Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 011955

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
155 PM CST Wed Mar 1 2017

.SHORT TERM...(This evening through Thursday)
Issued at 152 PM CST Wed Mar 1 2017

In the short term, while one system exits, another is taking aim on
parts of the forecast area.  This afternoon, the precipitation had
come to an end across the forecast area of southern MN and west
central WI. A widespread cu field has developed as anticipated.

This next weak shortwave was apparent on water vapor imagery this
afternoon pushing into the western Dakotas.  There is good agreement
that this wave will continue southeast through the night and bring
enough forcing through western MN through south central MN to
produce 1-2" of high ratio snow beginning early tomorrow morning and
lasting into the early afternoon.  Mainly to impact that area during
the rush hour tomorrow morning, visibility could fall under one mile
in the heaviest bands of snow.  This wave is expected to stay south
of the metro area, with just a slight chance of seeing some very
light snow/flurries.

In terms of temperatures, certainly cooler than we have been
recently.  In fact, temps will be very near normal tonight and
tomorrow with lows in the teens and low 20s tonight, and highs in
the upper 20s to lower 30s.

.LONG TERM...(Thursday night through Wednesday)
Issued at 152 PM CST Wed Mar 1 2017

A strong storm system will develop early next week, but it will
track to the north so Minnesota and Wisconsin will be in the warm
sector. This means above normal temperatures over the weekend, with a
chance for some showers and thunderstorms Monday and Monday night.

High pressure will be centered over the region Thursday night and
temperatures will fall into the single digits across the north and
lower teens elsewhere. This high pressure will gradually shift
eastward on Friday as the upper level jet driving the weather
transitions from northwest flow zonal flow while the upper level
ridge moves east. A weak wave will move through and bring a chance
for rain or snow, but confidence in seeing precip is low at this
time so only have a 10 to 20 percent chance. Soundings are dry and
the forcing is weak since the wave is getting sheared out in an area
of confluence.

Over the weekend the zonal flow will draw up warmer air from the
south, and by Saturday should have highs in the 40s, with warmer
temperatures on Sunday. By Sunday night a deep trough will form over
the desert southwest, and this will lead to cyclogenesis on the lee
side of the Rockies.

As of now, the main surface low is forecast to move into southern
Canada. Warm air advection ahead of this low should lead to clouds
and some light drizzle early Monday. The trailing cold front will
sweep through later on Monday, and forecast soundings show some
elevated instability so have continued with a chance for thunder.
Strong to severe storms are very, very unlikely. The CAPE is only a
few hundred joules at best, and there is a strong capping inversion
that will prevent and surface-based convection.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1215 PM CST Wed Mar 1 2017

Starting out, main stratus shield along with snow continues
progressing east early this afternoon with the clouds extending
into eastern MN. As the back edge continued east, an MVFR cu field
quickly popped, which was well anticipated given the current
trough moving through. There is a narrow gap to the west between
this cloud cover and the next shortwave incoming tonight. Expect
snow showers to move through west to east from late this afternoon
through the evening. The main precip with the shortwave coming
down from our northwest will arrive overnight and mainly affect
far southern MN along the MN river valley. Of the TAF sites, RWF
will be the most impacted. For now brought them down to 3sm -sn
but later shifts will likely be able to have confidence in
bringing the VIS down to IFR or LIFR overnight there.

KMSP...expecting the snow overnight to mainly stay south of MSP.
Could see some very light snow showers or flurries but not
expecting any VIS issues.

THU Night...chc MVFR early. then vfr. Winds NW 5-10 kts.
FRI...VFR. Winds S 5-15 kts.
SAT...VFR. Winds SE 10 kts.




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