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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KMPX 230356
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1056 PM CDT Mon Apr 22 2024

.KEY MESSAGES...

- Scattered showers this afternoon and evening, with wrap around
  showers possible for western Wisconsin tomorrow. Accumulations
  remain light under a tenth.

- Another frost/freeze Wednesday morning with temperatures
  falling back into the 20s outside the metro.

- Our next system arrives by Friday, with a more widespread rain
  looking likely. The system track still has yet to be resolved,
  thus thunderstorm chances are still possible but currently
  unknown in spread and strength.

&&

.DISCUSSION...
Issued at 246 PM CDT Mon Apr 22 2024

Satellite shows the system sliding across the area in the form of
higher level clouds above textured stratus stretching along the cold
front moving from west to east through this evening. Surface dew
points even in areas with radar returns remains in the 30s, thus we
continue to await stronger shower development before anything
reaches the ground. This is expected to happen once the front
reaches eastern Minnesota within the next couple hours, with western
Wisconsin more likely to see precipitation reaching the surface,
albeit light precipitation at that. The upper level trough
associated with the surface low will occlude over the Great Lakes
overnight, spinning in place which will allow cold air advection
showers to continue to fire into western Wisconsin tomorrow.
Additional precipitation will be showery with accumulations over
localized areas, but also only resulting in at most a tenth of an
inch. This system will push eastwards over the Great Lakes by
Wednesday with a return to quiet and dry conditions for the next
couple days.

Wednesday morning looks like another solid chance at a hard
frost/freeze across much of the area as temperatures drop into the
20s and 30s, with the coldest temperatures over western Wisconsin.
Precipitation should be over before temperatures fall such that no
snowfall is expected at this time, especially with dew points also
falling into the 20s behind the departing system. This looks to
potentially be our last big chance for frost/freeze as the longer
term forecast showcases warmer temperatures and a larger system
which takes us through the end of the month. For perspective, the
average final frost date at the Twin Cities is April 25th, so this
ends up being right around the normal time for the final 32 or lower
low for the season. Thursday morning shows low temperatures
generally back into the 40s, with a few 30s lingering in western
Wisconsin and only areas of Rusk County getting close to freezing.

Speaking of the larger system alluded to, guidance continues to show
a larger synoptic scale system entering the area from the southwest
by late Thursday to early Friday in a trajectory akin to a Colorado
Low we would see during Winter. Much like a winter system, the track
of the surface features are the key component to look at as it
pertains to chances for severe weather and rainfall across the area,
with guidance still somewhat split on how it evolves as it reaches
Minnesota. The deterministic GFS shows a southwest to northeast
trajectory towards Lake Superior which will result in widespread
showers directly under the low pressure center but keep the chances
for severe weather lower due to limited time within region south of
the warm front as it rapidly lifts northeast. The deterministic CFS
favors the surface low flattening out as the upper level system
struggles to occlude over western Lake Superior, which produces a
secondary low from the southern jet stream impacting the area the
2nd half of Sunday. The ECMWF is closer to the GFS solution with the
main difference being a deviation in the position of the system as
it occludes a bit farther to the north in Canada. As of right now,
this forecaster would lean towards more of a widespread rain
scenario than severe weather given the guidance, however as the
system rapidly moves through, heightened wind shear could allow for
some sporadic thunderstorms to develop. Depending on which solution
wins out, we are looking at around an inch of QPF on average for
much of the area from Friday through Sunday, with a potential break
for a portion of Saturday. CAM guidance will be crucial in helping
determine the finer forecast details and the severe weather
dynamics, thus we may have to wait until at least Wednesday before
having a more concrete picture of what we expect to occur. For now,
it would not hurt to keep an eye on future forecast discussions and
products to see how this one evolves as there is quite a bit of
variance still present within the forecast.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
-- Changed Discussion --
Issued at 1056 PM CDT Mon Apr 22 2024

Clouds will begin to increase late tonight as another disturbance
comes in Tuesday from the northwest. MVFR or lower end VFR cigs
and scattered to numerous showers will accompany this wave,
especially across central/eastern MN and WI. A few TS are also
possible in WI. Winds will increase from the northwest Tuesday
morning with gusts of 25-30 kts likely again.

KMSP...No concerns tonight. -SHRA chances increase after 17Z,
with better chances just to the east. Currently expecting VFR
conditions to prevail, but there could be some short periods of
MVFR cigs if steadier showers move overhead.

/OUTLOOK FOR KMSP/
WED...VFR. Wind SE 5-10kts.
THU...VFR. Chance MVFR/-SHRA late. Wind SE 10-15kts.
FRI...MVFR/-RA, chance IFR/TS. Wind SE 15-20kts gusts 25-30kts
-- End Changed Discussion --

&&

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

&&

$$

DISCUSSION...TDH
AVIATION...Borghoff