Area Forecast Discussion
Issued by NWS Twin Cities, MN

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196
FXUS63 KMPX 221711
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1111 AM CST Mon Jan 22 2018

.SHORT TERM...(Today and tonight)
Issued at 451 AM CST Mon Jan 22 2018

The winter storm remains on track for southern Minnesota and western
Wisconsin.  The hazards that were in place yesterday were left
untouched as the adjustments were mainly focused on tweaking the
northern gradient and adjusting the thermal profile from the Albert
Lea toward Eau Claire areas.

Early this morning, the deepening surface low was located over
extreme northwestern Missouri and will continue to deep and lift
into Iowa today.  Meanwhile, the main precipitation band is taking
shape from Nebraska through northern Iowa, and is lifting into
southern MN.  Albert Lea continues to report rain falling, but to
the east a cooler thermal profile has allowed a changeover to snow
to occur.

The hi-res models now cover the storm as it moves through and has
only increased our confidence in the forecast.  The heaviest band of
snow of 8-14" remains in the same place; from near Fairmont through
Red Wing, Menomonie, and Ladysmith.

The Twin Cities metro still looks to have a tight snowfall gradient.
With the RAP, HRRR, and HOPWRF now covering the temporal period of
the storm, confidence is increasing that the southeast metro will
see 6"+ of snow and the gradient may be a few miles northwest of
earlier expectations.  Did adjust the snow amounts upward along the
northern gradient. Further aiding in this decision was the fact that
overnight lightning across the state of Iowa wasn`t all that
widespread.  In addition, we`ve been watching a west to east band of
snow developing from Canby through the metro toward Menomonie.  This
will produce some light snowfall this morning before the main event
ensues for the metro mid morning, with the heaviest snow expected
this afternoon.

The HRRR and RAP show the potential for a heavy snow band to impact
the metro mid afternoon leading up to the evening commute.  This
band could have 1-2"/hr rates given the strong mesoscale forcing
associated with it and make for a very slow commute this evening.

The winds will continue to strengthen as the low moves through Iowa
today, with blizzard conditions developing from south and west of
Mankato. Again, the heaviest snow will arrive in far southern MN
early this morning, with the heaviest period of snow expected later
today in the metro and western WI. The morning commute will be
impacted across far southern MN by the onset of the snow, while the
metro and Wisconsin will see minimal issues this morning for the
commute. The afternoon commute will be a completely different
story.

.LONG TERM...(Tuesday through Sunday)
Issued at 451 AM CST Mon Jan 22 2018

No significant changes in the extended. Blended guidance shows a
slight cool down in the wake of today`s storm, with highs in the mid
to upper 20s Tuesday and Wednesday, but this is still about 2 to 5
degrees above the seasonal average for late January. A weak
shortwave will embedded in northwest flow will slide southeast
across the region Tuesday night, and this should be strong enough to
produce some clouds, but not enough to precipitate other than
perhaps a few flurries.

Upper level ridging will ensue for Wednesday night and Thursday,
keeping the region dry and mild. On Friday highs could reach the
lower 40s across the region as the low level thermal ridge advects
across the region. A cold front will follow Friday night with cold,
but not bitterly cold temperatures for the weekend into early next
week. No significant precipitation is expected at this time.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1110 AM CST Mon Jan 22 2018

A full scale winter storm will impact MPX taf sites from KRWF,
northeast to KRNH and southward through 00z, and possibly beyond
00z around KRNH/KMKT/KMSP. High confidence that LIFR/IFR
cigs/vsbys in snow and blowing snow will affect
KRWF/KMSP/MRNH/KMKT/KEAU through the afternoon, with some mixture
of PL near KEAU after 21z. There is a chance of vsbys/cigs near
airport minimums during the height of the storm. Only KAXN will
have IFR/MVFR cigs with no restrictions to vsby as all the
snowfall will be southeast of this airport. KSTC will be on the
edge after 21z, and possibly MVFR vsbys in snow between 21-03z.
Otherwise, conditions will slowly improve between 3-6z in east
central Minnesota, west central Wisconsin, but IFR/MVFR cigs will
likely continue through Tuesday morning. Winds will remain from
the northeast to north, with a more north to northwest direction
late this afternoon/evening. Gusty winds will continue until late
this evening.

KMSP...

Only additional comments are snowfall rates will approach or
exceed 1 to 1.5 inches per hour during the afternoon, and possibly
last through 00z. Confidence is high that LIFR/IFR conditions
will remain, with vsbys as low as 1/4SM in heavy snowfall/blowing
snow. There could be a short period of cigs/vsbys near airport
minimums during the height of this storm. Northeast winds of
16-18 kts, gusts to 24-28 kts, with slowly become more
north/northwest this evening/overnight and decrease in speed.
Total snowfall through this event could exceed 12 inches before
06z.

/OUTLOOK FOR KMSP/

Tue...MVFR thru mrng. Winds NW 5-10 kts.
Wed...MVFR/IFR cigs. Winds 5 kts or less.
Thu...MVFR/IFR cigs. Winds SE 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning until midnight CST tonight for WIZ014>016-
     023>028.

MN...Winter Storm Warning until midnight CST tonight for MNZ060-062-
     063-067>070-078.

     Winter Weather Advisory until midnight CST tonight for MNZ053-
     061-065-066-073.

     Blizzard Warning until midnight CST tonight for MNZ074>077-
     082>085-091>093.

&&

$$

SHORT TERM...SPD
LONG TERM...JRB
AVIATION...JLT



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