Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 240534

Area Forecast Discussion
National Weather Service Bismarck ND
1234 AM CDT Mon Oct 24 2016

Issued at 1234 AM CDT Mon Oct 24 2016

Main change this update was to include the mention of patchy fog
most areas...and "areas of fog" from the north central through the
James Valley. HRRR model indicating fog developing - especially
north central and James Valley. Models indicating low level moisture
is fairly high with temps/dewpoints in the lower 30s/upper
20s. Confidence is low regarding whether low stratus clouds will
form, and models not in agreement - so will leave that mention out
this update. Regarding other forecast elements, no big changes in
this forecast update. Hourly temperatures were a tad lower than
forecast...thus blended them with short term guidance for the rest
of the nighttime hours.

UPDATE Issued at 943 PM CDT Sun Oct 23 2016

Little change for tonight other than to lower overnight lows a
couple of degrees per observed trends through 02 UTC.

UPDATE Issued at 635 PM CDT Sun Oct 23 2016

The forecast remains on track for the night and was blended to
observed trends through 23 UTC. Overall, the potential for patchy
fog remains unchanged, with the greatest chances west of the
Missouri River with upslope return flow.


.SHORT TERM...(This evening through Monday)
Issued at 248 PM CDT Sun Oct 23 2016

Focus in the short term is on cloud cover and the potential for
fog tonight into Monday morning.

Model guidance has had a difficult time with cloud cover through
the day as in most places clouds stuck around a bit longer than
previous thought. Latest HRRR runs show clouds more or less
sticking around central and north through the night while other
models are more optimistic that central and north may clear out.
Went with a blend of models through the night but will have to
keep a close eye on it as cloud cover will play a role on if and
how much fog develops overnight and overnight lows in the James
River Valley.

As for fog the NAM has done a good job the past two nights of
showing where fog will develop. Tonight into Monday morning the
best chance appears to be north central and northwest with some
potential development across the central and west early Monday
morning. Low level moisture will be ample across the area, however
depending on when southeasterly winds pick up across the southwest
and cloud cover south central will play a large role in whether or
not fog develops.

.LONG TERM...(Monday night through Sunday)
Issued at 248 PM CDT Sun Oct 23 2016

Focus in the long term is on the chances for rain Tuesday into

Model guidance continues to show two upper level troughs develop in
the mean ridge Tuesday and Wednesday. The best chance for rain
comes from the southern wave that develops over the central
plains. Wrap around precipitation will bring rain to the
southeastern part of North Dakota Tuesday afternoon into early
Wednesday morning.

The second wave develops further north in Canada and progresses
more slowly. Model guidance is in less agreement on the track of
this upper level wave. Latest solutions of the ECMWF show chances
for rain across much of North Dakota for most of Wednesday while
the latest GFS solution keeps precipitation north of the border.
Either way any rain would be light across northern North Dakota
and for now have went with chances for rain for north central and


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1234 AM CDT Mon Oct 24 2016

Patchy fog is possible across much of western and central North
Dakota tonight into Monday morning, especially west of the
Missouri River including the terminal of KDIK. Otherwise, VFR
conditions are forecast for the 00 UTC TAF cycle. Southeasterly
winds with gusts of 20-25 kts are expected on Monday.




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