Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 122113
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
313 PM CST Thu Jan 12 2017

.SHORT TERM...(This evening through Friday)
Issued at 310 PM CST Thu Jan 12 2017

A true arctic cold front moved across the Dakotas and parts of
Minnesota this morning. This arctic front caused blizzard
conditions in North Dakota and portions of northern Minnesota
where winds gusted up to 60 mph. Although central and southern
Minnesota had the gusty winds, speeds were not as strong and
therefore, limited widespread blowing snow. Web cams across the
state noted the worst condition in northwest Minnesota where
blizzard conditions were met. Across central Minnesota, a few web
cams had lower visibilities, but it was mainly drifting snow
across the roadways which is more typical if winds are not as
gusty.

Although wind chill values will lower significantly this afternoon
and evening across Minnesota, and portions of west central
Wisconsin, wind speeds will lessen after sunset, limiting
consistent wind chill values of -25F or lower. Therefore, the
worst conditions will occur in central Minnesota early this
evening, and across southwest/south central Minnesota, as well as
west central Wisconsin between 9 pm and midnight. This is when
both temperatures will be cold enough, and wind speeds high
enough, to warrant a wind chill advisory. Later forecasters can
re-evaluate if the wind chill advisory needs to be extended past
midnight for southern Minnesota. The Twin Cities metro area will
likely not experience true wind chill values below -25F overnight,
but could briefing lower to -20F in outlying areas.

Overnight lows will be dependent on wind speeds decoupling and the
increasing cloud cover for a system brushing our region Friday.
Will continue to advertise lows near -30F in central Minnesota, to
around -10F along the Iowa border where previous forecast had.

As mentioned before, a weak storm system will brush southern
Minnesota Friday, with mainly flurries along the Iowa/Minnesota
border. However, a dusting of snow is possible if the atmosphere
can moisten up faster than models indicate. Current forecast has
less than a half inch along the Minnesota/Iowa border Friday
afternoon.

.LONG TERM...(Friday night through Thursday)
Issued at 300 PM CST Thu Jan 12 2017

The main forecast issues in the longer term remain overall model
development/movement of the upper trough and surface low from late
Sunday night through Tuesday.

Initially we start out with cold temperatures Friday and Saturday
as high pressure settles over the region. We should see any cloud
and flurry threat exit the eastern cwa Friday evening with clear sky
expected and lighter winds. This should result in below zero
temperatures most areas once again. This continues into Saturday
night as well as the high is forecast to exit tot he east. There may
be some cloud cover lifting into the area on the he backside of the
high later saturday night and may limit temperature dropping off t o
fast over the west. But the east should see below zero readings once
again.

The remainder of the long term deals with the development of the
upper trough over the central CONUS and how models have trended so
far. The ECMWF and Canadian model have been pretty consistent
overall with the cutoff low lifting northeast over the central CONUS
and over the western Great Lakes Monday/Tuesday time frame. The GFS
has been farthest east with its movement and now seems to have more a
split flow with some energy riding the northern stream and trying to
phase it with the southern system. We will continue to monitor
trends...but it does looks like we should see the eastern portion of
the cwa affected with some type of precipitation during this period.
Thermal structure continues to indicate a mixed p-type event...with
snow/freezing drizzle lifting north later Sunday night and Monday
morning and snow/sleet mix into Monday night...and the threat for
freezing rain/sleet/snow mix possible into Tuesday. We still have
plenty of time to tweak with timing and p-type issues...but it is
looking much of the cwa could be affected by this system early next
week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1121 AM CST Thu Jan 12 2017

VFR conditions will generally prevail through the TAF period.
Brief periods of MVFR visibility are possible across parts of
west-central Minnesota including AXN, RWF, and STC due to strong
winds resulting in blowing snow early this afternoon, but this
will diminish towards the late afternoon. Clear skies through the
night with increasing high-level VFR clouds from south to east
Friday morning.

KMSP...High confidence in continued VFR conditions. Gusty west
winds this afternoon will diminish this evening, with some
increasing high-level clouds towards Friday morning into Friday
afternoon. Brief flurry/snow shower possible late in the afternoon
but conditions will likely remain VFR through 00z Sat.

/OUTLOOK FOR KMSP/
Fri...VFR. Chc MVFR/-sn. Wind vrb 5 kt or less.
Sat-Sun...VFR. Wind S 5 kt.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Wind Chill Advisory from 9 PM this evening to midnight CST
     tonight for WIZ014>016.

MN...Wind Chill Advisory until 6 AM CST Friday for MNZ041>044-047>050-
     055.

     Wind Chill Advisory from 6 PM this evening to midnight CST
     tonight for MNZ045-051-052-054-056>059-064-065-073.

     Wind Chill Advisory from 9 PM this evening to midnight CST
     tonight for MNZ053-066-067-074-075-082-083-091-092.

&&

$$

SHORT TERM...JLT
LONG TERM...DWE
AVIATION...JJM/DLH


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