FXUS66 KMTR 300004
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
400 PM PST SUN NOV 29 2009

.DISCUSSION...AS OF 1:30 PM PST SUNDAY...IT HAS BEEN A BEAUTIFUL DAY
AROUND THE DISTRICT WITH TEMPS MAINLY IN THE 60S AND LOWER 70S. THESE
TEMPS ENDED UP BEING SEVERAL DEGREES WARMER THAN WAS THOUGHT THIS
MORNING...IN PARTICULAR THE NORTH BAY VALLEYS WHICH BENEFITED FROM
THE DOWNSLOPE WINDS. WINDS HAVE DECREASED DURING THE DAY AS THE
GRADIENT RELAXED.

THE UPCOMING WORK WEEK WILL FEATURE A RIDGE ALONG THE COAST WHICH
WILL CONTINUE THE DRY AND MILD WEATHER ACROSS THE DISTRICT.
TEMPERATURES WILL BE NEAR TO ABOVE NORMAL DURING THE DAY WITH COOL
NIGHTS. WITH LIGHTER WINDS OVERNIGHT LOWS SHOULD BE SIGNIFICANTLY
COOLER THAN LAST NIGHT.

NEXT WEEKEND INTO EARLY THE FOLLOWING WEEK...MODELS RAPIDLY DIVERGE
STARTING ON SATURDAY. THE MAIN ISSUE IS WHAT THE MODELS DO WITH THE
EXTRATROPICAL REMNANTS OF TYPHOON NIDA WHICH IS IN THE WESTERN
PACIFIC NEAR 19.6N/139.2E. THE 12Z GFS ESSENTIALLY KEEPS IT NEARLY
STATIONARY AND DISSIPATES IT NEAR ITS CURRENT POSITION. THIS FOLLOWS
THE JOINT TYPHOON CENTERS FORECAST. THE 12Z ECMWF LOOKS TO TAKE A
PIECE OF TYPHOON NIDA AND EJECTS IT INTO THE WESTERLIES...WHERE THE
ECMWF THEN BOMBS A 929 MB LOW (27.43 INCHES) NEAR 44/170W.

THE UPSHOT OF THIS IS THAT THE 12Z GFS KEEPS AN AMPLIFIED PATTERN
WITH A RIDGE IN THE EASTERN PACIFIC AND A DEEPENING OF THE HUDSON BAY
LOW. THIS WOULD KEEP THE DISTRICT MAINLY DRY WITH COOL TEMPS. THE GFS
ENSEMBLES THAT FAR OUT DOES SHOW A WIDE VARIETY OF SOLUTIONS. THE 12Z
ECMWF ON THE OTHER HAND BREAK THE WESTERLIES THROUGH TO THE COAST...
UNDERCUTTING THE RIDGE. THIS SCENARIO WOULD BRING WET WEATHER TO THE
DISTRICT THE END OF THE WEEKEND AND INTO THE FOLLOWING WEEK.

DUE TO THE BIG DISCREPANCY IN MODEL SOLUTIONS HAVE KEPT THE POPS
INHERITED AS IS FOR THE EXTENDED PERIOD. IT SHOULD BE AN INTERESTING
COUPLE OF DAYS AS THE MODELS CONTINUE TO STRUGGLE TO HONE IN ON A
SOLUTION.

&&

.AVIATION...AS OF 4:00 PM PST SUNDAY...HIGH PRESSURE OVER THE REGION
WILL MAINTAIN CLEAR SKIES ACROSS THE REGION THROUGH MONDAY.
NORTH WINDS WILL VEER TO THE EAST OVERNIGHT AND REMAIN
OFFSHORE THROUGH MONDAY.

VICINITY OF KSFO...VFR CONDITIONS THROUGH MONDAY. LIGHT WINDS
THROUGH THIS EVENING BECOMING EASTERLY OVERNIGHT.

KSFO BRIDGE APPROACH...SAME AS KSFO.

MRY BAY AREA TERMINALS...VFR CONDITIONS THROUGH MONDAY. NORTHWEST
WINDS BECOMING EASTERLY THIS EVENING AND TONIGHT.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
    .TNGT...NONE

$$

PUBLIC FORECAST: MHS
AVIATION/MARINE: CW

NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO