Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 211745

Area Forecast Discussion
National Weather Service Bismarck ND
1145 AM CST Sun Jan 21 2018

Issued at 1142 AM CST Sun Jan 21 2018

Included fog in the forecast for much of the James Valley today
and central North Dakota tonight. Low level moisture from
snowmelt, lack of mixing and cooler temperatures are leading to
fog development along the James Valley today. This fog is expected
to remain and expand westward later tonight.

UPDATE Issued at 915 AM CST Sun Jan 21 2018

No major changes required for this update.

UPDATE Issued at 620 AM CST Sun Jan 21 2018

Temperatures really bottomed out over northwest ND early this
morning under clear skies. Updated overnight lows based on latest
readings. Otherwise no changes to the going forecast other than
some minor adjustments to lower sky cover a bit south. Stratus
over eastern ND is dropping south and may be trending a bit west
as well, but will remain east of the forecast area at least for
the next couple of hours.

Updated text products will be sent shortly.


.SHORT TERM...(Today and tonight)
Issued at 205 AM CST Sun Jan 21 2018

Main forecast issue in the short term period will be fog potential

Quiet to begin the short term period with weak high pressure over
the forecast area. As of 9 UTC fog has yet to form over eastern
ND. Stratus is dropping south from Canada just to the east of the
CWA and there is some patchy fog reported in NW Minnesota.
Mesoscale models have been overdoing the fog potential so far with
widespread fog indicated over northwest ND as well. Think the
eastern CWA still has a chance for some patchy fog yet before
sunrise with a Zero dwpt depression at Rolla and low dwpt
depressions extending south into the northern James River Valley.
But if we don`t see anything before publish time will probably
hold off on a mention of fog.

For today, weak pressure pattern remains with slightly cooler
temperatures aloft than yesterday. Did bump temperatures up a
little southwest where more sun and a light westerly surface flow
is anticipated. Highs today from the low to mid 20s around the
Turtle Mountains, to the low to mid 30s southwest.

Tonight, it appears like another potential for low stratus/fog
most anywhere along and north and east of Lake Sakakawea and the
Missouri River. Low level surface convergence will continue to
keep the lower boundary layer moist. Models continue to pull the
lower stratus over Manitoba southward today over eastern ND and
potentially expand it westward into eastern portions of central
ND. The rest of central ND should see decreasing mid and high
level clouds tonight with good radiational cooling. Thus we may
see fog developing on the west edge of the stratus tonight.

Bufkit soundings do indicate a moderately favorable potential for
radiational fog tonight into Monday morning, exceeding crossover
temperature and with low turbidity. Mesoscale models have been
overdoing fog last couple of days but think the fog potential is
high enough to add a mention now for tonight into Monday morning
and later shifts can adjust as needed.

.LONG TERM...(Monday through Saturday)
Issued at 205 AM CST Sun Jan 21 2018

The long term also appears quiet, for the most part. Models keep
the Tuesday clipper further north and east, leaving most of North
Dakota dry. There still appears to be a storm that will impact
portions of the Northern Plains Friday into Saturday. Temperatures
over the next week should be slightly above normal, except
Thursday which may be well above normal, ahead of the
aforementioned storm system. Models have backed off on the
precipitation potential Friday into Saturday. A model blend still
brings some chance pops Friday into Saturday but the trend is
certainly drier. We cool back closer to normal on Saturday as
colder air gets pulled into the area behind the exiting system.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1142 AM CST Sun Jan 21 2018

Hazards to aviation for the 18Z TAF period will focus on MVFR/IFR
conditions from clouds and fog. An area of stratus across eastern
North Dakota at 18Z Sunday will slowly migrate westward over the
next 24 hours. Fog will form on the western periphery of this area
impacting KMOT-KBIS-KJMS in MVFR/IFR conditions. KISN-KDIK will
remain VFR.




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