Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 230831
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
231 AM MDT WED JUL 23 2014

.SHORT TERM...TODAY THROUGH THURSDAY. THE UPPER LOW APPROACHING
THE PAC NW EARLY THIS MORN IS FORCING STRONG SW FLOW OVER ID. A
MINOR TROF IN THE SW FLOW IS SETTING OFF TSTMS OVER THE NW PART OF
THE FCST AREA THIS MORNING...BUT THE THREAT WILL DIMINISH BY AFTN
WITH ONLY ISOLD TSTMS EXPECTED OVER THE CENTRAL MTNS TODAY. A
STRONG COLD FRONT WILL PASS THRU THE FCST AREA EARLY THU MORN AS
THE UPPER LOW MOVES THRU NORTHERN WA. THE NAM HAS THE FRONT
DEVELOPING SOME SHOWERS/TSTMS OVER THE UPPER SNAKE HIGHLANDS
IN THE PREDAWN HOURS...WHILE THE GFS REMAINS DRY. WILL HAVE TO
GIVE THE NOD TO THE NAM...AS IT IS REASONABLE TO ASSUME THAT
PRECIP IS POSSIBLE AS THE FRONT PUSHES INTO THE HIGHER TERRAIN OF
THE UPPER SNAKE HIGHLANDS. WINDY CONDITIONS AND COOLER TEMPS WILL
PREVAIL ON THU.

.LONG TERM...FRIDAY THROUGH WEDNESDAY. THE UPPER LOW WILL BE OUT
OF THE AREA BY FRI...BUT COOL TEMPS WILL CONTINUE. FRI MORN TEMPS
ARE EXPECTED TO RANGE FROM THE 40S IN THE SNAKE RIVER PLAIN...TO
THE LOWER 30S IN THE CENTRAL MTN BASINS. THE UPPER RIDGE BUILDS
BACK UP OVER THE WEEKEND...PUSHING TEMPS BACK TO MORE SUMMERLIKE
READINGS. NO PRECIP EXPECTED THRU THE WEEKEND...HOWEVER BY
MONDAY...THE GFS SHOWS MONSOON MOISTURE BEGINNING TO FLOW BACK INTO
IDAHO. THE GFS HAS BEEN RATHER CONSISTENT WITH THIS...SO WILL CARR
ISOLD AFTN/EVE TSTMS IN THE MTNS MON THRU WED. HEDGES

&&

.AVIATION...A STRONG/MOIST DISTURBANCE WAS NOTED LIFTING NE THROUGH
THE BOISE AREA EARLY THIS MORNING RESULTING IN MODERATE TO STRONG
CONVECTION EXTENDING FROM SW IDAHO THROUGH THE CNTRL MOUNTAINS NORTH
OF KSUN. THE DISTURBANCE IS EXPECTED TO LIFT NE INTO WRN MONTANA BY
NOON WITH A DRIER SW FLOW OVERSPREADING THE REGION. THE NAM WAS
SHOWING A JET SEGMENT DEVELOPING OVER CNTRL IDAHO LATE THIS AFTN/EVE
AS THE DEEP LOW OFF THE NW COAST BEGINS TO SWING INLAND. THE RESULT
IS AN AREA OF MODEST LIFT AND NOCTURNAL CONVECTION FIRING OVER THE
SRN/ERN HIGHLANDS TONIGHT POSSIBLY IMPACTING KBYI KPIH AND KIDA.
THIS IS A NEW WRINKLE AND ONE THAT IS NOT AS STRONG IN THE GFS
SOLUTION. WE WILL CONTINUE THE GOING FORECAST WHICH HAS A MENTION OF
VICINITY SHOWERS FOR THIS EVENING...OTHERWISE VFR CONDITIONS SHOULD
PREVAIL AT ALL TERMINALS. HUSTON

&&

.FIRE WEATHER...A DEEP PAC LOW WAS OBSERVED OFF THE NW COAST EARLY
THIS MORNING AS A SUB-TROPICAL WAVE WAS EJECTING RAPIDLY NE THROUGH
SW IDAHO. EARLY MORNING THUNDERSTORM ACTIVITY ACROSS THE CNTRL
MOUNTAINS IS EXPECTED TO LIFT NE INTO MONTANA BY NOON WITH RESIDUAL
ISOLATED CONVECTION LINGERING ACROSS THE CNTRL MOUNTAINS THIS
AFTERNOON AHEAD OF THE INCOMING LOW. WINDS ARE EXPECTED TO BEGIN
RAMPING UP ACROSS THE CNTRL MOUNTAINS LATE THIS AFTERNOON AS THE LOW
BEGINS TO EDGE INLAND...POSSIBLY NEARING WARNING CRITERIA IN ZONE
422 FOR A COUPLE OF HOURS. STILL...MAIN EVENT APPEARS TO BE THURSDAY
AS THE LOW LIFTS ENE INTO CANADA AND AN ASSOCIATED DRY COLD FRONT
SWEEPS THROUGH SRN IDAHO. THE NAM WAS SHOWING THE POTENTIAL FOR
ISOLATED NOCTURNAL THUNDERSTORM ACTIVITY ACROSS THE SRN AND ERN
HIGHLANDS LATE THIS AFTERNOON/TONIGHT AHEAD OF THE ADVANCING LOW
WHEREAS THE GFS MORE STABLE. WE WILL TAKE A LOOK AT THE MORNING
MODEL RUN AND POSSIBLY ADD SOME MENTION OF CONVECTION TO THE
FORECAST IF THIS WRINKLE PERSISTS. THE FRONTAL PASSAGE LOOKS TO TAKE
PLACE THURSDAY MORNING WITH A STRONG SURFACE PRESSURE GRADIENT
REMAINING ACROSS THE REGION THROUGHOUT THE DAY SUPPORTING RED FLAG
CONDITIONS...THUS THE FIRE WEATHER WATCH WILL CONTINUE FOR STRONG
WINDS AND LOW HUMIDITY WITH THIS MORNINGS PACKAGE. THE UPPER LOW
SHIFT NE OF THE REGION THURSDAY NIGHT WHILE THE 4-CORNERS HIGH
BEGINS TO EXPAND NORTHWARD THROUGH THE GREAT BASIN FRIDAY THROUGH
SUNDAY. ONCE AGAIN...THE MODELS ARE SHOWING AN INFLUX OF
SUB-TROPICAL MOISTURE WORKING AROUND THE WRN PERIPHERY OF THE HIGH
SUNDAY OPENING THE DOOR FOR CONVECTION AS EARLY AS MONDAY AND
CONTINUING THROUGHOUT THE WEEK. HUSTON

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING IDZ410-425.

FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING IDZ422-427.

&&

$$






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