Area Forecast Discussion
Issued by NWS Twin Cities, MN

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679
FXUS63 KMPX 201105
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
505 AM CST Fri Jan 20 2017

.SHORT TERM...(Today and tonight)
Issued at 500 AM CST Fri Jan 20 2017

Early morning water vapor imagery showed an upper level low across
the region. Low clouds and fog were widespread across much of MN,
with some light drizzle as well.

Low clouds or fog will remain in place for the foreseeable future as
an upper level low slowly rotates overhead. Light drizzle is likely
across the region given the low level saturation. A better chance
for a more steady rain will be later tonight as an upper level PV
anomaly rotates up from the south. This will provide a more focused
area for ascent, deeper saturation, and heavier precip. Temperature
will remain above the seasonal average for late January with little
diurnal fluctuation.

.LONG TERM...(Saturday through Thursday)
Issued at 500 AM CST Fri Jan 20 2017

Rain is expected Saturday...rain clears Sunday...snow looking
more likely TUE-WED.

A surface low will track directly over Minnesota on Saturday
bringing light rain to MN/WI throughout the day. It looks like
most locations will pick up 0.10"-0.20" by the time the wave lifts
northeast over Lake Superior by sunrise Sunday morning. A couple
days of dry weather are expected Sunday-Monday with building
heights by Monday. The longwave ridging early next week will
quickly be replaced with a trough on Wednesday. Ahead of the
upper trough, a deep surface cyclone will track from
Colorado...to Iowa...to Michigan from TUE-WED. This is a good
snowfall track for the local area, and over the past few runs
there has been good decent agreement on the track between
ECMWF/GFS. We have increased the probability of snow during this
time to reflect the increasing confidence. There`s still a long
way to go with this one, but the track looks reasonably steady and
past historical matches suggest winter storm warning criteria
potential (>6" snow). From CIPS...the top historical match off the
120hr GFS is a significant snowfall that happened on December 9,
2012. It was a whopper with a large swath of 12+". Good looking
jet and PV punch with this system. The surface temperature is
warmish and the low is fairly progressive, but the forcing is very
good.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1057 PM CST Thu Jan 19 2017

Plenty of low-level moisture with light southeast winds will
contribute to prolonged IFR-or-worse conditions for all sites
overnight, both for ceiling and visibility. In addition, MSP and
the WI TAF sites may deal with occasional rounds of -DZ or -RA
overnight through the first half of tomorrow. Once conditions drop
to IFR (or worse), conditions are expected to stay as such through
the day tomorrow. Conditions may well drop to worse than currently
advertised but will advertise IFR conditions then amend as needed
to LIFR/VLIFR.

KMSP...MVFR conditions to start then conditions go downhill going
into the early morning hours. Timing will be a little tricky but
confidence is high that IFR conditions will be realized overnight
and remain in place through the day tomorrow. Conditions may even
drop to LIFR at times, mainly due to ceilings. Some -RA is
possible overnight through the morning push but is not expected to
be freezing. Nevertheless, conditions in the morning are not
expected to be favorable for high rates.

/OUTLOOK FOR KMSP/
SAT...MVFR/IFR with chc -RA. Winds E 5-10 kts.
SUN...MVFR likely. Winds NW 5 kts.
MON...MVFR likely. Winds NW 5 kts.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Dense Fog Advisory until noon CST today for MNZ041-047-048-
     054>057-064-065-067-073>078-082>085-091>093.

&&

$$

SHORT TERM...JRB
LONG TERM...CLF
AVIATION...JPC



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