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Area forecast discussion
National Weather Service Pocatello Idaho
322 am MDT Mon Aug 21 2017

Short through Thursday. A minor upper trof in the
northern stream flow will pass thru Idaho this morning. The only
impact will be the band of high clouds associated with the trof.
The high clouds are expected to be south of the eclipse path by
mid morning. Another potential eclipse impact is smoke from
wildfires. The greatest threat will be in the central mtns where
smoke may remain trapped in valleys until mid to late morning.
Elsewhere...smoke may leave the sky somewhat hazy. Monsoon
moisture is expected to creep across the border from Utah late
Tue...resulting in isolated tstms near the border by evening. On
Wed...the upper ridge axis is displaced to the east as a deep
upper low approaches the pac northwest coast. This establishes stronger
southwest flow aloft and a pathway for monsoon moisture into the
fcst area. Tstms are expected to spread across the area Wed
afternoon and evening. Tstms continue into Thu eve when a cold
front sweeps thru the area.

Long term...Friday through Monday. A weak Post frontal trof is
expected to set off isolated tstms over the southern Highlands on
Fri. Upper ridging builds up over the west through the weekend
resulting in warm and dry conditions. Hedges


Aviation...a weak upper trof moving thru the area this morning
will bring high clds and not much else. Smoke from area wildfires
may result in hazy conditions...but VFR expected to prevail.


Fire weather...expect slightly breezy winds in northwest flow for
the majority of our area as high pressure starts to build into the
area. Our southeast area, mainly zone 413, will have breezy to
moderate gusts of 20 to 25 mph in the afternoon from a lingering
boundary. Relative humidity will remain critical mostly below 15
percent Monday and Tuesday. Relative humidity will rise
significantly Wednesday through the remainder of the week as
moisture make its way into our area in southwest flow. Isolated
thunderstorms and showers will start Tuesday evening near the Utah
border and gradually spread north. Look for scattered thunderstorm
and showers Wednesday and Thursday and to a lesser extent Friday as
a low pressure system moves through the area. The gacc continues to
highlight southeast Idaho for high risk for lightning on Wednesday.
This system also elevates winds across the area mainly on Thursday
and Friday. Wyatt


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