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Area forecast discussion 
National Weather Service Bismarck ND
627 am CDT Wednesday Aug 27 2014

issued at 623 am CDT Wednesday Aug 27 2014

Refined the fog areas to reflect fog over most of the west and
central this morning. Left the advisory area in place.


Short term...(today and tonight)
issued at 431 am CDT Wednesday Aug 27 2014

For the near term/early this morning...the current fog/stratus
imagery loop in combination with surface observations shows dense
fog expanding over most of central North Dakota. Based on current
visibility trends and latest hrrr visibility forecast...have
issued a dense fog advisory for most of central North Dakota
through late Wednesday morning.

Otherwise...a clear sky dominates west and north with the latest
water vapor imagery showing subsidence behind a northern stream
shortwave now into Minnesota. Split flow continues with the
southern branch extending from the Great Basin into South Dakota.
An upper low/trough was seen over western Nevada early this morning.

Expecting plenty of sunshine today with temperatures warming into
the 70s...and lower 80s in the far west. All model guidance...with
the exception of the GFS...are in agreement that the southern
branch makes a return into southern North Dakota Wednesday night.
As the aforementioned Great Basin low/trough shifts east...a
surface low will take shape over Nebraska and South Dakota later
today into tonight. Latest trends indicate the northern fringe of
precipitation will reach the James River Valley between 06z and
12z Thursday. After collaborating with Aberdeen and Grand
Forks...have introduced a slight chance mention for showers and will
let subsequent shifts look at the latest data to fine tune.

Long term...(thursday through tuesday)
issued at 431 am CDT Wednesday Aug 27 2014

During this period there will be several cold frontal passages that
will bring some active weather to the region over the Labor Day
weekend. First...the remnants of an upper level low will track south
of the state Thursday. While this feature will impact the areas
south of the state with several large mesoscale convective system type convective
systems...there will be some residual moisture pulled into the
state...mainly across the James River Valley Thursday morning. But
there will likely be more clouds through the day Thursday than
previously thought across a large portion of southern and eastern
North Dakota. After this a cold front will enter the northwest
supported by a rather weak leading shortwave trough ahead of a more
significant shortwave still lingering across the northwest US Friday.
Overall...have down played the probability of precipitation Thursday night and
Friday...waiting instead for the more significant shortwave due in
Saturday night and Sunday. With this next system will see more
significant precipitation with stronger warm/cold frontal passages.
So the Holiday weekend should be a bit soggy Saturday night with
scattered showers on Sunday. Cool cyclonic flow aloft should
maintain slight threat for thunderstorms Monday and Tuesday.


Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 623 am CDT Wednesday Aug 27 2014

Areas of dense fog from kbis to kjms will pose as the highest impact
to aviation through 14z Wednesday with vlifr cigs/vsbys. From 14z
through 16z expect a gradual improvement to MVFR then VFR. Kdik will
likely see a brief period of LIFR ceilings and MVFR visibilities through 15z.
VFR conditions expected the rest of the day...then clouds/low VFR
ceilings return to kbis/kjms Wednesday night...with a vcsh at kjms after
08z Thursday.


Bis watches/warnings/advisories...
dense fog advisory until 11 am CDT /10 am MDT/ this morning for



Update...warm air advection
short term...Kansas
long term...warm air advection
aviation...warm air advection

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