Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 171436

Area Forecast Discussion
National Weather Service Bismarck ND
936 AM CDT Wed May 17 2017

Issued at 934 AM CDT Wed May 17 2017

Large area of low clouds and areas of fog over the northeast half of
the state continues to push to the southeast. Expect the clouds to
continue spreading southwestward, then begin to dissipate during the
afternoon. Northeast winds were increasing across the state as
forecast. Only changes were to blend actual hourly wind and
temperatures/dewpoint observations with the hourly forecast

UPDATE Issued at 637 AM CDT Wed May 17 2017

Low dewpoint depressions and upslope flow is aiding in the
development of fog over southwest ND early this morning. Have
added a mention of fog through 15 UTC. Also stratus dropping south
and west from Manitoba is beginning to intrude into northern and
eastern portions of the CWA. There is some areas of fog over
northeast ND so added a mention of fog across the north this
morning. Otherwise no significant changes to the going forecast.


.SHORT TERM...(Today and tonight)

Issued at 340 AM CDT Wed May 17 2017

Forecast highlights in the short term period will be cooler
temperatures and mainly dry conditions.

Currently, upper level low pressure spinning over the
Intermountain West region of Oregon/Idaho, another closed low
moving into the Central Plains, and a weak S/WV ridge over the
Northern Plains. Quasi-stationary frontal boundary over southern
North Dakota early this morning south of a large and cool surface
high over central Canada. North to northeast low/mid level flow
from the high resulting in CAA into the region, with negative
Celsius 850mb temperatures just 150 miles north of the
Canadian/ND border. A stray shower popped up near KDIK the last
hour. Interestingly High Res models along with the NAM12 shows
this occurring. Forcing mechanisms would appear to be upper level
divergence and/or some low level forcing along the stationary
front. Will not mention any weather at this time due to the very
small coverage and zero impact, but will monitor in case other
isolated activity develops. Models trend dry as well 10-12Z.

Mid to upper level clouds continue to stream north into our
region as well as a large area of low stratus moving south from
Canada, just now pushing into the Turtle Mountain area. These
clouds will continue southward as northeast flow increases, with
the entire area eventually being enveloped by the low clouds this
morning. Increased gradient forcing through the morning as the
surface high slowly builds south will see winds ramp up. Upstream
wind gusts are in the 15-25KT range with Rolla just reporting a
peak gust of 16kts.

CAA continues today and tonight with noticeably cooler
temperatures. Daytime highs today will range in the 50s with a
breezy northeast wind gusting between 25-35 MPH. BUFKIT would
suggest some potential for 40 MPH gusts within the mixed layer.
Models have trended dry so did scale back on precipitation
chances again over the far south for both today and tonight.
Models suggest at least partial clearing later this morning and
in the afternoon so trended sky cover in this direction.

Chilly temperatures under a mostly clear sky tonight with lows
falling into the 30s except for the southern James Valley where
low 40s are expected. The day shift will evaluate whether frost
headlines are warranted and where. Biggest question for
temperatures: with winds remaining from the northeast at 10-15KTS,
will temperatures be able to fall into the lower 30s? Based on
upstream observations the answer appears to be yes, but will
defer headline decisions to the day crew to analyze latest model

.LONG TERM...(Thursday through Tuesday)

Issued at 340 AM CDT Wed May 17 2017

Models remain dry through Thursday night as surface high pressure
builds into the region. The latest runs of the GFS/ECMWF continue
to bring the upper low currently over the Intermountain West north
through the Dakotas Friday/Saturday. POPs were increased via the
forecast blend, especially for central and eastern areas of North
Dakota. Afterwards northwest flow aloft develops for the remainder
of the long term period with upper ridging over the west coast.
Global models continue to bring several embedded waves within the
flow aloft south-southeast across the Northern Plains late this
weekend and into early next week, each bringing chances for rain.
Cool temperatures are still advertised to accompany the surface
high through Saturday, with forecast highs in the 50s to low 60s.
The threat for frost will remain Friday and Saturday AM when high
pressure is over the Dakotas. A moderation in temperatures is
forecast for Sunday, but would expect cooler conditions early next
week given the flow pattern.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 637 AM CDT Wed May 17 2017

Areas of fog over southwest ND this morning, including KDIK in an
are of upslope flow. Widespread IFR-MVFR ceilings in stratus
dropping south and west from Canada will overspread the forecast
area this morning, lift to mainly MVFR late morning through mid
afternoon, then low VFR most area mid-late afternoon. In addition
strong north to northeast winds will develop today with gusts
above 30 mph from late morning into the early evening across the
forecast area.




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