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626
FXUS63 KMPX 071724
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1224 PM CDT Tue May 7 2024

.KEY MESSAGES...

- Showers & a few rumbles of thunder continue this morning
  across eastern Minnesota & western Wisconsin.

- Scattered thunderstorms redevelop this afternoon & evening
  across far-eastern Minnesota & western Wisconsin. A few strong
  storms are possible.

- Another round of thunderstorms & locally heavy rain is
  expected Wednesday night across far-southern Minnesota.

&&

.DISCUSSION...
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Issued at 313 AM CDT Tue May 7 2024

The line of showers & thunderstorms moving east out of western
Minnesota continues to weaken overnight, with only a few
sporadic lightning strikes remaining. These rain showers will
continue to move east across eastern Minnesota & western
Wisconsin into the morning with rainfall amounts generally
remaining less than 0.25".

ANother round of scattered showers & thunderstorms is likely
later this afternoon & evening, as the surface boundary
responsible for the current precipitation occludes & stalls out
over far-eastern Minnesota & western Wisconsin. Upper level
support arrives later this afternoon in the form of a lobe of
vorticity pivoting around the upper level low to our west, which
should generate enough lift to generate scattered showers &
thunderstorms along & ahead of the stalled-out surface boundary.
One concern is that cloud cover from this morning`s rain will be
slow to clear out this afternoon & reduce instability for
thunderstorms this afternoon & evening. However, this most
likely would just limit the potential for any strong to severe
thunderstorms, & at least a few showers/storms are still likely
to develop. If we are able to maximize the instability this
afternoon, mixed-layer CAPE values approaching 1000 J/kg &
effective bulk shear of 25-30 kts could support a few organized
storms, capable of small hail & brief gusty winds. Rainfall
amounts will be spotty given the scattered nature of the
showers, but amounts near 0.5" are possible wherever it does
rain later today, with the chances for more widespread rain
increasing as one goes farther east into Wisconsin.

The pattern remains active Late Wednesday into Thursday as the
upper-level low lingers over the northern plains & continues to
pivot lobes of vorticity over the region. The most pronounced
one of these comes Wednesday evening into Thursday morning over
far-southern Minnesota, where multiple rounds of slow-moving
thunderstorms are likely along a surface trough extending
northwest from the surface low lover the mid-Mississippi
Valley. Ensemble guidance shows some outlier solutions towards
heavy rain but this signal is highly evident on the higher
resolution convective-allowing models, where most of them
depict localized rainfall amounts of 3-5" somewhere across far-
southern Minnesota/northern Iowa/eastern South Dakota.
Obviously our confidence remains low on where exactly this heavy
rain could fall, but it`s presence on multiple CAMs means we`ll
have a heavy rain/flooding threat to keep an eye on Wednesday
night. A few strong thunderstorms are likely as well in addition
to the heavy rain potential.

The pattern generally dries out for the latter half of the week
& into the weekend,as the remnants of the upper level low
dissipate & drier northwest flow develops aloft. isolated
diurnally-driven showers can`t be ruled out with any weak lobes
of vorticity embedded with the flow, but these 10-20% PoPs
aren`t much higher than the background average changes for rain
in early May. temperatures will be seasonable through the
weekend wit afternoon highs generally in the upper 60s to low
70s. A trend towards warmer temperatures looks likely next week
as heights gradually rise over the region.
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&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
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Issued at 1211 PM CDT Tue May 7 2024

A line of showers has popped up between KRWF and KAXN early this
afternoon. This is much earlier/further west than models had
this morning, so adjusted TAFs accordingly. In far western
Wisconsin, a few light radar returns are starting to pop as
well. Still thinking that later this afternoon TSRA will become
more widespread from KMSP and points eastward, but will still be
fairly scattered in nature. As such, have opted to go with
TEMPO instead of prevailing. Thunder chances drop off quickly
after 03z. Winds will turn southwesterly and become light and
variable overnight as the surface low moves overhead.

KMSP...As mentioned above, still anticipating a few scattered
showers and thunderstorms this afternoon, mainly after 22z.
Another chance for showers exists near the end of the period,
but confidence is low just how far north these will extend.

/OUTLOOK FOR KMSP/
THU...VFR. Wind NE 10G20 kts.
FRI...Mainly VFR. Chance PM MVFR/-TSRA. Wind NW 15G25 kts.
SAT...VFR. Wind NW 10-15G20 kts.
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&&

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

&&

$$

DISCUSSION...ETA
AVIATION...Dye