Area Forecast Discussion
Issued by NWS Grand Forks, ND

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000
FXUS63 KFGF 130032
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
632 PM CST Tue Dec 12 2017

.UPDATE...
Issued at 632 PM CST Tue Dec 12 2017

Made a few tweaks to temperatures as the northeastern counties
have fallen into the teens this evening. Still think there should
be a steadying off or slow rise at some locations tonight with
clouds and warm air advection moving into the region. Will
continue to keep the precip we have going. Some of the high
resolution models have been trending a bit further south with the
precip band as it develops around midnight, but barely and still
close to where we have the higher POPs. Will hold off on any
changes to precip for now.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 256 PM CST Tue Dec 12 2017

Temperatures have warmed very nicely late this afternoon. The
warmest spots are just west of the Red River Valley. Winds have
not switched to the southwest to west in the northern valley or
east of the valley. Will probably not have a true diurnal temp
curve tonight. There will likely be additional warming through
sunset, then probably steady or even warming temps yet in some
areas, before a fall very late. With the warm temperatures aloft,
still looking like there will be some sort of mixed pcpn again
developing later this evening. Thinking it will hold off until
late evening in the north and several hours later in the south.
The NAM12 and GFS20 both develop a thin band of higher pcpn
values, which would correspond to potentially greater impacts
between midnight and sunrise. Both models show this potential area
to be the central Red River Valley into west central MN.
Confidence not great with this, but have to keep it in mind.

Greatest confidence is the strong wind potential developing behind
the mixed pcpn potential. Thinking it will lag behind the mixed
pcpn potential by about 3 to 6 hours or so. Therefore the
strongest winds should be arriving in the time prior to sunrise
probably through early afternoon. Still thinking gusts up in the
50 to 55 mph range will be possible, especially in the valley.
With the expected temp fall through the morning, any mixed pcpn
would change to light snow. Not looking at a lot of snow during
the day, but enough that when combined with the snow, vsbys below
a half mile will be likely. Not expecting these low vsbys to be
there continuously, but periods of them. To handle the expected
weather types mentioned above, have elected to go with a winter
weather advisory for the Red River Valley and west for the
combination of mixed pcpn and low vsbys due to blowing snow. Have
less confidence of the mixed pcpn for areas east of the valley,
and there will be less wind there too. Will issue an updated
special weather statement to cover the mixed pcpn potential east
of the valley. Conditions should begin to improve by late Wed
afternoon.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 256 PM CST Tue Dec 12 2017

Main impacts will continue to be clipper systems in NW flow aloft
and potential precipitation combined with wind for each clipper.
Track of each clipper and the blyr temp profile will continue to
allow the threat of a period of mixed phase precipitation. The next
couple of clippers will be Thursday and Friday. Thursdays appears to
bring light pcpn in the west and Fridays in the east. Neither system
appears to be a strong wind producer. Saturdays system appears a bit
more complex with an extended time frame for impacts as the ridging
in the west deamplifies. Models remain wide spread with a possible
central plains piece of energy merging with the southern stream and
developing a more robust system to the south of the FA Sunday.
Monday and Tuesday appear less active as of now. Timing in this flow
remains challenging 6 and 7 days out to say the least.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 632 PM CST Tue Dec 12 2017

IFR ceilings continue at KBJI, and that trend will continue
through the TAF period. The other TAF sites remain VFR, but
conditions will slowly deteriorate towards morning. A band of
mixed precip could bring some FZRA during the 06-12Z time frame,
but not confident enough to include at this point at any one TAF
site so will monitor and amend as needed. All sites should be MVFR
or lower by 15Z at the latest, with some IFR ceilings also at
times. Winds will increase out of the northwest to over 25 kts
sustained and gusts near 40 kts by morning. Some snow showers
could also create some lowered visibility at times with the strong
winds, but it is unknown at this point if any of these showers
will affect the airports. Winds should start to come down late in
the period.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Weather Advisory from midnight tonight to 3 PM CST
     Wednesday for NDZ028>030-038-039-049-052-053.

     Winter Weather Advisory from 10 PM this evening to 3 PM CST
     Wednesday for NDZ006>008-014>016-024-026-027-054.

MN...Winter Weather Advisory from midnight tonight to 3 PM CST
     Wednesday for MNZ002-003-029-030-040.

     Winter Weather Advisory from 10 PM this evening to 3 PM CST
     Wednesday for MNZ001-004-007.

&&

$$

UPDATE...JR
SHORT TERM...Godon
LONG TERM...JK
AVIATION...JR



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