Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 220851
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
251 AM MDT TUE JUL 22 2014

.SHORT TERM...TODAY THROUGH WEDNESDAY. MONSOON MOISTURE PLUME IS
SHIFTING TO THE NORTH TODAY...WHICH WILL RESULT IN THE SHOWERS AND
TSTMS STAYING OVER THE CENTRAL MTNS FOR THE MOST PART. ISOLD TSTMS
ARE STILL POSSIBLE ACROSS THE NORTHERN PARTS OF THE SNAKE RIVER
PLAIN THIS AFTN. THE REST OF THE FCST AREA IS EXPECTED TO REMAIN
DRY. LINGERING MOISTURE. THE UPPER RIDGE OVER THE CENTRAL US WILL
AMPLIFY ON WED AD AN UPPER CLOSED LOW MOVES INTO THE PAC NW. ISOLD
TSTMS WILL AGAIN BE POSSIBLE OVER THE CENTRAL MTNS WED AFTN AND
EVE DUE TO PAC MOISTURE BROUGHT IN BY THE UPPER LOW. TEMPS CLIMB
BACK UP ON WED DUE TO THE AMPLIFYING RIDGE.

.LONG TERM...THURSDAY THROUGH TUESDAY. THE UPPER LOW QUICKLY
MOVES NORTHEAST INTO ALBERTA ON THURSDAY...TAKING ANY THREAT OF
PRECIP ALONG WITH. A DRY COLD FRONT PASSES THRU THURSDAY
MORNING...CREATING WINDY CONDITIONS. THIS WILL ALSO RESULT IN
COOLER TEMPS THU AND FRI AS THE UPPER RIDGE IS PUSHED COMPLETELY
OUT OF THE AREA. TEMPS IN THE CENTRAL MTN BASINS ARE EXPECTED TO
FALL TO THE LOWER 30S FRI MORN...AND INTO THE 40S IN MUCH OF THE
REST OF THE FCST AREA. THE UPPER RIDGE BUILDS BACK UP OVER THE
WEEKEND...WHICH WILL PUSH TEMPS BACK UP AS WELL. THE GFS IS
HINTING AT MONSOON MOISTURE BEGINNING TO FLOW BACK INTO ID ON MON
AND TUE...BUT FOR NOW WILL LEAVE THE FCST DRY. HEDGES

&&

.AVIATION...A DRIER SW FLOW WILL SPREAD INTO THE SE HALF OF THE
FORECAST AREA TODAY WITH VFR SCT MID-LEVEL CLOUDS ANTICIPATED AT THE
KBYI KPIH AND KIDA TERMINALS. A SUB-TROPICAL MOISTURE PLUME
EXTENDING FROM A SHALLOW LOW OFF THE SRN CALIFORNIA COAST WILL LIFT
NE THROUGH THE CNTRL MOUNTAINS TODAY HELPING TO SUPPORT SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THAT REGION POTENTIALLY
IMPACTING THE KSUN TERMINAL. THE REMAINS OF THE LOW OFF THE
CALIFORNIA COAST LIFT THROUGH ERN OREGON OVERNIGHT SUPPORTING
ONGOING NOCTURNAL SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE CNTRL
MOUNTAINS. AT THIS TIME...THE BULK OF THIS ACTIVITY LOOKS TO BE
NORTH OF KSUN WITH LITTLE IF ANY IMPACT ANTICIPATED ON THE TERMINAL.
HUSTON

&&

.FIRE WEATHER...EARLY MORNING SATELLITE IMAGERY WAS SHOWING A DEEP
LOW PRESSURE SYSTEM SHIFTING SOUTH ALONG THE BRITISH COLUMBIA COAST
WITH A SHALLOW SUB-TROPICAL LOW POSITIONED OFF SRN CALIFORNIA AND AN
ASSOCIATED MOISTURE PLUME LIFTING NE ACROSS CALIFORNIA AND WRN
NEVADA. NUMERICAL MODELS SHOW THIS PLUME OF MOISTURE LIFTING NE
THROUGH CNTRL IDAHO TODAY SUPPORTING SCATTERED SHOWERS AND ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS. MEANWHILE...ACROSS THE SE
DISTRICTS...A DRY AND STABLE AIRMASS IS EXPECTED TO GRADUALLY WORK
INTO THE AREA THIS AFTERNOON/EVENING EFFECTIVELY SUPPRESSING ANY
CONVECTIVE POTENTIAL IN THAT REGION. ONGOING SHOWER ACTIVITY IS
EXPECTED TO CONTINUE ACROSS THE CNTRL MOUNTAINS OVERNIGHT AS THE
REMAINS OF THE SHALLOW LOW OFF THE CALIFORNIA COAST LIFT NE THROUGH
THE REGION. ONCE THIS SYSTEM CLEARS THE AREA WEDNESDAY MORNING...A
DRIER SW FLOW WILL ADVANCE ACROSS THE AREA AHEAD OF THE DEEP LOW NOW
POSITIONED NEAR PORTLAND. THIS LOW EJECTS NE THROUGH WASHINGTON
WEDNESDAY NIGHT AND INTO CANADA THURSDAY WHILE AN ASSOCIATED DRY
SURFACE COLD FRONT SWEEPS INTO/THROUGH SE IDAHO. WIND SPEEDS WILL
BEGIN TO RAMP UP WEDNESDAY AFTERNOON ACROSS THE CNTRL MOUNTAINS
AHEAD OF THE DEVELOPING FRONT WITH NEAR RED FLAG CONDITIONS
EXPECTED. A SOLID RED FLAG WIND/LOW HUMIDITY EVENT IS EXPECTED
ACROSS THE AREA THURSDAY AS THE FRONT ADVANCES THROUGH THE
REGION...THUS A FIRE WEATHER WATCH WILL BE POSTED WITH THE MORNING
FORECAST PACKAGE. STARTING FRIDAY AND CONTINUING INTO THE
WEEKEND...THE 4-CORNERS HIGH EXPANDS NORTHWARD ACROSS SRN IDAHO WITH
HOTTER TEMPERATURES RETURNING TO THE AREA BY SUNDAY. BY
MONDAY...SUB-TROPICAL MOISTURE IS EVIDENT LIFTING NORTH AROUND THE
WRN PERIPHERY OF THE HIGH...OPENING THE DOOR TO INCREASED
THUNDERSTORM ACTIVITY THROUGH THE FIRST HALF OF NEXT 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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