Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 110605
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1205 AM CST Sun Dec 11 2016

.SHORT TERM...(This evening through Sunday)
Issued at 325 PM CST Sat Dec 10 2016

Short term concerns are snow amounts and headlines through
Sunday.

Updated earlier to expand the advisory farther to the north...from
Morris...St Cloud east into west central Wisconsin and south across
southern Minnesota.  Looking at overall QPF trends...it still looks
like around one half inch across south central Minnesota...with
about one quarter inch over the far north.  Taking into account
overall SLR`s of around 20:1 to the north and around 15:1 far
south....we should see 6 to 8 inch snow accumulations into south
central MN with 3 to 6 inches over the north...over a 24 to 36 hour
period. Surface winds will be negligible for the period of snow
fall...and pick up some in the wake of the surface low into western
MN Sunday afternoon.  With the snow ending...overall blowing
snow is expected to remain minimal.

We have one band of moderate snow now working into the southern
metro as initial surge of isentropic lift moves in.  The other
moderate snow band is located farther south across south central MN.
Various models lift this southern band north into the central cwa
through 06z and into the northeast cwa 06z-12z. We should  see 2-3
inch snows with this band of snow as it moves through.

Improving conditions should ensue to the west Sunday morning...but
the snow should continue falling...at least lightly through much of
the day...possible ending Sunday evening over west central Wisconsin.
With the clouds and snow...temperatures should be nearly steady this
evening...slowly warming through the lower to middle 20s through
midday.

.LONG TERM...(Sunday night through Saturday)
Issued at 325 PM CST Sat Dec 10 2016

The Arctic blast is the main headline in the long term portion of
the forecast, although there could end up being an equally as big
headline toward the end of the upcoming week; this time in the
form of another winter storm.

Medium range models are in fairly good agreement that weak high
pressure will settle in on Sunday night in the wake of the storm,
with the real surge of cold arriving in the wake of the Arctic
front that pushes through Monday afternoon and evening. Scattered
snow showers are expected to accompany the frontal passage, along
with a shift to brisk northwest winds. Temperatures will plummet
into the single digits below zero on Monday night, with wind chill
values potentially nearing advisory criteria across west central
MN early Tuesday morning. High pressure will gradually spill
southeast through most of the work week, with highs in the single
digits and sub-zero lows. While winds will settle down a bit, wind
chill advisories will remain a possibility through Thursday
morning (for west central MN locations).

The forecast for Friday into the start of next weekend is looking
increasingly interesting. Both GFS and ECMWF Models forecast an
inverted trough to nose into the mid/upper Mississippi Valley.
While timing/spatial agreement is not perfect, model agreement is
sufficient to warrant the inclusion of high chance to low likely
precip probabilities. The early progs of this system look
comparable to the Plains low archetype composite for storms which
have historically brought 6 inch or greater snowfalls to the
area. Stay tuned...

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1204 AM CST Sun Dec 11 2016

Minor changes made to the TAFs with the 6z issuance. Heavier band
of snow south of the Twin Cities will remain there for the first 4
hours of the TAF or so, but will lift NE in the morning as wave
currently moving across the central Dakotas comes into MN.
Followed the RAP and HRRR to time higher rate (lower vsby) snows
into terminals currently north of the heavy snow band, which is
currently all terminals but RWF. Other change was to speed up
ending of snowfall outside of STC/AXN this afternoon to a timing
more in line with the RAP/HRRR. Snow will likely linger through
the afternoon across northern MN on the north end of an inverted
surface trough, which is why ending of snow at AXN/STC was
delayed, though this snow may end up north of them in the end.
Low confidence on skies behind the snow, but safest route is to
maintain an MVFR CIG until we see something different.

KMSP...Confidence is high in the snow forecast for MSP, with
heaviest snow (rates of 1/2 to 3/4 inch per hour) expected between
10z and 15z. Lower confidence in how low cigs will be in the wake
of the snow, but kept things optimistic for now with high MVFR,
though IFR cigs are certainly possible for several hours behind
the snow.

/OUTLOOK FOR KMSP/
Mon...MVFR/VFR. Chc -sn late. SW wind 5-10 kts. Bcmg NW 10G20kt
      overnight.
Tue...VFR. WSW wind 10G20 kts.
Wed...VFR. WNW wind 10G20 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 9 PM CST Sunday for WIZ014>016-
     023>028.

MN...Winter Storm Warning until 6 PM CST Sunday for MNZ069-070-
     076>078-084-085.

     Winter Weather Advisory until noon CST Sunday for MNZ047>049-
     055>058-066-082-091-092.

     Winter Weather Advisory until 6 PM CST Sunday for MNZ050>053-
     059>063-068-093.

     Winter Storm Warning until noon CST Sunday for MNZ054-064-065-
     067-073>075-083.

&&

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...MPG



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