189
FXUS66 KMTR 210520
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1020 PM PDT THU AUG 20 2026
..NEW SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 1017 PM PDT THU AUG 20 2026
- TEMPERATURES WILL BE CLOSE TO OR BELOW NORMAL INTO THE
BEGINNING OF NEXT WEEK
- WARM AND DRY CONDITIONS ABOVE 1000FT PERSIST INTO THE WEEKEND
SHORT TERM
ISSUED AT 1017 PM PDT THU AUG 20 2026
(FRIDAY AND FRIDAY NIGHT)
IMPROVED ONSHORE FLOW IN THE LOWER BOUNDARY LAYER ESPECIALLY FOR THE
NORTH BAY AND BAY AREA SHOULD RESULT IN MORE EXTENSIVE STRATUS
INTRUSION OVERNIGHT COINCIDING WITH OVERNIGHT LOWS CLOSER TO NORMAL
FOR THIS TIME OF YEAR. WARM AND DRY CONDITIONS WILL CONTINUE BOTH
OVERNIGHT AND THROUGH THE DAY ABOVE 1000FT INLAND AND NEAR THE
COAST, THIS INCLUDES IN VICINITY OF THE TIMBER FIRE WHERE RELATIVELY
LIGHT WINDS CONTINUE TO BE A MITIGATING FACTOR. SOME ELEVATED
CONVECTION EARLIER THURSDAY NIGHT HAS TAPERED OFF OR NOW IN THE
STEERING FLOW OF THE RIDGE. ANY MID/UPPER LEVEL MOISTURE ATTEMPTING
TO REACH THE CENTRAL COAST WOULD BE GREETED BY ANEMIC INSTABILITY
AND CONFLUENT FLOW ALOFT.
AS THE CLOSED PORTION OF THE UPPER LEVEL LOW RESPONSIBLE FOR THE
PERSISTENT TROUGHING RECENTLY WILL SLOWLY APPROACH THE OREGON COAST
LATER TONIGHT WITH A STEADY FETCH OF ONSHORE FLOW CONTINUING ACROSS
OUR AREA, WITH ONLY A MARGINAL INCREASE IN DEPTH OF THE MARINE LAYER
EXPECTED INTO EARLY SATURDAY MORNING.
LONG TERM
ISSUED AT 1017 PM PDT THU AUG 20 2026
(SATURDAY THROUGH NEXT THURSDAY)
THE PARENT LOW MENTIONED ABOVE MOVES ONSHORE INTO THE PACNWEST
DURING THE DAY SATURDAY WITH A WEAK TROUGHING PATTERN LINGERING
OFFSHORE AT OUR LATITUDE THROUGH AT LEAST THE WEEKEND. HOWEVER, THE
PERSISTENT RIDGING OVER THE DESERT SOUTHWEST WILL SHIFT EAST AS WELL
DURING THIS TIME , THUS WE'LL CONTINUE TO SEE THE COOLING TREND
THROUGH THE WEEKEND INTO THE BEGINNING OF NEXT WEEK. THERE'S A WEAK
SIGNAL FOR THE RIDGING TO THE EAST TO BUILD BACK TOWARD THE WEST
COAST BY THE MIDDLE OF NEXT WEEK, WHICH WOULD BRING WARMER
TEMPERATURES, BUT AT THAT POINT A POTENTIAL TROPICAL SYSTEM WELL TO
OUR SOUTHWEST MAY ADD NOISE TO THE NWP.
AVIATION
(06Z TAFS)
ISSUED AT 849 PM PDT THU AUG 20 2026
IT'S VFR EXCEPT ONSHORE WINDS WILL USHER STRATUS AND FOG /MVFR-IFR-
LIFR/ INLAND TONIGHT AND FRIDAY MORNING. PATCHY COASTAL DRIZZLE IS
POSSIBLE TONIGHT AND FRIDAY MORNING. CONDITIONS IMPROVE TO MVFR-VFR
LATE MORNING AND AFTERNOON FRIDAY.
VICINITY OF SFO...STRATUS /MVFR-IFR/ CONTINUES TONIGHT AND FRIDAY
MORNING, WITH MIX OUT TO VFR FORECAST 19Z FRIDAY. STRATUS /MVFR/
RETURNS FRIDAY NIGHT AND SATURDAY MORNING. WEST-NORTHWEST WIND 15
TO 25 KNOTS UNTIL 08Z TONIGHT THEN EASING TO 12 TO 15 KNOTS TONIGHT
AND FRIDAY MORNING THEN INCREASING TO 15 TO 25 KNOTS FRIDAY AFTERNOON
AND EVENING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...STRATUS, FOG /MVFR-IFR-LIFR/ AND POSSIBLY
A FEW PATCHES OF DRIZZLE DEVELOPING TONIGHT AND FRIDAY MORNING.
CONDITIONS IMPROVING TO MVFR-VFR FRIDAY AFTERNOON. STRATUS /MVFR-IFR/
RETURNS FRIDAY EVENING AND NIGHT. WEST TO NORTHWEST WINDS 5 TO 15
KNOTS.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 841 PM PDT THU AUG 20 2026
NORTHWEST MODERATE TO FRESH BREEZES PERSISTS INTO THE WEEKEND WITH
HIGHER WINDS EXPECTED NEAR THE COASTAL JET REGIONS OF POINT REYES
AND POINT SUR. OCCASIONAL STRONG GUSTS ARE POSSIBLE ACROSS THE
OUTER WATERS AND COASTAL JET AREAS THROUGH SATURDAY. WIND DRIVEN
SEAS REMAIN SLIGHT AT THE COASTLINE AND QUICKLY BUILD TO MODERATE
ACROSS THE OUTER WATERS THROUGH THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY FROM 11 AM TO 9 PM PDT FRIDAY FOR PIGEON PT
TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...JM
LONG TERM....JM
AVIATION...CANEPA
MARINE...CANEPA
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