149
FXUS63 KMPX 021415
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
915 AM CDT Sun Jun 2 2024

.KEY MESSAGES...

- Severe thunderstorms & localized heavy rain possible this
  evening, especially across western and central Minnesota.

- Another chance for widespread rain and potentially severe thunderstorms
  is likely Tuesday.

- Pleasant and mainly dry weather expected Wednesday into next weekend.

&&

.UPDATE...
Issued at 847 AM CDT Sun Jun 2 2024

Usually at this point in the morning we like to see models
coming into agreement, with confidence increasing on what the
strong/severe potential later in the day will look like, but
today is not that day! The biggest change we`ve seen comes from
the HopWRFs and the HRRR, both of which show the showers over
eastern SoDak in the zone of enhanced h85 southerly flow
plodding east through the morning across MN, reaching the Twin
Cities around 20z or 21z, though it looks like activity should
be on the downward trend by the time they get as far east as the
metro as they will be running away from the instability. It
looks like we`ll see quite a bit of disorganized activity within
the zone of enhanced southerly h85 winds and moisture transport
before any sort of more organized line arrives this evening. We
still expected a more organized line of storms to move through
tonight as the west edge of the LLJ works across the area, but
how much of a severe threat we`ll have is looking a bit more
uncertain given all of the pre-line activity expected. To this
point, the biggest change we`ve made to the going forecast is to
increase PoPs quite a bit (up to the 50% range for now) for
this afternoon into eastern MN. For those hoping for another
nice early summer afternoon to enjoy some outdoor activities may
be a little disappointed to need an umbrella...

&&

.DISCUSSION...
Issued at 405 AM CDT Sun Jun 2 2024

High clouds associated with a line of thunderstorms that have
developed ahead a weak boundary moving across Nebraska and Kansas
are making their way northward early this morning. The 06z WPC
surface analysis depicts a warm front across central Minnesota,
where some ACCAS have developed over the last few hours. Further
west back into North Dakota, a few isolated thunderstorms have
developed. Southerly flow will continue to bring warm, moist air
northward through this morning and into the early afternoon while
the parent surface low lifts into the western Dakotas. Aloft, a
subtle shortwave will push through this afternoon with an increasing
LLJ nosing into southwestern Minnesota. This could be enough to
spark some storms across southern Minnesota and northern Iowa during
the afternoon. This would be well ahead of the convection that will
be forming over the Dakotas and moving into Minnesota during the
evening along the cold front that hi-res models have been
advertising over the past couple of days. The main question with
this earlier chance of storms will be how it will impact the later,
main line of storms coming out of North Dakota. As these North
Dakota storms develop and progress eastward this afternoon, they are
expected to grow upscale into a QLCS during the early evening hours.
CAMs show this line diving south across central Minnesota and
eventually weakening. Wind will be the main threat, but a few spin
ups along the line in western Minnesota aren`t out of the question
along with some hail.

Even being only 12-18 hours out from the event, there are still some
questions and discrepancies in timing and the southern extent of
this line. As previously mentioned, there`s the question of storms
firing across southern Minnesota during the afternoon. There`s also
the model differences in the timing of the eventual QLCS from the
Dakotas. The ARW is by far the fastest, with the QLCS moving through
the Twin Cities around sunset while the majority of other CAMs hold
off until around or after 06z. There are also differences in
strength/coverage of the line as it moves into a more stable
environment to the east, but current thinking is that it will be
tough for western Wisconsin to see much in the way of severe storms
by early Monday morning. Showers will linger across eastern portions
of the forecast area during the first half of the day before clouds
clear from west to east with mostly sunny skies expected area wide
by Monday evening.

The clear skies will be short lived as cloud cover quickly returns
overnight into Tuesday as yet another warm front lifts northward.
Tuesday looks like it has the potential to be another active weather
day with the threat of heavy rainfall and a few severe
thunderstorms. With the return of strong southerly flow, dew points
look to climb into the mid to upper 60s with temperatures in the low
80s, despite ample cloud cover. Forecast soundings have PW values of
nearly 2", which is impressive considering the 90th percentile for
June 4 is not even 1.5". Aloft, a 500mb trough will take on a
negative tilt as it progresses across southern Canada and the
western Dakotas. A surface cold front is forecast to quickly move
through the area during the afternoon, which would be favorable
timing for thunderstorm development. Heavy rainfall in addition to a
few strong to severe storms look increasingly likely for Tuesday
afternoon and evening. Both of these threats are covered by an ERO
Slight Risk and a SWODY3 Marginal Risk respectively.

The middle of the week through the remainder of the period looks to
be much cooler and quieter as we see northwest flow return. A cutoff
low looks to stall over the northern Great Lakes through Friday. At
the surface, breezy west to northwesterly winds are expected with
gusts of 30-35 MPH possible on Thursday. Highs in the low to mid 70s
with minimal chances for afternoon showers are expected through the
end of the period.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 622 AM CDT Sun Jun 2 2024

VFR conditions this morning but chances for showers and
thunderstorms increase this afternoon into the evening and
overnights hours. A few storms could produce severe weather at
KAXN and KRWF, with decreasing chances to the east at the
remainder TAF sites. Fog and stratus may develop late tonight
after the storms move through.

KMSP...This morning should be dry, but the thunderstorms in the
Dakotas will be moving eastward this morning. They are expected
to weaken, but if they maintain themselves then MSP could see
thunder chances this afternoon, as opposed to later this
evening and overnight. Fog and stratus may develop late tonight
after the storms move through.

/OUTLOOK FOR KMSP/
MON...MVFR/-RA early chc TS, then VFR. Wind W 5-10 kts.
TUE...VFR early, then MVFR/SHRA with -TSRA/IFR possible. Wind S
bcmg W 10-20 kts.
WED...VFR. Wind W 20G35 kts.

&&

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

&&

$$

UPDATE...MPG
DISCUSSION...Dye
AVIATION...JRB