Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 190255

Area Forecast Discussion
National Weather Service Bismarck ND
955 PM CDT THU AUG 18 2016

Issued at 955 PM CDT Thu Aug 18 2016

Overall, the going forecast is on track and supported by RAP and
HRRR simulations and the 00 UTC NAM. Radar trends through 0255 UTC
show the earlier band of showers shifting east across the southern
James River valley, as expected, and the next batch of rain moving
into northeastern MT. The latter precipitation is tied to stronger
QG-forcing with a more well-defined shortwave trough, and may be
arriving a bit faster than model expectations, but not enough for
us to make any significant alterations to the forecast at this

UPDATE Issued at 743 PM CDT Thu Aug 18 2016

Quick update to increase the chance of precipitation into the 60
to 80 percent range along and ahead of the band of eastward-moving
showers that extend from near Jamestown to Wishek and Strasburg as
of 0040 UTC. As mentioned previously, we expect these showers to
continue pushing southeast concurrent with jet-induced forcing as
the evening progresses.

UPDATE Issued at 608 PM CDT Thu Aug 18 2016

Neither the 18 UTC global models (NAM and GFS) or the more recent
rapid-refresh suite (RAP and HRRR) are capturing the showers that
are moving across far south central ND late this afternoon. Thus,
this update focused on refining the chance of precipitation based
on recent radar trends. That activity appears to be driven by the
vertical motion in the right entrance region of a broad 60-70 kt
300 MB jet streak, which is forecast to gradually shift southeast
through the evening, taking this batch of showers with it. We did
continue a slight chance of thunderstorms in the forecast along
with the showers in respect to mid-level lapse rates of 6-7 C/km,
but no lightning has been observed recently.


.SHORT TERM...(This evening through Friday)
Issued at 247 PM CDT Thu Aug 18 2016

At 3 pm CDT Thursday a cold front extended from northern Minnesota
southwest through eastern South Dakota and will continue moving
east. A large region of high pressure will build into Montana and
the Dakotas tonight. At h500MB a trough extended from near Hudson
Bay southwest into Montana.

This cold front has pushed the majority of the instability
southeast of the region so any thunderstorms will be widely
scattered to isolated this evening.

Later tonight and Friday a shortwave will move through the base
of the h500 trough in Montana and swing through southwest North
Dakota. This will generate broad lift but very limited cape.
Expect mainly showers with an isolated thunderstorm possible
southwest. Elsewhere mainly dry.

.LONG TERM...(Friday night through Thursday)
Issued at 247 PM CDT Thu Aug 18 2016

By Friday night the h500 trough will be moving east of the area
and Saturday and Sunday the region of high pressure will become
the dominant weather feature. This will bring dry but cool
weather Saturday then moderating temperatures Sunday. Some
residual showers may still remain over the James river valley
Saturday but otherwise it should be dry. Monday the flow aloft
will bring an h500 ridge across the northern plains resulting in
dry and mild weather. High temperatures Monday will be in the 80s
to around 90.

Tuesday through Thursday will see some unsettled weather again with
another major h500 trough moving through the northern plains. This
will drag a cold front into the region resulting in scattered
thunderstorms Tuesday and cooling temperatures again from the
warmer Monday highs. By Wednesday and Thursday highs will be back
into the 70s.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 955 PM CDT Thu Aug 18 2016

An area of showers and possibly weak thunderstorms will move into
western ND overnight and into the south central during the day on
Friday. MVFR ceilings will likely develop across the west late
tonight and Friday morning, where the rain will be heaviest, and
local IFR ceilings are not out of the question. There`s a chance
that the MVFR ceilings could extend as far east as KBIS by Friday.


.BIS Watches/Warnings/Advisories...


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