000
FXUS63 KMPX 250809
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
309 AM CDT Thu Apr 25 2024

.KEY MESSAGES...

- Friday`s system brings widespread rain and gusty winds to the
  region. The heaviest rain expected Friday afternoon into
  Friday night.

- There is a Marginal severe threat for overnight convection
  along the I-90 corridor in southern MN.

- A break in the active weather is anticipated Saturday, with
  another strong system expected to bring additional widespread
  rain on Sunday.

- A more Summer-like warmth expected to start May, with an
  active weather pattern expected across the central CONUS.

&&

.DISCUSSION...
Issued at 253 AM CDT Thu Apr 25 2024

Strong WAA across SoDak is helping drive the clouds and radar
returns we`ve been seeing through the night. However, there was
ample dry air on the MPX sounding last night, which has held much of
these returns in the virga category and through the day today,
the virga theme is expected to continue, with perhaps a brief
sprinkle or two fighting its way to the ground through the
morning in west central MN. The big change for today is the
increasing pressure gradient and associated uptick in southeast
winds. The strongest winds are expected in western MN, where
sustained speeds will get up into the 20-25 kt range, just below
wind advisory criteria.

Tonight, showers will spread in across the area from west to east as
a better than 40 kt LLJ and its associated moisture transport move
into the region. We did slow the eastward progression of the rain by
a few hours as it will take time for the dry airmass to be overcome.
In fact, the HREF doesn`t really show precip crossing the MN/WI
border until Friday afternoon. We will see periods of showers
and occasional storms through Friday evening, but the heaviest
rain is expected Friday afternoon/evening as PWATs increase to
over 200% of normal (over 1") and h85 winds increase to over 50
kts. The severe risk on Friday continues to be more of an issue
down toward Omaha, with the surface low and warm front expected
to move across southern MN overnight Friday night. The continued
Marginal Risk for severe weather from the SPC for the southern
2 or 3 tiers of counties in MN continues to look adequate to
capture our limited severe storm threat during the overnight
hours.

Saturday continues to offer us a breather before a stronger wave
arrives on Sunday. Once again, the track of the low will be key to
our severe risk, though the 25.00 ECMWF continues to paint an
interesting picture for southeast MN on Sunday, with a warm front
bringing low 60s dewpoints up into southeast MN during the
afternoon. The main question for our severe potential on Sunday is
what kind of instability can we develop behind what will be
widespread WAA convection across the region Saturday night/Sunday
morning. There`s still a good deal uncertainty with exactly where
the Sunday low tracks, but it certainly bears keeping a close eye on
as we head for the weekend.

As for rainfall potential, not much has changed with either system.
A widespread 1-2" of rain expected between both systems. From an
overachieving perspective, it`s the second low on Sunday that will
have the potential for that, especially for eastern MN and western
WI where Pwats will be more in the ballpark of 1.5" with a favorable
coupled upper jet structure developing as well. We could easily see
a couple of swath of 2-3" with just the second system on its
own from southeast MN up through western WI.

We will dry out for Monday, but we will have zonal flow in place
to start the week. Models are starting to come into agreement
on a westerly jet streak coming across the Dakotas on Tuesday,
with the exit region of this jet streak leading to the
possibility of another round of scattered showers and
thunderstorms Tuesday. Model spread starts to increase
dramatically toward the end of the forecast period, though there
is agreement on the general idea of the flow becoming a bit
more amplified by the second half of next week as another trough
digs into the western CONUS.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 101 AM CDT Thu Apr 25 2024

Strong warm advection across SoDak is resulting in the cloud
cover we see spilling across MN, though very dry atmosphere in
place means most of the returns we are seeing on radar are just
virga and that will continue to be the case through the day
today. Main issue today is southeast winds will start getting
quite breezy again, especially the farther west you travel in
MN. Tonight, we will start to see -SHRA push across MN, though
given the dry air in place, followed the slower timing of models
like the RAP & HRRR for bringing precip into the area, which
means rain looks to hold off at most terminals through the 6z
TAF period. Even if rains move in faster than forecast, cigs
will remain VFR this period.

KMSP...At the tail end of this period (12z Fri) we will see
-SHRA pushing into the metro. Introduced some -shra at 10z Fri
 to account for that potential, though even that could be too
 quick to bring rain in.

/OUTLOOK FOR KMSP/
FRI...MVFR/-RA, chance IFR/TS. Wind SE 20-25G35 kts.
SAT...MVFR. -SHRA likely early and overnight. Chc IFR/TS
      overnight. Wind SW 15-20 kts becoming NW.
SUN...MVFR/-SHRA, chance IFR/TS. Wind NE 10-15G25 kts.

&&

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

&&

$$

DISCUSSION...MPG
AVIATION...MPG