Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 271526
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
926 AM MDT WED JUL 27 2016

.UPDATE...Shortwave along oregon coast expected to slide through
the Idaho panhandle this afternoon and evening. Lifting influence
moving into a small band of mid level moisture and increased
instability aloft. Most models indicating this region but differ
on either amount of moisture available or amount of instability
therefore have no consensus on development. Based on overwhelming
under performance on yesterdays models in similar conditions,
have spread convection a little further south off the divide
region for this afternoon and evening. Timing does appear to be
limited to later afternoon and evening hours associated with
timing of shortwave, which models do generally agree on. Believe
that loss of diurnal heating around sunset will lose tap into
instability aloft and shut off most of the potential by late
evening. DMH

&&

.PREV DISCUSSION... /issued 340 AM MDT WED JUL 27 2016/

Discussion...This morning there is a disturbance about 128W
approaching the WA/OR coast, which should cross north Idaho today.
Isolated thunderstorms look possible from about Howe to Spencer and
Island Park late afternoon and early evening. Prospects for
afternoon thunderstorms look less Thursday and Friday as high
pressure expands west across the Great Basin and into California.
The upper level flow becomes more northwesterly, displaces some
of the moist unstable air across the divide, but not far away. May
still have isolated thunderstorms as close a Yellowstone. By
Saturday, a new low pressure disturbance develops over British
Columbia. This increases southwesterly flow and potential for
monsoon moisture to move into southeastern Idaho. This would mean
nocturnal thunderstorms are also possible Saturday night. Current
models try to move this moist air and instability off to the east on
Sunday, but that probably will be to fast. Current forecast keeps
some thunderstorms over the South Central and Caribou Highlands
Sunday afternoon. Breezy winds expected Sunday and again on Tuesday
with a dry cold front coming through, except the Bear lake and
Caribou Highlands where isolated thunderstorms may develop Tuesday
afternoon. RS

AVIATION...VFR conditions at all sites the next 24 hours
with favorable winds and skies. NP/RS

FIRE WEATHER...Possibility of thunderstorms along the Idaho/Montana
border this afternoon and evening otherwise should be clear of
activity for today. Winds may gust to 20 mph or so across the
Central Mountain and Arco Desert locations. Much of a similar trend
is forecast for Thursday with even less opportunity for
thunderstorms.  Late Friday and over the weekend a rather nice surge
in monsoonal flow is expected across southern Idaho. Therefore,
expect humidities to increase. At the same time, this increases the
chance for thunderstorms. The other concern for this weekend will be
increasing winds and wind gusts. At this time it all but certain
winds will gust in excess of 25 mph across most of our region on
Sunday. Saturday is quite likely to gust this high as well across
the Central Mountain locations. We will be on the look out for Red
Flag conditions on both of these days.

On Monday, some uncertainly begins in the forecast models. There
seems to be a consensus in the progression of a deeper trough of low
pressure, however the timing of when it passes through differs
between which model you look at. The Canadian Model pushes it
through first, followed by the European model and surprisingly the
GFS is the last one. All have a few showers and/or thunderstorms
associated with it but nothing significant especially compared to
the weekend.
NP/RS

&&

.PIH Watches/Warnings/Advisories...
None.
&&

$$



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