990
FXUS63 KMPX 011915
AFDMPX

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

.KEY MESSAGES...

- Severe thunderstorms & localized heavy rain possible Sunday
  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.

&&

.DISCUSSION...
Issued at 213 PM CDT Sat Jun 1 2024

A weak boundary this afternoon is laid out from about Albert Lea up
to Rice Lake. SPC mesoanalysis shows a couple hundred j/kg has
developed along the boundary, which has been enough to keep some
scattered showers going along and east of it. This front will wash
out this evening. A plume of higher dewpoints will remain overnight
from southeast MN up through Eau Claire and combine this with
clearing skies and light winds and you have everything coming in
place for the potential for some widespread dense fog late tonight
into Sunday morning, with the HREF highlighting that potential being
greatest from Rochester up through Eau Claire on east into Wisconsin.

Also happening tonight in tandem with the front washing out over WI
is a warm front developing over central MN. The h85 flow over this
is weak, but there continues to be the potential that we could see a
few showers develop along this developing front after midnight from
roughly Fargo down toward St. Cloud. Looks like instability will be
limited enough to make even lightning questionable, so even if we do
see some showers develop, little in the way of hazardous weather is
expected with them.

Now for Sunday/Sunday night. There will be a pair of shortwaves
coming out of the Rockies for NoDak and Neb. In response, we`ll see
southerly winds increase through the day, with moisture/instability
increasing as well. By the afternoon, the HREF shows 1000-1500 j/kg
of CAPE out in western MN, with southerly h85 winds increasing to
between 30-40 kts. Though the h85/surface cold front will be across
the Dakotas during the afternoon, this degree of instability, with
the isentropic upglide associated with the southerly h85 winds could
be enough to spark some scattered storms in the afternoon, which if
they did form, the parameter space is there for severe weather.
From the 12z HREF, the ARW was the one model that went down this
road. Otherwise, our severe risk in the Day 2 period really looks to
be tied to what comes from storms that develop back toward Bismark
Sunday afternoon. By the time this threat reaches the western MPX
area, we`ll have a mature QLCS on our hands, with the CAMs showing
some good bowing with the line structure as well. From looking at
the HREF, we have a window from roughly 00z to 04z (so 7pm to 11pm
Sunday) where we look to have everything in place to support a
severe risk. In this window, h85 winds are forecast to increase to
over 40 kts (so increasing shear), with that instability from the
afternoon lingering into this window. This would really drive the
severe wind risk for west central/central MN give the expected
storm mode. After this point, our instability really looks to
diminish quickly, with eastern MN and far western WI seeing the
remnants of this activity in what looks to be another widespread
light to moderate rain with the occasional thunderstorm popping up.
For the Day 2 convective outlook, there was not much change from the
MPX perspective, with the severe probabilities being pushed back
west some, which makes sense given what we`re seeing with
instability trends.

Monday will see some showers linger in the morning in western WI,
but otherwise we get a breather as we turn our attention to Tuesday.
Tuesday continues to look like the strongest wave we are going to
see, with a negatively tilted h5 trough going from NoDak toward
northwest Ontario. This will send a cold front surging across MN on
Tuesday. For this front, we actually look to time a cold front with
peak heating, so the risk for severe weather on Tuesday continues to
look increasingly plausible. There are still issues with timing and
potential cloud cover during the day, but from what we`re seeing
with the deterministic models, it is looking like we`ll see storms
initiate over MN, with a quick transition to linear storm modes.
Besides the severe threat, there will be the heavy rain threat as
well, but once again, the progressive motion of things looks to
limit our flash flooding potential.

Beyond Tuesday, we see a pattern change to a seasonably cool and
mainly dry pattern from Wednesday into next weekend. That trough
that moves through Tuesday will evolve into a closed h5 low that
will slowly track from northwest Ontario through the Great Lakes.
This will put us in several days of northwest winds, with dewpoints
in the 40s, lows in the 50s, and highs in the 70s. Given this
pattern we will see gusty northwest winds develop every afternoon,
with the potential for some isolated diurnally driven showers as
well given the cool temperatures aloft. All in all though, we look
to string together some spectacular weather days for early June to
end next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1231 PM CDT Sat Jun 1 2024

A rather diffuse front now stretches from about AEL to RNH. This
front will wash out this afternoon near its current location,
with enough moisture remaining east of this boundary to keep
occasional showers going in the EAU area over the next few
hours. Tonight, this boundary will wash out, with a warm front
taking shape over central MN. We could see a few showers try to
form on this boundary for AXN/STC, but those probabilities are
low enough at the moment to keep those TAFs dry. Over in WI,
skies will clear out with winds going calm as the front washes
out. This setup is looking increasingly likely to create some
dense fog for EAU in the morning, with a possibility at RNH as
well, though the fog probabilities look much better to the east
of the them. Sunday will see increasing southeasterly winds
during the day. Southerly h85 winds will be increasing through
the day as well, which could produce scattered shra/tsra, but
CAMs are pretty muted at that potential right now, so the dry
TAFs continue through this period.

KMSP...With increasing southerly wind at 850mb Sunday
afternoon, you can`t completely rule out scattered shra/tsra
activity developing, but at this point, the next rain chances
look to be tied to the remnants of a line of storms that will be
coming out of NoDak Sunday afternoon, reaching MSP closer to 6z
Monday.

/OUTLOOK FOR KMSP/
MON...MVFR/-RA early chc TS, then VFR. Wind W 5-10 kts.
TUE...VFR early, then MVFR/SHRA/-TSRA. Wind S bcmg W 10-20 kts.
WED...VFR. Wind W 15-20G30-35 kts.

&&

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

&&

$$

DISCUSSION...MPG
AVIATION...MPG