Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 170023

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
623 PM CST Thu Nov 16 2017

.SHORT TERM...(This evening through Friday)
Issued at 225 PM CST Thu Nov 16 2017

The surface high that was to our north early this morning has
begun shifting east, introducing southeasterly winds to the region
this afternoon. A narrow band of virga is showing up on radar this
afternoon, and we did add a chance of light snow and flurries to
the forecast to account for this. So far, nothing is reaching the
ground. This band will race through quickly.

The main feature of interest in the short term period is the low
pressure system that is currently progressing eastward across
Montana and will continue on an easterly course. Expecting two
surface lows to develop, one will go well north of us, and the
other will sag south of our area. With the southern low, the warm
front will remain just to our south. The low level theta-e
advection really ramps up tonight, as warmer and more moist air
advects north of the front.

The forecast has been pretty consistent in holding off the
development of precipitation until the trough has pushed well
into MN, meaning western MN will likely remain dry. Farther
east, thinking drizzle is a good bet tomorrow along with low
stratus. Did reduce high temps by a few degrees tomorrow given
that we expect the low clouds to remain in place at least across
the east.

Thankfully in terms of impacts, temperatures will warm above
freezing before the arrival of the drizzle tomorrow, so expect
just wet roads, no ice.

.LONG TERM...(Friday night through Thursday)
Issued at 225 PM CST Thu Nov 16 2017

The main theme of the long term is continued dry weather and a
roller coaster of warm and cold. By tomorrow night, we will be in
cooler northwesterly flow that will scour the moisture out. We
could actually see the sun in southern MN on Saturday morning. The
northwesterly flow pattern holds through the weekend until a
clipper like system to our north puts us in the warm sector and
pulls warmer air northward into the state on Monday.

That warm up will be brief as the next dry cold front slams
through Monday night. Highs Monday will be in the mid to upper
40s, but Tuesday will be in the 20s to low 30s. That cooling
looks to last through Wednesday before we swing back the other way
very close to Thanksgiving. For Thanksgiving day itself, right
now we look to be in the transition zone of the cold trough to the
east and the warm ridge building in from the west. So, timing of
these features will really be the important part because a delay,
or a more progressive flow, will make the difference between it
being cold, near normal, or warm for Thanksgiving.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 623 PM CST Thu Nov 16 2017

Low clouds have been eroding across southern and west central MN,
with a swath of MVFR still from KAXN to part of the Twin Cities
metro. Some of the short term models bring the drier low level air
into central and east central MN later this evening, and that
certainly is plausible. It`s not a favorable time nor scenario
with southeast winds for such clearing. Have added tempo groups
for scattered clouds in this area later tonight, but confidence is
only average for this.

Other issue is the influx or development of MVFR conditions
tomorrow morning. Models are in very good agreement that moisture
will advance northward, and have continued the trend of MVFR
ceilings across the entire area, with drizzle in eastern MN and
west central WI. Incoming cold front Friday midday and afternoon
will end the drizzle, but MVFR should remain.

KMSP...Advancing drier air from the southwest may be halting just
before reaching KMSP, as both KLVN and KFCM have gone back to
overcast MVFR. Some models do bring the drier air and scattered
low clouds across the metro later this evening. Have added a
tempo group for scattering out late tonight, but this is far from
certain. Better moisture arrives Friday after 12Z and some lift
suggests drizzle could well begin late Friday morning and persist
until the cold front arrives around 23Z.

Sat...VFR with MVFR early. Wind NW 10-20 kts.
Sun...VFR. Wind SW-W 5-10 kts.
Mon...VFR. Wind S 5-10 kts.





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