Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 130549
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1149 PM CST Tue Dec 12 2017

.UPDATE...For 06z Aviation discussion below


&&

.SHORT TERM...(This evening through Wednesday)
Issued at 248 PM CST Tue Dec 12 2017

An active short term period ahead. First of all, we have an area
of light snow moving through the eastern portion of the area in
response to strong theta-e advection spreading over the area ahead
of the incoming clipper that we`ve been discussing. This area of
snow is on a diminishing trend and don`t expect much more than a
dusting across eastern MN and western WI.

The aforementioned clipper is currently dropping southeast through
Alberta, and is well defined in current water vapor imagery and
indicates a decent PV anomaly with this wave. This wave is going
to race southeast this evening and reach western North Dakota
around midnight. The surface response will be a deepening low that
will move from extreme eastern North Dakota through Minnesota
from about midnight through 10am tomorrow. This still looks to
spread mainly snow along the northern flank of the low, with
western WI in the most favorable location to see 1 to 3 inches of
snow. Farther south, mid level drying leads to limited icing aloft
and hence the forecast of freezing drizzle. Thinking the QPF will
be light south of the I-94, but the roads will likely turn slick
for the morning rush. However, the lack of QPF inhibited the idea
of issuing a winter weather advisory at this time, but will
continue to evaluate the possibility for a headline through the
night.

We do feel more confident in the wind potential for western and
southern MN tomorrow, so went ahead with a wind advisory.  These
areas can expect winds of 25-30 MPH with gusts up to 50 MPH at
times tomorrow. The precip should mostly stay east of the area
with the strongest winds.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 248 PM CST Tue Dec 12 2017

The series of upper level shortwaves and surface clipper-type low
pressure systems will continue through the rest of this week into
the upcoming weekend. None of the systems will be particularly
strong or put down any significant amount of precipitation, each
acting to be primarily a nuisance to the area. The next upper
level wave looks to drop southeast through the area late Thursday
afternoon, followed by late Friday through Friday night, then
another on Sunday then potentially another on Tuesday. However,
each wave is rather progressive and not deep with moisture (some
not even enough to produce precipitation), thus pops are limited
to the low- end chance range at best throughout the extended
portion of the forecast. Not looking at any systems that may have
icy precipitation either, with each small round of precip a mix of
mainly rain & snow.

As for temperatures, virtually no change in airmass is expected
through the weekend which will keep max temps in the lower 20s to
lower 30s. Starting early next week, a more E-W flow will take
hold (rather than a more NNW-SSE colder flow) which will allow for
modified Pacific air to be brought into the region, nudging the
temperatures up a bit across the area. Highs starting on Monday
look to climb into the 30s across the WFO MPX coverage area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1150 PM CST Tue Dec 12 2017

MVFR ceilings will spread across the area between 09z and 13z in
the wake of a trough dropping across the area. There is still a
chance of -FZDZ overnight and Wednesday morning...although
soundings are really dry so precip amounts look meager. Periods of
IFR cigs look possible throughout the day. South/southeast winds
will shift to the northwest on Wednesday morning and increase to
sustained 20-30kts with gusts to 40 kts.

KMSP...Freezing drizzle still looks possible during the morning
push...09z-13z. Any accumulations look to be light given how dry
the low levels are (a few hundredths of an inch).

/OUTLOOK FOR KMSP/
Thu...Chc MVFR. Wind NW 10-15 kts.
Fri...Chc MVFR. Wind WSW 5-10 kts.
Sat...Chc MVFR. Wind SW 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Wind Advisory from 6 AM to 6 PM CST Wednesday for MNZ041-047-048-
     054>058-064>067-073>076-082>084-091>093.

&&

$$

SHORT TERM...SPD
LONG TERM...JPC
AVIATION...LS



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