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Area forecast discussion 
National Weather Service Bismarck ND
1009 am CDT Friday Aug 22 2014

Update...
issued at 1009 am CDT Friday Aug 22 2014

Showers earlier over southwest and south central North Dakota
continue to dissipate as they track east across the James River
Valley and Devils Lake basin. Isolated showers also continue over
central North Dakota. In general...have lowered probability of precipitation to slight
chance to chance through the remainder of the morning and
afternoon...and also limited thunder chances to isolated. Bumped
up sky cover across the area this morning.

Update issued at 628 am CDT Friday Aug 22 2014

An area of light rain showers will continue to drift east across
southern North Dakota this morning. Areas of fog will develop in
its wake this morning...then will dissipate by the middle to late
morning hours. The current forecast is on track with no major
updates required. The freshened up products have been sent.

&&

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 18z tafs through 18z Saturday afternoon)
issued at 1009 am CDT Friday Aug 22 2014

MVFR to LIFR conditions associated with precipitation and areas of
fog will continue to develop over western and central North Dakota
this morning. A slow improvement to VFR is expected through the
day. Thunderstorms chances will then increase across the southwest
after midnight tonight.

&&

Bis watches/warnings/advisories...
none.
&&

$$

Update...twh
short term...aj
long term...tm
aviation...twh

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