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Area forecast discussion 
National Weather Service Bismarck ND
638 am CDT Thursday Sep 18 2014

Update...
issued at 631 am CDT Thursday Sep 18 2014

Have expanded patchy fog to the north and west with obbs starting
to come in along the northern border showing additional fog
development. Otherwise...going forecast is in good shape.

Update issued at 518 am CDT Thursday Sep 18 2014

Have updated for patchy dense fog forming in the James River
Valley and patches of stratus forming in the Bowbells to Mohall
areas. Otherwise...no changes.

&&

Short term...(today and tonight)
issued at 310 am CDT Thursday Sep 18 2014

An isolated rain shower was showing up southwest of Williston
early this Thursday morning...and another west of Bowman. Movement
was east into more stable and drier air. Will expect dissipation
of those over the next few hours.

Otherwise...warm air advection today as a trough at the surface
pushes to the Montana and North Dakota border by afternoon. The
tightening pressure gradient results in 15 to 25 miles per hour of wind
today...and increasingly moist air acts to destabilize the
atmosphere this afternoon. In addition...models show a weak middle
level wave riding through the mean 500 mb ridge. Together these mean
the chance that isolated thunderstorms could develop west in the
afternoon.

As the trough moves across the forecast area tonight a more potent
500 mb wave flattens the ridge and increases the coverage of storms
from isolated to scattered with higher probability of precipitation.

Temperatures will be warm today with most places ending up within
a few degrees of 80...the exception will be the far east where 75
will about do it ahead of the warm advection.

Long term...(friday through wednesday)
issued at 310 am CDT Thursday Sep 18 2014

Unsettled westerly flow remains over the area on Friday as a couple
of weak short waves push through...bringing continued low
precipitation chances. Upper ridge over the Pacific slides onshore
Saturday shifting flow northwesterly over our area...though the next
short wave slides down the ridge bringing continued low
precipitation chances mainly to northern and eastern North Dakota
while breezy northwest winds develop across the State. Ridge then
amplifies and slowly moves towards the east to start the week
bringing dry conditions and mild temperatures. Towards
mid-week...some medium-range models are suggesting a more unsettled
pattern developing as a low lifts towards the region. Will keep
forecast mainly dry for now...but will keep an eye on this and may
have to add some precipitation on subsequent forecasts if models are
persistent with this solution.

&&

Aviation...(for the 12z tafs through 12z Friday morning)
issued at 631 am CDT Thursday Sep 18 2014

Patchy fog resulting in local IFR visible over portions of
northern...central...and eastern North Dakota will diminish by middle-
morning. Later this afternoon....isold -tsra/-shra will be
possible over far western North Dakota...spreading east into the
evening. With low coverage expected will refrain from mentioning
in terminal forecasts at this time. Otherwise...VFR conditions are
expected.

&&

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

$$

Update...jjs
short term...jpm
long term...jjs
aviation...jjs

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