Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 272012

Area Forecast Discussion
National Weather Service Pocatello ID
212 PM MDT WED JUL 27 2016

.DISCUSSION...Persistent pattern continues with ridging to south
of SE Idaho and daily shortwave axis rolling through or just north
of forecast area. Starting to see evidence of weak convective
development along Montana border on satellite imagery this
afternoon. This activity ahead of shortwave axis moving through
Oregon, and in region of weak mid level moisture and instability
aloft. Have left weak precip chances in northeast corner of state
this afternoon and evening but expect little precipitation and
mainly isolated coverage. Similar but weaker feature occurs on
Thursday and Friday in same region and have left forecast dry at
this time. Meanwhile moisture showing signs of being pulled north
through California around high centered over Great Basin. NAM and
to lesser extent GFS favorable for some of this moisture nearing
southern Idaho borders by late Friday. This is faster than
previously targeted by models but not a complete surprise given
model tendency to underestimate speed of monsoonal surge north
through the Great Basin. Saturday looking to be a better chance
many areas as both GFS and NAM have pulled moisture north through
entire forecast area ahead of strengthening low in BC Canada and
increasing southwest flow over Idaho. Shortwave pushes through
base of trough Saturday night into Sunday with associated cold
front passage. At this point it appears that convection will
continue into Sunday but winds could become an additional concern
especially for fire-related activities. See discussion below for
further information. Otherwise upper trough shifts east Sunday
night with brief ridging Monday. Second Pacific trough follows
Tuesday and Tuesday night for similar convective threat and the
chance for breezier conditions into Wednesday. Temperatures
through most of the forecast period remain above normal, but the
cold front early next week could be enough to knock afternoon
highs down a few degrees toward climo. DMH


.AVIATION...Another wave/trough...slightly weaker than moving through this afternoon bringing slightly
breezy winds and will bring isolated thunderstorms for the far
Eastern Central Mountains and Island park region late this afternoon
into early evening. Do not expect any thunderstorms at TAF
sites...just a very slight increase in winds in the afternoon
continuing into the early evening. Wyatt


.FIRE WEATHER...Another wave/trough...slightly weaker than yesterday moving through this afternoon bringing slightly breezy winds
near 20 mph particularly in the Central mountains. Also expect
isolated thunderstorms with a few areas along eastern ridge lines
having widely scattered thunderstorms for the far Eastern Central
Mountains late this afternoon into the early evening. Look for
isolated thunderstorms for the Island Park region.

Expect dry...mostly West Northwesterly...flow Thursday and Friday.
Winds will become breezy again particularly Friday but look to
remain just below Red Flag criteria.

Highlights will likely be needed Saturday and Sunday...particularly
after a prolong dry winds and thunderstorms look to
impact the area.  Saturday look for Southwest flow ahead of a
moderate to strong Pacific trough. Winds will be near red flag
criteria particularly in the Central Mountains on Saturday. In
Southwest flow...models are still continuing to show monsoon
moisture make it into our area bringing isolated to scattered
showers and thunderstorms particularly for our Southern and Eastern
areas late Saturday afternoon through the evening. Models are
showing moderate to strong winds as well on Sunday as the trough
moves over Northern Idaho.

On Monday...models continue to show different timing and intensity
with the next system coming through either late Monday or late
Tuesday depending on which model. Models show moderate winds likely
needing a highlight with this system but differ in the amount of
thunderstorms...though it will be less thunderstorm coverage than
the weekend. Wyatt


.PIH Watches/Warnings/Advisories...

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