Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 170834
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
234 AM MDT THU JUL 17 2014

.SHORT TERM...TODAY THROUGH MONDAY MORNING. A WEAK WAVE WILL CROSS
EASTERN IDAHO TODAY. THIS WILL PROVIDE FOR SOME AFTERNOON CLOUDS
ACROSS MUCH OF THE AREA. THERE WILL BE JUST ENOUGH MOISTURE AND
SUPPORT FOR THUNDERSTORMS THIS AFTERNOON EVENING...GENERALLY
NORTHEAST OF A LINE FROM CLAYTON TO BLACKFOOT TO ALPINE, WYOMING.
WE MIGHT SEE A FEW BRIEF DOWNPOURS...BUT NOTHING THAT WILL CAUSE
ANY FLOODING CONCERNS AT THIS TIME. THE MAIN THREAT TODAY WILL BE
STRONG DOWNBURST WINDS...IN SOME CASES POSSIBLY IN EXCESS OF 50
MPH. WE MAY SEE A STORM OR TWO TRY AND PUSH GUSTS CLOSER TO 60MPH
BUT RIGHT NOW THAT IS A VERY LOW (NOT ZERO) PROBABILITY. OTHER
THAN THAT...IT WILL BE A BIT BREEZY BUT NOTHING THAT WILL PRODUCE
ANY REAL IMPACTS. THINGS WILL QUICKLY QUIET DOWN FOR TONIGHT AND
TOMORROW MORNING. WE WILL SEE SOME LINGERING MID AND HIGH LEVEL
CLOUDS ESPECIALLY ACROSS THE SOUTH. AS MORE MOISTURE CREEPS INTO
EASTERN IDAHO...ISOLATED STORMS ARE FORECAST IN THE MOUNTAINS FROM
AROUND ARCO TO ISLAND PARK. ISOLATED STORMS WILL ALSO DEVELOP
ACROSS THE MOUNTAINS CLOSER TO THE UTAH BORDER ALONG THE LEADING
EDGE OF THE MONSOON SURGE. AGAIN...THE MAIN THREAT WILL LIKELY BE
GUSTY WINDS.

THE WEEKEND AND INTO MONDAY LOOKS FAIRLY STORMY...ESPECIALLY
SUNDAY INTO MONDAY. THE MODELS ARE CONSISTENT IN SLOWING DOWN THE
ARRIVAL OF BETTER MOISTURE UNTIL THEN. THE NAM SEEMS A LITTLE BIT
FARTHER NORTH THAN THE GFS AND ECMWF BUT FEEL THERE IS ENOUGH
THERE TO KEEP A SLIGHT CHANCE SOUTH AND EAST OF THE SNAKE PLAIN.
THE MONSOON PUSH DOESN`T MAKE MUCH PROGRESS NORTHWARD UNTIL SUNDAY
MORNING/MONDAY MORNING. WE EXPECT THUNDERSTORMS TO FIRE OFF SUNDAY
AFTERNOON ESPECIALLY ACROSS THE SOUTH...WITH A SLIGHT CHANCE OF
STORMS CONTINUING SUNDAY NIGHT/MONDAY MORNING AS THE PUSH OF
MOISTURE FINALLY OVERTAKES THE ENTIRE AREA. IT STILL LOOKS LIKE
THE THREAT OF GUSTY DOWNBURST WINDS WILL BE WITH US BUT WITH
DEEPER MOISTURE COMES THE POSSIBILITY OF LOCALLY HEAVY RAIN.
BREEZY CONDITIONS WILL RETURN BUT STILL NOTHING TERRIBLY STRONG
OUTSIDE OF THUNDERSTORM AREAS. HIGHS THROUGH SATURDAY WILL BE
RUNNING ABOUT 5 DEGREES ABOVE NORMAL...BEFORE COOLING OFF DUE TO
INCREASING CLOUD AND STORM COVERAGE. KEYES

.LONG TERM...MONDAY AFTERNOON THROUGH NEXT THURSDAY. BOTH THE GFS
AND ECMWF WERE SHOWING A BROAD UPPER RIDGE CENTERED SE OF THE
4-CORNERS REGION WITH A PACIFIC LOW PRESSURE TROUGH ADVANCING INTO
THE SW BRITISH COLUMBIA COAST AND A WEAK SUB-TROPICAL CIRCULATION
POSITIONED WELL OFF THE SRN CALIFORNIA COAST EARLY IN THE PERIOD.
THE PATTERN WAS SUPPORTIVE OF MONSOONAL FLOW FROM THE SOUTH AND
SCATTERED AFTERNOON THUNDERSTORM ACTIVITY MONDAY POSSIBLY LINGERING
INTO TUESDAY. BY WEDNESDAY...BOTH MODELS DEPICTED THE PAC TROUGH
ADVANCING EAST INTO/THROUGH ALBERTA WITH A DRY COLD FRONTAL PASSAGE
AND INCREASED WINDS ACROSS SE IDAHO. FOR THE REMAINDER OF THE
WEEK...THE 4-CORNERS HIGH WAS EXPECTED TO EXPAND NORTHWARD THROUGH
THE NRN ROCKIES WITH MOSTLY DRY AND HOTTER CONDITIONS ANTICIPATED.
HUSTON

&&

.AVIATION...A PAC SHORT-WAVE DISTURBANCE WAS NOTED SHEARING EAST
THROUGH BRITISH COLUMBIA EARLY THIS MORNING. NUMERICAL MODELS
SUGGEST THAT THE SRN EXTENT OF THIS PASSING TROUGH COUPLED WITH
LINGERING INSTABILITY ACROSS THE CNTRL AND NRN MOUNTAINS SHOULD BE
ENOUGH TO TRIGGER ISOLATED AFTERNOON CONVECTION. AT THIS TIME THE
MODELS ARE SUPPORTIVE OF VICINITY TSTMS AT KSUN...KIDA AND KPIH LATE
THIS AFTERNOON/EVE ALONG WITH LOCALLY GUSTY WINDS...OTHERWISE VFR
CONDITIONS SHOULD PREVAIL AT ALL THE TERMINALS THROUGHOUT THE NEXT
24-HRS. HUSTON

&&

.FIRE WEATHER...ANOTHER SHORTWAVE WILL MOVE OVER THE AREA PRODUCING
MAINLY ISOLATED THUNDERSTORMS ONCE AGAIN THIS AFTERNOON IN ZONES
475...476...410...411 AND NORTHERN AREAS OF 413. THESE THUNDERSTORMS
WILL BE CAPABLE OF PRODUCING WINDS GUSTS AND OUTFLOWS OF AROUND 50
MPH AND FREQUENT LIGHTNING. MONSOON MOISTURE WILL BEGIN SLOWLY
WORKING ITS WAY FROM THE SOUTH INTO THE AREA WHICH WILL BRING THE
THREAT OF AFTERNOON THUNDERSTORMS...MAINLY IN THE
MOUNTAINS...THROUGH THE WEEKEND.
EP

&&

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

$$






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