Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 290910

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
410 AM CDT Mon May 29 2017

.SHORT TERM...(Today and tonight)
Issued at 410 AM CDT Mon May 29 2017

Today is expected to be cooler and breezy with increasing clouds,
scattered showers, and even an isolated thunderstorm possible. A
few stronger cells could bring down some wind gusts near 40 mph,
but not expecting enough instability for any severe weather today.
Tonight will be cool overnight lows about 5 degrees below the
seasonal average for late May.

Early morning satellite imagery with surface obs showed a counter
clockwise circulation over northern Lake Superior, with cyclonic
flow extending across all of Minnesota and Wisconsin as well. Low
clouds and drizzle were wrapping around this low, and should
overspread the region this morning. The abundance of cloud cover
will limit heating, so continued with cool temperatures today. It
will also prevent CAPE from building across the region, so unlike
Sunday, not expecting much in the way of deep convection. The best
chance for thunder is across southern Minnesota. It will be
breezy, so could see some gusty winds with a passing shower, but
smaller dewpoint depression should keep any wind gusts sub-severe.

.LONG TERM...(Tuesday through Sunday)
Issued at 410 AM CDT Mon May 29 2017

Another day of isolated-scattered showers, breezy conditions and
below normal temperatures is on tap for Tuesday with deep cyclonic
flow still in place. Showers should be less numerous than today with
poorer lapse rates.

A surface ridge axis will reach the eastern/central Dakotas
Tuesday night and pass overhead Wednesday and Wednesday night.
Strong WAA on the backside of the axis will bring returning
moisture rapidly northward with the Gulf remaining wide open. With
the trough stuck over the northeast and most of eastern Canada, a
boundary will have difficulty lifting north of I-94 and will
likely stall in the vicinity of southern MN/northern IA Thursday
through Saturday. The best forcing for ascent appears to be tied
to the LLJ impinging on the boundary over eastern SD Wednesday
evening, veering to southwestern MN and IA late Wednesday night
and remaining there through Friday, before again veering more
easterly Friday night. PWATs increase toward 1.5 inches and there
should be enough instability for thunderstorm development
throughout this corridor. Wind shear doesn`t look particularly
impressive so any severe threat should be disorganized and tied to
peak heating, however repeated rounds of storms and seasonably
high PWATs could lead to some heavy rain concerns.

Another approaching trough should bring a cold front through
Saturday/Saturday night with cooler and drier air returning
Sunday and Monday.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1045 PM CDT Sun May 28 2017

In the wake of the showers we will see winds calm down to around
or below 10 kts overnight. MVFR ceilings will arrive by 09z at
KAXN and expand south and east to the rest of the sites toward
(or shortly after) daybreak. MVFR cigs then persist through
Monday, with scattered showers developing by 17z. Winds will also
become gusty from the west, with sustained speeds 15-17kts and
gusts to around 25 kts. Monday evening gusts begin to diminish and
scattering of the MVFR deck occurs as well.

VFR conditions are expected until the stratus deck settles in
between 12z and 15z. Scattered showers will then be possible
through the day.

Tue...VFR. Isolated MVFR/-SHRA possible. Wind NW 10-20 kts.
Wed...VFR. Wind NW 5-10 kts.
Thu...VFR. Wind S 5 kts.




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