Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 100449
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1049 PM CST Fri Dec 9 2016

.SHORT TERM...(This evening through Saturday)
Issued at 306 PM CST Fri Dec 9 2016

Short term concerns are cloud trend overnight and snow
development Saturday.

Lower level cloud/moisture remains trapped under the subsidence
inversion across the area as the 1040mb high noses into MN Still
have some flurries associated with the clouds...but they should
become less numerous as the early evening progresses. Mentioned them
early to the east as clouds should remain much of the night. More
clouds moving into southwest into south central MN associated with
weak isentropic lift over that region.  That lingers mainly through
06z Sat and should end the light snow/flurry threat then. Clouds may
break up some...especially over the northwest cwa...and temepratures
could drop colder than forecast...if clouds clear quickly this
evening.

The main lift/weak waa pattern ahead of the main short wave moving
in Sat night/Sun should lift mainly light snow across the MN/River
Valley region toward east central MN through 00z Sun. Generally 1 to
2 inches expected to the southwest during the day Saturday...with
the more widespread snow moving in Saturday night.

.LONG TERM...(Saturday night through Friday)
Issued at 306 PM CST Fri Dec 9 2016

The bulk of the snowfall accumulations look to come Saturday night
and Sunday morning as the surface trough noses into southern
Minnesota, with additional (albeit lighter) accumulations
continuing through Sunday afternoon as a shortwave passes over.
The higher accumulations still look to occur across southern
Minnesota, where 5 to 8 inch totals are expected over the 36 hour
period...hence the issuance of a Winter Weather Advisory (vs. a
warning since the snowfall duration is longer). Furthermore, the
wind is not expected to be much of a factor with the storm system. We
will likely need to expand the advisory northward into central
MN/WI if the current expectations of 3-5 inches exhibit
consistency in future model runs.

Snow comes to an end Sunday night, and then the main story will be
the push of Arctic air by Monday night. By Tuesday morning, 850 mb
temperatures will be pushing -20C. This will translate to much of
the forecast area experiencing sub-zero temperatures, with highs
in the single digits. Even colder weather for Wednesday and
Wednesday night, with lows from -5F to -15F quite possible across
the forecast area. Given winds will be in the 10 to 15 mph range
Wednesday/Thursday at daybreak, we may need a wind chill advisory
for west central MN.

The cold will continue through the foreseeable future, with
readings remaining around 20 degrees below normal into next
weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1048 PM CST Fri Dec 9 2016

Most of the TAF sites are right along the edge of a stratus cloud
deck, so ceilings have been bouncing from VFR to MVFR given the
base of the clouds are 2000-2500ft in general. The trick is that
the wind direction is such that it will keep moving these clouds
in such a manner that the edge will hang near
KAXN/KSTC/KMSP/KRNH/KEAU. So, sort of a low confidence ceiling
forecast for the night. There has also been light snow falling
from these clouds at times.

KMSP...

Wish we had a higher confidence cloud forecast at the airport.
KMSP is right along the edge of the cloud cover and the clearing
earlier this evening has slowed, so the airport may end up with a
prolonged period of MVFR with snow flurries at times.

/OUTLOOK FOR KMSP/
Sun...IFR/MVFR with SN. E wind 5-10 kts.
Mon...MVFR/VFR. W wind 5-10 kts. Bcmg NW 15G25 overnight.
Tue...VFR. W wind 10-15 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Winter Weather Advisory from 9 AM Saturday to 3 PM CST Sunday
     for MNZ073>075-082-083-091-092.

     Winter Weather Advisory from noon Saturday to 6 PM CST Sunday
     for MNZ076>078-084-085-093.

&&

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...CLF


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