Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 252008
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
208 PM MDT SAT JUL 25 2015

.SHORT TERM...TODAY THROUGH MONDAY.
ANY CONVECTIVE ACTIVITY THIS EVENING SHOULD BE ISOLATED AT BEST
AND MAINLY LIMITED TO UPPER SNAKE HIGHLANDS. MOST ACTIVITY SO FAR
IN MONTANA. WOULD NOT RULE OUT STRAY CELL IN SOUTHERN HIGHLANDS
EITHER. MAIN EVENT WATCHING IS LARGE UPPER LEVEL TROF AND
ASSOCIATED COLD FRONT WHICH WILL MOVE THROUGH IDAHO SUNDAY NIGHT
AND MONDAY. EXPECT LOW IMPACTS SUNDAY WITH ONLY ISOLATED SHOWERS
AND THUNDERSTORMS MAINLY IN CENTRAL MOUNTAINS AND PERHAPS SOME
BREEZY CONDITIONS AHEAD OF FRONT MAINLY IN UPPER SNAKE RIVER
PLAIN. BIG IMPACTS WILL COME MONDAY WITH STRONG WINDS EXPECTED
MOST LOCATIONS ESPECIALLY IN SNAKE RIVER PLAIN WHERE COULD SEE
ADVISORY LEVEL WINDS AND SUSTAINED AT 30 MPH POSSIBLY. SHOWERS AND
THUNDERSTORMS WILL BE MORE WIDESPREAD SUNDAY NIGHT THROUGH MONDAY
EVENING IN CENTRAL MOUNTAINS AND UPPER SNAKE RIVER HIGHLANDS. NOT
EXPECTING MUCH PRECIPITATION IN THE SNAKE RIVER PLAIN OR SOUTHERN
HIGHLANDS WITH THIS SYSTEM. TEMPERATURES WILL REMAIN NEAR NORMAL
SUNDAY BUT WILL BE SUBSTANTIALLY COLDER ON MONDAY WITH HIGH
TEMPERATURES AS MUCH AS 15 TO 20 DEGREES BELOW NORMAL. ALSO EXPECT
SOME RECORD LOW TEMPERATURES MONDAY NIGHT AS WELL AS SKIES CLEAR
AND WINDS DIE DOWN.
GK

.LONG TERM...TUESDAY THROUGH SATURDAY.
MAIN THEME OF LONG TERM IS UPPER RIDGE BEGINS TO INTENSIFY OVER
IDAHO BY MID WEEK. EXPECT CONTINUED MUCH BELOW NORMAL TEMPERATURES
TUESDAY BUT THEN A WARMING TREND KICKS IN WEDNESDAY AND EXPECT
TEMPERATURES TO BE ABOVE SEASONAL NORMAL BY THURSDAY. IT WILL BE
DRY.
GK

&&

.AVIATION...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. ENOUGH
LINGERING LOW LEVEL MOISTURE EXISTS TODAY TO AID IN CUMULUS
DEVELOPMENT. ADDED VCSH FOR BYI WHERE HIGHEST CHANCES RESIDE FOR A
SNEAKY SHOWER...BUT CHANCES TOO LOW TO INCLUDE ELSEWHERE. A VIGOROUS
TROUGH WILL SLIDE ASHORE ALONG THE PACNW COAST SUNDAY. WINDS ARE
EXPECTED TO GRADUALLY INCREASE AHEAD OF THIS FEATURE...WITH SOME W-
SW GUSTS IN THE 20-25KT RANGE POSSIBLE BY SUNDAY AFTERNOON AT
BYI...IDA...AND PIH. AD/GK

&&

.FIRE WEATHER...LINGERING LOW LEVEL MOISTURE WILL PROVIDE FOR PLENTY
OF CUMULUS EARLY THIS EVENING IN HIGH TERRAIN AREAS...WITH AN
ISOLATED SHOWER POSSIBLE...GREATEST CHANCES OVER THE CENTRAL
MOUNTAINS. A STRONG TROUGH WILL MOVE ASHORE ALONG THE PACNW COAST
TOMORROW. THIS WILL AID IN AN INCREASE IN WINDS...WITH LATE
AFTERNOON AND EVENING GUSTS IN THE 20-25 MPH RANGE FOR RIDGE TOPS
ACROSS THE CENTRAL MOUNTAINS AS WELL AS FOR MUCH OF THE SNAKE RIVER
PLAIN. MIN RH APPROACHES 15 PERCENT ACROSS THE ARCO DESERT AND
VALLEYS IN THE SALMON-CHALLIS. AERIAL EXTENT OF THESE MIN RH VALUES
APPEAR TOO LOW TO WARRANT A RED FLAG AT THIS TIME. A STRONG COLD
FRONT IS THEN EXPECTED TO SWEEP FROM WEST TO EAST ACROSS THE REGION
MONDAY. BEHIND THE FRONT WIDESPREAD SHOWERS AND ISOLATED TO POSSIBLY
SCATTERED THUNDERSTORMS BREAK OUT ACROSS THE CENTRAL MOUNTAINS
BEGINNING LATER SUNDAY EVENING AND PERSISTING THROUGH MONDAY WHILE
SPREADING ACROSS THE TARGHEE AND CARIBOU BY LATER IN THE DAY MONDAY.
BEST CHANCE FOR MOST WIDESPREAD RAINFALL APPEARS TO BE MONDAY
MORNING ACROSS THE CENTRAL MOUNTAINS...WHERE CWR VALUES EXCEED 50
PERCENT...AND EVEN APPROACH 80 PERCENT TOWARDS THE MT BORDER. STRONG
WINDS EXPECTED MONDAY WITH 20-30 MPH GUSTS RIDGE TOPS AND 30-40 MPH
GUSTS ACROSS THE SNAKE RIVER PLAIN...HIGHEST ACROSS THE ARCO DESERT.
TEMPERATURES WILL COOL SIGNIFICANTLY ON MONDAY WITH COOL CONDITIONS
PERSISTING INTO TUESDAY...WITH TEMPERATURES APPROACHING RECORD LOWS
FOR BOTH DAYTIME HIGHS AND NIGHTTIME LOWS. PRECIPITATION ENDS ON
TUESDAY WITH A FORMIDABLE WARMING AND DRYING TREND COMMENCING ON
WEDNESDAY AND CONTINUING THROUGH THE WEEK. TEMPERATURES SHOULD WARM
TO JUST ABOVE SEASONAL NORMS BY FRIDAY. AD/GK

&&

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

$$


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