Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 251121
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
521 AM CST Sat Feb 25 2017

.updated for 12z aviation discussion below...

.SHORT TERM...(Today and tonight)
Issued at 340 AM CST Sat Feb 25 2017

The main short term concern is chance of light snow across
northern cwa tonight.

Yesterdays storm is exiting the region early this morning. Clouds
should exit western Wisconsin early before more clouds build east
ahead of our next short wave. Current water vapor imagery shows
that system now moving across western Montana and is expected to
move across the Dakotas today. Temperatures will remain on the
cool side today, generally at or below freezing most areas,
especially those seeing fresh snowcover.

Deterministic models in good agreement with the possibility of light
snow developing across the northern area overnight. Models indicate
decent isentropic lift associated with the short wave as it moves
across this region. Will spread some likely pops across that area
tonight. Accumulation`s are expected to remain light with little
moisture generally a dusting to an inch possible.

.LONG TERM...(Sunday through Friday)
Issued at 340 AM CST Sat Feb 25 2017

The main issue in the short term revolves around precip chances and
types Monday night/Tuesday. Otherwise, we will have fairly strong
flow across the CONUS as we see our pattern locally transition from
zonal over the weekend, to southwest flow for the first half of next
week, followed by northwest flow to end the week.

The long term starts Sunday morning with the series of mid-level
ripples currently from northwest NoDak back to the southern
BC/Alberta border bringing scattered light snow showers to areas
north of I-94 in central MN and NW WI. QPF from the deterministic
models and reflectivity forecasts from numerous CAMs support the
idea of scattered activity brushing our northern CWA, so kept the
idea of chance pops going here. The last and strongest of these
waves will help drive a weak cold front across the area Sunday
afternoon. Southerly flow ahead of the cold front will allow for
above normal temps, with highs in the low 40s not out of the
question north of the fresh snow cover from Friday`s system.

Monday, troughing will be building down western NOAM, with ridging
building down stream in response. This will transition our flow over
to the southwest for Monday.  This will allow even milder air back
into the area, with highs Monday getting into the 40s with bare
ground and staying in the 30s over the snowcover. With these warmer
temperatures coming up from the south, we`ll see a baroclinic zone
sharpen to our northwest Monday afternoon that will drift overhead
Monday night. Aloft, we`ll see a series of weak disturbance move
over this baroclinic zone in the southwest flow Monday night and
Tuesday.  Given the relatively weak forcing in relatively fast flow,
models are still all over the place with when/where precip will
fall, though our eastern areas Tuesday afternoon/evening still look
to have the greatest chance of seeing precip. Temperatures look
pretty warm with the system, with highs likely getting back up to
around 40 on Tuesday, with rain looking to be the main p-type save
for up around Alexandria by Tuesday afternoon. It`s Monday
night/Tuesday morning where we could have problems IF there is any
precip around. Current forecast has lows Monday night falling back
into the upper 20s/lower 30s as a warm nose and melting layer moves
in aloft. This means for the southeast half of our CWA or so, Monday
night/Tuesday morning will be a mix/rain scenario based on surface
temperatures. Given our current forecast, there is a good deal of
sleet/freezing rain mention Monday night.  Much of the MOS guidance
helps pull our temperatures down below freezing, but the NAM, GFS,
and even Canadian keep much of the area where we currently have a
mix mention above freezing. Given how warm we will be Monday and the
likelihood of cloudy skies and light southeast winds, this forecast
of a couple of degrees warmer isn`t unreasonable and those couple of
degrees would be enough to keep the freezing rain and sleet
currently mentioned as just rain. Of course this may be a moot point
as there may very will not be any precip Monday night/Tuesday
morning given moisture issues, but this will need to be looked over
closely in future forecasts.

Behind this system, the Canadian and ECMWF are backing away from the
potential clipper for Thursday, but its still in with the GFS and
several GEFS members, so we continue chance pops for then.  Though
the Canadian and ECMWF may not have the clipper, they do have the
glancing blow from arctic air to end the week, resulting in a return
to near normal temperatures to start March.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 500 AM CST Sat Feb 25 2017

Will maintain mainly VFR conditions during the period. Only chance
for MVFR cigs developing at KAXN mainly after 06z. Remainder of
the area will see a mix of clouds through the morning...becoming
bkn050-080 during the afternoon. Some threat of light snow over
the northern area tonight. We did mention -sn at kaxn and vcsh at
kstc for now. Northwest winds will be a bit gusty to the east
this morning...becoming w-sw into tonight.

.MSP...No concerns.

/OUTLOOK FOR KMSP/
Sun night...VFR. Chc MVFR. Wind SW-W 5-10 kts.
Mon...VFR becoming MVFR. Chance -SN Mon night. Wind S 5-10 kts.
Tue...MVFR/-RASN likely. E winds 5 kts shifting to NW.

&&

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

$$

SHORT TERM...DWE
LONG TERM...MPG
AVIATION...DWE


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