FXUS66 KSTO 240534
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
930 PM PST WED DEC 23 2009
.DISCUSSION...
HIGH PRESSURE WILL DOMINATE THE WEATHER INTO EARLY SATURDAY BEFORE
THE NEXT SYSTEM APPROACHES. TEMPERATURES TONIGHT AND AND CHRISTMAS
MORNING WILL BE COLD TO START THE DAY...WITH TEMPERATURES GENERALLY
IN THE UPPER 20S TO LOWER 30S FOR MOST VALLEY LOCATIONS AND SOME OF
THE COLDER FOOTHILL LOCATIONS COOLING INTO THE MID 20S. THE AIRMASS
THROUGHOUT THE INTERIOR IS FAIRLY DRY BUT AS WINDS SHIFT THURSDAY
NIGHT FOG MAY BE A LITTLE BIT MORE PERSISTENT...ESPECIALLY ALONE THE
SPINE OF THE VALLEY AND NEAR WATER WAYS. A FEW PATCHES MAY FORM FROM
NEAR STOCKTON SOUTHWARD LATE TONIGHT...WITH SOME FREEZING FOG
POSSIBLE THAT COULD MAKE SOME BRIDGE TOPS SLICK IN THE MORNING. THE
QUESTION AT THIS TIME IS WHAT WILL HAPPEN SATURDAY MORNING WITH THE
FOG. HIGH CLOUDS MAY START TO MOVE INTO THE REGION TO HELP PREVENT
THE FORMATION BUT AT THE SAME TIME THE LOWER LEVEL SHOULD BE A
LITTLE MORE MOIST AND IF THE CLOUDS REMAIN THIN THEN SOME PATCHES OF
DENSE FOG COULD FORM EARLY SATURDAY MORNING.
THE NEXT SYSTEM WILL BEGIN TO MOVE ALONG THE COAST ON SATURDAY BUT
MAY NOT MOVE INTO THE INTERIOR UNTIL SATURDAY EVENING. DUE TO THE
DYNAMICS MOVING IN ALOFT THE CHANCES FOR PRECIPITATION THAT ARE
CURRENTLY IN THE FORECAST FOR THE AFTERNOON LOOK GOOD AT THIS TIME
EVEN WITH THE MODELS HOLDING BACK THE ONSET OF PRECIPITATION UNTIL
THE EVENING. SNOW LEVELS LOOK TO LOWER TO BETWEEN 3500 AND 4500 FEET
SATURDAY NIGHT FOR THE SIERRA NEVADA AND DOWN TO AROUND 2000 TO 3000
FEET OVER SHASTA COUNTY.
&&
.AVIATION...
VFR CONDITIONS OVER THE AREA THROUGH THURSDAY EXCEPT FOR MVFR DUE
TO BR AFT 08Z AND LOCAL LIFR CONDITIONS AFT 08Z UNTIL 18Z DUE TO
PATCHY FOG FROM AROUND SACRAMENTO AND SOUTH INTO THE NORTHERN SAN
JOAQUIN VALLEY. LOCAL NORTHEAST WIND GUSTS UP TO 40 KT IN FAVORED
NORTHEAST-SOUTHWEST ORIENTED CANYONS IN THE SIERRA IN THE NIGHT AND
MORNING HOURS.
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
