FXUS66 KHNX 012304
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
304 PM PST TUE DEC 1 2009

.SYNOPSIS...
HIGH PRESSURE OVER THE AREA WILL CONTINUE NIGHT AND MORNING FROST AND
FOG THROUGH SATURDAY FOR THE SAN JOAQUIN VALLEY. A CHANGE TO A MUCH
WETTER WEATHER PATTERN WILL BEGIN SUNDAY AS THE FIRST IN A SERIES 
OF STORMS MOVES ACROSS THE REGION. 

&&

.DISCUSSION...HIGH PRESSURE ALOFT WILL CONTINUE OVER THE WEST
COAST THRU EARLY FRI. HOWEVER...AN UPPER TROF MOVING SOUTH ALONG
THE CONTINENTAL DIVIDE WILL DROP SOME CANADIAN AIR SOUTH INTO THE
GREAT BASIN OVER THE NEXT 24-48 HRS. SOME OF THIS COOLER AIR WILL
WORK INTO CENTRAL CA WITH SLIGHTLY COOLER TEMPS THE NEXT FEW
DAYS...BUT STILL A FEW DEGS ABOVE AVERAGE. VALLEY FROST COULD
BECOME A LITTLE MORE WIDESPREAD EARLY THURS AND/OR FRI...BUT
NOTHING UNUSUAL FOR EARLY DEC. FOG CONTINUES TO BE VERY LIMITED IF
ANY AT ALL...AS STRONG NOCTURNAL INVERSIONS HAVE BEEN VERY SHALLOW
AND A RELATIVELY DRY GROUND KEEPS LOW LEVEL SATURATION MINIMAL.

MODELS CONT TO INDICATE A LARGE-SCALE CHANGE IN THE PACIFIC OVER
TIME. A MASSIVE UPPER RIDGE IS FCST BY THE MEDIUM-RANGE MODELS TO
DEVELOP OVER THE GLF OF AK. THE IMPLICATIONS OF THIS ARE TWOFOLD
FOR CENTRAL CA. 

FIRST...BOTH GFS AND THE EURO DIG A COLD DOWNSTREAM TROF SOUTH
ACROSS WESTERN CANADA...INTO THE NW US...WITH ITS ARCTIC AIR
PUSHING SOUTH ACROSS THE NORTHERN ROCKIES...PAC NW...AND NRN GREAT
BASIN. THIS TROF WILL BRING A GENERALLY LIGHT MIX OF PRECIP TO
CENTRAL CA LATE SAT INTO SUN AS IT SAGS SOUTH. SNOW LEVELS
DROPPING TO 5-6K...POSSIBLY LOWER AROUND YOSEMITE...DEPENDING ON
HOW FAR SOUTH TROF MOVES.

SECOND...AND MORE IMPORTANTLY...IS A POTENTIAL WET PATTERN
DEVELOPING INTO CENTRAL CA...AS THE SOUTHERN BRANCH OF THE
WESTERLIES UNDERCUTS THE MASSIVE RIDGE. GFS AND THE ECM HAVE BEEN
HAVING SIGNIFICANT DIFFERENCES ON THE INITIAL ARRIVAL OF THE
MOISTURE PLUME FROM THE CENTRAL AND WESTERN PACIFIC AND WHEN...OR
EVEN IF...MOISTURE WITH TYPHOON NIDA WILL BECOME INVOLVED. AT THIS
TIME...THE FCST IS WEIGHTED TOWARD THE WETTER AND NOT AS COLD EURO
FOR EARLY NEXT WEEK...BUT THAT COULD CHANGE.

WITH SO MANY UNCERTAINTIES STILL UNRESOLVED...MADE ONLY MINOR
UPWARD ADJUSTMENTS TO PREVIOUS POP FCSTS...AND MAINLY FOR SUN NITE
THRU MON. REGARDLESS ON HOW EVENTS ACTUALLY PLAY OUT...ONE THING
IS PRETTY CERTAIN...IT WILL NOT RAIN CONTINUOUSLY SUN-TUES...AND
AMOUNTS WILL MAINLY BE LIGHT. POSSIBLY SOME BRIEF MODERATE PERIODS
OF PRECIP...DEPENDING ON WHERE...OR EVEN IF...THE MOISTURE TRAIN
ENDS UP.

&&

.AVIATION...
IN THE SAN JOAQUIN VALLEY...PATCHY FOG WILL DEVELOP OVERNIGHT WITH 
AREAS OF MVFR LOCAL IFR VISIBILITIES POSSIBLE FROM 10Z TO 18Z 
WEDNESDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL ACROSS THE 
CENTRAL CALIFORNIA INTERIOR THROUGH 00Z THURSDAY. 

&&

.AIR QUALITY ISSUES...
ON TUESDAY DECEMBER 1 2009... FIREPLACE/WOOD STOVE BURNING IS
PROHIBITED IN FRESNO... KERN AND KINGS COUNTIES.
FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

PUBLIC...BINGHAM
AVN/FW...MENDENHALL

WEATHER.GOV/HANFORD