FXUS66 KMTR 251753
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
953 AM PST FRI DEC 25 2009
.DISCUSSION...AS OF 9:00 AM PST FRIDAY...OTHER THAN SOME LOCALIZED
FREEZING FOG IN SANTA ROSA...SKIES ARE MAINLY CLEAR ACROSS THE
DISTRICT. TEMPS ARE MAINLY IN THE 30S AND 40S...WITH A FEW UPPER 20S
IN THE INLAND VALLEYS.
MODELS ARE STILL IN DISAGREEMENT FOR THE UPCOMING WEEKEND. THE 12Z
GFS IS QUITE DRY WHEREAS THE NAM12 IS WETTER. BASICALLY...THE
DISTRICT IS UNDER A RIDGE WHICH IS SANDWICHED BETWEEN THE LARGE
SYSTEM IN THE MIDWEST AND A DEEP TROUGH CENTERED NEAR 150W IN THE
PACIFIC. A SHORTWAVE EJECTS FROM THE PACIFIC LONGWAVE TROUGH AND
SPLITS AS IT REACHES 130W. THE GFS DROPS THE SOUTHERN PORTION SOUTH
ALONG 130W AND THEN SE TO NORTHERN BAJA. THE NAM12 ON THE OTHER HAND
KEEPS THE SOUTHERN PIECE MUCH FURTHER NORTH AND WEST...LEADING TO A
BETTER CHANCE OF RAIN FOR LATE SAT/SAT NIGHT. WITH SPLITTING SYSTEMS
IT IS GENERALLY BETTER TO FOLLOW THE DRIER SOLUTION. THE GFS KEEPS
THE DISTRICT MAINLY DRY THE REMAINDER OF THE UPCOMING WEEK.
NO UPDATES AT THIS TIME.
&&
.AVIATION...AS OF 9:53 AM FRIDAY...HIGH PRESSURE OVER THE GREAT BASIN
WILL MAINTAIN LIGHT OFFSHORE FLOW THROUGH SATURDAY. VFR CONDITIONS
EXPECTED EXCEPT FOR MORNING FREEZING FOG AROUND STS. THE SAN
FRANCISCO BAY AREA TERMINALS MAY SEE SHOWER ACTIVITY TOMORROW
EVENING BUT AT THIS POINT THE SHOWERS WOULD BE OUTSIDE OF
THE FORECAST PERIOD.
VICINITY OF KSFO...VFR CONDITIONS THROUGH SATURDAY AFTERNOON.
GENERALLY WINDS WILL BE LIGHT SOUTH SOUTHEAST WITH NORTHWEST WINDS
EXPECTED THIS AFTERNOON. WINDS WILL ONCE AGAIN BE SOUTH SOUTHEAST
THIS EVENING.
KSFO BRIDGE APPROACH...SAME AS KSFO.
MRY BAY AREA TERMINALS...VFR CONDITIONS THROUGH SATURDAY AFTERNOON
WITH LIGHT EAST TO SOUTHEAST WINDS. WINDS WILL SWITCH TO LIGHT
NORTHWESTERLY DURING THE AFTERNOON AND BECOME SOUTH SOUTHEAST ONCE
AGAIN IN THE EVENING.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDA...NONE
$$
PUBLIC FORECAST: MHS
AVIATION/MARINE: LARRY
NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO
