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

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000
FXUS66 KMTR 300006
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
506 PM PDT FRI MAY 29 2015

.SYNOPSIS...NO BIG WEATHER CHANGES FORECAST FOR SATURDAY WITH
COASTAL STRATUS SPREADING INLAND OVERNIGHT. BY SUNDAY A SYSTEM
WILL APPROACH THE COAST WITH A SLIGHT CHANCE OF SHOWERS IN THE FAR
NORTH BAY. AS THE SYSTEM APPROACHES THE MARINE LAYER WILL DEEPEN
AND COOLER WEATHER WILL RETURN SUNDAY AFTERNOON WITH ONSHORE FLOW.
SEASONABLE TEMPERATURES AND CONTINUED DRY WEATHER FORECAST MONDAY
THROUGH THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...AS OF 1:43 PM PDT FRIDAY...VISIBLE SATELLITE IMAGERY
SHOWS THAT LOW CLOUDS HAVE CLEARED FROM MOST AREAS. THE EXCEPTIONS
ARE MOST OF THE SAN FRANCISCO PENINSULA AS WELL AS THE SOUTHERN
MONTEREY BAY AND MONTEREY PENINSULA. THESE AREAS ARE RUNNING COOLER
THAN YESTERDAY AT THIS TIME WITH READINGS IN THE 50S...BUT
LOCATIONS FARTHER INLAND ARE SEVERAL DEGREES WARMER...WITH 60S AND
70S. EXPECT LOW CLOUDS TO SPREAD INLAND ONCE AGAIN TONIGHT AS THE
MARINE LAYER DEPTH REMAINS AROUND 1600 FEET AND THE SURFACE
PRESSURE GRADIENT IS STRONG ONSHORE AT 3.1 MB FROM SFO TO SAC.

LITTLE CHANGE IS EXPECTED IN THE OVERALL WEATHER PATTERN FOR
SATURDAY...BUT ON SUNDAY AN APPROACHING UPPER LEVEL TROUGH WILL
RAMP UP THE ONSHORE FLOW AND COOL TEMPERATURES SOMEWHAT. THERE
REMAINS A SLIGHT CHANCE OF LIGHT RAIN ACROSS THE FAR NORTHERN
PORTIONS OF THE NORTH BAY SATURDAY NIGHT AND SUNDAY...BUT THE MORE
LIKELY SCENARIO WILL BE AN INCREASED CHANCE OF COASTAL DRIZZLE BY MONDAY
MORNING.

MEDIUM RANGE MODELS KEEP A ZONAL FLOW ALOFT ACROSS NORTHERN
CALIFORNIA THROUGH MUCH OF NEXT WEEK. THUS...ONSHORE FLOW WILL
KEEP SEASONABLY COOL TEMPERATURES ACROSS THE AREA. NIGHT AND
MORNING COASTAL STRATUS WILL BE THE NORM FOR THE FIRST WEEK OF JUNE.

&&

.AVIATION...AS OF 5:00 PM PDT FRIDAY...STRATUS COVERS MUCH OF THE
COAST. UPPER LEVEL RIDGE MOVING OVER THE AREA IS STARTING TO
COMPRESS THE MARINE LAYER. ONSHORE FLOW IS STILL STRONG WITH 3.1
MB SFO-SAC SO STRATUS IS STILL EXPECTED IN EARLY WITH LOWER BASES.
THERE SHOULD BE ENOUGH SURFACE HEATING TO KEEP ANY CIGS IN THE SFO
BAY AREA ABOVE 1000 FEET THROUGH 04-05Z BUT AFTER THAT CIGS WILL
GRADUALLY DROP BELOW 1000 FEET.

VICINITY OF KSFO...MVFR CIGS AFT 01Z LOWERING TO IFR AFTER 05Z.
WEST WINDS TO 20 KT GUSTING TO 25 KT THROUGH 05Z.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...STRATUS COVERS THE SOUTHERN END OF
MRY BAY AND WILL FILL IN OVER MRY AFTER 01Z AND REACH SNS BY 04Z.

&&

.MARINE...AS OF 01:19 PM PDT FRIDAY...GENERALLY LIGHT TO LOCALLY
MODERATE NORTHWEST WINDS ARE EXPECTED TO PREVAIL TODAY...THE
STRONGEST WINDS ARE EXPECTED SOUTH OF POINT SUR AND ALONG THE
SONOMA COAST. WINDS ARE ANTICIPATED TO DECREASE ON SATURDAY AND
BECOME SOUTHERLY ON SUNDAY AS A LOW PRESSURE SYSTEM APPROACHES
FROM THE WEST. WINDS WILL STRENGTHEN OUT OF THE NORTH ONCE AGAIN
EARLY NEXT WEEK AS A THERMAL TROUGH BUILDS OVER CALIFORNIA.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...SF BAY SOUTH OF THE BAY BRIDGE UNTIL 11 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 11 PM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 11 PM
             SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 8 PM

&&

$$

PUBLIC FORECAST: SIMS
AVIATION: W PI
MARINE: LARRY

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