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

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000
FXUS66 KMTR 190543
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1043 PM PDT FRI APR 18 2014

.SYNOPSIS...DRY WEATHER WILL CONTINUE THROUGH THE WEEKEND.
LITTLE CHANGE IN TEMPERATURES IS FORECAST FOR SATURDAY...BUT
WARMER WEATHER IS EXPECTED ON SUNDAY AS ONSHORE FLOW DECREASES. A
WEAK WEATHER SYSTEM WILL ARRIVE ALONG THE NORTHERN CALIFORNIA
COAST BY LATE MONDAY AND BRING COOLER CONDITIONS ALONG WITH SHOWER
CHANCES MONDAY NIGHT AND TUESDAY. RAINFALL AMOUNTS WILL BE LIGHT.
DRY WEATHER WITH NEAR NORMAL TEMPERATURES WILL RETURN FOR THE
SECOND HALF OF NEXT WEEK.

&&

.DISCUSSION...AS OF 9:00 PM PDT FRIDAY...SIMILAR TO LAST
EVENING...COASTAL LOW CLOUDS LARGELY CLEARED OUT LATE IN THE DAY
AS BRISK NORTHWEST WINDS OVER THE COASTAL WATERS PRODUCED GOOD LOW
LEVEL MIXING. EXPECT STRATUS EVOLUTION TONIGHT TO BE SIMILAR TO
WHAT OCCURRED LAST NIGHT...WITH LOW CLOUDS FILLING IN ALONG MUCH
OF THE COASTLINE LATE TONIGHT AS COASTAL WINDS EASE. LOW CLOUDS
WILL ALSO DEVELOP INLAND BY SUNRISE SATURDAY. THE DIFFERENCE
THIS EVENING COMPARED TO LAST EVENING IS A WEAKER N-S SURFACE
GRADIENT WHICH SHOULD MEAN GREATER INLAND DEVELOPMENT OF LOW
CLOUDS AROUND SF BAY LATE TONIGHT COMPARED TO LAST NIGHT.

AN UPPER RIDGE OFF THE COAST OF SOUTHERN CA WILL BEGIN TO BUILD
NORTHWARD ON SATURDAY AND PREVENT THE WEATHER SYSTEM CURRENTLY
APPROACHING THE PAC NW FROM IMPACTING OUR AREA IN ANY WAY. THE
BUILDING RIDGE SHOULD COMPRESS THE MARINE LAYER A BIT TOMORROW SO
WE MAY SEE SLIGHT WARMING INLAND. BUT MODERATE ONSHORE FLOW AND
MORNING MARINE LAYER CLOUDS WILL KEEP COASTAL TEMPS NEAR
PERSISTENCE. WARMING IS FORECAST FOR ALL AREAS ON SUNDAY AS THE
UPPER RIDGE STRENGTHENS A BIT MORE AND ONSHORE FLOW WEAKENS.

THE LONGWAVE UPPER TROUGH CURRENTLY CENTERED IN THE GULF OF ALASKA
IS FORECAST TO DIG TO THE SOUTHEAST OFF THE WEST COAST ON SUNDAY
AND MONDAY AND THEN SWING INLAND ACROSS CALIFORNIA LATE MONDAY
NIGHT AND TUESDAY. ALTHOUGH THIS SYSTEM LOOKS RELATIVELY ROBUST
WITH GOOD COLD ADVECTION FORECAST FROM MONDAY EVENING INTO
TUESDAY...THE MODELS AGREE THAT IT WILL BE LACKING IN MOISTURE.
ONLY SCATTERED LIGHT QPF IS FORECAST BY THE MODELS FROM LATE
MONDAY INTO MONDAY NIGHT WITH DRY CONDITIONS DEVELOPING BY TUESDAY
ONCE THE UPPER TROUGH AXIS MOVES THROUGH. BASED ON LATEST MODEL
DATA...THE SYSTEM IS MOVING MORE QUICKLY THAN PREVIOUSLY FORECAST
SO WE MAY NEED TO CONSIDER ADDING POPS FOR LATE MONDAY. IN
ADDITION...POPS MAY NEED TO BE REDUCED FOR TUESDAY. THERE NO
LONGER APPEARS TO BE ANY THREAT OF THUNDER WITH THIS SYSTEM. RAIN
TOTALS FROM LATE MONDAY INTO EARLY TUESDAY WILL PROBABLY NOT
EXCEED A TENTH OF AN INCH. ALSO...MUCH OF OUR AREA MAY NOT PICK
UP ANY MEASURABLE PRECIP FROM THIS SYSTEM.

DRY AND MILD WEATHER IS FORECAST FOR THE SECOND HALF OF NEXT WEEK
AS A SHORTWAVE RIDGE BUILDS IN FOR A FEW DAYS.

BASED ON GOOD AGREEMENT AMONG THE MEDIUM RANGE MODELS...CONFIDENCE
IS INCREASING THAT OUR AREA WILL SEE WIDESPREAD RAINFALL FROM A
RELATIVELY STRONG AND WET LATE SEASON STORM SYSTEM BEGINNING LATE
NEXT FRIDAY AND CONTINUING INTO THE FINAL WEEKEND OF APRIL AND
BEYOND.

