Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 242005
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
305 PM CDT TUE MAY 24 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 305 PM CDT Tue May 24 2016

Finally seeing some isolated showers and storms popping across west
central Minnesota this afternoon...where an impressive 3000 J/KG
of Most Unstable CAPE and Lifted Indices around -6C are being
analyzed. Despite the presence of impressive instability, there
appears to be an absence of any strong lifting/forcing mechanism,
with low/mid level ridging building in from the west. Therefore,
while spotty storm development will likely continue to occur with
the afternoon heating, expect the severe threat is very
low/marginal.

Dewpoints stay elevated in the 50s to lower 60s tonight as we await
the arrival of more widespread convection from the southwest.
Conditions will remain rather muggy, with lows in the mid 50s to
lower 60s and little wind. This will also create the potential for
some fog development, primarily over east central MN and west
central WI where less cloud cover and lighter winds are projected.

Wednesday looks to be nearly a slam dunk for precipitation given the
progged support from a shortwave trough, favorable upper level jet
dynamics, and impressive low level moisture transport. By daybreak
Wednesday, expect to see the complex of showers and thunderstorms
having reached west/south central MN, then spreading toward the
MN/WI border by noon. We look to dry out over west/south central MN
by Wednesday afternoon. If we see some clearing, thunderstorm
redevelopment could mean severe storms, with the triple point
located just to the west in central South Dakota, a warm front
stretching into MN, and a trailing shortwave pushing into the
Dakotas. Large hail and damaging winds would be the primary
concerns, although the wind profiles and frontal boundary would also
suggest a tornado threat.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 305 PM CDT Tue May 24 2016

A warm and unstable pattern will prevail through the long term as
the local area is sandwiched between a trough of low pressure in the
west and a ridge of high pressure in the east.

Model agreement was pretty good today between the gfs and ecmwf. The
most significant period for showers and thunderstorms is from friday
night through Saturday night when a strong wave aloft moves
northward across the upper mississippi valley. widespread rain
amounts of an inch to an inch and a half are possible. this wave
will come into southern California on Wednesday and reach Colorado by
Friday morning then begin the trek northeast through the upcoming
weekend.

Weak ridging in the wake of this wave may yield a drier forecast for
Sunday over what we currently have. This will certainly be fined
tuned over the next several days as the entire holiday weekend will
not be a total washout. Some weaker waves will traverse the region
from Memorial Day through Tuesday, leading to more chances for
precipitation, but rain amounts with these look to be lighter and
less widespread.

In the meantime, the beginning of the long term (Wednesday night)
will see showers and thunderstorms moving north and east of the
forecast area as a wave exits the region. This will leave the
forecast area dry for a good part of Thursday before showers and
thunderstorms begin to sprout late Thursday night and Friday.

Both high and low temperatures will average around 10 degrees above
normal through the period. This is more representative of late June
weather.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1226 PM CDT Tue May 24 2016

The primary concern this TAF period is on the potential for
thunderstorms and MVFR conditions...primarily on Wednesday.

The pesky stratus deck that developed and lingered across central
MN this morning will continue lifting/eroding...with mainly sct-
bkn cumulus and cirrus clouds prevailing this afternoon. Could see
a few widely scattered showers and thunderstorms develop over
central MN this afternoon and early eve...but expect the bulk of
the activity to hold off until after 09Z Wednesday...as widespread activity
moves in from the southwest. Expect most sites to be affected with
showers and thunderstorms between 12z and 18z Wednesday. There
could be instances of mvfr cigs/vsbys in conjunction with the
heavier activity. Winds are variable as of now...but will
eventually take on a southwest directional component...then become
east/southeast tonight and Wednesday with gusts developing.

KMSP...
Northwest winds to start the period, but expect a shift to
southwest early afternoon. An isolated shower/ts is not entirely
out of the question by early eve...but probability is very low.
Higher chances arrive around daybreak Wednesday, with periods of
SHRA/TS expected through the morning.

/OUTLOOK FOR KMSP/
Thu...Mainly VFR. Chc TSRA/MVFR. Wind S to SW 5 kts.
Fri...Mainly VFR. Chc TSRA/MVFR. Wind SE 5 kts.
Sat...MVFR. TSRA/MVFR Likely. Wind SSE 5 kts.


&&

.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&

$$

SHORT TERM...LS
LONG TERM...RAH
AVIATION...LS



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