Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 130720

Area Forecast Discussion
National Weather Service Grand Forks ND
120 AM CST Wed Dec 13 2017

Issued at 120 AM CST Wed Dec 13 2017

Rain/Freezing rain is being observed so raised PoPs considerably
to near 100% for the current radar returns, and timed them to the
southeast through 12z. Received a report from Thief River Falls of
rain and icy roads, and as such expanded the winter weather
advisory into west central Minnesota. Highest icing impacts will
probably be within west central Minnesota since temperatures
should remain below freezing. Further to the west along and west
of the valley, where surface temperature are above (or will rise
above freezing), freezing rain impacts will be limited. With that
said, road temperatures in the valley still below freezing, and
walking outside here at the office the sidewalks are still icy.
Will need to consider cancelling the winter weather advisory
across the Western FA with road temperatures above freezing.


.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

.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 06Z TAFS through 06Z Wednesday night)
Issued at 1151 PM CST Tue Dec 12 2017

KBJI scattered out, and all TAF sites are currently VFR. Some rain
has entered the northern forecast area, so included some VCSH at
KDVL and KGFK and may see prevailing -RA at times. Current air
temps are above freezing so will keep FZRA mention out for now
although some pavement temps may be near the freezing mark and
cause slick runways. MVFR to IFR ceilings will move into the area
later tonight and tomorrow morning. Winds will pick up out of the
northwest Wednesday morning with gusts near 40 kts possible. Winds
will gradually diminish by afternoon. Categories will stay MVFR
for the most part although there could be some brief improvements
to VFR late.


ND...Winter Weather Advisory until 3 PM CST this afternoon for

MN...Winter Weather Advisory until 10 AM CST this morning for

     Winter Weather Advisory until 3 PM CST this afternoon for



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