Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 241721

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1221 PM CDT Wed May 24 2017

.SHORT TERM...(Today and tonight)
Issued at 315 AM CDT Wed May 24 2017

Surface analysis early this morning shows weak high pressure over
the Dakotas extending into the Deep South with one frontal system
over the Ohio River Valley and another over southern Alberta
province into the Pacific northwest. Aloft, the deep upper low
responsible for yesterday`s occasional showers has shifted into
the mid-Mississippi River valley while a NE-SW oriented ridge axis
is placed from western Ontario province through the Four Corners
region. Some low clouds are still shifting southeast through the
area in a last gasp of influence from the upper low. Otherwise,
the deep ridge of high pressure will slowly move east over the
region, allowing for a drier and warmer airmass to grab a hold of
the region`s weather for today into tonight. The ridge axis will
shift atop the area overnight then just off to the east by
daybreak Thursday morning. The western frontal system will have a
stacked low remain to the north of the international border but
increased moisture in advance of its warm front, expected to push
into the eastern Dakotas by Thursday morning, will allow for an
increase in cloud cover but be delayed enough to keep
precipitation out of the forecast through tonight. Highs today
will climb to 60-65 degrees across the WFO MPX coverage area. Lows
tonight will range from the lower 40s north and east to the upper
40s south, west and in the Twin Cities metro.

.LONG TERM...(Thursday through Tuesday)
Issued at 315 AM CDT Wed May 24 2017

The overall concerns in the long term remain the frontal passage
Thursday night into Friday. Then the overall evolution of the
upper trough over the northern CONUS into the holiday weekend.

Initially we should see clouds increasing out ahead of the next
short wave and waa pattern Thursday. This should spread a small
chance of mainly elevated showers into the west and central
portions of the cwa during the afternoon. The front and trough
advance east over the region into the day Friday with a continue
threat of light showers. We do see moisture increase to around 1
inch precipitable water into Friday afternoon. This may be enough
to generate a few heavier showers with some thunder. The GFS is
faster with the front...moving into wester WI by 18z Fri with the
ECMWF about 6 hrs slower...holding off until later afternoon. The
EC builds better instability as well. Dewpoints should rise to
the mid 50s and temperatures will warm ahead of the front with mid
to upper 70s.

This system exits to the east Friday night but the deterministic
differ greatly in development and evolution of the northern CONUS
trough. The GFS brings in moisture ahead of the trough into
Saturday afternoon...with the ECMWF holding off until later
Saturday night/Sunday. We will hold onto the slight chance PoP for
mainly the west Saturday afternoon. This may be removed if trends
more toward the ECMWF in future model runs.

The better shot of ran will develop Sunday into Monday as the
upper trough drops south over the region. This will eventually
cool temperatures back below normal by Memorial day. The thunder
threat looks best for the area Sunday afternoon with the troughs
arrival. We may see some lingering chances for isolated thunder
to the east on Memorial Day depending on timing. Overall...little
threat of severe weather. Trending more like a typical Memorial
Day weekend.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1215 PM CDT Wed May 24 2017

Residual boundary layer moisture from the departing storm system
across the Ohio Valley, will slowly dry things out with VFR cigs
through this evening. There remains some concerns with MVFR/IFR
cigs redeveloping once again Thursday morning as did today. As
winds veer to the east/southeast overnight, moisture will likely
increase from the departing storm system and affect west central
Wisconsin and east central Minnesota after midnight. There could
even be IFR/LIFR/FG vsby in some of the local higher terrain in
south central Minnesota. Otherwise, no other aviation concerns
with most of the precipitation holding off until after 18z
Thursday in western Minnesota.


VFR cigs will continue through sunset with an isolated shower
possible during max heating. Otherwise, MVFR cigs could once again
redevelop Thursday morning, but confidence remains low. However,
will introduce FEW009 SCT020 between 11-14z as moisture increases
and the typical diurnal trends of cigs lifting in the morning
occur. A northeast to east wind will prevail through the evening,
with winds becoming southeast and increasing Thursday


Fri...VFR. Isolated -SHRA. Wind SW 5-10 kts.
Sat...Mainly VFR. Slgt chc P.M. -SHRA/-TSRA. Wind W 5-10 kts.
Sun...Mainly VFR. Chc -SHRA/-TSRA. NW 5-10 kts.




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