797
FXUS63 KMPX 011442
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
942 AM CDT Sat Jun 1 2024

.KEY MESSAGES...

- Showers and clouds will gradually clear from west to east today.

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

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

&&

.UPDATE...
Issued at 922 AM CDT Sat Jun 1 2024

Cold front this morning is starting to become a little better
defined from roughly New Ulm up through the Twin Cities. As
convergence increases along the front with dewpoints around 60,
we`re seeing enough forcing with this moisture to start forcing
some showers/drizzle along the boundary. This boundary will push
east some, but will wash out this afternoon over western WI. An
isolated shower will be possible through the afternoon along
this boundary, but limited instability will keep the severe
threat with any of this activity very low.

Tonight, we`re seeing increasing agreement among the CAMs of
some isolated/scattered showers developing over central MN.
Basically, as the cold front washes out over southeast
MN/central WI, a warm front starts to sharpen over central MN
this evening, and it`s north of this feature we see the CAMs
trying to spit out some weak showers.

For Sunday, a slower trend in the timing of the shortwave/front
that will force convection in the afternoon in the Dakotas
continues to be noted. So the same concerns about the severe
risk for the MPX area due to limited instability mentioned in
the overnight AFD continues. The consensus we`re seeing from
the 12z guidance coming in is that we`ll see storms develop
along the boundary in Dakotas (more so in the northern version)
quickly line out, with that line approaching western MN in the
evening. How far north that line will be is a bit in question,
with the HRRR taking it across northern MN, while the NAMnest
would have it moving through our western CWA. The current Day 2
outlook still looks reasonable, though may have a bit more of
eastern buffer in the severe probabilities than needed, so it
seems unlikely that we`ll see an eastward expansion of
probabilities with the afternoon update.

&&

.DISCUSSION...
Issued at 326 AM CDT Sat Jun 1 2024

Today through Monday...Showers continue to diminish in coverage and
intensity early this morning along and east of a line from roughly
Fairmont to Mankato to the eastern Twin Cities metro up through
Taylors Falls. An additional tenth to two tenths of an inch of
rainfall is possible through sunrise as the showers continue to
progress to the northeast. Hi-res models indicate that some
redevelopment of showers in this same general area and western
Wisconsin is possible later this morning as a weak 700mb wave moves
through. Otherwise, skies will become mostly sunny with highs in the
mid to upper 70s. Attention then turns to Sunday afternoon and the
threat of additional rain and severe thunderstorms. While the SPC
SWODY2 Slight Risk was expanded eastward to include the western half
of Minnesota and the Marginal Risk encompassing the remainder
of the MPX forecast area, there are a few factors that may
impact how much severe weather we end up seeing. First and most
notably, forecast CAPE values have decreased from run to run
over the last 24 hours or so. This may be in part to some Sunday
morning convection that CAMs are highlighting across western
and southern Minnesota associated with a LLJ/WAA. This cloud
cover would prevent afternoon highs from reaching the low 80s
from previous forecasts and limit instability. Another factor
is the timing of the cold front moving from the Dakotas into
Minnesota, which seems to have slowed down from previous
forecasts. Storms coming from the Dakotas are expected to grow
upscale into an MCS as it crosses into Minnesota Sunday evening
with the main threat being damaging winds and heavy rain. The
system would weaken as it continues eastward into Wisconsin
around sunrise Monday with showers ending by mid afternoon.

Tuesday through Friday...After a brief break from active
weather Monday afternoon, rain and thunderstorm chances return
Tuesday. A negatively tilted 500mb trough is forecast to move
across southern Canada and the Dakotas through early Wednesday
morning. There are still timing differences between the guidance
as well as slight differences in placement and strength, but
another round of heavy rain and some strong thunderstorms
appears likely. There will be plenty of Gulf moisture advected
northward with PW values above the 90th percentile of
climatological norms and high temperatures in the low to mid
80s. As of right now, this system looks to be stronger than
Sunday`s and definitely bears watching over the next couple of
days. Behind this system, we get back into northwest flow aloft
with the 500mb low lingering across northeastern Minnesota.
Additional shower chances are possible through the second half
of the week with highs in the low to mid 70s.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 646 AM CDT Sat Jun 1 2024

Generally VFR conditions, but there are a few pockets of IFR
clouds and fog across the region, as well as some light rain
that will impact KRNH and KEAU this morning. For the rest of
today, winds will be light, and skies will clear as drier air
moves across the region.

KMSP...
The lowest stratus is just to the west of KMSP. For now have a
tempo for MVFR, but it is possible that clouds could be IFR.
Drier air will move across the region this afternoon, with VFR
conditions expected the remainder of the TAF period.

/OUTLOOK FOR KMSP/
SUN...VFR, MVFR/-RA likely late chc TS. Wind S 10-20 kts.
MON...MVFR/-RA early chc TS, then VFR. Wind SW to NW 10-15 kts.
TUE...VFR early, then MVFR/SHRA/-TSRA. Wind S 10-20 kts.

&&

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

&&

$$

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