Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 152006
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
306 PM CDT Sun Apr 15 2018

.SHORT TERM...(This evening through Monday)
Issued at 214 PM CDT Sun Apr 15 2018

Quiet weather continues in the short term period.

Another cold start to the day on Monday with lows mainly in the
teens over central and eastern North Dakota, some upper single
digits are not out of the question between Bismarck and Jamestown
and northward toward Garrison and Rugby where more snow remains.

A little warmer most areas on Monday. However, it will be windy
Monday afternoon over western ND. Bufkit soundings and NAM/GFS
boundary layer winds and lapse rates indicate the potential for
Advisory criteria winds in the west. Will not issue anything now
and give the overnight shift a chance to see if this trend
continues. We did utilize the MOS based model blend for winds on
MOnday which were more representative than our given blend.

.LONG TERM...(Monday night through Sunday)
Issued at 214 PM CDT Sun Apr 15 2018

Strong winds in the west Monday spread into central ND Monday
night in response to developing low pressure over the northern
high plains ahead of a splitting upper level trough. We bumped up
winds Monday night and Tuesday. Tuesday winds are not as strong
though as the pressure gradient weakens as the main surface low
becomes established over the central plains.

Over the northern plains, an inverted surface trough remains over
western ND on Tuesday, moves slowly into central ND Tuesday night
and weakens on Wednesday as the surface low pulls away and upper
support is sheared between a northern stream trough and the main
upper low that joins up with the surface low over the upper
midwest. The combination of the low level convergence associated
with the inverted trough and mid and upper level forcing from the
splitting upper level trough will produce an are of light
precipitation that tracks slowly across western and central ND
late Monday night through Wednesday.

Model consensus is low with this feature. The NAM/GFS are faster
and wetter than the ECMWF/GEM with the QPF pattern as it tracks
across the forecast area. The main problem with that is our
blended solution for ProbIce grids is a mess, and when combined
with 6 hour Pop/QPF grids, overdoes the threat of freezing rain.
Forecast soundings from across the CWA do show a small potential
for freezing precip, if any precip would reach the ground, on the
leading edge of the precip. And another very small potential on
the back side of the system. Will keep a mention of freezing
precip but will downplay it for now.

After this system exits, expect mainly dry conditions with a slow
warming trend through Sunday

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 214 PM CDT Sun Apr 15 2018

VFR conditions are expected through the 18Z TAF period. Strong
southeast winds develop over far western North Dakota Monday
afternoon. Winds aloft are nearly unidirectional compared to the
surface winds. Surface winds don`t drop off either in the far west
so LLWS is just barely reaching 30 knots for just a short period
around 12 UTC Monday. Will mention this to the evening shift but
will not include in the KISN TAF at this time.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...TWH
LONG TERM...TWH
AVIATION...TWH



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