Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 230503

Area Forecast Discussion
National Weather Service Bismarck ND
1203 AM CDT TUE AUG 23 2016

.UPDATE...Issued at 1203 AM CDT Tue Aug 23 2016

Thunderstorm quickly developed in Foster County and have since
issued a severe thunderstorm warning based on mesh and dcape
values for severe hail and wind. Latest surface analysis places
the cold front from near Baker Montana, to Stanley and Bowbells at
this hour. Density gradients are quite impressive with a dewpoint
of 33F at Williston to 67F at Minot and Bismarck. Expecting the
front to progress into central ND by 12z Tuesday, from near
Shields to Bismarck and into Harvey. CAMs all differ on the
degree and location of showers/thunderstorms overnight, but the
favored area is the James River Valley which is where the low
level jet is strongest. Mid level lapse rates impressive at around
8.5c/km. The other concern is closer to the stronger cyclonic flow
and upper low across northwest and far north central.

Fire weather concerns in the far southwest for Tuesday afternoon will
be addressed in the next update cycle.

UPDATE Issued at 934 PM CDT Mon Aug 22 2016

Latest surface analysis shows surface low pressure near Mobridge
SD, with a weak surface trough into west central ND. A Cold front
was just pushing into northwest ND. Currently, no convection
across the area with plenty of CIN across western and central ND.
Later tonight some mesoscale models are indicating convection
developing with the development of a low level jet in the vicinity
of the James River Valley and points east. This has been the case
since earlier today, but not a strong consensus with various
models. Therefore will keep the slight chance pops near the
jamestown area later tonight. Toward morning other mesoscale
models like the 22 AUG 12Z NSSL WRF indicate convection developing
near Minot ahead of the approaching cold front. This also was
covered in the previous forecast with slight chance to chance pops
from around Minot to the International border beginning around 12
UTC. Overall, see no need to deviate from the current forecast.
The 23 UTC HRRR was showing the potential for some low cloud/fog
development over the eastern portion of Lake Sakakawea up towards
Minot in an area of low level surface convergence. BUFKIT model
soundings are not impressive with low level moisture at this time.
Will pass this along to the overnight crew but no plans at this
time to make any aviation forecast adjustments.

UPDATE Issued at 637 PM CDT Mon Aug 22 2016

No major changes were needed for this update. Still monitoring
trends for thunderstorm development in northeastern Montana and
should spread into northwest and perhaps north central North
Dakota later tonight. Otherwise, just blended the latest
observations with the current forecast.


.SHORT TERM...(This evening through Tuesday)
Issued at 307 PM CDT Mon Aug 22 2016

Fire weather concerns far southwest Tuesday highlight the short
term forecast.

A cold front across central Montana this afternoon is forecast to
enter western North Dakota late tonight, and move through central
North Dakota Tuesday morning. See the fire weather discussion
below for details regarding fire weather concerns across far
southwest North Dakota Tuesday afternoon and early evening.

Isolated thunderstorms are possible across far northwest and north
central North Dakota late tonight into Tuesday morning with the
cold front, with additional storms possible tonight potentially
across the James River Valley in deeper moisture and forced by
the low level jet as depicted by the 15-19 UTC RAP iterations.
Severe weather is not expected.

.LONG TERM...(Tuesday night through Monday)
Issued at 307 PM CDT Mon Aug 22 2016

Slowly moderating temperatures into the weekend highlight the
extended forecast.

After a cool start to the extended forecast with highs in the 60s
for much of the area on Wednesday in the wake of the cold front
from the short term, the 12 UTC global deterministic and ensemble
suites are in agreement on cyclonic northwest flow aloft
potentially remaining over the Northern Plains Thursday and
Friday. This would support continued below normal but slightly
warmer highs in the 70s. Thereafter, the upper level flow pattern
may transition to quasi-zonal by the weekend. This would mark a
continued moderation in temperatures back to near normal with
highs in the lower 80s Sunday into Monday.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1203 AM CDT Tue Aug 23 2016

A cold front was located between KISN and KMOT and west of KDIK
at 06z Tuesday. This front will slide east into the central
terminals KMOT/KBIS around 12z Tuesday. Frontal passage at KJMS
will occur between 18z and 21z Tuesday, with low level wind shear
through 13z Tuesday at KJMS. Possible fog/vcfg at KMOT between
09z-15z Tuesday followed by vcsh through early afternoon. Rest of
the terminals will be dry with vfr cigs/vsbys but gusty northwest
winds 15ktG25kt through 00z Wednesday.


Issued at 307 PM CDT Mon Aug 22 2016

For Tuesday afternoon, increased fire danger is anticipated
behind a departing cold front across far southwest North Dakota.
Dry fuels, particularly in the western portions of Golden Valley,
Slope, and Bowman counties, combined with sustained northwest
winds of 20 to 25 mph, and minimum relative humidity of around 20
percent, may result in near critical fire weather conditions. Thus
a Fire Weather Watch remains in effect for Tuesday afternoon into
early Tuesday evening.


.BIS Watches/Warnings/Advisories...
Fire Weather Watch from Tuesday afternoon through Tuesday
evening for NDZ031-040-043.



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