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Area forecast discussion 
National Weather Service Pocatello Idaho
200 PM MDT Sat Jul 26 2014

Short term...tonight through Sunday. An east-west oriented upper
ridge was observed on satellite imagery across the southern tier states
this afternoon as a well defined sub-tropical vortex was rotating
west across Baja California. The models remain fairly consistent with the idea
that high-level sub-tropical moisture will begin to work around the
western periphery of the high tonight and into southern Idaho Sunday
resulting in a slight chance of late afternoon/evening convection across
the southern Highlands and central mountains.

Long term...Sunday night through next Saturday. The upper ridge
becomes more southeast-northwest oriented by Monday drawing the Baja California vortex
northward across Nevada and into southern Idaho Tuesday as it curves
slowly east into Wyoming Wednesday. A very moist airmass will
accompany the sub-tropical vortex into the region Tuesday/Wednesday
driving precipitable water amounts well above an inch resulting in
the potential for flash floods with any of the stronger convective
cells that may develop over the region. Both the GFS and European model (ecmwf)
continue the monsoon flow over the region clear into the weekend.
However...the models are still a bit hazy on the details and/or
timing concerning any additional waves that may lift north into the
region. Thus have painted a fairly uniform chance/slight chance
mention of thunderstorms across southern Idaho throughout the remainder
of the week until we can sort out the details. Huston

Aviation...high pressure and monsoon moisture move back into
eastern Idaho in the next 24 hours. We will see an increase in
higher clouds tomorrow. We should see isolated mountain storms
developing...mainly in the southern ranges. For now...we will not
include thunderstorms in the vicinity for any taf sites but it's possible they could get
close enough to kbyi to be an issue in the afternoon. Keyes

Fire weather...monsoon moisture will keep creeping into eastern
Idaho tomorrow and will become entrenched over the region throughout
the week as high pressure also builds in. This means storms will be
slow moving with an increasing potential for wetting rains and
eventually heavy rain later in the week. We are looking for isolated
storms tomorrow mainly in the mountains south of Burley and toward
Jackpot. We also cannot rule out a stray storm in the central
mountains or in the mountains toward Malad and Bear Lake. Expect
nothing more than sprinkles...but strong winds are possible. There
will be a little better chance area-wide Monday...but still only
isolated to widely scattered. Tuesday through Wednesday right now
looks the be the big days for showers. The main issue will be how
much instability will be present which will determine the extent of
thunderstorm coverage. Right may be a situation where we
have rain showers around but only isolated/widely scattered storms.
Right now...that's what we are forecasting but we are not 100
percent confident in that idea. It we get more cloud breaks...we are
looking at an active 2 day period with plenty of thunderstorms and
very heavy rainfall. Keyes

Pih watches/warnings/advisories...none.


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