552
FXUS66 KMTR 190026
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
526 PM PDT MON AUG 18 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 245 PM PDT MON AUG 18 2025
- WARMING TREND INTO THE WEEKEND
- MODERATE HEATRISK FOR THE INTERIOR THURSDAY-SATURDAY
- SEE HEAT SAFETY TIPS BELOW
SHORT TERM
ISSUED AT 245 PM PDT MON AUG 18 2025
(THIS EVENING THROUGH TUESDAY)
CLEAR SKIES AND WARMER TEMPERATURES THAN WE'VE SEEN THE PAST COUPLE
OF DAYS HAVE MADE FOR A BEAUTIFUL DAY ACROSS OUR AREA. A WEAK FETCH
OF OFFSHORE FLOW TODAY ACROSS PORTIONS OF THE CENTRAL COAST HAS
RESULTED IN A BUMP IN DAYTIME HIGHS THROUGH THE SALINAS VALLEY AND
MONTEREY PENINSULA. LOW STRATUS HAS ERODED AND SHOULD MAKE FOR A
WONDERFUL SUNSET UP AND DOWN OUR COASTLINE LATER THIS EVENING. A
COMPRESSED MARINE LAYER WILL LIMIT STRATUS COVERAGE DURING THE
OVERNIGHT INTO EARLY TUESDAY MORNING, KEEPING IT MOSTLY CONFINED
TO THE IMMEDIATE COASTLINE WHERE STRATUS DOES DEVELOP. IT SHOULD
BE A GREAT NIGHT TO WATCH THE SUNSET, FOLLOWED BY THE PERSEID
METEOR SHOWER.
LONG TERM
ISSUED AT 245 PM PDT MON AUG 18 2025
(TUESDAY NIGHT THROUGH NEXT SUNDAY)
A GRADUAL WARMUP FOR THE FIRST HALF OF THE WORK WEEK WILL ACCELERATE
FOR THURSDAY AND FRIDAY, AND THEN GRADUALLY EASE INTO THE WEEKEND. A
BUILDING DOME OF HIGH PRESSURE WILL BEGIN TO CENTER AROUND THE FOUR
CORNERS AREA TUESDAY, THEN EXPAND WESTWARD FOR THE SECOND HALF OF
THE WORK WEEK. CONSENSUS IN THE SYNOPTIC PATTERN IS GOOD THROUGH
FRIDAY, PROVIDING HIGH CONFIDENCE FOR AREAS OF MODERATE HEATRISK
ACROSS MUCH OF OUR INTERIOR THURSDAY THROUGH SATURDAY. CONSENSUS IN
DETERMINISTIC GUIDANCE BEGINS TO BREAKDOWN FOR THE WEEKEND INTO THE
BEGINNING OF NEXT WEEK. IT IS TOO SOON TO KNOW WHETHER THE
PERSISTENT TROUGHING TO OUR WEST THAT WE'VE SEEN MOST OF THE SUMMER
WILL WIN OUT OVER THE EXPANDING RIDGE AS WE HEAD INTO THE WEEKEND
AND INTO THE BEGINNING OF NEXT WEEK. IF THE RIDGING BECOMES THE
DOMINANT SYNOPTIC INFLUENCE WE MAY SEE A LONGER PERIOD OF MODERATE
HEATRISK THROUGH THE EXTENDED FORECAST, WHICH WOULD HAVE
COMPOUNDING IMPACTS. NOW IS THE TIME TO BEGIN TO BE AWARE AND
PREPARE FOR UPCOMING HEAT IMPACTS.
HEAT SAFETY TIPS:
HEAT IS THE NUMBER 1 WEATHER RELATED KILLER IN THE UNITED STATES.
FOLLOW THESE TIPS TO PROTECT YOURSELF, YOUR LOVED ONES, AND YOUR
ANIMALS.
-STAY INSIDE IN AN AIR CONDITIONED ENVIRONMENT BETWEEN 10AM AND 7PM.
-SUSPEND UNNECESSARY OUTDOOR ACTIVITIES DURING MODERATE HEAT, BUT
IF YOU MUST BE OUTDOORS, TAKE FREQUENT BREAKS IN THE SHADE OR AC
AND DRINK COOL WATER.
