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Area forecast discussion 
National Weather Service Bismarck ND
343 am CDT Friday Aug 22 2014

Short term...(today and tonight)
issued at 343 am CDT Friday Aug 22 2014

The main impact over the short term is fog...and heavy rainfall
returning to the region Friday night.

Ongoing showers and thunderstorms associated with a weak upper
level shortwave will continue to push east and dissipate later
this morning. Portions of southwestern North Dakota received
1 to 2 inches of rain...according to radar estimates...with these
early morning showers.

As the upper level wave exits the region we should see a brief
respite from the rain this afternoon. However...thick cloud cover
and fog will remain. With a very moist boundary layer...fog may
become widespread by the late morning hours. Additionally due to
fog and cloud cover temperatures will struggle to rebound into
the low 70s today. Another upper level shortwave trough and a
potent surface low will begin to influence southern and western
portions of North Dakota late Friday into early Saturday.
According to the latest guidance (00 UTC GFS/NAM/ecmwf) the
heaviest and most widespread rain will impact North Dakota
Saturday into Sunday. This is the time period of most concern with
respect to flooding.

Long term...(saturday through thursday)
issued at 343 am CDT Friday Aug 22 2014

The medium range models continue to forecast a wet and cool weekend
for western and central North Dakota. A drying/warming trend is
then forecast to develop next week.

A broad upper trough is prognosticated to enter the northern rockies
Saturday. Thunderstorms are forecast to develop ahead of the
trough over western and central North Dakota. The highest probability of precipitation and
quantitative precipitation forecast amounts are forecast over western North Dakota...proximate to
the greatest upper level forcing. Thunderstorms should remain
below severe limits. However...heavy rain will continue to be the
primary threat.

As the upper trough rotates north across eastern Montana/western
North Dakota Saturday night and Sunday...the highest precipitation
chances/amounts will remain over western North Dakota. Heavy rain
will continue to be the primary threat through Sunday. At this
time...the model consensus is for the overall highest totals to be
over the western half of the state with 1-2.5 inches possible. The
hit-and-miss character of warm-season thunderstorms will likely
result in some areas receiving higher amounts...while other
locales will likely receive less than the anticipated area-wide
average. Overland flooding will be likely in those areas that
receive more than an inch or two of rain.

By Sunday night...the upper low/trough is prognosticated to lift into
Canada with some dry slotting forecast over North Dakota. Quasi-
zonal flow aloft is then prognosticated to develop through the first half
of next week with low chances for showers each day.

The medium range models are advertising an upper level ridge over
The Rockies to transition into the northern plains towards the end
of the period. Mainly dry conditions are forecast with highs in
the 80s by the end of next week.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1217 am CDT Friday Aug 22 2014

Widespread showers and thunderstorms continue to push east and
will enter the kbis/kisn terminals within the next 2 hours. The
main threats to aviation are thunderstorms and MVFR to IFR
conditions associated with the precipitation and areas of fog. VFR
conditions will gradually deteriorate to MVFR by early morning
across the west impacting kisn-kdik-kmot-kbis. VFR expected at
kjms until some fog sets in with at least MVFR conditions late
tonight through middle morning Friday.


Bis watches/warnings/advisories...



Short term...aj

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