Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 232346

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
546 PM CST Fri Feb 23 2018

.UPDATE...For 00Z Aviation discussion below


.SHORT TERM...(This evening through Saturday night)
Issued at 328 PM CST Fri Feb 23 2018

Clearing has resumed this afternoon after some stratocu filled
back in behind the clearing line this morning. The abundance of
sun today over much of the area combined with the fresh snow
cover has led to some melting as temperatures hover around
freezing. Temperatures tonight will plummet into the single
digits above and below zero, well below current dew point values
in the teens and 20s. IN addition, light or calm winds will be in
place. All of this should result in widespread freezing fog
from late evening into tomorrow morning, which will likely be
dense in some locations. The fog should improve Saturday morning,
but low clouds may remain.

The storm for Saturday and Saturday night still looks on track. Snow
will begin Saturday afternoon from southwest to northeast and
become heavy rapidly after its onset. Heavy snow will continue
for about 8 or 9 hours before ending. Snowfall rates of 1 to 2
inches per hour are expected at times with this snow given
dynamics and moisture present.

Not too much has changed from the previous forecast. NAM/NAMnest
remain strong/western outliers. The ECMWF and GFS may not be quite
strong enough, but generally have good support with their
ensembles. Continued a general blend of solutions, which aligned
quite well with the WRF-NMM and WRF-ARW. This resulted in a
continuation of 6 to 8 inches for southern/eastern MN and western WI,
and 4 to 6 inches to the west and east of there. Similar to last
night, it isn`t impossible to see higher totals (in this case closer
to 9 inches) on a localized scale given the rates and banding
expected. Those areas won`t be known until hi-res models begin to
get ahold of the event tonight and tomorrow. Upgraded to a warning
in the locations with 6-7+ inches, and an advisory where we should
remain just below 6. The headlines extend several hours past the
time snow is expected to end due to winds increasing and blowing
snow ramping up for a few hours after.

.LONG TERM...(Sunday through Friday)
Issued at 328 PM CST Fri Feb 23 2018

Tranquil and mild conditions will prevail into midweek. Highs in
the 30s with sunshine each day will chip away slowly at the snow.
There will likely be fog development overnight at times.

Many questions remain late week with how the pattern evolves. A
broad trough will be in place out west with low amplitude ridging
out east. A disturbance will pass across the southwest mid week,
and given the low amplitude pattern it`s tough to say at this
range where it will track. Chances for rain and snow are still in
the forecast for Wednesday night and Thursday.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 547 PM CST Fri Feb 23 2018

Few-scattered stratocu clouds will linger this evening, but
ceilings at most sites should be prevalent VFR. Fog/freezing fog
becomes a concern around/after midnight given the melting that
occurred during the day. As winds become light to calm and
temperatures cool, fog is expected to develop. Model guidance
isn`t handling this well, but think dense fog seems reasonable
where winds go calm. The fog should improve Saturday morning, but
low clouds will likely remain until the onset of snow, which is
expected after 20Z. Once the snow begins rapid reductions to LIFR
conditions are probable. Easterly winds increase to around 10-12
knots on Saturday.

Fog will be the main concern overnight. Currently expecting winds
to go calm around 08Z, which would be the trigger for
visibilities to drop below 1SM. Conditions briefly improve
Saturday morning, although broken MVFR cigs will likely persist.
Snow onset looks to be around 22Z, with conditions LIFR conditions
shortly after that. 1 to 2 inch per hour rates possible 00-06Z

Sun...MVFR early, VFR during the afternoon. Wind W at 20G25kt.
Mon...VFR. Wind SW at 15G20kt.
Tue...MVFR with -SN possible. Wind NE at 05kts.


WI...Winter Storm Warning from 3 PM Saturday to 6 AM CST Sunday for

     Winter Storm Warning from 6 PM Saturday to 6 AM CST Sunday for

     Winter Weather Advisory from 6 PM Saturday to 6 AM CST Sunday
     for WIZ028.

MN...Winter Storm Warning from 3 PM Saturday to 6 AM CST Sunday for

     Winter Weather Advisory from 3 PM Saturday to 6 AM CST Sunday
     for MNZ041>043-048-049-057.

     Winter Storm Warning from 6 PM Saturday to 6 AM CST Sunday for

     Winter Weather Advisory from noon Saturday to 3 AM CST Sunday
     for MNZ047-054>056-064-093.

     Winter Storm Warning from noon Saturday to 3 AM CST Sunday for



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