Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 240333

Area Forecast Discussion
National Weather Service Bismarck ND
933 PM CST Thu Feb 23 2017

Issued at 927 PM CST Thu Feb 23 2017

Lowered overnight lows into the 5 to 15 above range for most
areas, especially those that are under clear skies as of 03 UTC,
and will remain clear at least for the next few hours. Otherwise,
maintained a patchy fog mention for late tonight into Friday
morning as supported by the 23-02 UTC RAP/HRRR iteration
visibility forecasts.

UPDATE Issued at 659 PM CST Thu Feb 23 2017

Based on observed trends through 00 UTC of increasing ceilings
southwest and continued clearing of stratus as suggested by the
23 UTC RAP/HRRR, have removed the potential for freezing drizzle
with this update.


.SHORT TERM...(This evening through Friday)
Issued at 159 PM CST Thu Feb 23 2017

Main problem in the short term period will be fog/drizzle late
this afternoon and this evening.

Latest surface analysis shows High pressure over Canada with
strong low pressure over the central Plains. This is producing a
northeast surface flow over western and central ND. Latest radar
and satellite analysis indicates very weak reflectivities over
central into southwest ND, with areas of clearing in the far
northwest and north central. Latest webcams indicate areas of fog
and possible drizzle over west central into southwest ND. Bufkit
soundings are not overly impressive but there is some support for
patchy drizzle. Therefore we have introduced an area of patchy
freezing drizzle over portions of central into west central and
southwest ND late this afternoon and this evening.

By late evening and overnight, think any drizzle threat should end
as seeder/feeder mechanism would kick in as mid and upper levels
saturate, also any remaining forcing continues to weaken. Did keep
a mention of fog through the night as low level moisture remains
in place. Areas that do clear out across the north could also see
possible radiation fog late tonight into early Friday. Weak cold
advection continues tonight so cooler than last night with lows in
the single digits above zero around the Turtle Mountains to the
upper teens far south. Also a little colder on Friday with highs
ranging from the upper teens northeast to upper 20s southwest. We
utilized a blend of given guidance with some of the colder
guidance both tonight and Friday, but moreso tonight.

.LONG TERM...(Friday night through Thursday)
Issued at 159 PM CST Thu Feb 23 2017

The main issue in the long term period will be occasional
precipitation chances in a northwest upper flow pattern.

A colder northwest flow pattern remains entrenched over the
northern plains through the middle of next week, with some
indications of possible western ridging pushing us back above
normal toward the end of the extended period.

Our northwest flow pattern is conducive to periodic shortwaves
bringing mainly light qpf amounts. With cold temperatures firmly
established over the area we should not have to worry about any
significant mixed precipitation events.

A couple stronger upper level troughs track through the area
Saturday and again on Tuesday. Each bringing chance pops across
the forecast area, as indicated by our current blended model
guidance. This seems reasonable given the current deterministic
model agreement for each trough but the lack of agreement between
the resulting qpf patterns depicted.

Temperatures remain seasonable cool through the middle of next
week with highs mainly in the mid 20s to mid 30s, and lows in the
upper single digits to teens. Some possible moderation is
suggested at the end of the extended period, especially over the


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 927 PM CST Thu Feb 23 2017

MVFR/IFR ceilings across southern North Dakota as of 03 UTC will
continue to slowly clear from north to south, potentially
remaining most widespread across the James River Valley
overnight. Patchy fog is possible across much of western and
central North Dakota late tonight into Friday morning. MVFR/VFR
stratus across southern Canada will slowly build south into
northern North Dakota through the night.




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