Area Forecast Discussion
Issued by NWS Bismarck, ND

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700
FXUS63 KBIS 141501
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1001 AM CDT Mon Aug 14 2017

.UPDATE...
Issued at 955 AM CDT Mon Aug 14 2017

Surface high pressure over central and eastern ND this morning
will move southeast today as low pressure with showers and a few
storms push into western ND this afternoon and tonight.

For the morning updated we adjusted sky cover over the south
central into the James River Valley. With the surface high
remaining over this area, clouds have been slow to dissipate and
have actually expanded farther west (to around Bismarck) and
north the past few hours. We also removed the mention of thunder
in the west this morning. Otherwise the only other changes were to
update latest sensible weather observations and interpolated to
late morning values.

&&

.SHORT TERM...(Today and tonight)
Issued at 415 AM CDT Mon Aug 14 2017

Some low clouds and patchy fog were over the James River Valley
to start the day, and GOES 16 satellite fog images show they were
advancing to the west, toward the mighty Missouri River.
Jamestown was overcast with low cloud along with Gwinner, and
Linton was reporting fog as of this writing. GOES 16 shows that
the westward movement has slowed. Included low cloud and fog from
the aforementioned river valley (MO) through the James River
Valley and as far north as highway 200. GOES also showed that
there were thin areas in the cloud deck so will expect a fairly
quick burn through / off this morning.

The next system was already on our doorstep. The H5 low was
pushing into Alberta with diffluent flow ahead of it supporting
upward motion. The initial short wave was moving through
southeast Montana / northeast Wyoming with some weak radar returns
there. The surface support for the system is in reality weaker
than earlier forecast. Surface convergence and moisture pooling
are much weaker due to the much weaker surface trough. With that
the MU CAPE is also considerably less. And, for any storms that do
fire, the available shear is considerably less. With that goes a
decrease in expected storm intensity. Have not included any T+
(severe) in the forecast for today / tonight.

With all that said the system should support showers and isolated
storms, just not severe weather for this forecast area. Better
surface support from upslope flow into the Black Hills could
support stronger to severe storms there.

.LONG TERM...(Tuesday through Sunday)
Issued at 415 AM CDT Mon Aug 14 2017

By Tuesday the long wave trough is from Saskatchewan to the
western Dakotas with a parade of short waves keeping rain chances
going. By Wednesday there is no short wave support but with
cyclonic flow aloft isolated showers and storms in the heating of
the day will be possible.

Ridging with highs back above 80 for the end of the week and
weekend? Looks like it. But not a dry one as there is another
trough passage for storm chances Friday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 955 AM CDT Mon Aug 14 2017

Low clouds and patchy fog from the Missouri River Valley near KBIS
through the James River valley (KJMS) to start the TAF valid
period. Pockets of IFR ceilings and visibilities will continue to
burn off this morning as satellite images show thin spots in the
overcast. Other than that, VFR weather today and tonight but with
scattered showers and thunderstorms KISN-KDIK today, and across
the area tonight. At this time severe storms are not in the
forecast for today nor for tonight.

&&

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

$$

UPDATE...TWH
SHORT TERM...JPM
LONG TERM...JPM
AVIATION...TWH



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