FXUS65 KLKN 232313 CCA
AFDLKN

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ELKO NV
313 PM PST WED DEC 23 2009

.SYNOPSIS...HIGH PRESSURE WILL SIT OVER THE SILVER STATE FOR THE 
NEXT SEVERAL DAYS...RESULTING IN MOSTLY CLEAR SKIES AND VERY COLD 
TEMPERATURES. PATCHY LATE NIGHT AND EARLY MORNING FREEZING FOG IS 
EXPECTED IN SHELTERED VALLEYS...MAINLY NORTH OF HIGHWAY 50. A SERIES 
OF WEAK STORM SYSTEMS WILL PASS MOSTLY TO THE SOUTH OF THE REGION 
EARLY NEXT WEEK...BRINGING CLOUDS BUT LITTLE IF ANY PRECIPITATION.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY. SHARP UPPER LEVEL RIDGE IS
CURRENTLY SITTING TO OUR WEST NEAR THE PACIFIC COAST...WITH A DEEP
TROUGH OVER THE ROCKIES AND PLAINS TO OUR EAST. THIS IS PROVIDING
A BRISK NORTHERLY FLOW TO THE REGION ALOFT...BUT A STRONG
INVERSION WILL KEEP THE WIND AT THE SURFACE LIMITED. OVER THE NEXT
SEVERAL DAYS...THE RIDGE WILL MOVE INLAND WHILE SLOWLY WEAKENING.
THIS WILL KEEP SKIES MOSTLY CLEAR...AND THE LOW LEVEL INVERSION
SHOULD REMAIN INTACT EVERY DAY...KEEPING SURFACE TEMPERATURES IN
THE VALLEYS QUITE COLD. BACKED OFF A LITTLE BIT ON THE EXTREMENESS
OF THE COLD GIVEN BRISK FLOW ALOFT MAY KEEP THE INVERSION FROM
GETTING VERY STRONG. HOWEVER...GIVEN HISTORY WITH STRONG
INVERSIONS...DID INCLUDE SOME PATCHY LATE NIGHT AND EARLY MORNING
FREEZING FOG ACROSS NORTHER NEVADA DURING THE NEXT SEVERAL DAYS.
TEMPERATURES WILL BE ABOUT THE SAME EACH DAY...WITH MOST VALLEYS
SUBZERO FOR LOWS AND NOT BREAKING FREEZING FOR HIGHS. 

THINGS CHANGE A BIT BY THE END OF THE DAY SATURDAY AS A PACIFIC
STORM SYSTEM APPROACHES FROM THE WEST. GFS AND NAM ARE IN CLOSE
AGREEMENT BRINGING CLOUDS INTO THE SW PORTION OF THE CWA BY DAYS
END...SO INCREASED CLOUD COVER ACROSS THIS AREA PARTICULARLY
DURING SATURDAY AFTERNOON. RCM

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY... THE UPPER LEVEL
RIDGE WILL BEGIN TO BREAK DOWN AS PACIFIC ENERGY APPROACHES THE
WEST COAST. EXPECT THE UPPER LEVEL FLOW TO BECOME
SOUTHWESTERLY...SLIGHTLY WARMER MOIST AIR TO ADVECT INTO THE
SILVER STATE. ANTICIPATE INCREASED CLOUD COVERAGE AND UPWARD TREND IN
TEMPERATURES...TOWARDS SEASONAL NORMS. SOME OF THIS MOISTURE WILL 
SPILL OVER THE SIERRA RESULTING IN A CHANCE OF RAIN/SNOW SHOWERS OVER
HUMBOLDT COUNTY AND ISOLATED POCKETS OF LIGHT SNOW OVER THE 
REMAINDER OF THE CWA...ALTHOUGH SIGNIFICANT ACCUMULATIONS ARE NOT 
ANTICIPATED. THE LATEST RUNS OF THE OPERATIONAL GFS AND ECMWF ARE IN 
GOOD AGREEMENT THROUGH MONDAY. HOWEVER...AS THE FORECAST PERIOD 
UNFOLDS...THE GFS IS QUICKER TO GO MORE NEGATIVELY TILTED WITH THE 
TROF. THE ECMWF SPINS UP TWO H5 LOWS OVER THE WEST...ONE OVER THE 
NORTHERN ROCKIES AND THE OTHER SOUTH OF THE US/MEXICAN 
BORDER...WHEREAS THE GFS DEVELOPS AN H5 LOW OVER THE GREAT BASIN. 
PAST MONDAY THERE IS UNCERTAINTY IN THE MODELS.

&&

.AVIATION...UPPER LEVEL JET HAS CLEARED THE REGION...AND THE WINDS 
HAVE CALMED OVER CENTRAL NEVADA. FOR THE MOST PART...VFR CONDITIONS 
ARE ANTICIPATED FOR THE TAF LOCATIONS. HOWEVER...THE POTENTIAL 
EXISTS FOR PATCHY FREEZING FOG TO DEVELOP IN THE VICINITY OF EKO AND 
WMC.

&&

.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

93/97/97