Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 290955
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
355 AM MDT FRI JUL 29 2016

.Discussion...Forecast today remains hot and dry. Saturday we have
competing effects of westerly winds across central and northern
Idaho and at the same time, moist monsoon associated unstable air
circulating into California and expected to turn back east, moving
into southeast Idaho during the afternoon and overnight hours.
Focus of afternoon thunderstorms Saturday will be in the Upper Snake
Highlands and South Central and Caribou Highlands. By Sunday
afternoon, the westerlies will push much of the monsoon moisture
quickly eastward. Winds will breezy Saturday over the Central
Mountains and snake Plain with more windy conditions expected on
Sunday. A new disturbance develops Monday and moves into the Pacific
Northwest, then across northern Idaho on Tuesday. Cold front comes
through on Tuesday with strong gusty winds again across the central
mountains and Snake Plain. Southwesterly winds aloft both days will
bring some of the monsoon moisture across the Caribou Highlands,
keeping potential for thunderstorms in the forecast both of those
days. Wednesday and Thursday should be mostly dry again. RS

&&

.AVIATION...VFR conditions persisting this forecast period. Winds
may reach 12 kts at Burley and Pocatello this evening otherwise less
than 12 kts for all sites. May see some scattered cloud cover this
afternoon at mid levels across the Snake Plain with clear skies
continuing at Sun Valley.
NP/RS
&&

.FIRE WEATHER...A weak surface low pressure area is currently sitting
near Pocatello early this morning with a trough extending toward
Salt Lake City, which is guiding wind directions across our area.
This trough is expected to shift eastward and into Wyoming by the
afternoon. Meanwhile, another hot dry day with some afternoon
breezes in the Snake Plain are forecast today. Gusts to 25 mph are
possible out of the southwest.  The primary headlines remain the
increase in monsoonal flow overnight and Saturday. Increasing cloud
cover, increased humidities and thunderstorm potentials all increase
on Saturday as a result. Saturday afternoon is when most shower and
thunderstorm is expected to begin, though it cannot be completely
ruled out that portions of zone 427 could see a stray thunderstorm
in the morning. Widely scattered to scattered dry thunderstorms are
forecast for the Central Mountains, portions of the Southern
Highlands (primarily zone 427), and across portions of zone 411 and
410 along the Divide. Therefore, the issuance of Fire Weather Watch
is in effect for zone 427 for Saturday afternoon and evening. At the
same time, wind gusts of 25 to 30 mph are expected without any
influence from thunderstorms with humidity values at or near 15%.

Showers and thunderstorms are expected to continue into the
overnight hours through Sunday with a general eastward progression
of activity during the day. In the afternoon and evening Sunday,
look for much increased winds for all zones with the exception of
427 and 413 with speeds of 20 to 28 mph and gusts of 25 to 35 mph
likely. Therefore, issuances of additional Fire Weather Watches or
Red Flag Warnings are possible based on these forecast weather
conditions and dry fuels. A new strong low pressure trough looks to
approach Idaho by Tuesday, resulting in another windy day. There may
be some monsoonal flow out ahead of this trough, however only one
forecast model is showing this solution at this time and confidence
in this is marginal at best.
NP/RS
&&

.PIH Watches/Warnings/Advisories...
Fire Weather Watch from Saturday afternoon through Saturday
evening for IDZ427.

&&

$$



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