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fxus63 kmpx 171138 aaa 
afdmpx

Area forecast discussion...updated
National Weather Service Twin Cities/Chanhassen Minnesota
538 am CST sun Nov 17 2019

Short term...(today through monday)
issued at 351 am CST sun Nov 17 2019

The axis of a shortwave trough is beginning to push across the
region early this morning. With this trough comes a surface cold
front which is shifting winds northwest behind it, but no
significant temperature contrasts are expected. Precip continues
in advance of these features, which has shifted into eastern Minnesota
and western WI. From the westernmost tier of Wisconsin counties
and westward, it remains all rain. Farther east in the Rice Lake,
Ladysmith, and Eau Claire areas, cooler and drier air in place is
allowing all snow to fall. The precipitation won't last too long,
so only anticipating an inch to inch and a half in some of those
places.

Clouds are likely to linger all day and into at least this
evening. Forecast soundings do show some drying in the boundary
layer after sunset, but am a bit skeptical of this given the
extent of stratus this morning and the weak flow pattern heading
into tonight. It's more likely clouds will linger this evening
before they would have increased again anyway overnight in
advance of the next shortwave. Warmer air aloft will lift
northward ahead of this feature and it could allow for a bit of
mixed precip late tonight and early Monday morning across far
western Minnesota. This precip should spread east throughout the day in
the form of patchy drizzle with little or no measurable amounts
expected.

Long term...(monday night through saturday)
issued at 351 am CST sun Nov 17 2019

Near to slightly above normal temperatures are expected to continue
through the long term. Precip potential looks best Monday night and
again Wednesday night into Thursday, though no high impact weather
is expected with either of these systems.

Monday night, we'll see weak warm air advection and some positive vorticity advection out ahead of a
positively shortwave embedded within the mean northwest flow which
will have the potential to send a narrow band of light precip across
the area. P-type was a bit tricky with this as a large number of
models are dry during the period, which really drove down our
probability of ice present grids. These low probice grids resulted
in all liquid being forecast (so rain or freezing rain depending on
surface temps). However, when looking at models that are producing
precip (the European model (ecmwf) and Canadian in particular), you see ample
moisture present in the -10c to -20c layer to allow for ice to be
present in the clouds. As a result, we upped the probice grids
considerably to allow any potential melting layers aloft or near the
surface to drive our p-types, which resulted in a rain/snow mix for
eastern Minnesota and western WI. Quantitative precipitation forecast only looks to amount to a few
hundredths at best, so impacts look minimal if we do see any precip.

For mid-week, models are starting to come into better alignment on a
system tracking across the center of the Continental U.S.. there will be two
waves to watch, a positively tilted northern stream trough dropping
down from Canada and a southern stream wave that will be the
remnants of the h5 low currently spinning near the Baja Peninsula.
Models are showing better agreement on this southern stream wave
sending a surface low up from about Kansas City to Alpena, Michigan
Wednesday night/Thursday. Such a track would place areas roughly
along and east of a St. James, to the southeast Twin Cities Metro,
and Rice Lake, WI line in line for having the greatest threat for
seeing precip. This looks like a fairly warm system, with most of
the precip falling as rain, though the far western edge of the
precip shield looks cold enough for mostly snow. Of course this
places the narrow snow threat zone over our area. Another difference
with this system and the past few we have seen is that it will be
tapping into Gulf moisture, so it will have considerably more
moisture to work with. However, it looks fairly progressive, so that
should keep things from getting out of control. Still, the wpc day 4
probability of seeing greater than 0.25" of quantitative precipitation forecast as snow does show
some low probabilities from south central Minnesota into western WI, so we
will have to keep a close eye on this system as it could yield some
plowable snow.

Behind this system, we get a brief cool down Thursday/Thursday
night, otherwise it's mild and dry zonal flow for US into next
weekend.

For much of the period, the nbm sits down around the 25th percentile
for forecast highs/lows when looking at the model spread. As result,
forecast highs and lows next week could easily end up a few degrees
warmer than what we have. The one period where we did boost temps
above the nbm were highs for Tuesday, basically sticking with what
the existing forecast had. It looks like the main trouble maker for
temps is the NAM, which is often a large cold outlier for highs.

&&

Aviation...(for the 12z tafs through 12z Monday morning)
issued at 538 am CST sun Nov 17 2019

Steady precip is exiting Minnesota to the east, but patchy drizzle and
light fog will follow the rain for an hour or two. Steady snow has
begun at eau with IFR conditions. The snow will exit there by 15z.
MVFR cigs likely through the period area wide, with clearing
appearing possible this evening only across southwestern Minnesota.

Kmsp...conditions dropped to IFR levels at taf issuance time, but
this should be short-lived before conditions rebound (possibly to
VFR for a short time) back to MVFR after 13-14z. MVFR cigs likely
then expected into Monday.

/Outlook for kmsp/
Tue...MVFR cigs possible. Wind northwest 5 kts.
Wed...chc MVFR and -rasn late. Wind southeast bcmg north 5-15 kts.
Thu...chc MVFR/IFR and -sn early. Wind northwest 10-20 kts.

&&

Mpx watches/warnings/advisories...
WI...none.
Minnesota...none.
&&

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