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781
FXUS63 KBIS 230519
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1219 AM CDT Fri Sep 23 2016

.UPDATE...
Issued at 1215 AM CDT Fri Sep 23 2016

The only change to the going forecast was to increase sky cover
in the overnight period to 100, cloudy.

UPDATE
Issued at 1020 PM CDT Thu Sep 22 2016

Another quick adjustment to POPs. Best chances and favorable
coverage remains across the west and north central through
tonight.

UPDATE
Issued at 901 PM CDT Thu Sep 22 2016

Forecast remains on track. Fog with low cigs reported in northwest
SD so southwestern ND should see widespread fog as low level
moisture increases this evening and into the overnight.

UPDATE
Issued at 645 PM CDT Thu Sep 22 2016

Scattered rain showers developing across south central and
especially southwestern ND as upper level divergence
overspreading the region combines with increasing thermal upglide
across the Dakotas. Tweaked POPs for this update based on latest
high res model data along with regional radar trends the past hour
or so. Models are indicating increasing elevated instability as
well from south to north across my southwest and south central
counties as the evening progresses into the overnight hours, so
threw in isolated thunderstorm chances for these locations
tonight. Areas with the best chances for accumulating moisture
continue to be across the west and into the north central parts of
the state tonight.

&&

.SHORT TERM...(This evening through Friday)
Issued at 232 PM CDT Thu Sep 22 2016

Concerns for the short term focus on the chance for rain and the
amounts.

The surface weather features in the short term include surface high
pressure across the Prairie provinces of Canada and a developing
low pressure area across the high plains of Montana and Wyoming.
This weather pattern will be favorable for strong upslope flow
across southwest North Dakota tonight and Friday. The GFS/NAM
soundings show a nearly saturated boundary layer which will favor
areas of fog in additions to showers. This is expected to begin
tonight and persist through much of Friday.

Looking aloft, the global models depict the upper low over northwest
Nevada Thursday afternoon and track this feature east then northeast
toward the northern plains on Friday. This low will be the focus for
showers and scattered thunderstorms across the region Friday into
the weekend. Most of the day Friday there is little if any CAPE
to support thunderstorms west so will limit the mention of
thunderstorms on friday to the central and east. Lows tonight will
be in the mid 40s to lower 50s and the highs Friday will be mid
50s to mid 60s. A moderate east to northeast wind of 15 to 30 mph
will prevail.

.LONG TERM...(Friday night through Thursday)
Issued at 232 PM CDT Thu Sep 22 2016

Above average uncertainty continues in the extended picture.
Initially a negatively tilted h500 low lifts north through the
northern plains Friday night through Saturday. The global
deterministic models agree reasonable well in the track and
precipitation field associated with this low through Saturday.

By Sunday there is significant departure between the GFS and ECMWF
with the Ecmwf much more progressive and the GFS reforming the
h500 low in eastern North Dakota and dumbelling it around
Minnesota. The result is the ECMWF is dry with a ridge over the
northwest and north central CONUS.

There is much uncertainty here in temperature and precipitation
early next week. For now have stuck with the superblend guidance
which gives scattered showers and highs in the 60s early in teh
weak moderating to the 70s by Thursday. If teh ECMWF is more
closer to the true solution warmer temperatures will be in the
offing. The GFS results in cooler temperatures next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)

Issued at 1215 AM CDT Fri Sep 23 2016

MVFR ceilings developing across southwestern ND will expand north
and east and trend to IFR through 12Z Friday. Likely rain showers
most terminals, especially KDIK-KISN- KMOT. Models are indicating
IFR-LIFR CIGS developing during the day Friday and persisting into
Friday evening all sites. Winds will remain 10 to 20 knots from
the northeast/east through the period.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JPM
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...JPM