Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 292042

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
342 PM CDT THU SEP 29 2016

.SHORT TERM...(This evening through Friday)
Issued at 315 PM CDT Thu Sep 29 2016

The main feature of interest continues to be the deep vertically
stacked low that has moved over Kentucky this afternoon as evident
by the tight circulation on satellite.  To the west of this system
in our area, an upper ridge has been slowly pushing in from the
west, bringing drier air and mostly clear skies to the Upper
Midwest. The exception today was the cool and moist air off Lake
Superior that spread stratus across much of Minnesota.

The cloud cover across central Minnesota is scattering out quickly
this afternoon and that trend will continue, with skies expected to
be clear tonight.  The concern late tonight is for fog across the
area with the ridge axis in place.  Very light winds and clear
skies, along with hydrolapses increasing with height indicate the
potential for some fog across the area, some locally dense.

Tomorrow will be mostly clear, and a few degrees warmer than the
past couple, but the low in Kentucky today will be drifting back
north-northwest and spread clouds late in the day into western WI
and eastern MN.

.LONG TERM...(Friday night through Thursday)
Issued at 315 PM CDT Thu Sep 29 2016

Movement of the upper low over the Ohio River Valley/Great Lakes
and the western CONUS trough into midweek are the main concerns in
the longer term.

The longer term deterministic models continue to show moisture
advecting westward over the cwa Friday night and lingering over
most of the area into Saturday night. We expect another mostly
cloudy trend as this moves through. There may be some light
showers affecting a small portion of west central Wisconsin late
Friday night into Saturday as the lower level moisture
arrives...but the remainder of the area should be dry. With more
clouds around...overnight lows shouldnt drop off too much with
upper 40s/low 50s common through Saturday night. If we see more
clearing...temperatures a be a little cooler than forecast...but
that is not expected at this time.

With the upper low exiting the area later Sunday into Monday...we
expect a little more sunshine to develop along with warmer
temperatures. The western CONUS trough will move slowly east and
begin to draw moisture northward back into area by late Monday
night to far western CWA and spread east into west central
Wisconsin mainly Tuesday night through Thursday. We continued the
slower trend of drawing in higher pops during this period. The GFS
ultimately has a problem with phasing the tropical system lifting
north from the Caribbean/Matthew and begins to split energy with
the amplified trough over the upper Mississippi River valley. We
like the evolution/movement of the 12z ECMWF concerning the
trough...and followed this more at least initially. We did retain
the chance thunder with the system as well. Cooler temperatures
will accompany and follow the system through the end of next week.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1238 PM CDT Thu Sep 29 2016

The upper low that was over the southern Great Lakes yesterday has
moved south into southern IN/northern KY, with a surface high in
Ontario. Stronger than expected northeast flow in between these
areas led to cool and moisture advection off Lake Superior this
morning and low ceilings moved in to parts of West Central
Wisconsin and eastern Minnesota. Farther south, LIFR ceilings and
fog have since dissipated. The southern end of the the stratus
from the Lake Superior is expected to slowly erode from the south
this afternoon and evening. STC and AXN will deal with the clouds
the longest, but bases should remain at VFR levels. Tonight, fog
will be possible across the area and included some mention of fog
at each TAF site. The HRRR indicates moisture off Superior
affecting north central MN, so we think AXN would be most
susceptible to fog overnight. ENE winds today will become light
overnight, and increase to near 7 knots from the NE tomorrow.
Clouds from the Upper Low will approach from the southeast
tomorrow during the day.

KMSP...Starting off with a tempo BKN025 for an hour as ceilings
should lift and continue a scattering trend this afternoon. Expect
clear skies tonight, but could see some fog early tomorrow
morning. ENE winds gusting to 16 knots this afternoon are expected
to become light tonight, and around 5-7 knots tomorrow. Could see
stratus filling in from the east tomorrow late afternoon as that
upper low lifts north.

Sat...VFR. Wind ENE at 5 kts.
Sun...VFR. MVFR possible. Wind NE at 5 kts.
Mon...VFR. Wind SE at 5-10 kts


.MPX Watches/Warnings/Advisories...


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