Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 152030

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

.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

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 18Z TAFS through 18Z Thursday afternoon)
Issued at 1253 PM CST Wed Nov 15 2017

Northwest wind gusts will taper off this evening. MVFR stratus
will persist today and linger overnight across the eastern part of
MN an western WI. Areas in western MN should see cloud dissipate
as high pressure builds in across the region. On Thursday expect
VFR conditions to spread across the rest of the region with
southeast winds.

Ceilings should remain above 1700 ft, and clouds should scatter
out later tonight.

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.




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