HAMweather.com Area Forecast Discussion for County Warning Area PIH

Thu, 16 Feb 2012 06:49:11 GMT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
200 PM MST WED FEB 15 2012

.SHORT TERM...TONIGHT THROUGH SATURDAY. THE LATEST SATELLITE IMAGERY 
WAS SHOWING A SPLIT UPPER TROUGH SHIFTING SOUTH AND EAST OF THE 
REGION EARLY THIS AFTERNOON WITH LIGHT SNOWFALL NOTED ACROSS THE 
BEAR LAKE REGION ON THE NRN FRINGE OF THE SRN BRANCH OF THE SPLIT. 
HAVE GENERALLY HELD ON TO A SLIGHT CHANCE MENTION OF PRECIPITATION 
IN THE SE EARLY THIS EVENING FOLLOWED BY CLEARING ALOFT LATER 
TONIGHT AS A RIDGE BUILDS INTO THE REGION AHEAD OF THE NEXT PAC 
SYSTEM. WITH CLEARING SKIES LATE TONIGHT...POTENTIAL EXISTS FOR 
PATCHY VALLEY FOG AND HAVE CONTINUED A MENTION WITHIN THE SNAKE 
PLAIN/ERN MAGIC VALLEY THURSDAY MORNING. NEXT UPSTREAM WAVE TOPS 
LONG-WAVE RIDGE POSITIONED ALONG THE COAST THURSDAY MORNING AND THEN 
DIGS SE INTO/THROUGH THE NRN ROCKIES THURSDAY NIGHT/FRIDAY. GFS 
MODEL HAS BEEN SOMEWHAT PERSISTENT IN GENERATING LIGHT SNOWFALL 
ALONG THE MONTANA/WYOMING BORDER REGIONS WHEREAS THE NAM HAS BEEN 
DRY. HAVE OPTED TOWARD THE GFS SOLUTION AND MAINTAINED A LOW END 
CHANCE MENTION OF PRECIPITATION LATE THURSDAY NIGHT THROUGH FRIDAY. 
A SECOND...STRONGER WAVE...BREAKS INTO THE PAC NW STATES LATE FRIDAY 
NIGHT WITH THE ASSOCIATED PRECIPITATION SHIELD SPREADING ACROSS THE 
FORECAST AREA SATURDAY/SATURDAY NIGHT PER THE GFS/ECMWF MODELS. THE 
NAM HAS A SOMEWHAT FASTER/MORE PROGRESSIVE SOLUTION SHOWING 
PRECIPITATION SPREADING INTO THE CNTRL MOUNTAINS AS EARLY AS FRIDAY 
NIGHT. WILL STICK WITH THE GFS/ECMWF SOLUTIONS FOR NOW WHILE 
MAINTAINING A LOW END MENTION OF PRECIPITATION IN THE CNTRL 
MOUNTAINS FRIDAY NIGHT. SYSTEM APPEARS TO PRODUCE SUB-ADVISORY LEVEL 
SNOWFALL ACROSS THE CNTRL MOUNTAINS...THUS WILL ALLOW SPECIAL 
WEATHER STATEMENT TO EXPIRE THIS AFTERNOON WHILE REFRESHING THE 
HAZARDOUS WEATHER OUTLOOK TO ADDRESS THE STORMS POTENTIAL. HUSTON

.LONG TERM...SATURDAY NIGHT THROUGH NEXT WEDNESDAY NIGHT.  500MB 
LONGWAVE PATTERN UNDERGOES A DE-AMPLIFICATION WITH A SHIFT OF THE 
STORM TRACK SLIGHTLY NORTHWARD.  THUS AFTER THE SAT/SAT NIGHT/SUN 
STORM EXITS...POPS LOWER QUITE A BIT...THOUGH NOT QUITE TO ZERO.  
THE HIGHER 500MB HEIGHTS ALSO INDICATE A WARMING WITH TEMPERATURES 
GETTING BACK ABOVE NORMAL BY TUE.  THE TROUGH ON SUN IS BY FAR THE 
STRONGEST PRECIPITATION EVENT OF THE PERIOD.  ADVISORY LEVEL SNOW IS 
THE MOST LIKELY TYPE OF EVENT.  HAVE BOOSTED POPS FOR THE FIRST 24 
HOURS OF THIS TIME.  AFTER THIS...MAINLY THE CENTRAL IDAHO MOUNTAINS 
AND THE ID-MT BORDER REGION ARE AFFECTED BY TROUGHS MOVING IN FROM 
THE NORTHWEST AND GENERATING MAINLY LIGHT MOUNTAIN SNOWS. DRIEST 
TIME IS MON AFTERNOON THROUGH TUE MORNING.  IN GENERAL..THE GFS 
CONTINUES TO BE THE WETTER GUIDANCE...AND TRENDED WETTER FOR THE 
WEEKEND STORM.  HOWEVER IT IS TRENDING DRIER AFTER MON.  STRONGEST 
WIND OCCURS WITH THE WEEKEND STORM AS WELL.  MESSICK 

.AVIATION...STRATUS CONTINUES TO HAMPER KBYI AND KIDA.  
HOWEVER..EXPECTING A NORTH WIND TO DEVELOP TONIGHT WHICH SHOULD 
BRING A DRYING CONDITION TO THE VALLEY.  THUS NO REPEAT OF IFR OR 
MARGINAL VFR EXPECTED LATE TONIGHT OR EARLY THU MORNING.  GFS MOS 
INDICATES CATEGORY 1 CIG AT KIDA FOR AFTER SUNRISE...BUT THE USUALLY 
BETTER NAM MOS GUIDANCE HAS NO RESTRICTED CIG.  KIDA IS WHERE THE 
NORTHERLY FLOW SHOULD BE STRONGEST...THUS ADIABATIC WARMING IN THE 
DOWNSLOPE FLOW SHOULD KEEP THE STRATUS AND FOG AWAY AND WILL GO WITH 
THE NAM EXPECTATIONS.  KSUN SHOULD ALSO STAY IN FINE SHAPE WITH 
NORTHWESTERLY FLOW THERE. MESSICK

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