Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 041608
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1008 AM MDT TUE AUG 4 2015

.DISCUSSION...SKIES ARE MOSTLY SUNNY OVER THE AREA THIS MORNING
NOW THAT NOCTURNAL THUNDERSTORMS HAVE MOVED EAST OF THE AREA.
LATEST MODELS INDICATE CAPE VALUES OF SEVERAL HUNDRED FOR MUCH OF
THE AREA THIS AFTERNOON/EVENING. THIS CAPE DECREASES SLIGHTLY BUT
BASICALLY EXTENDS OVERNIGHT...WHICH IS UNUSUAL. THIS IS
CONSISTENT WITH THE HIGHER POPS ALREADY IN THE FORECAST FOR THE
OVERNIGHT HOURS. WE EXPECT STORMS TO FIRE ON THE HIGHER TERRAIN
AND THEN MOVE NE FROM EARLY THIS AFTERNOON INTO THE EVENING
HOURS...THEN REINTENSIFY AFTER MIDNIGHT AS A STRONG SHORTWAVE
TROUGH MOVES THROUGH. THIS OVERALL SCENARIO HAS PROMPTED THE
ISSUANCE OF A RED FLAG WARNING FOR MUCH OF THE SE THIS AFTERNOON
AND EVENING...AND EXTENDING NORTH AND EAST TOMORROW AFTERNOON AND
EVENING AS THE SHORT WAVE CONTINUES ITS TREK THROUGH MAINLY THE
EASTERN HALF OF THE CWA. WILL DO AN UPDATE TO INCREASE POPS IN THE
TREASURE VALLEY THIS AFTERNOON AND ESPECIALLY THIS EVENING...ALONG
WITH SMALL CHANGES IN OTHER AREAS.

&&

.AVIATION...VFR WITH INCREASING MID-HIGH LEVEL CLOUDS. SHOWERS AND
THUNDERSTORMS AFTER 04/18Z...MAINLY IN THE MOUNTAINS SOUTH OF THE
TREASURE VALLEY...THEN SPREADING THROUGH SOUTH TO NORTH TO THE
ENTIRE AREA BY 05/12Z AND CONTINUING THROUGH 06/03Z. SURFACE WINDS
GENERALLY 10 KTS OR LESS...WITH OCCASIONAL GUSTS TO 20 KTS...AND
VARIABLE GUSTY OUTFLOW WINDS NEAR 45 KTS NEAR STRONGER
THUNDERSTORMS. WINDS ALOFT NEAR 10K FT MSL...WSW 10-15 KTS.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH WEDNESDAY...A LINGERING CLUSTER OF
THUNDERSTORMS IS MOVING THROUGH SOUTHWEST IDAHO AT 4 AM
MDT...EXPECT THIS CLUSTER TO MOVE THROUGH THE TREASURE VALLEY AND
EAST-NORTHEAST INTO THE WEST CENTRAL MOUNTAINS...DYING OUT BY 6
AM MDT. ASIDE FROM THIS CLUSTER...THE CLOUD SHIELD HAS MOVED OUT
OF THE REGION BEHIND THE PASSING OF MONDAY/S SHORTWAVE. AN UPPER
LEVEL TROUGH WILL ALLOW FOR RAIN AND A SLIGHT CHANCE OF
THUNDERSTORMS TO RETURN TO THE REGION AS EARLY AS THIS AFTERNOON
LASTING INTO THE EVENING...MAINLY ALONG THE NEVADA BORDER...THE
MAGIC VALLEY...AND INTO THE SOUTHERN BOISE MOUNTAINS. THE BRUNT OF
THE TROUGH WILL COME WEDNESDAY WITH RAIN SHOWERS AND A CHANCE OF
THUNDERSTORMS WITH INCREASED INSTABILITY AND AMPLE MOISTURE OVER
THE ENTIRE REGION. EXPECTING HIGH QPF WITH THIS TROUGH...UP TO 0.1
INCHES IN SOME PLACES...MOSTLY IN THE WEST CENTRAL AND BOISE
MOUNTAINS. TEMPERATURES WILL REMAIN ABOUT NORMAL TODAY AND DROP
5-10 DEGREES BELOW NORMAL WEDNESDAY WITH DECREASING HEIGHTS AND
AMPLE CLOUD COVER.

LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY...ACTIVE
WEDNESDAY EVENING IS EXPECTED OVER IDAHO DUE TO THUNDERSTORMS. UPPER
TROUGH OVER ID THURSDAY WILL KEEP HIGH TEMPS 4-7F BELOW NORMAL THEN
SW FLOW WILL DEVELOP FRIDAY AHEAD OF A COASTAL CALIFORNIA UPPER LOW.
FRIDAY AFTERNOON THUNDERSTORMS COULD REACH ACROSS THE ORE-NV BORDER
WHICH IS FASTER THAN GFS/EC. SATURDAY LOOKS QUITE ACTIVE AGAIN. CA
LOW HAS 80KT UPPER JET SUPPORT WHICH LIFTS NE ACROSS S IDAHO
SATURDAY MORNING SO NOCTURNAL STORMS ARE STILL ON TRACK...AS ARE
THUNDERSTORMS LATER SATURDAY AS THE UPPER LOW/TROUGH  LIFTS NE.
SUNDAY THROUGH TUESDAY THE LONG WAVE PATTERN LOOKS TO START TO
RETROGRADE FOR A RETURN TO NEAR NORMAL TEMPERATURES AND POPS
FAVORING NE OREGON. AN OFFSHORE TROUGH AND HOT CENTRAL U.S. RIDGE
DOMINATE THE LAST OF THE LONG TERM.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...RED FLAG WARNING FROM 9 AM TO 9 PM MDT WEDNESDAY
     IDZ400-401-420-424.
     RED FLAG WARNING FROM 3 PM THIS AFTERNOON TO 9 PM MDT WEDNESDAY
     IDZ423-426.
OR...RED FLAG WARNING FROM 9 AM TO 9 PM MDT WEDNESDAY ORZ637.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...SP
AVIATION.....EP
PREV SHORT TERM...AB
PREV LONG TERM....VM


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