Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 260433

Area Forecast Discussion
National Weather Service Bismarck ND
1133 PM CDT MON JUL 25 2016

Issued at 1133 PM CDT Mon Jul 25 2016

Surface low pressure along the ND/SD border, between Linton and
Mobridge, is located along a boundary/wind shift or convergence
zone extending from just south of Bowman, along the border and
into Jamestown and northeast ND. Distinct surface convergence
with northeasterly winds north of the boundary and south to
southeast winds across SD. This has been the focus for isolated
showers/thunderstorms given the high cape and little shear per SPC
mesoanalysis. The HRRR/RAP13 both seem to have a better handle on
the given situation compared to the 00z NAM, which has failed to
capture the current precipitation area, and the 00z GFS which is
way overdone, especially going forward overnight. Hence following
the higher resolution models, will continue with slight chance/chance
of showers/thunderstorms overnight. The next shortwave/precipitation
now over central MT should reach western ND between 12z-15z Tuesday.

UPDATE Issued at 916 PM CDT Mon Jul 25 2016

A few showers/storms continue to develop along boundary that is
now draped from east-central North Dakota into south-central North
Dakota. Models continue to show strong instability, though with
weak shear in place storms have been pulsing up and down. Will
keep precipitation chances in the forecast through the night
mainly over the southern half of the area. Updates have been sent.

UPDATE Issued at 626 PM CDT Mon Jul 25 2016

Stronger instability remains in place over the area this evening,
though shear is weak and there is no strong forcing mechanism in
place. Therefore, only expect some isolated storms to develop
tonight. Storms could become strong, but with the lack of shear do
not expect them to be long lived.


.SHORT TERM...(This evening through Tuesday)
Issued at 347 PM CDT Mon Jul 25 2016

Main forecast issue in the short term period will be possible
thunderstorm chances late this afternoon through Tuesday.

Currently, sunny skies across western and central ND. The
exception being an area of cu development over the far southwest.
Instability continues to increase across central ND with mlcapes
approaching 2000-2500 j/kg. However, lapse rates are not
impressive and bulk shear is lacking most areas. In the north
central where there is an area of impressive shear is where lapse
rates are the lowest. Convection-allowing models are still
indicating isolated convection from mainly Sioux/Grant counties
in the far south central, into the James River Valley and into
east central/northeast ND. Will utilize a time-lagged blend of
short term models for late afternoon/evening pops, which is
yielding 20-30 pops in this general area through mid evening. The
potential for severe weather appears limited given the meager
shear and mid level lapse rates. But due to the unstable
conditions, a briefly severe thunderstorm can not be ruled out.

The boundary that convection fires on this afternoon/evening
becomes nearly stationary just south of south central/southeast
ND late tonight and Tuesday. This will set up a moist easterly
flow along and north of the boundary, keeping the chance for
showers and thunderstorms across southern ND through tonight and
Tuesday. Surface high pressure north of this boundary currently
over southern Alberta/Saskatchewan will move east into Manitoba
Tuesday bringing more stable conditions into the northern half of
ND Tuesday. After lows around 60 tonight, highs will range from
the upper 70s north to the upper 80s southwest on Tuesday. The
threat for severe weather on Tuesday will be marginal with the
best chances over the southern half of the state.

.LONG TERM...(Tuesday night through Monday)
Issued at 347 PM CDT Mon Jul 25 2016

A persistent eastern Canadian trough and Western N.A ridge will
maintain a nearly stationary boundary from the northern Rockies
into the northern and central Plains. This will keep the risk of
showers and thunderstorms in the forecast through the work week.
For western and central ND the best chances for precipitation
will be across the west and south central, while the north central
will see limited chances. By the weekend the western ridge begins
to build over the central U.S. perhaps bringing a little drier
weather, but with warming temperatures, at least a slight chance
of diurnally driven thunderstorms will remain through the upcoming
weekend. As for temperatures, we cool down into the 70s and lower
80s Wednesday through Friday but then warm back into the 80s and
lower 90s over the weekend, into early next week.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1133 PM CDT Mon Jul 25 2016

Low confidence on when a shower/thunderstorm will impact any one
terminal through the TAF period. Have utilized a vcsh/vcts at
most terminals for now, and will adjust when something develops
prior to impacting a terminal. KMOT should remain dry through the
period and thus have no mention of precipitation here. Vfr cigs/vsbys
next 24hr at all terminals.


.BIS Watches/Warnings/Advisories...


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