Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 271722
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1222 PM CDT WED JUL 27 2016

.UPDATE...
Issued at 1218 PM CDT Wed Jul 27 2016

Only a few minor updates were made for this update. The latest run
of the HRRR has a pretty good handle on the ongoing precipitation
across eastern Montana and western North Dakota. Utilized this to
tweak afternoon precipitation chances. It appears the bulk of the
precipitation should remain along and west of the Missouri River
today.

UPDATE Issued at 1032 AM CDT Wed Jul 27 2016

POPs were updated with the latest radar and short term models to
reflect the latest trends. No major changes were made. Forecast is
still on track with keeping chances for showers and thunderstorms
in the west.

UPDATE Issued at 630 AM CDT Wed Jul 27 2016

The area of showers with a few thunderstorms were moving into
western North Dakota this morning. Updated the pops with the
latest HRRR run which maintains a slow eastward progression as the
system diminishes slowly. Left the mention of patchy fog in until
mid morning.

&&

.SHORT TERM...(Today and tonight)
Issued at 229 AM CDT Wed Jul 27 2016

For the near term this morning, the experimental HRRR and RAP13
continue with the idea of areas of stratus/fog developing over
southwest and into south central ND through mid morning before
dissipating. Also, showers and thunderstorms approaching from
eastern Montana will spread into western ND before sunrise. A
bowing segment within the thunderstorm complex evident earlier
between Glasgow and Jordan, Montana. Gusts at that time were
around 40kt or 46 mph.

The latest water vapor imagery shows a transition from west to a
northwest upper flow. One shortwave trough was exiting the James
River Valley early this morning as scattered showers and
thunderstorms are slowly weakening and exiting. Subsidence behind
the departing shortwave will produce tranquil weather today for
most of central ND. However upstream, another shortwave is seen
near Great Falls, Montana, which has been producing a line/area of
showers and thunderstorms from Glasgow south to Miles City early
this morning. The experimental HRRR captures this area and is on
track as the area approaches western ND at this time. The shortwave
associated with this area is forecast to pinch off into a closed
mid/upper level low this morning, which will considerably slow its
movement east. In fact, the 00z NAM and 00z GFS indicate the
closed low will meander in northeast Montana through Thursday
night. This will result in the bulk of unsettled weather and showers
and thunderstorms to favor the west through the short term period,
while most of central ND will see dry conditions. Minimal cape and
shear forecast in the northwest (100-200 j/kg, with 20kt bulk
shear), increasing to around 500-1000 j/kg southwest with along
with 0-6km bulk shear of 30kt to 40kt. SPC has a portion of Slope
and Bowman counties in a Marginal or isolated severe thunderstorm risk
area through the short term period. The rest of western and far
south central ND is in a General or non-severe risk. Concur with
this given the cape and shear mentioned above. Highs today will
mainly be in the 70s with a mix of sun and clouds, with clouds
dominating more so in the west.

.LONG TERM...(Thursday through Tuesday)
Issued at 229 AM CDT Wed Jul 27 2016

A progressive flow at h500 is expected to bring a variety of weather
in the extended period.

Northwest flow between h500-h700 continues across North Dakota for
Thursday into Friday morning. Within the flow a weak closed upper
low can be seen in the NAM/GFS which should enhance thunderstorms
chances across Western North Dakota during this period. Severe
weather threat should be low however as shear is very weak.

After the departure of this feature a mid level ridge develops over
the northern plains resulting in a warming trend for the weekend.
Highs into the 80s are expected Saturday and 80s and 90s Sunday
and Monday. Convection may be suppressed a bit with the ridge in
place so thunderstorms should be only widely scattered.

By Sunday night and Monday a more active pattern is expected as the
ridge moves east and an h500 trough over the west coast brings a
surface cold front into the region. With cape and shear
sufficiently strong expect the front to focus thunderstorms over
portions of west and central North Dakota. Although the timing is
still a bit uncertain.

Tuesday into Wednesday should be post frontal with temperatures
cooling back into the 70s and 80s by Wednesday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1218 PM CDT Wed Jul 27 2016

High pressure over the eastern Dakotas and low pressure in eastern
Montana will keep a east to southeast surface flow over western and
central ND through the 18Z taf period. VFR conditions expected at
KMOT and KJMS through the forecast period. Scattered showers and
isolated thunderstorms with periods of mvfr cigs will be possible at
KISN...KBIS and KDIK through the period. Areas of IFR cigs and
visibilities in fog will be possible Thursday morning at KDIK.


&&

.BIS Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...AJ
SHORT TERM...KS
LONG TERM...WAA
AVIATION...TWH



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