Area Forecast Discussion
Issued by NWS Bismarck, ND

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229
FXUS63 KBIS 301447
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
947 AM CDT TUE AUG 30 2016

.UPDATE...
Issued at 908 AM CDT Tue Aug 30 2016

Not many chances were needed for this update, as I just blended
the latest observations with the current forecast. Main question
for the short term will be in regards to thunderstorm coverage and
strength this afternoon and into the overnight hours. I am most
confident in a strong storm or two along the northwest and north
central, but some guidance does suggest storm formation further
south closer to central North Dakota. Will not change
precipitation chances until we have more confidence in where
storms will form later. A few of the storms that do for will have
the chance to be marginally severe, mainly in the west. Large hail
and gusty winds will provide the greatest threats. The latest
iterations of the HRRR seem to be consistent with a marginal
multicell/weak supercell mode in regards to development.
We will be monitoring observations closely throughout the day.

UPDATE Issued at 618 AM CDT Tue Aug 30 2016

Surface high pressure remains firmly in control across North
Dakota this morning. Skies were mostly clear across the region.
Temperatures had dipped into the lower 40s in central North
Dakota with Hazen reporting 41. A little taste of fall already in
late August. Current forecast looks good with just updating the
current conditions.

&&

.SHORT TERM...(Today through Thursday night)
Issued at 357 AM CDT Tue Aug 30 2016

Winds and resultant fire weather issues will be the main concerns
in the short term forecast period.

Currently...a surface high extended from its center in northern
Alberta/Saskatchewan southeastward into central/eastern ND. Broad
surface low pressure was over the Rockies. At upper levels, a ridge
was building over the Rockies as a low pressure center/trough
approaches the western British Columbia/Washington coast.

The surface high moves eastward into Minnesota today with a
return southerly flow developing over the western Dakotas, along
with continued upper level ridging. There are some
indications of a possible thunderstorm Tuesday evening into
Wednesday morning on the leading edge of a developing low
level jet. Will keep low chance pops northwest and north central
this afternoon into Wednesday morning.

Wednesday and Thursday the strong low level jet remains over
western ND with increasing boundary level winds and a building
thermal ridge. Daytime minimum humidities around 20-25 percent on
Wednesday with sustained winds around 20-25 mph could bring a period
of extreme fire danger across the far west. However, increasing
moisture with the return flow could be a limiting factor. On
Thursday winds will be even stronger with possible wind highlights
over a good portion of the west and central. The low level moisture
return from the models suggests higher dewpoints in the far west
with lower minimum relative humidity across western parts of central
ND...mainly west of highway 83. The uncertainty in how the moisture
return develops is a concern, with low confidence in whether there
will be any fire weather issues. The higher confidence is in the
strong southerly winds of 20-30 mph with gusts up to 40 mph
possible.

Late Thursday night, an upper level wave moving through the upper
ridge could interact with the strong jet over the western Dakotas
providing another chance of thunderstorms. However the latest models
downplay the areal coverage of any storms and limit the chance to
the northwest/north central.

.LONG TERM...(Friday through Monday)
Issued at 357 AM CDT Tue Aug 30 2016

chances of thunderstorms Friday night through Saturday with the
potential for a period of strong to severe storms late Friday night
into Saturday morning...followed by a cool and wet period Sunday
into Labor Day Monday highlights the long term period.

The upper level low over the Pacific Northwest moves east across the
Rockies Friday, lifting northeast into northern Manitoba on Sunday.
Meanwhile another low forms in the base of the parent trough, digs
into the central Rockies and lifts northeastward into the Dakotas
Monday/Tuesday. This will result in southwest flow aloft and a
nearly continuous series of upper level shortwaves moving across the
Northern Plains.

Friday/Saturday:
The already established low level jet continues Friday night across
central ND, ahead of a shortwave trough and surface cold front
pushing into western ND late Friday night, sweeping east across the
state late Friday night and Saturday, exiting into the Red River
Valley Saturday evening. Plenty of CAPE and shear for possible
strong to severe storms. Warm Friday ahead of the cold front with
highs lower 80s to lower 90s. Cooler Saturday behind the cold front
with highs in the upper 70s to mid 80s.

Sunday/Monday:
The secondary upper level low lifting northeast through the plains
with a resultant surface low developing northeastward towards the
Dakotas will bring several rounds of showers and thunderstorms to
our area. Cooler with highs in the 60s and 70s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 628 AM CDT Tue Aug 30 2016

High pressure will dominate the weather across North Dakota
with VFR conditions expected through Wednesday. isolated
thunderstorms are possible northwest Tuesday evening but are too
widely scattered and uncertain to include in TAFs at this time.


&&

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

$$

UPDATE...ZH
SHORT TERM...JV
LONG TERM...JV
AVIATION...WAA



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