Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 270518

Area Forecast Discussion
National Weather Service Bismarck ND
1218 AM CDT MON JUN 27 2016

Issued at 1218 AM CDT Mon Jun 27 2016

Latest water vapor imagery loop shows a shortwave near Scobey
Montana, moving southeast with time. A couple thunderstorms
ahead of this shortwave continue to move toward Dickinson at this
time...which have been pulsing back up. The main 700mb-500mb
shortwave trough is still farther upstream near Saskatoon. This is
forecast to also move southeast tonight through Monday. Regional
and Canadian radar loops show another area of showers associated
with this shortwave now developing in southern Saskatchewan.
Current forecast has this handled well.

UPDATE Issued at 907 PM CDT Sun Jun 26 2016

This update focused on adjusting PoPs over western ND through 06
UTC to account for the showers and thunderstorms moving southeast
toward the area out of northeastern MT. Both the operational and
experimental HRRR runs capture the idea of this convection well
in their recent iterations, but are too slow and not far enough
south with it compared to reality at 02 UTC. We thus relied on a
simple extrapolation of trends to bring somewhat higher PoPs in
the 30 to 40 percent chance into west central ND through the late
evening, and extended the chance of showers and isolated storms as
far south and east as Beach, Medora, Dickinson and Killdeer. Based
on upstream radar trends and MLCAPE up to 500 J/kg with deep-layer
speed shear near 40 kt and relatively low freezing levels around
8800 ft AGL per the 00 UTC Glasgow sounding, a strong storm could
occur before the near-ground layer cools sufficiently to further
reduce the modest instability.

UPDATE Issued at 553 PM CDT Sun Jun 26 2016

Overall the going forecast is on track and no significant changes
were needed with this update. BUFKIT momentum transfer techniques
applied to recent RAP and HRRR forecast soundings suggests winds
will rapidly diminish between 01 and 03 UTC. This is perhaps an
hour or two later than previous hourly forecasts advertised, so
we made minor adjustments to the rate of wind speed decrease this
evening. Finally, we did increase sky cover late tonight through
the day Monday, mainly in central ND, using a consensus of short
range guidance and in respect to upstream cloud cover on visible
satellite imagery and an expected weak shortwave trough passage
Monday (the wave currently seen on water vapor images along the
Montana/Alberta/Saskatchewan border region).


.SHORT TERM...(Tonight)

Issued at 252 PM CDT Sun Jun 26 2016

Marginal wind advisory wind gust magnitudes the main highlight
for today, possible thunderstorms northwest tonight.

Currently...Wrap around moisture continues to push south across
south central Canada into the Northern Plains. Extent of
associated cloud deck extends from northwestern ND southeast
through southeastern ND. Models were a tad aggressive with
precipitation coverage earlier so scaled back a bit with this
forecast issuance, mainly keeping pops across the Turtle Mountains
region where the better mid level forcing is at. Winds breezy
across the state today. While mostly sub-advisory magnitudes,
there have been a few wind obs between 45-50 mph. I opted to
mention the periods of stronger wind gusts in the HWO and to not
issue headlines. Carrington and Moffit (Long Lake ob) have been
the two locations recording the higher winds, with marginal/sub-
advisory levels between. Bufkit still shows a trend towards weaker
winds aloft near the top of the mixed layer as the afternoon
progresses, and have already been seeing this trend west and just
recently central.

For tonight, will maintain thunderstorm chances northwest. An
embedded S/WV over northcentral MT will track east into
northwestern ND late this evening. Scattered t-storms near this
feature at this time. Kept pops on the low side for now as it
appears these are mainly diurnally driven. Models still show
several hundred Joules of elevated instability so it is possible
they will stay maintained.

.LONG TERM...(Monday through Sunday)

Issued at 252 PM CDT Sun Jun 26 2016

A quasi-stationary broad upper level ridge across the western
CONUS will be maintained throughout much of the long term period.
Surface high pressure will be over the Northern Plains region for
much of next week, followed by increasing return flow towards the
end of the work week and extending into next weekend.

Very pleasant week ahead with forecast daytime highs in the 70s
to mid 80s, lows in the 50s, and generally low humidity. Dry
weather Monday will be followed by daily chances for showers and
thunderstorms thereafter for the remainder of the period as
several embedded S/WV impulses in northwest flow aloft are steered
southeast across the region.

While uncertainty remains high at this time, models portray a
pattern change towards more zonal starting next weekend into the
early parts of the following 4th of July holiday week...suggesting
increasing chances/greater coverage of strong to severe storms.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1218 AM CDT Mon Jun 27 2016

Mvfr cigs will be the dominate ceiling at KISN/KMOT/KJMS through
until 12z-18z Monday, with tempo ifr cigs at KBIS between 11z-14z.
Thinking is KDIK will remain vfr. After 18z Monday, a vcts has
been carried at the KBIS/KISN/KMOT terminals, which continues
until approximately 00z Tuesday.


.BIS Watches/Warnings/Advisories...


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