Frost Advisory 7, NWS San Francisco Bay Area, CA

834 
WWUS76 KMTR 121056
NPWMTR

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
256 AM PST THU NOV 12 2015

CAZ506-516-121700-
/O.CON.KMTR.FR.Y.0007.151112T1100Z-151112T1700Z/
NORTH BAY INTERIOR VALLEYS-
SOUTHERN SALINAS VALLEY...ARROYO SECO...AND LAKE SAN ANTONIO-
256 AM PST THU NOV 12 2015

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST THIS MORNING...

* TEMPERATURES...TEMPERATURES WILL FALL INTO THE LOW TO MID 30S
  EARLY THIS MORNING...COLDEST JUST BEFORE AND AFTER SUNRISE.

* LOCATIONS...NORTH BAY VALLEYS AND SOUTHERN SALINAS VALLEY.

* IMPACTS...DAMAGE TO FROST SENSITIVE VEGETATION WILL BE 
  POSSIBLE. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FROST ADVISORY MEANS THAT FROST IS POSSIBLE. SENSITIVE OUTDOOR
PLANTS MAY BE KILLED IF LEFT UNCOVERED.

&&

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
951 AM PST WED NOV 11 2015

.SYNOPSIS...A RIDGE OF HIGH PRESSURE WILL BUILD INTO OUR REGION
ALLOWING FOR TEMPERATURES TO WARM FOR THE REST OF THE WEEK. OUR
NEXT STORM SYSTEM IS EXPECTED TO IMPACT THE REGION SUNDAY INTO
MONDAY OF NEXT WEEK WITH RAIN LIKELY.

&&

.DISCUSSION...AS OF 09:06 AM PST WEDNESDAY...AFTER A VERY CHILLY
START TO THE MORNING WITH REPORTS OF DENSE FOG AND AREAS OF
FROST...TEMPERATURES CONTINUE TO WARM UNDER MOSTLY SUNNY SKIES.
DAY TIME TEMPERATURES ARE FORECAST TO BE A FEW DEGREES WARMER
COMPARED TO YESTERDAY AS 850 MB TEMPERATURES WARM AND WEAK RIDGING
DEVELOPS OVER THE EASTERN PACIFIC. OVERALL...DRY CONDITIONS WILL
PERSIST TODAY WITH AFTERNOON TEMPERATURES IN THE LOW TO MID 60S
REGION-WIDE. THE ONGOING FORECAST REMAINS ON TRACK AND NO UPDATES
ARE NEEDED AT THIS TIME.

&&

.PREV DISCUSSION...AS OF 3:00 AM PST WEDNESDAY...AS EXPECTED A
COMBINATION OF DRIER AIR PLUS CLEAR SKIES AND LIGHT WINDS HAS
ALLOWED TEMPERATURES TO DROP TO SOME OF THEIR LOWEST READINGS OF
THE WINTER. SO FAR TEMPS HAVE DROPPED INTO THE UPPER 30S TO MID
40S FOR MANY SPOTS ALTHOUGH SAN FRANCISCO REMAINS ONE OF THE
"WARMEST" LOCATIONS WITH TEMPS JUST DOWN TO 50. BASED ON CURRENT
DEW POINT VALUES, WOULD EXPECT A FEW MORE DEGREES OF COOLING BY
SUNRISE. WILL KEEP THE FROST ADVISORY GOING AS IS.

A RIDGE OF HIGH PRESSURE WILL BUILD BACK INTO OUR REGION OVER THE
NEXT SEVERAL DAYS ALONG WITH WARMER 850 MB TEMPS. THIS WILL LEAD
TO A GRADUAL INCREASE IN TEMPS WITH MANY HIGHS RETURNING BACK INTO
THE MID 60S TO LOWER 70S FOR FRIDAY AND SATURDAY. LOWS WILL
MODERATE AS WELL EACH MORNING.

MODELS REMAIN IN GOOD AGREEMENT THAT A SYSTEM WILL DROP DOWN FROM
THE NORTH AND BRING THE NEXT ROUND OF RAIN TO OUR CWA ON SUNDAY
WITH POST-FRONTAL SHOWERS EXPECTED INTO MONDAY. ALTHOUGH THE GFS
HAS SLIGHTLY DECREASED RAINFALL AMOUNTS, THE ECMWF AND GEM
CONTINUE TO BRING AN DECENT AMOUNT OF RAIN THROUGH OUR AREA
ASSOCIATED WITH A COLD FRONT. CURRENT QPF AMOUNTS LOOK TO BE IN
THE 1/4"-1/2" RANGE FOR MOST OF OUR CWA, ALTHOUGH WITH PW VALUES
FORECAST TO BE 1 TO 1.2" WE COULD SEE HIGHER AMOUNTS. POPS WERE
INCREASED FOR THE PERIOD.

MODELS HAD BEEN SUGGESTING ANOTHER SYSTEM WOULD DROP DOWN BY THE
MIDDLE OF NEXT WEEK. LATEST GUIDANCE HAS BACKED OFF ON THAT WITH
GENERALLY DRY WEATHER NOW FORECAST.

&&

.AVIATION...AS OF 9:51 AM PST WEDNESDAY...A COLD DRY AIRMASS WILL
HELP MAINTAIN VFR CONDITIONS AT THE TERMINALS THROUGH THE NEXT 24
TO 36 HOURS. THE EXCEPTION BEING KSTS WHICH WILL SEE DENSE FOG
OVERNIGHT.

VICINITY OF KSFO...VFR. LIGHT OFFSHORE WINDS WILL BECOME WESTERLY
UP TO 10 KT WITH THE AFTERNOON SEA BREEZE.

CONFIDENCE IS HIGH.

KSFO BRIDGE APPROACH...VFR.

MONTEREY BAY AREA TERMINALS...VFR. OFFSHORE WINDS WILL BECOME
WESTERLY UP TO 10 KT WITH THE AFTERNOON SEA BREEZE.

CONFIDENCE IS HIGH.

&&

.MARINE...AS OF 09:06 AM PST WEDNESDAY...A WEAK SURFACE PRESSURE
GRADIENT WILL MAINTAIN RELATIVELY LIGHT NORTHERLY WINDS ACROSS THE
COASTAL WATERS TODAY. THE SURFACE PRESSURE GRADIENT WILL
STRENGTHEN TONIGHT RESULTING IN INCREASING WINDS. WINDS WILL
FURTHER INCREASE ON THURSDAY. A LONG PERIOD NORTHWESTERLY SWELL
WILL ENTER THE WATERS ON SATURDAY.

&&

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

&&

PUBLIC FORECAST: RGASS
AVIATION: LARRY
MARINE: LARRY

VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO

FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA