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

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000
FXUS66 KMTR 141156
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
356 AM PST SUN FEB 14 2016

...WARM TODAY THROUGH TUESDAY...

.SYNOPSIS...HIGH PRESSURE WILL STRENGTHEN OVER CALIFORNIA DURING
THE NEXT FEW DAYS. RECORD HIGH TEMPERATURES ARE POSSIBLE THROUGH
TUESDAY. COOLING IS FORECAST FOR WEDNESDAY AS A LOW PRESSURE
TROUGH APPROACHES...WITH RAIN BECOMING LIKELY WEDNESDAY NIGHT INTO
THURSDAY. RAIN CHANCES WILL CONTINUE IN THE NORTH THROUGH FRIDAY.
DRY WEATHER IS FORECAST TO RETURN TO ALL AREAS BY NEXT WEEKEND.

&&

.DISCUSSION...AS OF 3:40 AM PST SUNDAY...SKIES REMAIN MOSTLY
CLEAR EARLY THIS MORNING AS NORTHERLY FLOW BRINGS A DRIER AIRMASS
INTO OUR REGION. SURFACE GRADIENTS REMAIN WEAK ONSHORE AND SO IT
IS STILL POSSIBLE WE COULD SEE PATCHY DENSE FOG FORM NEAR THE
COAST PRIOR TO SUNRISE...MAINLY AROUND MONTEREY BAY. OTHERWISE
SKIES SHOULD REMAIN MOSTLY CLEAR.

AN UPPER RIDGE BUILDING JUST OFFSHORE IS FORECAST TO CONTINUE
STRENGTHENING THROUGH MONDAY...AND SHIFT EASTWARD OVER CALIFORNIA.
SUBSIDENCE UNDER THIS RIDGE WILL RESULT IN AN UNSEASONABLY WARM
AIRMASS OVER OUR REGION THROUGH TUESDAY WITH 850 MB TEMPS IN
EXCESS OF 15 DEG C. IN ADDITION...SURFACE HIGH PRESSURE WILL
BUILD INLAND TO OUR NORTH AND EAST AND DRIVE LOCALLY GUSTY
OFFSHORE WINDS...MAINLY IN THE HILLS...FROM TODAY THROUGH MIDDAY
MONDAY. THESE DEVELOPMENTS WILL RESULT IN THREE WARM DAYS FROM
TODAY THROUGH TUESDAY...WITH HIGH TEMPERATURES EXPECTED TO BE
ANYWHERE FROM 10 TO 20 DEGREES WARMER THAN AVERAGE FOR THIS TIME
OF YEAR. AT LEAST A FEW RECORD HIGHS ARE LIKELY...ESPECIALLY ON
MONDAY AND TUESDAY WHEN TEMPS ARE EXPECTED TO REACH THEIR PEAK.

NORTHERLY WINDS WILL BEGIN TO INCREASE IN THE HILLS BY SUNRISE
THIS MORNING AND THEN REMAIN GUSTY ON THROUGH TONIGHT AND INTO
MONDAY MORNING. THE LATEST WRF INDICATES STRONGEST WINDS TODAY
WILL BE IN THE SANTA LUCIA MOUNTAINS AS WELL AS LOCALLY IN THE
SANTA CRUZ MOUNTAINS AND SOUTHERN DIABLO RANGE. GUSTY WINDS WILL
MIX LOCALLY DOWN TO SEA LEVEL BY LATE MORNING AND INTO THE
AFTERNOON. GUSTS TO 40 MPH ARE POSSIBLE IN THE HILLS. WINDS ARE
NOT EXPECTED TO REACH ADVISORY LEVELS EXCEPT PERHAPS ACROSS SOME
OF THE EXPOSED HIGHER RIDGES FOR BRIEF PERIODS OF TIME. WINDS
WILL DECREASE IN ALL AREAS BY MONDAY AFTERNOON.

OFFSHORE FLOW WILL DIMINISH BY TUESDAY WHICH WILL PROBABLY RESULT
IN SLIGHT COOLING IN MOST COASTAL AREAS. BUT INLAND AREAS WILL
REMAIN WARM ON INTO TUESDAY WITH MANY SPOTS LIKELY TO REACH OR
EXCEED 80 THAT DAY.

THE MODELS AGREE THAT THE UPPER RIDGE WILL MOVE WELL OFF TO OUR
EAST BY TUESDAY NIGHT...ALLOWING A SHARP UPPER TROUGH TO APPROACH
OUR COAST BY LATE WEDNESDAY AND THEN MOVE INLAND WEDNESDAY NIGHT
AND THURSDAY MORNING. THERE HAS BEEN SOME MODEL INCONSISTENCY
REGARDING THE AMOUNT OF RAIN THIS SYSTEM WILL GENERATE FROM LATE
WEDNESDAY THROUGH MIDDAY THURSDAY. RECENT MODEL RUNS HAVE
INDICATED THAT THE BEST DYNAMICS WITH THIS SYSTEM WOULD NOT BE IN
PHASE WITH THE MOST MOIST AIRMASS...WITH A MOIST PLUME EXPECTED
TO MOVE INLAND WELL TO THE SOUTH OF OUR AREA AND AWAY FROM THE
BEST DYNAMICS ASSOCIATED WITH THE UPPER TROUGH. THUS...RAINFALL
AMOUNTS WITH THIS SYSTEM HAVE GENERALLY BEEN IN THE QUARTER TO
HALF INCH RANGE...WITH LOCAL AMOUNTS UP TO THREE-QUARTERS OF AN
INCH. THE 06Z GFS PHASES THE DYNAMICS AND MOISTURE SOMEWHAT BETTER
AND PRODUCES GREATER RAINFALL TOTALS...ANYWHERE FROM A HALF INCH
TO AN INCH AND A HALF. IN ANY CASE...CONFIDENCE IS GROWING THAT WE
WILL SEE WIDESPREAD LIGHT TO MODERATE RAINFALL FROM THIS SYSTEM AS
IT MOVES THROUGH...WITH MOST OF THE RAIN EXPECTED ON WEDNESDAY
NIGHT. SHOWERS WILL TAPER OFF BY THURSDAY AFTERNOON.

