Area Forecast Discussion
Issued by NWS Pocatello, ID

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226
FXUS65 KPIH 220911
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
311 AM MDT SUN MAY 22 2016

.SHORT TERM...Today through Tuesday Night. Pesky upper level low
pressure area that has been responsible for our recent cool and
unsettled weather will track into southern Alberta by this
afternoon, placing the region within broad southwest flow. As
such, have hoisted a Lake Wind Advisory for the American Falls
Reservoir. This is somewhat of a low-end advisory as winds
struggle to meet the 15 mph threshold. Nonetheless, winds will be
strong enough to create chop which will impact small crafts. Despite
the fact the low is pulling away from the area, a combination of
factors including favorable upslope flow across the Eastern
Highlands, adequate low-level atmospheric moisture, a weak
disturbance and daytime heating will once again induce showers
and isolated thunderstorms. Showers and isolated thunderstorms
will be most numerous over Highland areas, with the least coverage
over the Snake Plain. Thunderstorms today will once again have the
potential to produce small hail and strong wind gusts, and will be
most prominent during the afternoon and early evening.
Temperatures will be cold enough for patchy frost in valley
locations Monday morning, but think the combination of moist
soils, lack of calm winds and a few clouds should prevent
widespread frost.

Monday`s sensible weather highlights will be vary similar to
today`s, with showers and isolated thunderstorms most numerous
during the afternoon and early evening, and most prominent over
Highland areas with precipitation coverage more limited across
the Snake Plain. Precipitation coverage may be a bit enhanced when
compared to Sunday given a boost in forcing aided by a stronger
disturbance. Breezy afternoon and early evening winds are
anticipated as well, strongest over the Snake Plain, albeit a bit
less breezy than expected for Sunday. The theme of continued
unsettled weather continues into Tuesday as a secondary upper
level circulation meanders south along the CA coast. Showers and
isolated thunderstorms are again expected, most numerous in the
afternoon and early evening. Activity may be a bit more widespread
than what is expected for Monday. Temperatures will warm a couple
of degrees both days, mitigating any continued frost threat, but
will remain below normal. AD/Hedges

.LONG TERM...Wednesday through Sunday night. The Pac NW will
continue to be dominated by upper trofs/lows thru the weekend. Both
GFS and ECMWF in agreement. Some difference in the positioning of
the deep upper low expected to move into the Pac NW on Fri...but the
result will be the same. Scattered showers/isolated tstms during the
aftn/eve over the mtns...and somewhat lesser coverage in the
valleys. Overall coverage will decrease overnight through morning.
Some hope for the Memorial Day weekend is with the upper low
settling more south...precip chances are a little lower Sat and Sun.
Temps will remain on the cool side. Hedges


&&

.AVIATION...The large upper low over the Pac NW today will result in
showers/tstms again...but mainly over the mtns. Activity in the
Snake River Plain/eastern Magic Valley will be more isold. VFR
conditions expected to prevail. SW winds will pick up this aftn.
Hedges


&&

.PIH Watches/Warnings/Advisories...
Lake Wind Advisory from noon today to 6 PM MDT this evening for
IDZ021.

&&

$$



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