FXUS65 KPIH 250830

Area Forecast Discussion
National Weather Service Pocatello ID
230 AM MDT Sun Aug 25 2019

.DISCUSSION...Satellite imagery and observational fields confirm
the presence of an incoming disturbance racing eastward into
northwest Washington state early this morning, with an attendant
core of winds and punch of mid-level dry air. These features,
along with an associated dry cold front, will pass across SE Idaho
today. The end result will be a windy day, with west to southwest
winds gusting to around 45 mph across the eastern Magic Valley,
lower Snake Plain, Arco Desert and mid/upper slopes of the
southern highlands and Albion mountains. The strongest winds are
expected generally in the 11AM to 9PM timeframe, coincident with
the ongoing Wind Advisory, with the core of the strongest winds
likely between 2PM and 7PM. Isolated wind gusts over 50 mph are
possible, especially across the Arco Desert. Rough chop on area
waterways, patchy blowing dust, and difficult driving
conditions for drivers of high-profile vehicles or vehicles with
trailers along north-south routes. Winds will ramp down gradually
after 9PM.

Cooler temperatures will gradually filter into the region today
behind the cold front, with comfortable, just below climatological
average temperatures for Monday and Tuesday. By Tuesday, a ridge
of high pressure will begin to build over the region, and this
ridge is expected to remain in place through early next weekend.
This will bring a return to above average temperatures across the
region from Wednesday into at least early next Weekend. A
disturbance embedded in the emerging SW flow across the region,
along with an uptick in moisture will allow for isolated to
perhaps scattered showers and thunderstorms across the region
beginning Thursday morning, with coverage increasing by Thursday
afternoon. The best chance for this activity will be across high-
terrain areas, but an isolated storm or associated outflow could
very well sneak into the Snake Plain. Shower/storm coverage will
decrease on Friday, and is expected to occur mainly along/near
the Montana border. Stout SW flow is expected to develop by later
next Weekend as a strong area of low pressure strengthens just off
of the Washington and Oregon coasts. This will maintain warm
temperatures, result in occasionally breezy conditions, and if
there's enough moisture perhaps result in an isolated thunderstorm
or two by late next Weekend, particularly over high-terrain areas
once again. Overall, we have high confidence in the forecast and
its details due to excellent forecast guidance agreement. By the
way, the above-mentioned low and an associated cold front may
meander over the region during the East Idaho State Fair week, and
we'll continue to monitor those details over the course of the
next week. AD


.AVIATION...A strong west-northwest flow aloft will settle over the
region today resulting in gusty afternoon and evening winds. Dry and
stable conditions will bring mostly clear/VFR sky cover. Huston


.FIRE WEATHER...A strong west-northwest flow aloft will settle
over the region today resulting in gusty afternoon and evening
winds and dry conditions. RED FLAG WARNINGS continue for fire
zones 410, 413, and 425 this afternoon and evening with zone 427
being added to the mix with this mornings forecast issuance.
Cooler temperatures and less wind Monday will mitigate any further
RED FLAG concerns. The ridge of high pressure rebounds across the
region Tuesday and Wednesday resulting in warming and drying
conditions. The models continue to show a weak sub-tropical
disturbance rotating up over the ridge into the region Thursday
and Friday resulting in a chance/slight chance potential for
thunderstorm activity. By Saturday, the ridge expands across the
west once again resulting in more warming and drying into early
next week. Huston


Red Flag Warning from 1 PM this afternoon to 9 PM MDT this
evening for IDZ410-413-425-427.

Wind Advisory from 11 AM this morning to 9 PM MDT this evening
for IDZ051-052-054-055-058.


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