Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 111755
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1255 PM CDT Wed Oct 11 2017

.UPDATE...
Issued at 638 AM CDT Wed Oct 11 2017

Updated to include 12z aviation discussion below.

&&

.SHORT TERM...(Today and tonight)
Issued at 300 AM CDT Wed Oct 11 2017

Surface analysis early this morning shows extensive high pressure
across the region from the Upper Midwest through the central
Plains. Aloft, a ridge axis sits over northern WI through southern
MN into northern KS. Associated with a potent upper level low
over moving onshore the Pacific Northwest, a low pressure center
in southern Alberta with a trailing cold front through northern
California will move in conjunction with each other east over the
next 24 hours. The main surface low will move into central
Manitoba by daybreak Thursday morning with the cold front sagging
south through the central Dakotas then southwest into WY/CO. The
upper Mississippi River Valley will remain generally in the warm
sector of this system which will allow for a warming trend of
temperatures through tomorrow. However, due to a rotating deep
upper level ridge over the southeastern CONUS, a pronounced plume
of Gulf of Mexico moisture will be advected northward into the
mid-Mississippi River Valley. Just enough mid-to-upper level
moisture will make it as far north as MN/WI such that clouds will
be on the increase today through tonight. In addition, a very weak
buckling in the prevailing southwest flow aloft may allow for
isolated rain showers to develop mainly after midnight in far
eastern MN into western WI. There may also be some patchy fog
and/or drizzle in southeastern MN overnight as the lower level
moisture fills in south of I-94 (and closer to I- 90). As alluded
to earlier, the more southerly flow available for this region
today will make for highs roughly 5-10 degrees warmer today than
what was experienced yesterday and this trend will continue into
Thursday. Lows this morning in the lower 30s to lower 40s will
rise nearly 15 degrees warmer this time tomorrow.

.LONG TERM...(Thursday through Tuesday)
Issued at 300 AM CDT Wed Oct 11 2017

The main long term concerns remain timing of cold front Friday and
development/movement of the weekend system.

There may be some drizzle/light rain across eastern portions of
the area Thursday morning as low level waa and moisture are driven
east ahead of the next frontal system over the Dakotas. Clouds are
expected to clear west to east during the day. Depending on
timing of clearing, temperatures should warm through the 60s.

The cold front is progged to move into eastern areas Friday
afternoon. By that time, a strong 130 kt 300 hPa jet will be
streaking southwest/northeast across southern Minnesota and will
enhance strong mid level F-gen across mainly the southeast cwa. We
will continue the higher end PoPs for that region. This system
exits Friday night ahead of the next incoming trough.

The deterministic 00Z GFS switched to the previous 00Z ECMWF
handling of the weekend trough. It is now deeper than the ECMWF.
However, forcing with either model solution should be strong
enough to generate widespread rains over the region Saturday
night into Sunday. The 00Z GEFS ensembles continues to focus the
higher QPF off just to the southeast of our cwa during this
period.

Following this system we will see some brief cooling with
temperatures moderating quickly as the upper flow becomes a bit
more zonal into the first part of the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1232 PM CDT Wed Oct 11 2017

A 40kft cloud deck has built in across southeastern MN and West
Central WI. This cloud deck is expected to continue expanding west
and north through the afternoon and evening. At this time, AXN
will likely remain mostly free of low clouds, but cloud cover will
continue to be watched closely. Ceilings where there is extensive
cloud cover will fall overnight, causing MVFR conditions. Ceilings
should begin to rise again late Thursday morning as southerly
winds increase across the area. Wind gusts near 25kt may be
possible, especially in western MN.

KMSP...Skies should remain mostly cloudy through Thursday morning
and we expect ceiling heights to become MVFR overnight. There is
not sufficient confidence to include IFR ceilings or -SHRA, and
MSP will likely remain dry through this TAF period.

/OUTLOOK FOR KMSP/
Fri...Mainly VFR. MVFR late with p.m. SHRA possible. Wind N 5-10
kts becoming NE.
Sat...Mainly VFR. MVFR late with p.m. SHRA likely. Wind ENE 5-10
kts.
Sun...Mainly VFR. MVFR early with a.m. SHRA possible. Wind NW 5-10
kts.

&&

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

&&

$$

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



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