768
FXUS63 KMPX 160522
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1222 AM CDT Thu May 16 2024

.KEY MESSAGES...

- Brief funnel clouds possible across southwestern Minnesota this
  afternoon.

- A band of showers with a few rumbles of thunder will gradually drift
  from western Minnesota into western Wisconsin this afternoon
  through Thursday morning. Rainfall amounts of 0.25" or less
  expected.

- Dry to end the work week, followed by the chance for scattered
  showers and storms on Saturday.

&&

.DISCUSSION...
Issued at 155 PM CDT Wed May 15 2024

Early afternoon satellite imagery illustrates clouds expanding to
the east across the region, tied to the advance of a surface low
spinning through eastern South Dakota. MPX Radar imagery captured an
initial band of echoes across western Minnesota earlier today, but
surface observations reveal that little if any precipitation was
able to reach the surface given notable dry air throughout the
column. Better support for precipitation will arrive this afternoon,
as a shortwave located within the upper flow advances across the
Upper Midwest. The forcing associated with this wave will be
recognized by way of a cold front, which is forecast to slowly move
across Minnesota and western Wisconsin starting this afternoon and
continuing into tomorrow morning. Regional MRMS picture depicts the
first showers developing along the South Dakota/Minnesota state
border at this hour. CAMs are in fairly solid agreement with the
timing of the narrow band of rain showers, such that our PoP timing
reflects the highest PoPs (80-90%) across western Minnesota this
afternoon, moving across I-35/Twin Cities Metro by late evening, and
eventually wrapping up across western Wisconsin by mid-morning
Thursday. We can`t rule out some thunder, especially across
southwest Minnesota where a few hundred joules of CAPE are present
on forecast soundings. Additionally, we will have to watch for the
potential for funnel clouds/perhaps a quick spin-up with the initial
convection this afternoon, given ample surface vorticity co-located
with an axis of 0-3km CAPE per SPC mesoanalysis. Rainfall amounts of
0.25" or less are expected for most locations, with slight chance
that a few spots observe higher amounts due to convective nature of
the rainfall.

The last of the showers will depart western Wisconsin by midday
tomorrow, which will open the door for a dry end to the work week.
Little change in the airmass will allow for highs to climb into the
low 70s tomorrow afternoon. Our focus will shift back to the
northwest on Friday, as an upper low is forecast to take shape
across southern Canada. Synoptic scale warm advection will increase
across the Upper Midwest ahead of this system, which will warm
temperatures well above normal heading into the weekend. Friday`s
highs are forecast to climb into the to a developing upper low
across southern Canada low to mid 80s for much of the region and
it`s conceivable that locations in western Minnesota make a run
towards 90 degrees. As the upper low transitions east Saturday, a
cold front will swoop across the region. Scattered showers and a few
thunderstorms appear possible with this frontal passage. Forecast
soundings show a capping inversion present across south/west
portions of the area Saturday morning, with less capping (later in
the diurnal curve) across eastern Minnesota and western Wisconsin
during the afternoon and evening. For this reason, the highest PoPs
(40-60%) exist for locations along and east of I-35. Temperatures
will cool back to the 70s following the passage of this storm system.

As mentioned by the midnight shift, the pattern from early next week
onward will be dominated broad southwest flow aloft, such that the
main storm track appears to setup south of Minnesota/Wisconsin. We
have maintained slight chance PoPs for several days next week, as
it is possible that portions of the area (mainly south) may be
"brushed" by the passing disturbances. Global ensembles feature a
northward shift in the general storm track by the end of next week,
which may result in the return of more widespread rain chances
towards the end of the extended forecast.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1217 AM CDT Thu May 16 2024

MVFR and -SHRA is likely early on for the WI sites with
visibility dropping to 4-6sm, with MVFR for most MN sites as
CIGS lower to around 010-015 level early on. CIGS will gradually
lift throughout the day eventually becoming VFR by the afternoon
as skies scatter out and continue to lift with only high clouds
by the end of the period. Winds at 10-15kts will gradually shift
towards 330-360 with limited gusting through the period.

KMSP...Kept any -SHRA mention out of the TAF as the final line
passes through right around TAF start and should be out by
08-09z. Otherwise we remain MVFR through around 21z when skies
begin to scatter out and cloud level increases by period`s end.

/OUTLOOK FOR KMSP/
FRI...VFR. Wind SE 10-15kts.
SAT...VFR, chc MVFR/-TSRA. Wind SE to W 15-20G30kts.
SUN...VFR. Wind SW 10-15kts.

&&

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

&&

$$

DISCUSSION...Strus
AVIATION...TDH