349
FXUS63 KMPX 290417
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1117 PM CDT Sun Apr 28 2024

.KEY MESSAGES...

- Showers & thunderstorms return on Tuesday, with a few strong to
  severe storms possible across southern Minnesota.

- Active pattern continues with additional chances for rain
  Thursday & next weekend.

- Temperatures will remain Spring-like through the work week.

&&

.DISCUSSION...
Issued at 314 PM CDT Sun Apr 28 2024

It is a rather raw & soggy day across the Upper Mississippi
Valley today. Widespread rain has spread across the region and
will persist through this evening before tapering off
overnight. Temperatures are more similar to mid-March, in the
mid 40s, with sustained E/NE winds 10-15mph adding additional
insult to injury to end April. The surface low located over NE
Nebraska will track through southern Minnesota into northern
Wisconsin before exiting through the northern Great Lakes. We`ll
see steady showers through the afternoon with an area of
heavier rain setting up in the deformation axis across western
Minnesota and eastern Dakotas. We`re looking at 0.5 to 1.0"
total rainfall by Monday morning with locally higher amounts
possible across portions of western and central Minnesota. The
cold & dry E/NE flow has limited any attempt to build
instability into S MN & latest CAMs fail to bring the warm front
into Minnesota or Wisconsin. This lines up with the SPC
removing the Marginal risk of severe across S MN for this
afternoon. There could be a few thunderstorms embedded in the
precipitation that`ll produce heavier rains & a few rumbles of
thunder. Otherwise, we`ll "dry out" overnight before the
deformation zone pivots through Monday morning.

Monday will see shower chances return in the first half the of
day, especially across W WI, before we actually dry out. Cool
flow & overcast skies will limit our highs into the upper 40s
and lower 50s for the second straight day. Tuesday will be a
stark contrast to Monday. High temperatures will be in the 60s
and lower 70s. A thermal ridge will move through during the day,
allowing ample WAA to occur ahead of shortwave trough. That
potent shortwave is forecast to dig into northern Plains and
become negatively tilted by Tuesday afternoon. This will enhance
flow and provide additional ascent across Upper Midwest Tuesday
afternoon/evening, which will support shower and thunderstorm
development across much of the area along and ahead of a sfc
front. Timing is favorable, at peak diurnal heating, but our
limiting factor will be the lack of CAPE (500 j/kg) & weak lapse
rates (6.0-6.5 deg/km). So this isn`t going to be a widespread
severe but low CAPE/high(er) shear setup. Hires guidance brings
a line of thunderstorms across Tuesday PM. A few strong to
severe thunderstorms will be possible, and SPC`s day 3 places us
in a Marginal risk. What`s more impressive is the trend in
higher QPF associated with this wave. We`ve seen QPF more or
less double since yesterday so another solid rain event is on
tap for much of the area. We`ve also opted for 3 hourly PoP
grids to better represent the passing line of thunderstorms on
Tuesday.

Wednesday will be a brief return to drier, seasonal conditions
with highs in the 60s and lower 70s. Guidance has doubled down
on an another shortwave impacting the region Thursday into
Friday. This was hinted at yesterday by a few ensemble members,
but was far from the best signal. Fast forward a day and we`re
looking at solid chance for another widespread rain maker.
Temperatures cool into the 50s and 60s with likely PoPs now
appearing in the NBM. As this system exits on Friday we`ll see
our active pattern continue as yet another system is possible
this weekend before the pattern resets after next weekend. While
temperatures have trended cooler for the first weekend of May
appears to trending cooler, there is a signal for warmer
temperatures to return for the second week of May.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1103 PM CDT Sun Apr 28 2024

Large rain shield continues to push off to the northeast,
bringing in a fairly broad dry slot across the area to start so
have initialized all sites as precip-free. From this point on,
chances for additional precipitation through this TAF duration
drop off with potentially only a few weak showers the rest of
the overnight hours through late Monday morning. Ceilings will
drop back to IFR for all sites by the early morning hours and
remain there through most of the day Monday then slowly rise.
Winds will be a bit tricky to time, especially directions, as
the low pressure circulation crosses southern MN, although
speeds will be 10kts or less during these wind shifts.
Eventually, by late Monday afternoon, winds will become
westerly with speeds upwards of 15G20kts.

KMSP...Ceilings to bounce between low-MVFR and IFR for the first
few hours before settling on IFR shortly before daybreak. IFR
ceilings expected to hold most of the day and into Monday
evening before conditions improve Monday evening through Tuesday
morning. Winds to undergo frequent shifts from E to S to W
during the day Monday then become a bit breezy Monday evening.

/OUTLOOK FOR KMSP/
TUE...VFR through mid afternoon. MVFR or IFR with TSRA late
aftn/evng. Wind SE 10-15G30 kts.
WED...VFR. Wind light/variable.
THU...MVFR/-SHRA likely. Wind ENE 10-15G25kts.

&&

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

&&

$$

DISCUSSION...BPH
AVIATION...JPC