Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 201528

Area Forecast Discussion
National Weather Service Bismarck ND
928 AM CST Fri Jan 20 2017

Issued at 912 AM CST Fri Jan 20 2017

Dense fog advisory remains valid over south central portions of
the area into the southern James River Valley so will let it
continue through noon CDT. Main change for mid-morning update was
to place areas of fog through much of the region through the
remainder of the day going through tonight into early Saturday.
Latest HRRR keeps fog over the area through the day into tonight,
and latest sounding analysis is quite reluctant with mixing the
low level moisture out with light winds. Will keep a close eye on
how this fog evolves as additional changes may be needed.

UPDATE Issued at 624 AM CST Fri Jan 20 2017

Dense fog continues across the southern Missouri river valley east
to the James River valley. Current forecast looks good with just
updates to the current observations.


.SHORT TERM...(Today and tonight)
Issued at 311 AM CST Fri Jan 20 2017

In the short term concerns continue to be dense fog and the
potential for freezing drizzle as the low levels are saturated
with relatively dry air aloft.

The current dense fog advisory which runs through noon Friday looks
good with the edge of the stratus/fog layer now around the
missouri river.

Surface temperatures a few degrees above freezing in the James
River Valley will also complicate the drizzle/freezing drizzle
forecast this morning. The Metro model at Medina mp 231 on I-94
keeps the road surface below freezing through 9 am CST so the
potential for drizzle may be east of this area and freezing
drizzle west. So far have not seen to much in precip yet but the
NAM soundings are saturated with weak verticaL motion. So
reasonable to continue DZ/FZDZ.

After the dense fog advisory ends at noon will keep patchy fog
through the afternoon then expect foggy conditions will return

.LONG TERM...(Saturday through Thursday)
Issued at 311 AM CST Fri Jan 20 2017

No real issues in the extended at this time. The upper level low
will continue to drift north Saturday and Sunday. This will keep
low chances for snow across the north and east with amounts very

The next chance for snow will be across southern North Dakota
Tuesday. Currently all the deterministic models depict a closed
h500 low tracking eastward south of the state during this period.
The GEFS plumes have a cluster of runs around a tenth of an inch
or less for Bismarck with a few outliers above a half an inch. So
feel current low pops less than 30 percent across the south seem
reasonable. Wednesday and Thursday could be a little breezy as the
GFS and ECMWF build a ridge over the western CONUS and a trough
to the east. This leaves the Northern Plains in a bit of a
pressure gradient. Current grids have 15 to 20 mph which will be
ok for now as its fairly far out. But will continue to watch the
trends as the GFS ensemble mean Surface pressure gradient is
significant while all other models including the GFS deterministic
run more moderate.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 624 AM CST Fri Jan 20 2017

LIFR/VLIFR conditions in freezing fog/low ceilings will continue
at KJMS and KBIS, and will develop into KMOT. Both KISN and KDIK
will trend MVFR-IFR by Friday evening. Patchy MVFR/IFR fog is
possible elsewhere across western North Dakota this morning. For
KJMS & KBIS, some improvement during the day but conditions
deteriorate again Friday night.


Dense Fog Advisory until noon CST /11 AM MST/ today for NDZ022-



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