Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 141244
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
644 AM CST Sun Jan 14 2018

.UPDATE...
Issued at 630 AM CST Sun Jan 14 2018

Updated PoPs to match current radar trends and obs. Snow coming a
bit faster than earlier expected. Hires model guidance continues
to show around 10 to 15 hundredths of QPF this morning down the
valley with snow ratios around 20 to 1 producing 2 to 3 inches of
snow. Winds will be the primary concern or impact once the snow
is mostly done with reduced visibilities developing late this
morning into the afternoon. Will leave the start time to the
advisory at 10am.

&&

.SHORT TERM...(Today and tonight)
Issued at 344 AM CST Sun Jan 14 2018

Clipper system today expected is expected to bring a band of
higher snowfall amounts down the valley this morning. Intense lift
with strong 700mb Omega and 850mb WAA underneath 500mb divergence
as system evolves and deepens bringing a 2 or 3 hour period of
enhanced snowfall. Snowfall rates of a 1/2 to 1 inch an hour this
morning will be followed by increasing NNW winds. Winds will be
mixing from 900mb or so based on bufkit soundings within the
valley at 25 to 30 kts through the afternoon. These winds are
expected to cause some areas of blowing and drifting snow reducing
visibilities down to a half of a mile this afternoon especially
across areas where a deeper snowpack resides. The arctic air
plunging into the region will again create dangerous wind chills.
Will be issuing winter weather advisory for the northern valley
during the day for the combo of snow, blowing snow and wind chills
and then expecting wind chill headlines for the entire FA for the
overnight period as wind chills fall to around 40 below by monday
morning.

.LONG TERM...(Monday through Saturday)
Issued at 344 AM CST Sun Jan 14 2018

Upper level trough begins to exit the area Mon. Coldest air over
the area Mon with a respectable pressure gradient. Surface high
pressure settles over the central and eastern Dakotas Tue morning.
Tue should be the coldest morning. Upper level ridge over western
North America shifts east and flattens as eastern Pacific upper
trough moves onshore. Upper ridge reaches eastern MT by 84 hours.

Wednesday to Saturday...Long wave pattern de-amplifies this
period and becomes more progressive. Split flow regime develops
after Thu with northern stream over central and eastern Canada and
southern stream over the northern states. Upper flow more zonal
after Thu.

The GFS was the faster solution initially then the ECMWF becomes the
faster solution by the end of the period. Will blend the models.

Little change to high temperatures for Wed through Sat compared to
yesterdays forecast package.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 630 AM CST Sun Jan 14 2018

MVFR CIGs and some intermittent IFR VSBYS today with snow moving
through this morning. Blowing snow concerns this afternoon with
winds gusts to around 30kts. MVFR CIGs may linger into the
overnight. Clearing expected towards Monday morning although winds
remain 15 to 20kts overnight.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Wind Chill Advisory from 9 PM this evening to noon CST Monday
     for NDZ038-039-049-052-053.

     Wind Chill Advisory from 6 PM this evening to noon CST Monday
     for NDZ006>008-014>016-024-026>030-054.

     Winter Weather Advisory from 10 AM this morning to 6 PM CST this
     evening for NDZ008-016-027-030.

MN...Wind Chill Advisory from 9 PM this evening to noon CST Monday
     for MNZ003-017-023-024-027>032-040.

     Wind Chill Advisory from 6 PM this evening to noon CST Monday
     for MNZ001-002-004>009-013>016-022.

     Winter Weather Advisory from 10 AM this morning to 6 PM CST this
     evening for MNZ001-002-004-007.

&&

$$

UPDATE...JK
SHORT TERM...JK
LONG TERM...JH
AVIATION...JK



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