126
FXUS63 KMPX 220933
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
433 AM CDT Sat Jun 22 2024

.KEY MESSAGES...

- Excessive rain threat is diminishing this morning, but one
  more round of showers and thunderstorms is expected this
  afternoon. The threat for severe weather is low.

- There`s a Slight Risk (level 2 of 5) of severe storms Monday
  evening.

- More unsettled weather expected Thursday afternoon through
  Friday night.

&&

.DISCUSSION...
Issued at 432 AM CDT Sat Jun 22 2024

The worst of the heavy rain threat has shifted southeast of the MPX
area with the LLJ early this morning. We have let Flash Flood
Warnings expire overnight, but have replaced them with a couple of
Areal Flood Warnings that continue through tonight to cover ongoing
flooding seen along the Watonwan, Blue Earth, Le Sueur, Cannon, and
Straight rivers and their tributaries in south central MN. Though
the main heavy rain risk is shifting east of us, water vapor imagery
shows we have one more shortwave coming across SoDak that we`ll have
to contend. Most CAMs show this wave pushing another area of
scattered showers into western MN late this morning, with that
activity working across the rest of central and southern MN during
the afternoon. By then, the main cold front will be across eastern
Iowa into southern WI, so this activity will be elevated, with more
limited instability in turn keeping the severe risk for the MPX area
very low. This activity will also be progressive, so the heavy rain
threat will be low as well, but with how wet we`ve been, the bar is
set pretty low for seeing flash flood concerns across south central
Minnesota. However, with the primary warm front and eventual surface
low remaining across Iowa, we don`t look to have the redevelopment
of heavy rain like we`ve seen the past couple of days, so for now we
look to be transitioning to the river flood phase of this event.

Sunday looks to finally be a drier day and an opportunity to tackle
the jungle that has likely become your yard, but there is a threat
for some scattered afternoon showers/storms northeast of I-94 as a
shortwave in northwest flow tracks from northeast MN to northern
lower Michigan. Instability will be under 500 j/kg, so the severe
risk Sunday looks low as well.

Monday and Tuesday look to be the warmest days of the week as warm
air gets drawn north in response to a shortwave moving across
southern Canada. The cold front with this trough looks to come
through the MPX area Monday night, with that timing looking to help
hold highs both days in the 80s. The bigger issue is that front will
bring us our next chance of thunderstorms. This will be one of those
cases where forcing will be strongest north, but we`ll have the
better instability. Looking at the deterministic models, QPF from
them all show a pretty classic MCS signal for Monday evening as
storms develop in the Red River Valley and track southeast through
the evening into the better instability in southern MN. Given the
warmth on Monday, along with the moist airmass in place, we`re
seeing a favorable thermodynamic environment develop with mlCAPE
values possibly exceeding 3000 j/kg Monday afternoon ahead of what
would come down from the northwest. There`s still a good deal of
uncertainty with exactly when/where storms would develop and then
track through the evening, but the environment we`ll have in place
will definitely support a severe risk if we can drop some updrafts
into it.

Tuesday is trending dry, with the cold front looking to be far
enough south/east of the MPX area to have the next round of storms
fire south of our area, though it won`t take much of a slowing to
see storms again Tuesday afternoon in south central MN up into
western WI. After that, high pressure comes in and we get a breather
Wednesday and Wednesday night.

For Thursday afternoon through Friday night, it`s looking unsettled
once again as a shortwave moves across the international border from
the northern Rockies over to Lake Superior. These falling heights
back over Montana on Thursday will result in another resurgence in
the LLJ across the Dakotas. This LLJ right now looks to come across
the MPX area Thursday night, with our best chances for storms coming
Thursday night, then Friday afternoon over eastern MN and western WI
along the advancing cold front. This looks to be another system that
will support both the chance for severe weather and excessive
rainfall.

It`s then trending drier for the following weekend, but ensembles
are already showing the next active stretch of active weather
loading up for the start of July.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1204 AM CDT Sat Jun 22 2024

Radar reveals widespread rain and thunderstorms across southern
Minnesota early this morning, with the greatest impacts observed
at MKT and RWF. The heaviest of the convection is starting to
push further south into northern Iowa. Rain will continue over
the next several hours, eventually ending from west to east. IFR
ceilings prevail through much of the morning, followed by
another round of rain and a few storms. Hi-res models have
focused in on scattered showers and storms developing across
west central Minnesota late morning and drifting east through
the afternoon. Have included PROB30`s at RWF, MKT, MSP, and RNH
to account for this potential. Winds kick northwesterly after
daybreak.

KMSP...Chance for thunder is trending lower from this point
onward. Rain will continue through ~9/10z, before drying out for
a period later this morning. IFR ceilings likely through late
morning. Hi-res models have focused in on another round of
showers and perhaps a few thunderstorms early this afternoon,
so have opted to include a PROB30 for this potential.

/OUTLOOK FOR KMSP/
SUN...VFR. Wind NW 10-15 kts.
MON...VFR. Chc-TSRA/MVFR late. Wind SE 10-15 kts.
TUE...VFR. Wind NW 5-10 kts.

&&

.HYDROLOGY...
Issued at 303 PM CDT Fri Jun 21 2024

Despite a lack of confidence in the location of highest QPF for
tonight, we`ll see enough rain in areas already having issues from
last night`s and this morning`s rain to warrant an areal flood
warning in south central MN. This warning will need to be watched
for extension to the south depending on how the precip sets up along
I-90, could also go through the night. River forecasts are mainly on
track this afternoon, paying particular attention to the Cannon
where training has occurred today, along with the mid/lower
Minnesota where lots of inflow coming from the tribs south of
Mankato.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Flood Watch until 1 PM CDT this afternoon for Blue Earth-
     Dakota-Faribault-Freeborn-Goodhue-Le Sueur-Nicollet-Rice-
     Scott-Sibley-Steele-Waseca.
     Flood Watch until 7 AM CDT this morning for Brown-Martin-
     Redwood-Watonwan.
WI...Flood Watch until 1 PM CDT this afternoon for Eau Claire-Pepin-
     Pierce.

&&

$$

DISCUSSION...MPG
AVIATION...Strus
HYDROLOGY...CCS