhaps portions of western Wisconsin another
shot of light rain on Thursday. This second, weaker system will be
followed by synoptic scale ridging aloft which should keep
conditions fairly mild but also a little cooler for the upcoming
weekend, with clear skies allowing temperatures to drop and a chance
for a hard frost/freeze both Saturday and Sunday mornings. This
ridging moves eastwards by Monday, with a hint of another system by
the middle of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 133 AM CDT Wed Apr 17 2024

KMPX radar clearly shows the broad rotation of precipitation
bands around the low pressure centered over southern MN. Thus,
with the rain expected to continue spreading across much of
central-southern MN and western WI, periods of rain can be
expected at all sites, including some mod-heavy at times which
may well reduce visibility into MVFR range. Ceilings have
generally dropped into MVFR range at/near all sites, with
ceilings likely to drop into IFR range later this morning
through early afternoon. As the center of the circulation
slides east, this will allow winds to become more W to NW and
also increase in speed with a tightened pressure gradient and
deeper mixing aloft. Winds will diminish late tonight into
Thursday morning in conjunction with conditions improving to VFR
and clouds scattering out as the system exits to the east.

KMSP...MVFR to start but with additional bands of rain likely to
drift across MSP shortly after initialization time, ceilings may
well drop to IFR prior to sunrise and stay there through the
morning push, continuing through midday. Improvements will be
slow-to-come-by through the day today, including ceilings
potentially staying sub-1700ft through the afternoon push, with
improvement to VFR not coming until Wednesday evening. Breezy
winds will increase to around 20G30kt this afternoon and
evening, but are expected to have a 300 direction, right down
the 30s, thus any cross-wind component will be quite minimal.

/OUTLOOK FOR KMSP/
THU...VFR. Wind W 10-15 kts increasing to 15-20G25-30 kts.
FRI...VFR. Wind WNW 15-25G30-40 kts.
SAT...VFR. Wind NW 10-15G20-25 kts.

&&

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

&&

$$

DISCUSSION...TDH
AVIATION...JPC