Area Forecast Discussion
Issued by NWS Pocatello, ID

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000
FXUS65 KPIH 180839
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
239 AM MDT MON AUG 18 2014

.DISCUSSION...UPPER LOW THIS MORNING IS SEEN DIGGING OVER COASTAL
WA/OR AS DOWNSTREAM RIDGE AMPLIFIES. CONVECTION HAS INITIATED AROUND
AN IMPULSE OF ENERGY EAST OF THE LOW IN NORTHEAST OREGON. NAM MOST
AGGRESSIVE WITH CONVECTION ALONG SOUTHERN BORDER THIS MORNING AND
EXPANDING INTO THE CENTRAL MOUNTAINS THIS AFTERNOON. BY
TOMORROW...PATTERN WILL BE MORE AMPLIFIED AND UPPER LOW WILL SPIN UP
SOME MONSOON MOISTURE INTO THE AREA WHICH WILL LEND ITSELF TO HIGHER
POPS. NAM AGAIN SUGGESTS MORE WIDESPREAD CONVECTION THAN GFS TUESDAY
WITH FOCUS OVER THE EASTERN HIGHLANDS AS UPPER LOW SINKS INTO
SOUTHERN CALIFORNIA. HOWEVER...NORTHERN BRANCH TROUGH WILL SLIDE
INTO THE REGION TUESDAY NIGHT KEEPING PRECIP CHANCES IN THE FORECAST
THROUGH MUCH OF THE REST OF THE WEEK. NORTHERN BRANCH TROUGH GETS A
LITTLE REINFORCEMENT THURSDAY NIGHT AND FRIDAY WHICH MAY TRIGGER
MORE WIDESPREAD CONVECTION. MOISTURE SHIFTS EASTWARD SATURDAY AND
SUNDAY ALONG WITH UPPER TROUGH AS RIDGE BUILDS BACK INTO THE PAC NW.
THIS WILL BRING A COOLER NORTHWESTERLY FLOW TO THE REGION IF RIDGING
SOLUTION HOLDS. HINSBERGER
&&

.AVIATION...ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE
SOUTH CENTRAL HIGHLANDS FROM NEAR KBYI TO KPIH THIS AFTERNOON...ALSO
OVER THE MOUNTAINS AROUND KSUN. MONDAY NIGHT...INCREASED SOUTHERLY
FLOW WILL BRING DEEPER MONSOON MOISTURE TO THE SOUTHERN BORDER
AREAS. CONVECTIVE ACTIVITY MAY PERSIST CLOSE TO THE KBYI AREA
THROUGH THE NIGHT. MOISTURE REACHES A PEAK TUESDAY AFTERNOON AND
EVENING IN THE SOUTH CENTRAL AND CARIBOU HIGHLANDS. THUNDERSTORMS MAY
PUT DOWN SOME GOOD RAIN SHOWERS THAT COULD REDUCE VISIBILITY
LOCALLY. RS
&&

.FIRE WEATHER...THE LOWEST AFTERNOON HUMIDITY OCCURRED SUNDAY AND
AGAIN THIS AFTERNOON IN PORTIONS OF THE ARCO DESERT AND THE HIGHWAY
93 CORRIDOR THROUGH CHALLIS...RANGING FROM 11 TO 13 PERCENT. A LOW PRESSURE
CIRCULATION IS FORECAST TO DEVELOP TODAY NEAR THE NORTHERN
CALIFORNIA COAST AND BECOME CUT OFF FROM THE MAIN WEST TO
NORTHWESTERLY FLOW ACROSS WASHINGTON AND NORTHERN IDAHO. A SHORT
LIVED INCREASE IN SOUTH WINDS AND MONSOON MOISTURE BEGINS
TODAY...PEAKS ON TUESDAY AFTERNOON AND EVENING...AND THEN WILL BE
REDIRECTED TO THE EAST WITH A LOW PRESSURE TROUGH CROSSING THE
STATE. THIS AFTERNOON...ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS
THE SOUTHERN SAWTOOTH AND CARIBOU FOREST AREAS...ALSO IN THE CENTRAL
MOUNTAINS PRODUCING JUST A FEW HUNDREDTHS OF AN INCH RAIN.
TUESDAY...THE MONSOON MOISTURE WILL PEAK IN THE SOUTHERN
HIGHLANDS...WITH ISOLATED TO WIDELY SCATTERED THUNDERSTORMS AND AT
LEAST SOME OF THOSE CELLS PRODUCING .1 TO .2 INCH PRECIPITATION. THE
AIRMASS WITH INCREASED MONSOON MOISTURE MAY REMAIN UNSTABLE WITH
ISOLATED THUNDERSTORMS OVERNIGHT. THE TROUGH PASSES WEDNESDAY INTO
THURSDAY. SOME DRIER AIR FROM THE WEST IS EXPECTED BUT MINIMUM
HUMIDITY WILL PROBABLY BE LIMITED TO THE HIGH TEENS AND LOWER 20S
INTO NEXT WEEKEND. RS
&&


.PIH WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$



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