Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 181944
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
144 PM MDT MON AUG 18 2014

.DISCUSSION...CENTER OF UPPER LOW OVER NORTHERN CALIFORNIA PER WV
IMAGERY. MOISTURE PULLING NORTH THROUGH NEVADA AND NORTHERN
ARIZONA THROUGH GREAT BASIN TOWARD EASTERN IDAHO. PAIR OF WEAK
SHORTWAVES MOVING THROUGH EAST IDAHO...ONE ALONG DIVIDE AND
ANOTHER ALONG SOUTHERN BORDER. SOME MOISTURE IN PLACE ALREADY AND
CONVECTION HAS BEGUN TO REDEVELOP ALREADY EARLY THIS AFTERNOON
ALONG/AHEAD OF SHORTWAVES.  NAM/RAP SEEMS TO HAVE BEST HANDLE ON
CONVECTIVE THREAT THIS AFTERNOON AND EVENING WHILE HRRR STRUGGLING
TO CATCH UP. BOTH NAM/GFS CONTINUE CONVECTION OVERNIGHT INTO EARLY
TUESDAY BUT CONVECTION BLOOMS DURING THE AFTERNOON AS MID LEVEL
MONSOON FLOW REACHES EAST IDAHO. HAVE NUDGED POPS UPWARD TUESDAY
ALL AREAS. SOME DIFFERENCES IN MODELS AS NAM STRONGER WITH
SHORTWAVE EJECTING OUT OF EAST IDAHO TUESDAY NIGHT. DIFFERENCES
AMPLIFY THROUGH THURSDAY WITH NAM A BIT FURTHER SOUTH WITH BASE OF
TROUGH. GFS HOLDS EAST IDAHO IN NEUTRAL FLOW ALOFT WITH SOUTHERN
CUT OFF LOW FURTHER NORTH THAN THE NAM. BOTH MODELS REMAIN
UNSETTLED WITH PLENTY OF MOISTURE IN PLACE TO CONTINUE THREAT OF
SCATTERED THUNDERSTORMS ACROSS THE REGION. SHORTWAVE ROUNDS TROUGH
WEDNESDAY NIGHT INTO THURSDAY FOR ANOTHER WET DAY MOST AREAS WITH
EASTERN IDAHO JUST AHEAD OF MAIN TROUGH AXIS. BOTH MODELS
PRODUCING MORE WIDESPREAD CONVECTIVE CONVERAGE SO NUDGED POPS
UPWARD AGAIN FOR THURSDAY AFTERNOON/EVENING.

ECMWF AND GFS AGAIN DIFFEREING IN DETAILS FOR REMAINDER OF FORECAST.
ECMWF LOOKING AGAIN TO DROP CLOSED SHORTWAVE INTO BASE OF BROAD
PACNW TROUGH THURSDAY NIGHT INTO FRIDAY BUT THEN OPENS IT UP AGAIN
FRIDAY NIGHT. PLACEMENT/DEPTH OF TROUGH SIMILAR WITH HINTS OF DRY
SLOT WORKING IN FROM OREGON FRIDAY INTO SATURDAY. BOTH MODELS
TREAT NORTHERN PACIFIC ENERGY A LITTLE DIFFERENTLY. EAST IDAHO
UNDER SOME INFLUENCE OF BASE OF TROUGH...BUT FLOW RANGES FROM
WEST/DRY IN THE GFS TO NORTHWEST/MOIST IN THE ECMWF. OVERALL OPTED
TO MAKE NO CHANGES TO CURRENT EXTENDED RANGE WITH ISOLATED POPS
CLOSE TO CLIMO AND TEMPS NEAR GUIDANCE BLEND. DMH


&&

.AVIATION...SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH TOMORROW
ACROSS EASTERN IDAHO. COVERAGE WILL BE ISOLATED TODAY BECOMING
CLOSER TO SCATTERED IN SOME AREAS ON TUESDAY. GUSTY WINDS OVER 30KTS
ARE POSSIBLE WITH STORMS...WITH AN INCREASING THREAT OF HEAVY
DOWNPOURS TONIGHT AND TUESDAY. EITHER COULD BRING REDUCED
VISIBILITY. WE WILL BE CARRYING AT LEAST VCTS OR VCSH FOR ALL SITES.
KEYES


&&

.FIRE WEATHER...SHOWERS AND STORMS WILL CONTINUE TO INCREASE ACROSS
EASTERN IDAHO THROUGH THE NEXT 24 HOURS. THUNDERSTORM COVERAGE WILL
BE ISOLATED TODAY AND WIDELY SCATTERED TOMORROW. THE SOUTHEAST
CORNER WILL BE INTERESTING TO WATCH AS THEY MAY BE TOO STABLE TO SEE
ANY THUNDER AT ALL IF CLOUDS AND TIMING MATCH UP. STORMS WILL BE
CAPABLE OF PRODUCING WIND GUSTS OVER 35 MPH AND LOCALLY HEAVY
DOWNPOURS. WE ARE NOT EXPECTING ANY ISSUES WITH SLIDES OR FLOODING
THIS TIME AROUND. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL
CONTINUE THROUGH THE END OF THE WEEK AS THE LOW OUT OF CANADA SAGS
SOUTH INTO THE NORTHERN STATES. THE BETTER CHANCES WEDNESDAY-FRIDAY
WILL BE ACROSS THE NORTH AND ALONG THE WYOMING BORDER. DRIER
CONDITIONS WILL FILTER INTO PORTIONS OF THE SNAKE PLAIN AND
SOUTH-CENTRAL HIGHLANDS...HELPING TO REDUCE SHOWERS/STORMS. WE WILL
ALSO SEE THE WIND PICKING UP...BUT INCREASED HUMIDITY SHOULD NEGATE
THIS AND PREVENT ANY ISSUES WITH CRITICAL FIRE CONDITIONS. THE
MODELS CONTINUE TO SHOW WIDELY VARYING FORECASTS EACH DAY IN THE
EXTENDED...BUT ONE TREND IS EMERGING DESPITE ALL OF THIS. IT DOES
APPEAR FOR THE WEEKEND AND EARLY NEXT WEEK...WE SHOULD BR PRETTY DRY
BUT BREEZY ACROSS THE SOUTH AND SNAKE PLAIN. WE SLOWLY TRENDED THAT
DIRECTION WITH THE FORECAST WHERE IT WAS NEEDED...BUT NOT COMPLETELY
TO THAT END OF THE SPECTRUM. KEYES


&&

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

$$







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