&&

.AVIATION...AS OF 10:40 PM PDT FRIDAY...HIGH CLOUDS ARE MOVING IN
AHEAD OF AN APPROACHING COLD FRONT. LOW CLOUDS APPEAR TO HAVE
TAKEN A BREAK IN THE MONTEREY AREA BUT ARE EXPECTED TO RETURN
SHORTLY. THE FORT ORD PROFILER STILL INDICATES THAT THE MARINE
LAYER IS HANGING TOUGH AT 2000 FEET AND A LOOK OUT OF THE OFFICE
WINDOW ALLOWS US TO SEE STRATUS LINGERING OVER THE BAY. IN SAN
FRANCISCO THE SODARS ARE STILL NOT INDICATING AN INVERSION
SIGNATURE AND DEW POINT DEPRESSIONS ARE RUNNING AROUND 5 DEGREES
CELSIUS. THEREFORE...DON`T ANTICIPATE STRATUS TO IMPACT THE SAN
FRANCISCO BAY TERMINALS ANYTIME SOON IF AT ALL TONIGHT.

VICINITY OF KSFO...VFR IS EXPECTED TO PERSIST THROUGH THE NEXT 24
TO 36 HOURS. PATCHY STRATUS MAY DEVELOP TO THE NORTH AND EAST OF
THE TERMINAL LATE TONIGHT. SOUTHWEST WINDS 5 TO 10 KT OVERNIGHT.

MODERATE CONFIDENCE.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO WITH STRATUS POSSIBLE LATE
TONIGHT EAST OF THE APPROACH.

MODERATE CONFIDENCE

MONTEREY BAY AREA TERMINALS...A BRIEF PERIOD OF CLEAR SKIES
TONIGHT WITH MVFR CIGS ARE EXPECTED TO RETURN SHORTLY AND PREVAIL
THROUGH 1200Z TONIGHT AT WHICH CIGS WILL FALL TO AROUND OVC007.
CIGS WILL IMPROVE TO OVC015 BY 1700Z SATURDAY MORNING. WEST
SOUTHWEST WINDS 5 TO 10 KT ARE EXPECTED OVERNIGHT.

HIGH CONFIDENCE.

&&

.MARINE...AS OF 10:40 PM PDT FRIDAY...NORTHERLY WINDS ARE EXPECTED
TO SUBSIDE OVERNIGHT. HOWEVER...WINDS WILL INCREASE ONCE AGAIN
SATURDAY AFTERNOON AS THE SURFACE PRESSURE GRADIENT STRENGTHENS. A
STORM SYSTEM APPROACHING THE COAST OF BRITISH COLUMBIA HAS
GENERATED A LARGE MODERATE PERIOD NORTHWEST SWELL WHICH IS
EXPECTED TO REACH THE NORTHERN AND CENTRAL CALIFORNIA COAST LATE
SATURDAY NIGHT EARLY SUNDAY MORNING. INITIALLY THE FORERUNNER
WAVES WILL ARRIVE EARLY SUNDAY MORNING AT A HEIGHT OF 5 TO 8 FEET
AND A PERIOD OF 18 SECONDS. THE WAVES WILL BUILD TO 13 TO 15 FEET
WITH A PERIOD OF 15 TO 16 SECONDS THROUGH THE DAY SUNDAY.

THESE LARGE WAVES WILL RESULT IN SHOALING ALONG COASTAL SAND BARS,
REEFS AND ROCK OUTCROPPINGS. MARINERS AND FISHERMEN PLEASE USE
CAUTION NEAR THESE UNDERWATER FEATURES. AT THE BEACH HIGH SURF IS
EXPECTED AT EXPOSED BEACHES SUCH AS OCEAN BEACH. STRONG RIP
CURRENTS ARE EXPECTED AT BEACHES FROM SONOMA TO MONTEREY
ESPECIALLY ON WEST AND NORTHWEST FACING BEACHES. ON STEEPER
BEACHES SUCH AS CARMEL RIVER BEACH AND MONTARA STATE BEACH A
HEIGHTENED RISK OF SNEAKER WAVES IS ANTICIPATED. PLEASE DO NOT
TURN YOUR BACK TO THE OCEAN WHILE VISITING THE BEACH THIS WEEKEND.
ADDITIONALLY...PLEASE DO NOT CLIMB ON OR FISH OFF OF COASTAL ROCKS
AND JETTIES AS YOU WILL RUN AN EXTREME RISK OF BEING WASHED INTO
THE SEA BY A WAVE. THAT DRAMATIC PHOTO OF THE WAVE BREAKING BEHIND
YOU IS JUST NOT WORTH BEING WASHED INTO THE SEA.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM

&&

$$

PUBLIC FORECAST: DYKEMA
AVIATION: LARRY
MARINE: LARRY

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