689
FXUS63 KMPX 102339
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
639 PM CDT Fri May 10 2024

.KEY MESSAGES...

- Showers and thunderstorms possible across western Wisconsin
  late this afternoon. A few storms could strong wind gusts.

- Strong geomagnetic storm tonight combined with mostly clear
  skies making strong chances to observe Auroras.

- Sunny and warm spring weather this weekend with highs in the
  70s on Saturday and 80s on Sunday.

&&

.DISCUSSION...
Issued at 236 PM CDT Fri May 10 2024

A clipper system continues to make its way southward over Minnesota and
Wisconsin this afternoon. Surface observations showing blustery 35-40
mph wind gusts across western Minnesota. With windy conditions, and
warm temperatures, RH values near 25 percent this afternoon will make
for elevated fire conditions. Winds will decrease tonight once the
trough vacates southeastward.

THE REST OF TODAY...Current visible satellite showing a defined band of
cumulus stretched from the U.P. of Michigan down to northern Iowa which
is a frontal boundary associated with the upper-level trough. Some
showers are possible with this cloud band but dry air likely
evaporating most water droplets before reaching the surface. Just off
to the west across the St. Croix River Valley, another pocket of cu has
developed to which will likely be the culprits of any convection this
afternoon, mainly for our western Wisconsin counties. The storm
environment for the rest of today only looking marginal at best.
Forecast soundings showing a dry surface layer at least 1km deep with
only a few hundred joules/kg of instability. The primary hazards for
any storm that becomes organized may have strong wind gusts and
potentially small hail less than 1 inch in diameter. The bulk of
showers and thunderstorms should clear western Wisconsin by 7 PM
tonight. As this occurs, clearing will begin from west to east
overnight just in time to likely see the Auroras in non-light polluted
areas. Lows tonight forecasted to reach low to mid 40s.

SATURDAY AND SUNDAY...Today`s clipper system will reach the Great Lakes
by Saturday, and a weak ridge of surface high pressure will settle
across the Upper Midwest. Winds will become westerly with mostly clear
skies, and afternoon highs will warm into the 70s across the area. On
Sunday another clipper system will track across Canada, and southwest
winds ahead of a weak cold front will bring warmer temperatures across
the region. Highs on Sunday will reach the 80s at many locations. This
cold front will pass through dry, but there is a small chance (10 to
20%) for a light rain shower for areas near Lake Mille Lacs MN to
Chippewa Falls WI.

MONDAY THROUGH FRIDAY...No significant changes from the previous
forecast. The aforementioned weak cold front will pass through to the
south and be the focus for showers and thunderstorms across Iowa and
the I-80 corridor. On Tuesday a shortwave trough will approach from the
west, and this will bring the next widespread chance for showers and
thunderstorms. The current forecast calls for about a 50/50 chance for
rain, mainly due to uncertainties with timing and placement. For now,
continued with the blended forecast since we`re using a 6hour time
window for rain chances. If you were to look at the entire system as a
whole, most locations probably have a 70 to 80% chance of seeing some
rainfall between Wednesday and Thursday according to the ensemble
guidance.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 622 PM CDT Fri May 10 2024

Showers dropping down from central MN are associated with the
main upper level shortwave. Radar returns have been diminishing
as the approach the radar, indicating these are predominantly
virga showers, which is no surprise given cloud bases up at
9k/10k feet with surface dewpoint depressions of over 30
degrees. As we lose daytime heating, these clouds will
dissipate pretty quick, with mainly clear skies expected for a
likely northern lights display we`ll have tonight. On Saturday,
WAA sparked by a surface low going across Manitoba will result
in some mid level clouds developing, but dry low level air will
continue to keep us dry.

KMSP...With showers on radar over central MN producing few, if
any reports of rain at the surface, kept even a VCSH mention out
of the MSP TAF. After that, there are few concerns until late in
the period, when the wind direction looks to change enough to
require a shift fram a 30s operation over to a 12s.

/OUTLOOK FOR KMSP/
SUN...VFR. Wind W 10-15G25kts BCMG N 10-15kts.
MON...VFR. Wind NNE 10-15kts.
TUE...VFR. Wind E at 5-10kts

&&

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

&&

$$

DISCUSSION...JRB/Dunleavy
AVIATION...MPG