819
FXUS66 KMTR 201009
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
309 AM PDT SAT JUN 20 2026
..NEW MARINE, BEACHES
KEY MESSAGES
UPDATED AT 1245 AM PDT SAT JUN 20 2026
- HAZARDOUS BEACH CONDITIONS WITH INCREASED RISK OF SNEAKER WAVES
AND STRONG RIP CURRENTS CONTINUE THROUGH THE EXTENDED FORECAST
- MINOR HEATRISK WITH BELOW NORMAL TEMPERATURES THROUGH THE
WEEKEND
- WARMER TEMPERATURES AND MODERATE HEATRISK CONCERNS RETURN BY
MIDWEEK ACROSS THE INTERIOR
SHORT TERM
ISSUED AT 1245 AM PDT SAT JUN 20 2026
(TODAY AND TONIGHT)
THE PATTERN OVERALL WILL REMAIN SIMILAR TODAY AS A BROAD UPPER
LEVEL TROUGH SITS OVERHEAD. STRATUS WILL EXPAND ACROSS MOST AREAS
THIS MORNING WITHIN A MARINE LAYER AROUND 3000 FEET DEEP. DRIZZLE
MAY DEVELOP ALONG THE COAST THIS MORNING AS WELL, RESULTING IN
LOCALLY SLICK ROADWAYS. THE DEEP MARINE LAYER AND CONTINUED
ONSHORE FLOW WILL KEEP TEMPERATURES SIMILAR TO YESTERDAY, WITH
HIGHS ALONG THE COAST RANGING FROM THE UPPER 50S TO AROUND 70.
INLAND, TEMPERATURES WILL REMAIN BELOW NORMAL WITH HIGHS REACHING
THE 70S TO LOWER 80S. CLOUDS SHOULD RETREAT BACK TO THE COAST THIS
AFTERNOON, GIVING WAY TO SUNNY SKIES IN MOST AREAS. HOWEVER,
CLOUDS MAY NOT FULLY ERODE IN COASTAL AREAS DUE TO ONSHORE FLOW
AND OROGRAPHIC EFFECTS. ONSHORE WINDS WILL ONCE AGAIN BE BREEZY
THIS AFTERNOON AND EVENING WITH GUSTS 15-30 MPH, STRONGEST IN
GAPS/PASSES.
THE MARINE LAYER WILL BEGIN TO COMPRESS TONIGHT AS THE UPPER
LEVEL TROUGH WEAKENS. MARINE STRATUS WILL STILL FILL IN MOST
VALLEYS TONIGHT, BUT THE EXTENT SHOULD BE LOWER OVERALL. PATCHY
FOG WILL ALSO BE POSSIBLE ALONG THE COAST AND IN WIND-SHELTERED
VALLEYS.
LONG TERM
ISSUED AT 1245 AM PDT SAT JUN 20 2026
(SUNDAY THROUGH FRIDAY)
THE UPPER LEVEL TROUGH WILL CONTINUE ITS WEAKENING TREND ON SUNDAY
AND THE MARINE LAYER WILL COMPRESS FURTHER. DECREASING MARINE
INFLUENCE AND WARMING TEMPERATURES ALOFT WILL BEGIN A WARMING
TREND, ESPECIALLY INLAND, WHERE MANY LOCATIONS WILL REACH THE 80S,
WITH A FEW READINGS APPROACHING 90 DEGREES IN THE WARMEST SPOTS.
THE WARMING TREND WILL CONTINUE MONDAY AND TUESDAY AS A BROAD
RIDGE BUILDS ACROSS THE WESTERN U.S. HIGHS WILL REACH THE 80S AND
90S THROUGH THE WEEK ACROSS THE INTERIOR. HOT TEMPERATURES WILL BE
ACCOMPANIED BY THE POTENTIAL FOR MODERATE HEATRISK AND INCREASED
HEAT IMPACTS, ALTHOUGH OVERNIGHT COOLING LIMITS CONCERNS SOMEWHAT.
CLOSER TO THE COAST, CONFIDENCE IN THE TEMPERATURE FORECAST IS
LOWER, BUT AT LEAST SOME WARMING IS EXPECTED. MORE SIGNIFICANT
WARMING ALONG THE COAST/SF BAY SHORELINE COULD DEVELOP IF A WEAKER
ONSHORE OR OFFSHORE WIND PATTERN OCCURS, BUT CONFIDENCE IN THIS
SCENARIO IS LOW. THIS POTENTIAL WILL CONTINUE TO BE MONITORED AS
WE HEAD INTO NEXT WEEK.
AS MENTIONED IN PREVIOUS DISCUSSIONS, ENSEMBLE GUIDANCE CONTINUES
TO INDICATE MOISTURE ROTATING NORTH AROUND THE UPPER RIDGE
CENTERED OVER THE DESERT SOUTHWEST. BY WEDNESDAY AND THURSDAY,
THERE IS A LOW (AROUND 10%) CHANCE THAT THE MOISTURE AND
ACCOMPANYING INSTABILITY MAKES IT FAR ENOUGH WEST TO BRING A
THREAT FOR THUNDERSTORMS TO THE BAY AREA AND CENTRAL COAST.
OVERALL, THE CHANCE OF THIS SCENARIO OCCURING IS LOW, BUT IT
COULD HAVE A LARGE IMPACT. WHILE THE CURRENT FORECAST PACKAGE DOES
NOT INCLUDE THUNDERSTORMS, THIS POTENTIAL WILL CONTINUE TO BE
CLOSELY MONITORED OVER THE COMING DAYS.
