Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 171948
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
148 PM MDT SUN JUL 17 2016

.SHORT TERM...Today through Tuesday. We are still watching a
little bit of moisture and very weak disturbances working across
Idaho today. One is trying but struggling (other than virga) to
kick off isolated showers and storms across the southeast
highlands. The other is working toward the central mountains and
the Panhandle. Several higher resolution models insist on storms
firing up there in earnest through this evening. Afternoon clouds
are forming as a tongue of slightly more moist air moves in.
Whether it`s enough to pop off more than dry storms remains to be
seen. All of this should move off to the northeast this evening at
tonight. It will be interesting to see what happens after midnight
as there is an air of mid level moisture moving north across
eastern Idaho. Right now, it`s hard to say if that will produce
any showers or virga, or nothing at all. Something to monitor over
the next several hours. For Monday and Tuesday, there story will
be more wind and will there be any thunderstorms as monsoon
moisture will be lurking nearby. Again, some models want to fire a
few storms north of Challis tomorrow. We kept with the idea of
maybe A storm (10% chance) in that area. The big question mark is
will the monsoon push clip the eastern highlands or stay in Utah
and Wyoming. At the moment, we stayed with isolated storms over
the southeast corner tomorrow as there MIGHT be a little more
moisture. Tuesday we kept with dry as we are back to a split
decision between bone dry and isolated storms. Winds will likely
be strongest tomorrow, peaking in the afternoon at 15-25mph with
gusts of 25-35 mph for most of us. Right now, that will not be
enough for any regular headlines. Keyes

.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 Thursday, bringing a resulting increase in winds and a
potential for a critical fire weather day.  With the closed low
shearing eastward, the previously advertised monsoonal moisture
plume is effectively shunted eastward across Wyoming, so little to
no precipitation expected through Friday.   so have continued the
trend of reducing shower and thunderstorm potential mid-late week.
GFS model trends a weak shortwave trough 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.
EC model this morning hints at this trend but confidence overall is
low for any big impacts at this time.  Preston

&&

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

&&

.FIRE WEATHER...Southwest will become firmly established over
eastern Idaho for the next few days. Usually that means the
monsoon kicks in this time of year, but that`s really not the
case this time. We look to be mostly under the dry slot in between
the ridge centered to our southeast and a low over the Pacific
Northwest. That means low humidity will continue with thermal
belts increasing in many areas at night. Gusty winds will crank
up each afternoon and evening, with some gusts overnight for some
mid/upper slopes. In fact, tomorrow will be pretty gusty with
speeds of 25-35mph common. That will be enough to match up with
critical fuels across lower elevations of Zones 410/413, therefore
we will upgrade the watch to a Red Flag Warning. The rest of the
week appears to come in with slightly lower winds and the moment
not hitting Red Flag thresholds, but likely still enough to be
aware that fires could still take off with fuels likely drying out
even more. Moving on to the thunderstorm threat. We could still
see storms across Zones 413/475/476 through sunset. So far both
areas are storm free as moisture is very limited. For tomorrow,
there might be just enough for isolated storms over the northern
end of 475/476. The main issue lies across the eastern highlands
and what happens with the monsoon moisture. In fact, this is the
other big issue for the rest of the week. There seems to be an
even split on some of that push to sneak westward into Idaho or
keeping off to our southeast. At the moment the only days we have
isolated storms in are tomorrow, Thursday and Friday. This will
likely handled on a day-by-day basis as we will see how the
moisture plume develops.  Keyes

&&

.PIH Watches/Warnings/Advisories...
Red Flag Warning from noon to 9 PM MDT Monday for IDZ410-413 below
6000 feet.

&&

$$


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