861
FXUS65 KPIH 130309
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
909 PM MDT MON AUG 12 2013
.UPDATE...LATEST SATELLITE AND RADAR IMAGERY SH0W THUNDERSTORM
ACTIVITY MOVING FURTHER NORTH AND OUT OF THIS FORECAST AREA. WILL
UPDATE FORECASTS TO SCALLE BCK ACTIVITY THE REMAINDER OF THE NIGHT
BUT KEEP MENTION OF ISOLATED SHOWERS AND THUNDERSTROMS ALONG THE
MONTANA BORDER FOR A FEW HOURS YET. FIRST LOOK AT THE 00Z NAM12
MODEL SUPPORTS A REPEAT OF THUNDERSTORM ACTIVITY. RED FLAG
WARNINGS CONTINUE IN EFFECT FOR TUESDAY. RS
&&
.PREV DISCUSSION... /ISSUED 222 PM MDT MON AUG 12 2013/
DISCUSSION...SERIES OF SHORTWAVES ROTATING AROUND UPPER LOW
ACROSS EAST IDAHO TODAY AND INTO TUESDAY. CONVECTION HAS ALREADY
FIRED EARLY THIS AFTERNOON ACROSS HIGHER TERRAIN. BELIEVE SNAKE
PLAIN WILL REMAIN MAINLY DRY AT LEAST TODAY. REPEAT FOR TUESDAY
AS STRONGER WAVE CURRENTLY REACHING CALIFORNIA COAST MAKES IT INTO
EASTERN IDAHO. PWATS SLIGHTLY HIGHER TUESDAY WHICH SHOULD LEAD TO
BETTER COVERAGE ACROSS THE REGION. THUS HAVE NUDGED UP THE
POPS...LEAVING ENOUGH SUPPORT FOR RED FLAG HEADLINES FOR THE FIRE
DISTRICT. UPPER RIDGE AXIS STRENGTHENS OVER EAST IDAHO WEDNESDAY
INTO THURSDAY. NAM HOLDS ON TO SMALL POCKETS OF MOISTURE AND QPF
OVER HIGHER ELEVATIONS EACH AFTERNOON. GFS SHOWING SOME SIGNS OF
MOISTURE BUT NO QPF SO HAVE LEFT EACH AFTERNOON DRY FOR NOW. IN
ADDITION...GUIDANCE PUSHES TEMPS THURSDAY BACK INTO THE MID 90S.
THIS SHOULD BE ABOUT 5-7 DEGREES SHORT OF RECORDS ACROSS THE AREA.
RIDGE PERSISTS INTO FRIDAY WITH CONTINUED DRY AND VERY WARM
CONDITIONS.
BREAKDOWN OF THE UPPER RIDGE BEGINS SATURDAY WITH GFS SLIDING A
BROAD TROUGH INTO THE WESTERN STATES. BASE OF TROUGH MOVES INTO
THE GREAT BASIN SATURDAY WITH ATTEMPT AT A CUT-OFF LOW. CONVECTION
REMAINS FOCUSED EITHER WITH THIS FEATURE MAINLY OVER NEVADA/UTAH
OR FURTHER NORTH OVER THE CENTRAL MOUNTAINS AS TROUGH AXIS MOVES
THROUGH WASHINGTON. TROUGH MAINLY OVERHEAD ON SUNDAY...WITH
CONTINUED THREAT OF CONVECTION HIGHER ELEVATION AREAS. DMH
AVIATION...THUNDERSTORMS HAVE DEVELOPED IN CENTRAL IDAHO MOUNTAINS
AS WELL AS SOUTHEAST IDAHO. VFR CONDITIONS PREVAIL WITH HIGH BASED
CLOUD BOTTOMS BUT EXPECT GUSTY WINDS AS STORMS PULSE. EXPECT THESE
CONDITIONS TO CONTINUE THROUGH 8 PM. TOMORROW IS A BETTER CHANCE
FOR WIDE SPREAD THUNDERSTORMS BUT SHOULD KEEP VFR CONDITIONS BUT
WITH GUSTY WINDS. PRESTON
FIRE WEATHER...UPPER LOW POSITIONED ALONG THE WASHINGTON COAST THIS
AFTERNOON AS THE NEXT UPSTREAM STORM SYSTEM WAS VISIBLE
SHIFTING EAST ACROSS THE PACIFIC. SE IDAHO REMAINS UNDER A FAIRLY
DRY SW FLOW ALOFT WITH LINGERING INSTABILITY CONTINUING OVER THE
CNTRL MOUNTAINS AND IDAHO PANHANDLE. SEVERAL WEAK DISTURBANCES WERE
CLEARLY VISIBLE IN SATELLITE IMAGERY WHICH MAY HELP TO INITIATE
CONVECTION ACROSS THE REGION TODAY AND TUESDAY. THE FIRST FEATURE
WAS LIFTING NE OUT OF NRN CALIFORNIA AND IS EXPECTED TO CONTINUE ITS
NE TREK CLIPPING THE CNTRL MOUNTAINS THIS AFTERNOON. INSTABILITY
ALSO ALLOWING STORMS TO DEVELOP IN SOUTHEAST PARTS.
THE 00Z...06Z..12Z NAM RUNS APPEAR TO BE GENERATING GREATER
THUNDERSTORM POTENTIAL ACROSS THE SNAKE PLAINS AND SE HIGHLANDS
TUESDAY AFTERNOON/EVE AS A RESULT OF A FAIRLY WELL DEFINED SYSTEM
CURRENTLY ROTATING INTO THE NRN/CNTRL CALIFORNIA COASTAL WATERS.
THIS FEATURE MAY PROVIDE THE DYNAMICS NECESSARY FOR THUNDERSTORM
ACTIVITY ACROSS THE REGION TUESDAY BUT THE AVAILABILITY OF AMPLE
MOISTURE IS A LINGERING QUESTION. DUE TO ONGOING FIRES AND LOW RH
COMBINED WITH DRY THUNDERSTORM POTENTIAL RED FLAG WARNINGS WILL BE
ISSUED TOMORROW FOR MOUNTAIN AREAS. STABLE CONDITIONS DEVELOPING
ACROSS THE REGION WEDNESDAY/THURSDAY AS THE AFOREMENTIONED PAC
TROUGH APPROACHES THE COAST AND THE RIDGE EXPANDS NORTH ACROSS THE
REGION. THE RIDGE BREAKS DOWN AND THE TROUGH SWEEPS INLAND
FRIDAY/SATURDAY WITH A FRONTAL PASSAGE ANTICIPATED SOMETIME SATURDAY
AFTERNOON/EVE FOR POTENTIAL HIGH IMPACT WEATHER EVENT. PRESTON/
HUSTON
AIR STAGNATION...WILDFIRE SMOKE HAS PROMPTED IDAHO DEQ OFFICES TO
ISSUE AIR QUALITY ADVISORY FOR PORTIONS OF CENTRAL MOUNTAINS. HAVE
ADDED SMOKE TO CUSTER AND BLAINE COUNTIES...AND ALSO INCLUDED AREA
IN VICINITY AND DOWNSTREAM OF STATE FIRE NEAR SAMARIA. WILL EXPECT
AIR QUALITY ISSUES TO CONTINUE AS LONG AS FIRES CONTINUE TO BURN. DMH
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 10 AM TO 9 PM MDT TUESDAY IDZ413-427.
RED FLAG WARNING FROM 10 AM TO 9 PM MDT TUESDAY IDZ422-475-476.
&&
$$