Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 221607

Area Forecast Discussion
National Weather Service Bismarck ND
1007 AM CST Wed Feb 22 2017

Issued at 1001 AM CST Wed Feb 22 2017

Only minor changes to the going forecast. Mainly adjusting pops
based on latest radars. We increased pops across the south through
this morning as from reports and webcams, light snow does extend
back through most of the southwest. We also extended the mention
of thunder east across Dickey and Lamoure counties for a couple
hours this morning as lightning continues to be detected along the
South Dakota border, currently moving out of Mcintosh and into
Dickey county. We also adjusted temperatures utilizing a blend of
short term models. May see a few hours of temperature rise across
the far south, then steady or slowly falling temperatures
thereafter. This resulted in highs a bit lower than previously
forecast across the south.

UPDATE Issued at 650 AM CST Wed Feb 22 2017

Overall the going forecast is on track, but we did lower forecast
additional snowfall accumulations in north central ND to one-half
inch or less as recent trends in radar imagery and HRRR/RAP runs
suggest precipitation will remain focused from western into south
central ND the rest of the morning. It`s in that area where ascent
tied to a mid-level shortwave trough is strongest. Low-level cold
air advection is pushing a rain-snow line steadily southeast, and
dual-pol data from the KBIS WSR-88D and web camera images suggest
the transition to snow is approaching Bismarck. Finally, steep
mid-level lapse rates near 7.5 C/km in the 700-500 mb layer over
far south central ND have contributed to weak upright instability
and a few lightning strikes in Sioux County, so we have chosen to
add a slight chance of thunderstorms from Fort Yates to Linton and
Ashley for a few hours this morning.


.SHORT TERM...(Today and tonight)

Issued at 415 AM CST Wed Feb 22 2017

Forecast highlights in the short term period will focus on
ongoing precipitation amounts and type.

Currently, embedded S/WV impulses moving through the Northern
Plains continue to generate precipitation and extensive cloudiness
over western and central North Dakota. Forcing is being enhanced
with upper level divergence in the left exit region of an upper
level jet along with a surface cold front dropping south across
the state. Precipitation is now all snow north behind the boundary
with rain south. Surface air temperatures and road surface
temperatures across the south are right around freezing so will
continue to mention a window of freezing rain and/or sleet this
morning. Snow accumulations of 1-2 inches still forecast
northwest and north central, centered along Highway 2. Possible a
3 inch total may pop up but overall expect less.

Will maintain likely to categorical POPs through the early
afternoon hours, tapering off from north to south with time as
main forcing mechanisms push southward. Expect precip type to
transition to all snow as the cold front moves through the state
and temps aloft cool to below freezing. Temperatures today will
pretty much be where they are at now, or steady to slightly
dropping, with observations upstream in southern Canada still
showing upper 20s to low 30s (similar as we are observing this

Clouds remain tonight with partial clearing north possible. This
will result in lows mainly in the 20s despite the CAA. Mainly dry
though some light snow or flurries may be lingering about.

.LONG TERM...(Thursday through Tuesday)

Issued at 415 AM CST Wed Feb 22 2017

Cooler temperatures and mainly dry conditions highlight the long
term period.

Colder air continues southward through the remainder of the week
and upcoming weekend as the upper level jet sags southward into
the southern CONUS. Forecast high temperatures will be seasonal in
the 20s to low 30s by Friday and remaining so through next
weekend. Main storm track will also be to our south with the upper
level jet. Models do indicate a few embedded waves that may move
through the Northern Plains, though QPF will be light and
precipitation type should remain all snow.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1001 AM CST Wed Feb 22 2017

Widespread IFR and LIFR ceilings with light rain and snow will
continue across western and central ND this morning.
Precipitation will decrease from north to south during the
afternoon. Ceilings are accordingly forecast to rise back to the
MVFR range across all of the west and central by tonight.




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