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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
602 PM CST Sat Feb 28 2015

Updated for 00z aviation discussion...
issued at 558 PM CST Sat Feb 28 2015


Short term...(this evening through sunday)
issued at 337 PM CST Sat Feb 28 2015

Split upper level flow is forming over North America this
evening...with a positively tilted trough moving through the western
US and a second trough diving southward through western Canada. This
northern feature will move into the upper Midwest tonight...but with
little moisture and mediocre forcing...little if any measurable
snowfall will fall in our County Warning Area during this period.

Weak isentropic lift will coincide with a shortwave moving into Minnesota
tonight...likely providing enough forcing for some light snow in
central Minnesota and western WI. Most models show a band of light snow
moving into northwestern parts of our County Warning Area during middle-late
evening...progressing through central Minnesota and western WI by early
morning Sunday. A dusting is possible in these areas...with a few
flurries possible in the Twin Cities area. The precipitation will end
Sunday morning...with quiet conditions and seasonable temperatures
expected on Sunday.

Long term...(sunday night through saturday)
issued at 337 PM CST Sat Feb 28 2015

The main concern in the long term is the snow and wind event on
Tuesday. Model solutions were consistent today on spreading warm air advection
snow across the forecast area Monday night...especially after midnight. Snow
accumulation of around an inch is likely over much of the forecast area by
daybreak Tuesday. The main snow event is during the day on Tuesday
as a middle level wave passes across northern Iowa and southern WI. The
middle level forcing is highlighted by all solutions from the Minnesota/Iowa
border on northeast towards Green Bay. This is the area where the
heaviest snow should occur with the potential for 4 or more
inches. This agrees well with the wpc 57 member ensemble at the
50th percentile. This same product shows around 3 inches for the
Twin Cities with 1 to 2 inches from St cloud on north and west.
Hence...likely to categorical probability of precipitation remain for the forecast area from late
Monday night through Tuesday with the greatest snow accumulation
of near 5 inches from Albert Lea to Eau Claire.

The biggest concern on Tuesday is not the snow but the increase
in wind that will spread down the Minnesota River Valley during
the afternoon in the wake of the wave. Solutions were unified on
near 30 knot sustained surface winds developing during the
afternoon and lasting into the early evening from Morris through
Redwood Falls to Fairmont and Albert Lea. The top of the momentum
channel shows gusts over 40 knots are likely as well. The wind
and the fresh snow are a recipe for a blizzard during the
afternoon and evening and something that we will be monitoring
very closely over the next few days.

Beyond Tuesday...dry weather is forecast into next weekend as
high pressure takes control. Highs on Wednesday will only be in
the single digits above zero with lows Thursday morning from 5
below to 15 below zero. After this cold period...confidence is
increasing that a warming trend will develop the following week
with temperatures climbing above normal.


Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 558 PM CST Sat Feb 28 2015

A few light snow showers will bring MVFR conditions across the
region this evening and tonight. However...conditions will improve
to VFR by Sunday morning with westerly winds.

VFR/MVFR conditions expected tonight as a few low clouds move
across the region. These clouds may produce some light flurries as
well...but should not reduce visby below 4sm. Conditions will
improve to VFR by Sunday morning.

/Outlook for kmsp/
Monday...VFR with MVFR/IFR -sn likely late. Winds S at 10kts.
Tuesday...MVFR/IFR and snow likely. Winds S 10kts becoming northwest 20g30kts.
Wednesday...VFR. Winds northwest 15g20kts.


Mpx watches/warnings/advisories...


Short term...additional
long term...rah

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