Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 300845
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
245 AM MDT SAT JUL 30 2016

.SHORT TERM...Saturday through Monday...Today begins the increase
in monsoonal moisture from the south, which will aid in dry
thunderstorm development initially along the Utah/Nevada/Idaho
state lines this morning. As the day progresses, expect continued
development in these areas with new thunderstorms across the
Southern and Caribou Highlands and additional storms over the
Central Mountain progressing to the Continental Divide. These
storms will be capable of lightning, and wind gusts in excess of
25 mph. Precipitation amounts are expected to be low, and less
than 1/10 of an inch across the board. A slowly progressing
frontal boundary will slowly be approaching Southeast Idaho
overnight tonight through Sunday. Ahead of this boundary, enhanced
winds will result today. Wind speeds of 20 to 25 mph with higher
gusts are expected this afternoon and evening for much of the area
with the lightest winds to the south of 10 to 15 mph or so. Also,
portions of the Central Mountains and Upper Snake Plain today may
notice some smoke from the Pioneer Fire in Boise National Forest.
With winds forecast as strong as they are today, progression of
this smoke is likely further east.

The position of the front for Sunday generally lingers across the
southern portion of our state which will keep winds elevated
Sunday in the 20 to 25+ mph range with higher winds at ridge tops.
Gusts in excess of 35 mph are expected across the Central Mountain
locations. An ever so slight cool down will be noticed due to the
front, and due to these stronger winds, and will be most noticed
across Central Idaho. By Monday, there will be no more trace of
said front and conditions will begin to retreat back to warmer
temperatures.
NP/RS

.LONG TERM...Tuesday through next Saturday...A new cold front is
forecast to pass across Idaho Tuesday with strong winds yet again.
Some dry thunderstorms may develop across portions of the Caribou
Highlands however is not high that this will occur. A decent
cooldown is expected behind this stronger front for mid-week with
highs in the upper 80s for the Snake Plain.
NP/RS
&&

.AVIATION...Moist unstable air expands north from the Great Basin
today, while a front embedded in the westerlies will be crossing the
Idaho central mountains about noon time. Smoke from local fires
beginning to affect visibility at KSUN. Thunderstorms develop this
morning 17-19Z at KBYI, 19-20z for the other TAF sites. Isolated
thunderstorms possible early Sunday morning over the highlands
east of KIDA and KPIH, otherwise convective activity will move
quickly east of the state leaving strong gusty winds in the
afternoon for all TAF sites. RS

&&

.FIRE WEATHER...Monsoon moisture expands from the Great Basin into
the Southern Sawtooth Forest and Caribou Highlands today. Red
Flag Warnings have been posted for dry thunderstorms in zones 427 and
413. Meanwhile, a front disturbance embedded in the westerly winds
over the rest of the state will cross the Salmon-Challis area by
noon time and reach the Arco Desert early afternoon. Strongest winds
today will be over the higher elevations of Zones 475 and 476 where
a Red Flag Warning is also in effect. A second area of dry
thunderstorms is  expected with this front mid to late afternoon as
it sweeps through Zone 411. Winds this afternoon are not expected to
be strong enough to support Red Flag criteria in the Upper Snake
Plain.

Sunday, those westerly winds over the state will push much of the
monsoon moisture to the east of the state. Very dry air follows,
along with strong gusty winds across the Salmon-Challis and Idaho
Falls BLM/Arco Desert, a lot of single digit RH values return. We
did not include Zone 425 in the watch/warning for Sunday as the
winds look marginally below criteria and possibly the humidity as
well.

A slightly stronger trough moves over Northern Idaho late Monday
into Tuesday. Monday evening thunderstorms are possible over the
Bear Lake Region extending North along the Wyoming border near
Driggs with a brief return of monsoon moisture. Expect gusty winds
of 25 to 30 mph yet again mainly over the Central Mountains and
Snake River plain on Tuesday. A dry cold front associated with this
trough will sweep across the area Tuesday bringing dry conditions
and more seasonable temperatures...just slightly above
normal...Wednesday and Thursday.

By late Thursday night into Friday, we will repeat this pattern with
a new low pressure disturbance moving into the Pacific Northwest and
monsoon moisture once again surging northward through the southern
and eastern highlands. RS


.PIH Watches/Warnings/Advisories...
Red Flag Warning from noon today to 11 PM MDT this evening for
IDZ411-413-427.

Red Flag Warning from 2 PM this afternoon to 8 PM MDT Sunday for
IDZ475-476.

Fire Weather Watch from noon Sunday to 9 PM Sunday for IDZ410.
&&

$$


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