LATEST MODEL OUTPUT NOW SHOWS A SECOND SYSTEM PRODUCING ADDITIONAL
RAINFALL ACROSS AT LEAST THE NORTH BAY ON FRIDAY. DRY WEATHER IS
THEN EXPECTED TO RETURN TO ALL AREAS BY NEXT WEEKEND AS AN UPPER
RIDGE BEGINS TO BUILD ONCE AGAIN. THE 00Z GFS ENSEMBLE MEAN
FORECASTS THAT RIDGE TO PERSIST NEAR THE WEST COAST WELL BEYOND
NEXT WEEKEND...POSSIBLY MAINTAINING DRY WEATHER THOUGH THE END OF
THE MONTH.

&&

.AVIATION...AS OF 4:00 AM PST SUNDAY...VFR CONDITIONS EXPECTED AT
ALL TERMINALS THROUGH THE PERIOD DUE TO MODERATE NORTHERLY FLOW.
CURRENT FOG PRODUCTS SHOW NO DEVELOPMENT NEAR SF BAY REGION WITH A
SMALL AREA IN MONTEREY BAY THAT WILL NEED TO BE WATCHED. WINDS
WILL GENERALLY BE FROM THE NW. MODERATE TO HIGH CONFIDENCE.

VICINITY OF KSFO....MVFR THROUGH THE PERIOD WITH WINDS OF 290 TO
300 GUSTING TO 20 KT AFTER 21Z. HIGH CONFIDENCE.

SFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR LIKELY THROUGH THE PERIOD WITH
WINDS OF 280 TO 300 TO 15 KT DURING THE AFTERNOON. ONLY ISSUE OF
CONCERN IS A SMALL PATCH OF FOG IN MONTEREY BAY. WILL NEED TO
MONITOR THAT TO SEE IF IT NEARS KMRY. MODERATE TO HIGH CONFIDENCE.

&&

.CLIMATE...HERE IS A LIST OF RECORD HIGH TEMPERATURES FROM SUNDAY
FEBRUARY 14 THROUGH TUESDAY FEBRUARY 16. THE RECORD HIGH IS LISTED
FOR EACH DAY ALONG WITH THE YEAR THE RECORD WAS SET (IF THE RECORD
WAS SET ON MORE THAN ONE YEAR...THE MOST RECENT YEAR IS LISTED).

                          SUNDAY         MONDAY         TUESDAY
LOCATION                  FEB 14         FEB 15         FEB 16

SAN FRANCISCO BAY AREA...
  KENTFIELD               84/1930        79/1930        77/1930
  SAN RAFAEL              78/1977        78/1977        77/1977
  NAPA                    81/1930        81/1943        81/1930
  SAN FRANCISCO DOWNTOWN  78/1930        76/1930        75/1930
  SAN FRANCISCO AIRPORT   74/1977        75/2015        69/2007
  OAKLAND MUSEUM          80/1977        80/2015        75/2015
  OAKLAND AIRPORT         72/2013        73/1977        73/1977
  RICHMOND                77/1977        75/1977        75/2015
  LIVERMORE               79/1977        80/1933        78/1977
  MOFFETT FIELD           82/1977        79/1977        73/1977
  SAN JOSE                80/1930        80/1930        78/1930
  GILROY                  80/1996        81/1991        81/1977

MONTEREY BAY AREA...
  MONTEREY                81/1943        79/1977        73/2013
  SANTA CRUZ              82/2015        82/1916        85/1930
  SALINAS                 83/2015        81/2013        80/1977
  SALINAS AIRPORT         84/2015        81/2015        77/2013
  KING CITY               85/1977        86/1977        90/1977

&&

.MARINE...AS OF 2:40 AM PST SUNDAY...GUSTY NORTHWESTERLY TO
NORTHERLY WINDS ARE EXPECTED OVER THE COASTAL WATERS WITH LIGHTER
WINDS OVER THE BAYS DUE TO A BUILDING RIDGE OF HIGH PRESSURE. RAIN
WILL RETURN LATE WEDNESDAY NIGHT INTO THURSDAY MORNING OF NEXT
WEEK AS A SYSTEM MOVES THROUGH.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT REYES TO PIGEON PT 0-10 NM
             SCA...PIGEON PT TO PT PINOS 0-10 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PT ARENA TO PIGEON PT 10-60 NM
             SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
             SCA...ROUGH BAR ADVISORY FOR SF BAR

&&

$$

PUBLIC FORECAST: DYKEMA
AVIATION: BELL
MARINE: BELL
CLIMATE: DYKEMA


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