Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 170527

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1127 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 06Z TAFS through 06Z Friday night)
Issued at 1127 PM CST Thu Nov 16 2017

Low clouds have been eroding across most of southern and central
MN, with some MVFR still from north of KSTC to northwest WI. These
should continue slowly moving northward and eroding.

Main concern will be incoming and developing MVFR/IFR with reduced
visibility in drizzle. This should be widespread by 15z across
central and southern MN and western WI. One large batch has been
moving north-northeast out of Oklahoma and eastern Kansas, while
some has also been developing over central Iowa. A third area in
southwest Wisconsin and far southeast MN may clip KEAU before
12Z, but this is uncertain. Regardless, short term models have
been in excellent agreement as to timing of low clouds. Have gone
with IFR ceilings for all but west central MN.

Incoming cold front from the northwest will enter west central MN
around 15Z. Lowest level will dry out slightly and ceilings should
lift, but it will take a few hours.

KMSP...Expecting MVFR to develop around 14Z, with IFR quite likely
soon thereafter, probably around 16Z. Confidence is above average,
although timing may vary by an hour or two. Drizzle should begin
late Friday morning and persist through the afternoon as surface
low approaches from the southwest and gradient weakens. Improvement
to MVFR will not take place until later Friday evening, a few
hours after front from the northwest has moved through.

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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