Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 171544 AAA

Area Forecast Discussion...UPDATED
National Weather Service Pocatello ID
944 AM MDT SUN JUL 17 2016

.UPDATE...We made a quick update to add isolated showers across
the southeast corner. While it appears this is mid level clouds
and virga, we can`t rule out a few actual rain showers. Otherwise,
it still looks like that area and the central mountains will see
showers and a few storms this afternoon and evening. We are still
concerned that the air may be too dry for things to fire in the
central mountains, based on upstream soundings. For now though we
will keep the forecast as is.  Keyes


.PREV DISCUSSION... /issued 300 AM MDT SUN JUL 17 2016/

SHORT TERM...Today through Tuesday. Broad southwesterly flow
remains in place across the region as a closed low begins to take
shape just off of the WA/OR coast while a strong area of high
pressure builds across the southern CONUS. A weak disturbance is
noted near west-central NV this morning and this will track
northeastward across SE Idaho late this afternoon and evening.
As a result, convective-allowing guidance suggests isolated
showers and thunderstorms will develop this afternoon and continue
this evening, with the primary focus over the Southeast Highlands
and to a lesser extent the areas bordering the Lemhi region. Due
to a lack of moisture, think this guidance is overdone in its
depiction of shower and thunderstorm development today.
Nevertheless, think there will be just enough moisture, forcing
and instability for an isolated shower or storm, and the going
forecast will maintain this mention across the above-outlined areas.
On Monday, a jet max and associated disturbance will track across
the area, and this will bring an expanse of stronger winds for
Monday afternoon and evening. These winds combined with low
relative humidity values has necessitated a Fire Weather Watch for
Monday afternoon and early evening for the SE corder of SE Idaho
and the upper Snake Plain/Highlands. An isolated shower or
thunderstorm is possible across the Bear Lake area Monday
afternoon and evening as well. Currently anticipating dry
conditions Tuesday. Temperatures will range a couple of degrees
above seasonal normals Sun-Tue.

LONG TERM...Tuesday night through Sunday. Latest indications are
that the closed low over the WA/OR coast will shear northeastward
into southern BC/Alberta Thursday and across Montana Friday. As
a result, a trough/dry cold front is now forecast to sweep across
the region on Thu, bringing a resulting increase in winds. Will
have to watch Thu for the potential for critical fire conditions.
With the closed low shearing eastward, the previously advertised
monsoonal moisture plume is effectively shunted eastward across
Wyoming, so have continued the trend of reducing shower and
thunderstorm potential mid-late week. A new trend includes the
introduction of an eastward propagating trough/closed low across
OR/WA and the ID panhandle next weekend. This may result in an
increase in winds next weekend along with a slight shower or
thunderstorm threat across the Central Mountains eastward across
the MT border region. Given this new development, have slightly
tweaked precip potential upwards across these areas next weekend
to begin to reflect this trend. AD/DSH

AVIATION...Generally dry conditions with a slight potential for
isolated convective showers in the highlands along the WY border
this afternoon.  Strong gusty winds return for Monday afternoon
primarily in the Snake Plain and Eastern Highlands.   DSH

FIRE WEATHER...Forecast area under southwesterly flow as an upper
low sets up over WA/OR today. Most areas remain relatively dry with
exception of zones 475 and 476 the northern Central Mountains and
portions of zone 413 in the Southeast Highlands.  Not much in the
way of dynamic forcing for convection but can not rule out isolated
thunderstorms in those locations for this afternoon and early
evening. Dry southwest flow will dominate the region for Monday as
the upper low over the Pacific NW shifts offshore and associated
moisture is focused over OR/WA.  Gusty winds and low relative
humidity are expected for Monday afternoon and have issued a Fire
Weather Watch to highlight the potential for Red Flag Conditions.
Monsoon moisture plume surges northward into UT today and Monday,
however it appears that this moisture will remain south and east of
Idaho. Thus warm and dry conditions are expected to persist until
late in the week. DSH


.PIH Watches/Warnings/Advisories...
Fire Weather Watch from Monday afternoon through Monday evening
for IDZ410-413.


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