Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 010044

Area Forecast Discussion
National Weather Service Bismarck ND
644 PM CST Tue Feb 28 2017

Issued at 620 PM CST Tue Feb 28 2017

Shortwave energy moving through central into eastern Montana with
an associated surface trough situated over southeast Montana and
northeast Wyoming. These will track east across the forecast area
tonight bringing a swath of light snow to the forecast area.
Currently, more convective looking showers were poised to move
into southwest ND. There is some weak cape with strong low and mid
level lapse rates into far southwest ND. However, shear is very
weak and lapse rates lessen quickly as you move east into ND. We
will add a mention of an isolated evening snow shower in the
southwest. Farther north and east across northwest into the north
central light reflectivities were increasing but have not seen any
recent observations with snow yet. Expect snow chances to
increase here this evening. The most likely area for any light
accumulations will be across the north.

For the early evening update we adjusted pops a bit as mentioned
above. Populated latest sensible weather elements and interpolated
to mid evening values. Did adjust the northeast a bit where Rugby
had already dropped to 3 above, which was already lower than the
forecast low. May drop a few more degrees this evening but expect
steady or rising temperatures with increasing clouds and snow
chances later this evening.


.SHORT TERM...(This evening through Wednesday)
Issued at 309 PM CST Tue Feb 28 2017

Current surface analysis places low over central and eastern
Montana with weak ridge over central and eastern North Dakota.
Upper level analysis places weak trough sliding through
central/eastern Montana with some light snow starting to develop.

For the rest of this afternoon into tonight...aforementioned
light snow over Montana will slide over the area from west to
east. Most snow should remain mainly over the northern 2/3rds of
the area with accumulations of possibly an inch or two.

On Wednesday...aforementioned snow will exit the area by mid-day,
though the next short wave will be right behind, pushing into far
western areas in the afternoon, into central areas in the evening.
Again, accumulations of an inch or two are possible, primarily
over central portions of the area.

.LONG TERM...(Thursday through Tuesday) Issued at 309 PM CST Tue
Feb 28 2017

Train of perpetual short waves continue into the area on Thursday,
with another wave sliding through Thursday night into early
Friday bringing snow chances. Changes do come to the area, though,
on Friday as a ridge starts building into the area bringing a
warming in temperatures. This will remain into the weekend, though
locations over north central North Dakota may not warm quite as much
where a denser snowpack remains. A few weak waves move through
during the weekend into early next week bringing an occasional
chance for rain or snow.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 620 PM CST Tue Feb 28 2017

An upper level trough and associated surface system will move west
to east across the forecast area tonight into Wednesday morning.
This will bring lowering ceilings to MVFR to occasionally IFR,
especially from KISN to KMOT and KJMS. Although an occasional
MVFR-IFR ceiling can not be ruled out at KBIS and KDIK. MVFR
visibilities in light snow are expected to impact mainly KISN and
KMOT tonight and spreading into KJMS Wednesday morning. Ceilings
will lift and winds will shift west-northwest from west to east
during the day Wednesday. Another system may bring another wind
shift and lowering ceilings already into KISN toward the end of
the TAF period.




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