Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 241151

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
651 AM CDT Tue Oct 24 2017

.Updated for 12Z Aviation Discussion...
Issued at 643 AM CDT Tue Oct 24 2017


.SHORT TERM...(Today and tonight)
Issued at 353 AM CDT Tue Oct 24 2017

As of 3AM this morning, the Great Lakes low pressure system was
lagging in deepening as much as we had anticipated at this time, and
peak winds overnight have remained around 25-35 MPH.  The low is
quickly deepening though, and should continue on a northwestern path
over the next few hours.  Still think it will deepen to around 980mb
and stall over the eastern UP of Michigan today.  So, we still
expect winds to increase to around 30-35 MPH with gusts in the 40-45
MPH range today as that low deepens and pushes west.  So, the Wind
Advisory remains in effect through the afternoon hours.

Widespread cloud cover in association with the Great Lakes low will
stay in place and even push west this morning, keeping mostly cloudy
to overcast skies in place across western WI and eastern MN.  Skies
are expected to clear rather quickly this afternoon as dry air
continues advecting in from the northwest.  Highs today will be
below normal for a change, with mid to upper 40s expected.  We`ve
only had 5 days this month at MSP below normal, but today will be
number 6.

For tonight, a fast moving shortwave will drop through the arrowhead
toward eastern WI, and a light mix of rain and snow is possible in
western WI from this wave.

.LONG TERM...(Wednesday through Monday)
Issued at 353 AM CDT Tue Oct 24 2017

The main issues in the long term period are the strong winds on
Thursday in western MN and the chance for some light snowfall
accumulations late Thursday night through Friday, in addition to the
colder weather on the way for the weekend.

The next system of interest will be quickly advancing southeast from
British Columbia tomorrow.  We`ll remain essentially on the warm
side of the system through Thursday morning, with southerly winds
and highs in the 50s and even in the low 60s across southwest MN.
This low will develop in a highly amplified upper air pattern and by
Thursday morning, a 996mb low should be crossing the North Dakota
border into Minnesota at the surface.  Upped the forecast wind
speeds for western Mn on Thursday as strong cold air advection slams
into the area behind the cold front.  Winds at the top of the
boundary layer Thursday afternoon could approach 50 knots and given
the strong CAA, most of this should be mixed down to the surface. So
there is potential that another wind advisory could be needed later
this week.

As the system moves east and the front moves through, the models are
in decent agreement that a deformation zone of snow will setup
across Minnesota and into western WI.  There is potential for a
couple tenths of an inch of qpf and we do expect a mix of rain and
snow, eventually transition to snow as the lower atmosphere cools by
Friday morning.  Eastern MN and western WI still look to remain near
or above freezing during this time, so don`t expect much in terms of
accumulation, with the most likely scenario being a dusting to less
than an inch of snow of grassy surfaces.  A slow warm up to around
40 degrees during the day will allow the precip to transition
back to rain.

With the cold air in place behind this system and high pressure
working in from the north, expect widespread 20s Friday and Saturday
nights for lows.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 643 AM CDT Tue Oct 24 2017

Windy today with gust near 35 kts. VFR conditions across
Minnesota with MVFR clouds expected in western Wisconsin this
morning, eventually lifting to VFR. Wind gusts will taper off this
evening, take on a more westerly component tonight, but then shift
back to the northwest near morning.

Clouds should remain VFR. Did decrease wind gusts slightly since
over the past 24 hours the forecast guidance seems to have
overestimated speeds. Low stratus should break up by late morning.

Thu...VFR with -SHRA/MVFR cigs late afternoon, becoming -SHSN Thu
eve and overnight. Wind W 10-15 kts becoming NW 20G35kts.
Fri...VFR with MVFR/-shsn possible early. Wind NW at 10-15 kts.
Sat...VFR with MVFR possible. Wind NNW at 15G25kts.


WI...Wind Advisory until 6 PM CDT this evening for WIZ014>016-023>028.

MN...Wind Advisory until 6 PM CDT this evening for MNZ041>043-047>051-

     Wind Advisory until 6 PM CDT this evening for MNZ044-045-052-053-



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