Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 152315
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
515 PM CST Wed Nov 15 2017

.UPDATE...
Issued at 506 PM CST Wed Nov 15 2017

Updated to include 00z aviation discussion below.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 230 PM CST Wed Nov 15 2017

Early afternoon satellite imagery together with Surface obs and
RAP13 analysis showed a beautiful cyclone developing across the
Great Lakes Region with the cold front approaching Indiana and the
surface low across the Upper Peninsula of Michigan. Strong
northwest flow and cold air advection kept Minnesota and Wisconsin
breezy and overcast today with steady or falling temperatures at
most locations.

Over the next 24 hours, this surface low will move towards New
England and H500 height falls from the approaching upper level
ridge will lead to subsidence and surface high pressure building
across the Upper Mississippi River Valley which should lead to
clearing skies across western Minnesota later tonight. Areas to
the east could hang onto the clouds a bit longer, but most
locations should see some sun on Thursday with southeast winds
developing. Unfortunately H850 theta_e advection ahead of the next
system will lead to clouds increasing throughout the day on
Thursday so don`t be fooled by the widespread sunshine currently
ongoing to the west over the high plains. Clouds will keep
afternoon highs only in the 30s for most locations tomorrow.

.LONG TERM...(Thursday night through Wednesday)
Issued at 230 PM CST Wed Nov 15 2017

Long term concerns remain precipitation chances for the Friday
weather system and overall upper level flow pattern into next
week.

The deterministic models are similar on handling the western conus
trough energy Friday into Saturday. They tend to split the trough
with a northern and southern extension of the trough. They still
merge the trough over the western Great Lakes into Saturday. This
still should bring at least likely PoPs into western Wisconsin
Friday. Depending on eventual trough evolution these higher PoPs
may have to be pulled a bit farther west. The 12z GEFS probability
12 hour one tenth of an inch of precipitation has high PoPs to
over Wisconsin wit the hundredth probability covering most of the
cwa Friday into Saturday.

Colder air follows this front/trough as high pressure builds
across briefly for Sunday. Then the next Pacific trough arrives
Monday which should draw in some warmer air again. We did warm the
blended guidance a degree for Monday which could yield a 50 to the
southwest.

The models diverge once again into midweek next week with the GFS
dropping some very cold air with an amplifying trough through
Wednesday. This is quite a change from earlier model runs. The 12Z
ECMWF does drop a front through but doesnt draw in quite as cold
air and is much more progressive. We will trend colder but not as
extreme as the GFS.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 506 PM CST Wed Nov 15 2017

Low stratus still hanging tough across central-southern MN into
western WI with little indication it will dissipate anytime this
evening or for much of the overnight period. Have maintain MVFR
ceilings at all sites; not expecting IFR as there are no sites
reporting as such upstream and have delayed the prevailing model
thinking of trying to scatter out clouds by daybreak. Ceiling may
well rise to VFR levels but still with at least BKN coverage. Then
ceilings will likely remain through much of tomorrow while rising
to between 7-12 kft. Gusty NW winds this evening will settle down
to 5-10kt early this evening then become light/variable as high
pressure moves atop the region during the early morning hours.
Winds will then pick up from the SE and become breezy tomorrow
afternoon.

KMSP...Ceilings will remain above 1700ft but MVFR ceilings will
remain in place through the overnight hours and potentially
through the Thursday morning push. No visibility restrictions or
precipitation expected.

/OUTLOOK FOR KMSP/
Fri...MVFR with chance -DZ. Wind S becoming NW 5-15 kts.
Sat...VFR with MVFR early. Wind NW 10-20 kts.
Sun...VFR. Wind W at 10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

UPDATE...JPC
SHORT TERM...JRB
LONG TERM...DWE
AVIATION...JPC


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