AVIATION
(06Z TAFS)
ISSUED AT 953 PM PDT FRI JUN 19 2026
THE MARINE LAYER HAS BEGUN TO MOVE ONSHORE WITH PATCHY STRATUS
DEVELOPING NEAR SJC, LVK, AND SNS WILL RESULT IN WIDESPREAD MVFR
CEILINGS ACROSS THE REGION. COASTAL SITES MAY SEE SOME DRIZZLE
AROUND SUNSET TIME THROUGH MIDNIGHT. ANY ACCUMULATING
PRECIPITATION IS EXPECTED TO REMAIN VERY LIGHT, BETWEEN 0.02-0.03
INCHES, AND MAY CAUSE A SLIGHT REDUCTION IN VISIBILITY. STRATUS
WILL RECEDE BACK OFF LAND AROUND 18 TO 19Z SATURDAY.
VICINITY OF SFO...SW WINDS ARE GRADUALLY WEAKENING IN THE AREA
AND WILL CONTINUE INTO THE OVERNIGHT HOURS RETURNING AFTER 20Z
SATURDAY. AS THE MARINE LAYER DEEPENS TO AROUND 2500 FEET
OVERNIGHT, MVFR CEILINGS ARE EXPECTED TO IMPACT THE TERMINAL AS
EARLY AS 08Z SATURDAY AND PERSIST THROUGH 19Z SATURDAY.
SFO BRIDGE APPROACH...SW WIND AND GUSTY PATTERN IS SIMILAR TO SFO.
MVFR CEILINGS WILL DEVELOP SLIGHTLY AFTER SFO (09-10Z) AND DISSIPATE
TO SCT BEFORE SFO DOES (17-18Z). WILL REMAIN PATCHY THROUGH THE LATE
MORNING AND BECOME FULLY VFR BY 19Z.
VICINITY OF SJC AND OAK...SW WINDS ARE CONTINUING TO WEAKEN AND
WILL CONTINUE INTO THE OVERNIGHT HOURS. MVFR CEILINGS WILL IMPACT
OAK FIRST AROUND 07Z SATURDAY FOLLOWED BY SJC A COUPLE HOURS
LATER (09Z SATURDAY). WINDS EASE OVERNIGHT BEFORE INCREASING AGAIN
SATURDAY MORNING WHEN THE STRATUS BEGINS TO SCATTER OUT OF THEIR
RESPECTIVE AREAS.
MONTEREY BAY TERMINALS...WINDS CONTINUE TO GRADUALLY WEAKEN AND
WILL CONTINUE INTO THE OVERNIGHT HOURS. MVFR CEILINGS RETURN THIS
EVENING, IMPACTING SNS FIRST AROUND 06Z AND MRY BY 07Z SATURDAY.
MEDIUM CONFIDENCE ON THE TIMING OF STRATUS AT MRY AS IT MAY BE
INTERMITTENT AT TIMES. THERE ALSO MIGHT BE SOME LIGHT DRIZZLE
ASSOCIATED WITH THE MARINE LAYER AS IT COMES ONSHORE, SIMILAR TO
THIS MORNING, BUT CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAF.
MARINE
(TODAY THROUGH THURSDAY)
ISSUED AT 308 AM PDT SAT JUN 20 2026
LIGHT WINDS TODAY WILL INCREASE ACROSS THE NORTHERN OUTER WATERS
LATER TONIGHT AND PERSIST THROUGH EARLY MONDAY MORNING, WHILE
REMAINING RELATIVELY LIGHT ACROSS THE REMAINDER OF THE INNER AND
OUTER WATERS. LONG PERIOD SOUTHWEST SWELL IS LIKELY TO CONTINUE
THROUGH THE REMAINDER OF THE EXTENDED FORECAST PERIOD.
BEACHES
ISSUED AT 308 AM PDT SAT JUN 20 2026
LONG PERIOD SOUTHERLY SWELL AT AROUND 15 TO 17 SECONDS WILL
PERSIST FOR THE REMAINDER OF THE WEEKEND, AND INCREASE TO 17 TO
19 SECONDS BY THE MIDDLE OF THE UPCOMING WORK WEEK AS ENERGETIC
STORMS IN THE SOUTHERN HEMISPHERE CONTINUE TO AFFECT THE
CALIFORNIA COAST, ESPECIALLY FOR SOUTH AND SOUTHWEST FACING
BEACHES. HAZARDOUS BEACH CONDITIONS ARE ADVERTISED, SPECIFICALLY
FOR MODERATE TO STEEPLY SLOPED BEACHES ALONG THE PACIFIC COAST OF
THE NORTH BAY, SAN MATEO, SANTA CRUZ COUNTIES. A BEACH HAZARDS
STATEMENT FOR PACIFIC COAST BEACHES CONTINUES THROUGH WEDNESDAY
AFTERNOON. BE SURE TO CHECK BEACH CONDITIONS BEFORE YOU HEAD OUT.
SNEAKER WAVES WILL RUN UP THE BEACH MUCH FARTHER THAN OTHER
WAVES, POTENTIALLY CATCHING BEACHGOERS BY SURPRISE AND RESULTING
IN PEOPLE BEING SWEPT INTO THE WATER. RIP CURRENTS ARE STRONG
ENOUGH TO PULL THE STRONGEST SWIMMERS AWAY FROM SHORE. SWIM NEAR A
LIFEGUARD IF POSSIBLE. STAY BACK FROM THE BEACH, AND AWAY FROM
JETTIES, PIERS, BEACHSIDE ROCKS, AND OTHER INFRASTRUCTURE NEAR THE
WATER. NEVER TURN YOUR BACK TO THE OCEAN!
MTR WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT THROUGH WEDNESDAY AFTERNOON FOR CAZ006-
505-509-529-530.
PZ...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 AM PDT MONDAY
FOR PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...TANGEN
LONG TERM....TANGEN
AVIATION...MALARKEY
MARINE...JM
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