Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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000
FXUS66 KMTR 231801
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1101 AM PDT THU OCT 23 2014

.SYNOPSIS...THE WEAK TAIL END OF AN APPROACHING PACIFIC WEATHER
SYSTEM WILL LIKELY BRING SOME LIGHT RAINFALL TO THE NORTHERNMOST
PORTIONS OF OUR DISTRICT TODAY...OTHERWISE MILD CONDITIONS ARE
EXPECTED. FRIDAY LOOKS TO BE MOSTLY SUNNY AND MILD...BUT THEN A
SOMEWHAT WETTER SYSTEM WILL MOVE IN ON SATURDAY AND SPREAD RAIN
CHANCES ACROSS MUCH OF OUR AREA. AFTER A FEW RESIDUAL SHOWERS ON
SUNDAY...DRY CONDITIONS AND SEASONAL TEMPERATURES ARE PROJECTED
INTO THE FIRST PART OF NEXT WEEK.

&&

.DISCUSSION...AS OF 09:21 AM PDT THURSDAY...A DEEP MOISTURE PLUME
CONTINUES TO IMPACT NORTHERN CALIFORNIA THIS MORNING WITH JUST
ABOUT ALL OF THE PRECIPITATION OCCURRING NORTH OF THE REGION.
LOOKING AT THE LATEST HRRR AND OTHER MODEL OUTPUT...HAVE BACKED
OFF ON PRECIPITATION ACROSS THE NORTH BAY AND KEPT ONLY A CHANCE TO
SLIGHT CHANCE OF RAIN NORTH OF THE GOLDEN GATE. FURTHER SOUTH...WE
CAN EXPECT WARMER TEMPERATURES THIS AFTERNOON WITH PLENTY OF HIGH
CLOUDS STREAMING OVER OUR NORTHERN AREAS. OTHERWISE...THE FORECAST
REMAINS ON TRACK FOR THE REMAINDER OF THE DAY.

&&

.PREV DISCUSSION...AS OF 3:09 AM PDT THURSDAY...MAINLY HIGH
CLOUDS ARE STREAMING ACROSS THE NORTHERN TWO THIRDS OF THE CWA AT
THIS TIME...AS THE SOUTHERN EDGE OF A SYSTEM NOW AFFECTING THE
PACIFIC NORTHWEST MOVES THROUGH. LATEST RADAR IMAGERY SHOWS ECHOES
ARE MAINLY REMAINING NORTH OF SONOMA AND NAPA COUNTIES AT THIS
TIME AND NO APPRECIABLE RAINFALL HAS YET BEEN PICKED UP BY
AUTOMATED GAUGES. EXPECT THE RAIN LINE TO SAG INTO THE NORTH BAY
TODAY BUT NOT MUCH RAINFALL IS EXPECTED WITH THIS WEAK SYSTEM.

AFTER THIS WEAK SYSTEM MOVES TO THE EAST...A STRONGER SYSTEM IS
PROGGED TO AFFECT MORE OF THE DISTRICT LATE FRIDAY NIGHT AND
SATURDAY WITH RAIN CHANCES EXTENDING AS FAR SOUTH AS WELL INTO
MONTEREY COUNTY BY MIDDAY SATURDAY. RAINFALL AMOUNTS OF UP TO ONE
INCH ARE POSSIBLE ACROSS PORTIONS OF THE NORTH BAY...WITH MUCH
LESS FROM THE BAY AREA SOUTH. AS THE UPPER LOW CENTER MOVES
ACROSS...ENOUGH INSTABILITY AND COLDER AIR ALOFT FOR A SLIGHT
CHANCE OF THUNDERSTORMS ACROSS PORTIONS OF THE NORTH BAY SATURDAY
AFTERNOON. SHOWERS TO TAPER OFF ON SUNDAY THEN DRIER CONDITIONS
ARE EXPECTED INTO THE EARLY PART OF NEXT WEEK. THERE CONTINUES TO
BE LARGE DIFFERENCES AMONGST THE MEDIUM RANGE MODELS REGARDING
RAIN CHANCES NEXT WEEK. THUS HAVE LEFT SOME SLIGHT CHANCE POPS
ACROSS THE NORTH FOR TUESDAY AND WEDNESDAY BUT DRY ELSEWHERE. LOW
CONFIDENCE.

&&

.AVIATION...AS OF 10:50 AM PDT THURSDAY...LARGE AREA OF MID AND
HIGH CLOUDS STREAMING ACROSS THE NORTHERN HALF OF THE BAY AREA AS
A LOW MOVES INTO THE PACIFIC NORTHWEST. CURRENT EXPECTATIONS ARE
THAT THE RAIN WILL NOT MAKE IT TO ANY TERMINALS SO HAVE NOT
MENTIONED ANY RAIN IN THE TAFS. LOWER CLOUDS WILL DEVELOP LATE
TONIGHT ESPECIALLY TOWARDS THE 12Z FRI TIME FRAME. THESE LOWER
CIGS WILL PERSIST THROUGH MOST OF THE REMAINING TAF PERIOD.

VICINITY OF KSFO...VFR CONDITIONS WITH JUST MID AND HIGH CLOUDS.
INCREASING LOW LEVEL MOISTURE WILL PRODUCE REDUCED CEILINGS AFTER
07Z. THIS WILL PERSIST THROUGH THE END OF THE TAF PERIOD. LOW-
MODERATE CONFIDENCE.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR CONDITIONS EXPECTED ALL DAY WITH
JUST SOME MID LEVEL CLOUDS MOVING IN. MVFR-IFR CONDITIONS DEVELOP
AFTER 06Z AND WORSEN AROUND 13Z FRI AND PERIST THROUGH END OF TAF
PERIOD.

&&

.MARINE...AS OF 10:51 AM PDT THURSDAY...HIGH PRESSURE CONTINUES
OFF THE SOUTHERN CALIFORNIA COAST WHILE LOW PRESSURE IS OFF
VANCOUVER ISLAND. THIS IS BRINGING LIGHT WINDS TO THE AREA WITH
STRONGER WINDS IN THE SOUTHERN WATERS. SOUTHERLY WINDS WILL
INCREASE FRIDAY NIGHT AND SATURDAY AS A LOW PRESSURE SYSTEM
DEEPENS OFF THE OREGON COAST. HIGH PRESSURE WILL BUILD OFF THE
CALIFORNIA COAST SUNDAY AND MONDAY AFTER THE LOW MOVES INLAND.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...NONE.

$$

PUBLIC FORECAST: RGASS
AVIATION/MARINE: JOHNSON

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