Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 230932

Area Forecast Discussion
National Weather Service Bismarck ND
332 AM CST Fri Feb 23 2018

.SHORT TERM...(Today and tonight)
Issued at 236 AM CST Fri Feb 23 2018

Main forecast problem in the short term period will be snow
exiting the southeast CWA and possible cloud/aviation issues
across the north.

Currently, surface low pressure is situated over southern
Minnesota with an inverted trough extending into south central ND.
Light snow continues to dissipate over the south central into the
James River Valley. An interesting note was a local enhancement in
reflectivities on the back edge of the precipitation shield. Rap
analysis shows weak trowal within the deformation zone and some
hints of conditional instability, lending to the enhanced
reflectivities. Latest reflectivities continue to show some local
enhancement on the very back edge of the precipitation shield, but
with no real impacts. This area is expected to dissipate/move
out of the area by mid morning.

To the north, stratus continues to sink south from Saskatchewan
into northwest ND and appears destined to move into KISN shortly
with MVFR ceilings. Latest iterations of mesoscale models bring
the lower stratus mainly east of KISN and into KMOT this morning.
However, latest satellite is showing the leading edge drying up as
it approaches KMOT. Will likely be a last minute decision for 12Z
Aviation forecast as how to handle the stratus at KMOT and KISN.

Otherwise pretty quiet today with temperatures similar to

High pressure tracks across the forecast area tonight and moves
into the northern Great Lakes region by early Saturday morning. We
utilized a blend of Bias Corrected raw model guidance for
forecast lows tonight which was cooler than our given guidance.
This seems reasonable and it has been performing well recently.

.LONG TERM...(Saturday through Thursday)
Issued at 236 AM CST Fri Feb 23 2018

Main forecast issue in the long term period will be precipitation
chances on Saturday.

Overall, an active weather pattern in the long term period across
the continental U.S. but the northern plains region looks to be
among the quieter areas during this period.

Another wave moves from the southern Rockies into the southern and
central plains on Saturday, bringing widespread precipitation the
plains into the Upper Midwest and Great Lakes region. We will be
on the northern fringe of the precipitation shield on Saturday
with light snow spreading from South Dakota Saturday morning into
Minnesota by Saturday evening. glancing the south central into
eastern North dakota with light snow. Snowfall amounts are
expected to be an inch or less over the south central into the
James River Valley with the exception of possibly a little more
than an inch over eastern Dickey and Lamoure counties. The west
and north central will remain dry.

Upper level energy tracking along the international border will
keep a small chance of snow showers Sunday and Monday and
possibly into the middle of next week, but the energy tracking
across the northern plains will be weak as the main storm track
remains well to our south. Temperatures through the period are
expected to be seasonable with highs mainly in the 20s to lower
30s and lows in the single digits to teens.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 236 AM CST Fri Feb 23 2018

MVFR to IFR conditions in light snow from south central ND into
the James River valley will gradually end before 12 UTC, allowing
conditions to become VFR at the KJMS terminal. Elsewhere, an area
of low clouds with MVFR ceilings is moving slowly southeast out of
Saskatchewan and simple extrapolation and a consensus of rapid-
refresh model guidance suggests they will move into north central
and parts of northwest ND by 12 UTC. Confidence is high that KMOT
will thus experience MVFR conditions Friday morning, but was too
low to include a predominant ceiling in the KISN TAF with the 06
UTC forecast release. Finally, VFR conditions will prevail across
southwest ND through Friday under the influence of high pressure.




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