Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 242119

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
419 PM CDT MON OCT 24 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 400 PM CDT Mon Oct 24 2016

Tonight and tomorrow morning are the lull before the storm. There
is an impressive low pressure system off the Pacific Northwest
coast that is spreading moisture across the entire western CONUS
and Rockies. Ridging has set up across the center of the U.S. and
high pressure has settled overhead in MN/WI today. Tonight, a
shortwave will take shape across WY/MT and head across the Dakotas
by tomorrow morning. The response at the surface will be a slowly
deepening low that will track across NE/SD throughout the day
tomorrow. High clouds will be on the increase during the morning,
but the deep moisture and widespread rain chances really don`t
arrive until late tomorrow afternoon and tomorrow evening. There
could be a couple warm advection bands of showers/light rain as
early as tomorrow morning in western MN, but that rain will come
from high-based clouds and the rain shouldn`t be persistent or
heavy in intensity until the surface low approaches after sunset.

.LONG TERM...(Tuesday night through Monday)
Issued at 400 PM CDT Mon Oct 24 2016

The longer term concerns remain timing of the upper trough moving
through the area Tuesday night into Wednesday night along with the
QPF and thunder threat.

Strong moisture feed ahead of the upper trough along with strong
forcing should be enough to generate at least some isolated thunder
over mainly the southern quarter of the state into Tuesday night.
Most deterministic models drive this east during the night and
across mainly the eastern portion of the cwa into Wednesday morning.
Better moisture feed rides across far southern MN as well. QPF
forecast continues to have a swath of 1 to 1.7 inches of rain over
the southeast half of the region during this period. This currently
looks a pretty reasonable forecast.

Clouds will linger through much of Wednesday...especially to the
east as an inverted trough moves slowly to the east.  A few light
showers will linger east of this trough.  High temperatures will
struggle to warm through the 40s to around 50.

Drying follows into Thursday as a surface high pressure area moves
through.  A southerly wind will redevelop later Thursday and this
will draw limited moisture north as the next short wave move through
on Friday. A small chance of showers will be retained with this
system...mainly to the east.  Temperatures are expected to warm out
ahead of the frontal system...with some lower 60s likely over the
southern third of the area.

Models diverge some on handling the next short wave.  The GFS
becomes more amplified with ridging over the central CONUS keeping
the area dry through the weekend. The 12z ECMWF resolves a flatter
flow...with an embedded short wave moving through the area on
Saturday. For the moment we will follow the GFS...which gives most
of the cwa a dry and breezy Halloween.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 200 PM CDT Mon Oct 24 2016

VFR with just a few passing high clouds through the night. Cloud
cover gradually increases through the morning. Winds will be light
and somewhat variable.


Calm before the rain tonight and tomorrow morning. Winds have been
light and somewhat variable between northeast and southeast
today. Gradually the winds are expected to settle in out of the
east southeast. Rain moves in during tomorrow afternoon and will
remain in place until Wednesday once it arrives.


Tue Night...Becoming MVFR with -RA. Chc IFR late. Wind SE at
Wed...MVFR/IFR with -RA early. Wind ENE at 10kt.
Thu...VFR. Wind VRB 5kts.


.MPX Watches/Warnings/Advisories...


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