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Area forecast discussion 
National Weather Service Bismarck ND
1241 PM CST sun Nov 23 2014

issued at 1233 PM CST sun Nov 23 2014

Trimmed back probability of precipitation again especially south. Winds behind the
pressure rise bubble dropping off a bit. May be able to drop a
portion of the Wind Advisory early across the northwest this

Update issued at 945 am CST sun Nov 23 2014

Trimmed probability of precipitation down across the southeast where new NAM is trending
lower. Also trimmed back mention of blowing snow. The snow cover
southwest is too crusted.

Update issued at 641 am CST sun Nov 23 2014

Surface low pressure in far north central North Dakota...north of
Bowbells and Mohall. Cold front extending to the west is currently
moving into far northwest North Dakota. Light snow is also
beginning to push into northwest North Dakota. MVFR to low VFR
stratus has dropped south to cover all but the far southwest so
expect cloudy conditions through the morning. Raised sky cover to
cloudy most areas this morning. Otherwise no significant changes
to the going forecast.


Short term...(today and tonight)
issued at 345 am CST sun Nov 23 2014

Challenges in the short term include precipitation type south early
this morning...then strong northwest winds and potential for blowing

At 3 am CST...the strong surface low was centered over extreme
southeastern Saskatchewan with a cold front extending southwestward
across northern Montana. Ahead of the cold front in western North
Dakota the west winds had increased the past few hours to 20 to 25
miles per hour. This has kept temperatures up above freezing there. In central
North Dakota...winds had turned west to southwest...and an area of
light precipitation continued moving east across south central North
Dakota. Saturday evening and early this the area of
precipitation approached temperatures would rise above freezing -
and fortunately the areas that received light precipitation likely
received rain rather than freezing rain.

Still cannot rule out a mix of rain/freezing rain/sleet early this
morning in south central North Dakota.

By sunrise this morning the cold front will have entered the
northwest corner of North Dakota. Precipitation type behind the
front should be all strong cold advection will act quickly
to cool all low/middle levels below freezing. Expecting northwest winds
of 30 to 40 miles per hour to develop from west to east today. Thus these winds
are high enough to reach Wind Advisory criteria across western and
central North Dakota. Pressure rises behind the front appear to be
highest over northern North Dakota...but by afternoon the pressure
rises...h850 winds of 45 knots...and strong cold advection will
affect all of western and central North Dakota. Thus have added
counties to the Wind Advisory this afternoon and evening to include
the rest of the counties in south central North Dakota. Therefore
all of western and central North Dakota will be under a Wind
Advisory today.

Regarding snowfall...expect snow to develop from northwest to
southeast today behind the cold front. It appears that precipitation
- and the resulting snow accumulation - is a bit less than
previously thought according to the latest model runs. Expecting
around an inch of accumulation across the northern tier of
counties...with lesser amounts south. However...snow showers
combined with the strong winds should result in patchy/areas of
blowing snow today through this evening. Will address the blowing
snow in the wording of the Wind Advisory as previous shifts have

Winds should begin decreasing slowly from west to east
tonight...beginning in western North Dakota this evening...and
finally in the James Valley after midnight. Kept things simple with
the valid end time of the Wind Advisory at midnight tonight. Later
shifts can take western counties out of the advisory as conditions

Long term...(monday through saturday)
issued at 345 am CST sun Nov 23 2014

The main forecast highlight in the extended period will be
precipitation chances and the continued battle between cold air to
our north and mild Pacific air. In general...the battle will
continue through the extended period. Below normal temperatures seem
reasonable through the period...with brief moderations...which will
likely bring precipitation chances as the warmer air interacts with
the cold airmass...combined with occasional impulses moving through
a northwest upper flow. Deterministic models continue to go back and
forth between the varying solutions.

On Monday high pressure builds over the area as our short
term system exits to the east. Will keep a mention of patchy blowing
snow over the far east through around 15 UTC but precipitation
should be over. A weak wave moves across the area Monday night and
will keep a slight chance of light snow during the evening.

Tuesday...another shortwave traversing a western upper ridge drops
southeast across North Dakota. The GFS is the outlier here with a
weaker surface low tracking through southwest North Dakota. Most
deterministic models as well as the naefs ensemble track the low
farther to the north and the shortwave sharpens as it drops into a
mean eastern U.S. Upper trough. Have followed this solution which
resulted in increasing probability of precipitation significantly across the north through
east central Tuesday afternoon and evening. HPC westward depicts
generally 1-2 inches north of a line from Minot to Jamestown with
2-3 inches over our far northeast County Warning Area. This is similar to our snow
amounts utilizing HPC quantitative precipitation forecast with a blend of non-GFS quantitative precipitation forecast. Will add a
mention of this in the hazardous weather outlook. But with the
continued run to run model inconsistency...too early for any
highlights at this time. Will need to monitor as we could get a
brief shot of gusty winds behind the surface low if the stronger
non-GFS solution does verify.

As this system exits to the east..the 23 Nov 00 UTC GFS/ECMWF/Gem
are all showing a quasi-stationary frontal boundary developing
northwest to southeast from northern Montana through southwest
ND/western South Dakota beginning late Tuesday night into early
Wednesday. Aloft a strong jet streak will interact with the surface
boundary to produce a swath of accumulating snowfall under strong
thermal lift along to east of the front. This would result in some
accumulating snows over southwest North Dakota Wednesday and
Wednesday night...a busy travel day. Have raised probability of precipitation over the
southwest during this time period. Confidence is higher with this
scenario compared to previous runs...but we are getting too far out
to do much other than continue to highlight in the severe weather potential statement. And there is
still time for models to change solutions. It does look like the
impact from blowing snow would be minimal as winds are not too

Models do diverge after Wednesday night with the GFS bringing a
shortwave and associated surface low across the forecast area late
Thanksgiving day into Friday as Pacific flow briefly takes hold.
This would bring another round of snow across the area followed by
colder temperatures by Friday night into Saturday as cold high
pressure takes hold. The ec/Gem shunt this system well south as the
modified Arctic air drops south over the entire region earlier than
the GFS. This results in a rather cold but dry Thursday and Friday
with the colder temperatures likely lasting into the Holiday
weekend. Stay tuned as we head into a busy travel period.


Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1233 PM CST sun Nov 23 2014

Surface low tracking through northern Minnesota at 18z. Cold front
extends through southeast North Dakota. Snow will diminish from
west to east this afternoon and end tonight. MVFR conditions will
prevail this afternoon...then also diminish from west to east
tonight. VFR on Monday.


Bis watches/warnings/advisories...
Wind Advisory until midnight CST /11 PM MST/ tonight for



Update...warm air advection
short term...jv
long term...twh
aviation...warm air advection

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