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Area forecast discussion 
National Weather Service Grand Forks ND
1132 am CST Thursday Dec 18 2014

Update...
issued at 959 am CST Thursday Dec 18 2014

Cloud trends the main issue today. Area of middle clouds and then
lower MVFR clouds advancing northeast east of the upper trough
over western ND. This will continue to spread east into this afternoon.
Also got a fast moving area of lower stratocu moving north-
northwest from Wisconsin into NE-ecntrl Minnesota and its headed toward
our eastern counties so increased cloud cover there. Also quite a
bit of flurries in this cloud area...so matched up with weather forecast office dlh
and included flurries this afternoon in the far eastern forecast area. Kept
flurries in far west but havent seen any signs of precipitation in central
ND.

&&

Short term...(today through friday)
issued at 314 am CST Thursday Dec 18 2014

Main issue today will be clouds moving into the west and if we get
any snow of mention or just flurries.

A weak upper shortwave trough is seen on WV loop rotating over the
Montana/ND border...and that feature will move into the eastern Dakotas
today. This will help bring some fairly weak synoptic lift into the
region. The surface high will move off to the east...allowing south
winds and more moisture to move back into the area. There has been
a decent band of snow over central ND...which matches pretty well
where the rap has some q vector convergence coinciding with
frontogenesis. The rap has this feature weakening significantly as
it moves east into our County Warning Area later this morning...so think a well
defined band of snow is not too likely. However...some very light
snow is not out of the question. Included some low probability of precipitation in the far
west with some flurries gradually moving towards the Red River as
clouds continue to increase throughout the day in the western
counties. Temperatures today should be a bit warmer even with clouds as
temperatures under the clouds are already close to 20 degrees out west.
Will continue to keep highs in the upper teens to 20s.

Tonight...the weak upper trough continues over the northern
plains...with warm air advection continuing throughout the night.
Clouds will continue to move into the area and that along with the
south winds will prevent temperatures from bottoming out tonight. Temperatures
should stay mainly in the teens. The warm air advection will
continue into Friday...allowing temperatures to get well into the 20s to
near 30 in the south. Models continue to show some very light
precipitation as isentropic lift continues and condensation pressure
deficits become more favorable...mainly in the northeastern
counties. Will continue to keep 20 probability of precipitation going for light snow...but
think that any accumulation will be very light.

Long term...(friday night through wednesday)
issued at 314 am CST Thursday Dec 18 2014

Friday night through Saturday night...the weak upper trough
lingers over northern Minnesota...and the next shortwave trough begins to
approach from the west. South winds will continue and moisture
should be increasing. There continue to be some signs of precipitation
moving in with that second shortwave late Saturday into Saturday
night. There is a lot of variation from the NAM showing up to a
tenth of an inch to the European model (ecmwf) having hardly anything...so kept
probability of precipitation low for now. The sref shows some freezing rain probabilities for
Saturday night...but the top down method gives mostly snow in the
north where probability of precipitation are located with the warm layer aloft staying
mostly in our south where currently we are going dry. Will keep a
close eye on the situation. Temperatures will be above average with highs
pushing 30 degrees and lows staying in the teens to even low 20s.

For Sunday through Wednesday...upper pattern shifts a bit becoming
more of a northwest flow regime with the ridge axis over the intermountain
west. However...the main jet energy is expected to remain west and
south of the area. A few waves pushing across the area will bring
chances for light precipitation...while temperatures continue to remain near
or slightly above normal.

&&

Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1112 am CST Thursday Dec 18 2014

As high pressure drifts east...the area will see light S to southeast
winds continue through the next 24 hours. Based on the latest
trends and model data...lower MVFR to IFR ceilings will be increasing
over much of the area over the next 6-12 hours. The NAM MOS data
support ceilings below 1000 feet...with NAM bufr soundings saturated in
the low leves as well. Some ceilings may dip below 500 feet by late
tomorrow morning according to the NAM MOS. Have not included ceilings
this low yet...but will need to monitor trends and model data to
see if the likelihood increases.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

Update...Riddle
short term...Jr
long term...Jr/Hopkins
aviation...knutsvig

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