Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 192016
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
216 PM MDT Sun Aug 19 2018

.SHORT TERM...Tonight through Wednesday.
Flow aloft turning southwest and will allow moisture to return to
southeast Idaho as an upper level low moves on shore in Oregon.
This will allow for thunderstorms to return in the short term
period with Monday likely the most widespread development. Red
Flag warnings have been issued for Monday due to thunderstorms.
Isolated thunderstorms are expected Tuesday and Wednesday as well.
High temperatures should be near seasonal normals through
Wednesday.
GK

.LONG TERM...Thursday through Sunday.
The upper trof is expected to finally shift east Thursday and
drier conditions on a more westerly flow aloft is expected. Dry
conditions are in grids in the long term for the latter part of
the week through next weekend. Above normal temperatures are
expected again as well. GK

&&

.AVIATION...VFR weather for the most part is expected through
tomorrow. We`ve had some smoke that`s dropped visibility a bit at
KIDA, KPIH and KSUN to MVFR occasionally. That trend should continue
until tomorrow afternoon and evening. With the low developing to our
northwest, we are looking for an increase in monsoon moisture
Monday. We will see showers and thunderstorms developing and moving
in from the south and west. We will gradually see VCSH and/or VCTS
at all TAF sites, with probably -TSRA at some point especially later
in the day at KSUN. It all just depends on development. Expect gusts
over 35kts. We could see locally heavy downpours that COULD drop
weather into MVFR. That is most likely for the central mountains and
the Upper Plain/Highlands, potentially affecting KSUN, KIDA and
KDIJ. Those areas could also see some small hail.  Keyes

 &&

.FIRE WEATHER...As a low develops from central Montana back into
southwest Oregon, expect some monsoon moisture to pull northward
into Idaho. We should see isolated showers and thunderstorms
tomorrow. The exception is closer to the center of the low across
the central mountains, as there has been a consistent signal for
scattered storms. After coordinating with local partners. IMETS and
neighboring offices, we will issue a RED FLAG WARNING for
thunderstorms and gusty winds. Most storms could produce gusts over
40mph, but a few could gust closer to 60 mph. There will be a mix of
wet and dry thunderstorms as well, with the potential for over 0.25"
with wet storms. That risk should diminish after sunset and into the
overnight hours. On the back edge of that, a dry slot begins working
into southeast Idaho. This will bring a burst of strong winds and
lower humidity right up the Snake Plain and Magic Valley. We should
see a period of strong winds (mixing up high enough to tap into
30+mph winds aloft) in the late afternoon through sunset. There is
some question on how quickly those winds work across the Magic
Valley into Craters of the Moon. We are going with a FIRE WEATHER
WATCH for Zone 425 tomorrow afternoon and evening because of this.
It could go either way, things slow down or speed up a couple hours
and we are looking at a warning or nothing. The low slowly gathers
forward speed and scoots across the state Wednesday night. Tuesday
and most of Wednesday looks like we only see isolated showers and
thunderstorms with lighter winds outside of storms. When the storm
moves through, we may see a window where storm coverage becomes
scattered and stronger surface winds develop. There is quite a bit
of uncertainty on when things move through, so stay tuned. There is
even greater uncertainty beyond that. We continue to see struggles
and inconsistency with the models in the long range. There seems to
be some minor consensus that we will be far enough between the ridge
and the next low that we stay dry. However, this would put us in a
persistent breezy pattern IF it comes to fruition.  Keyes

&&


.PIH WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday afternoon through Monday evening
for IDZ425.

Red Flag Warning from noon to 9 PM MDT Monday for IDZ422-475-476.

&&

$$



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