-KNOW THE SIGNS AND SYMPTOMS OF HEAT EXHAUSTION VS. HEAT STROKE!
HEAT STROKE CAN BE DEADLY IF NOT TREATED IMMEDIATELY BY A MEDICAL
PROFESSIONAL. CALL 911 IF YOU SUSPECT SOMEONE IS SUFFERING FROM HEAT
STROKE.
-WEAR A LIFE JACKET, SWIM NEAR A LIFEGUARD, AND CHECK CONDITIONS
BEFORE ENTERING THE WATER IF GOING TO A RIVER OR OCEAN TO COOL OFF.
RIVERS AND THE OCEAN ARE EXTREMELY COLD, AND COLD WATER SHOCK CAN
TURN INTO PARALYSIS AND DROWNING IF YOU ARE NOT CAREFUL.
-USE A COOL AND DAMP TOWEL ON YOUR BODY IF YOU DO NOT HAVE AC AND
ARE FEELING HOT. OR, TAKE A COOL SHOWER OR BATH.
-DO NOT LEAVE KIDS OR PETS IN A PARKED CAR.
-ENSURE PETS AND LIVESTOCK HAVE ACCESS TO SHADE AND WATER.
AVIATION
(00Z TAFS)
ISSUED AT 526 PM PDT MON AUG 18 2025
VFR ACROSS THE BOARD WITH SOME POTENTIAL FOR LOW CLOUDS TO RETURN TO
THE SF BAY SHORELINE AND COASTAL AREAS TONIGHT. CURRENTLY SATELLITE
SHOWS CLEAR SKIES WITH A FEW CLOUDS TO OUR SOUTHWEST OVER THE
PACIFIC OCEAN. PATCHY STRATUS LOOKS TO FILL IN LATE TONIGHT/EARLY
TOMORROW MORNING WITH THE MARINE LAYER STAYING COMPRESSED TO AROUND
500 FT. HIGHEST CONFIDENCE IN HAF FILLING IN AROUND 10Z WITH CIGS
LOWERING AROUND 12Z. MODERATE CONFIDENCE THAT STRATUS WILL REACH OAK
AND MRY AND LOW CONFIDENCE THAT STRATUS WILL REACH SFO AND SNS.
WINDS LARGELY STAY ONSHORE AND BECOME BREEZY (10-15 KNOTS) DURING
THE DAY WITH LOCALLY HIGHER GUSTS EXPECTED AT SFO.
VICINITY OF SFO...KEPT A SLIGHTLY MORE OPTIMISTIC TAF OF VFR FOR SFO
WITH SIMILAR THOUGHTS TO THE PREVIOUS FORECASTER. CONFIDENCE IS
HIGHEST ON STRATUS FILTERING IN OVER OAK BUT NOT EXTENDING ACROSS
THE BAY TO SFO. IF ANYTHING, PATCHY STRATUS MAY IMPACT THE TERMINAL
BETWEEN 12 TO 16Z BUT HREF KEEPS THIS AT AROUND A 30% CHANCE. THE
GFSLAMP SHOWS A CLOSER TO 50% CHANCE OF STRATUS DEVELOPING AT SFO
BUT CONFIDENCE IS LOW IN THIS SCENARIO. WINDS REMAIN ONSHORE THROUGH
THE PERIOD WITH GUSTS UP TO 25 KNOTS EXPECTED TO DEVELOP DURING THE
AFTERNOON/EVENING HOURS.
SFO BRIDGE APPROACH...PATCHY STRATUS MAY IMPACT THE BRIDGE APPROACH
EARLY TOMORROW MORNING WITH HIGHEST POTENTIAL DURING THE 12Z-16Z
TIMEFRAME. OTHERWISE, SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CURRENTLY VFR WITH LOW CONFIDENCE IN
STRATUS DEVELOPING OVERNIGHT AT MRY AND SNS. CONFIDENCE IS SLIGHTLY
HIGHER THAT STRATUS COULD DEVELOP AT MRY OVER SNS WITH LAMP
PROBABILITY GUIDANCE SUPPORTING THIS. CURRENT THINKING LEANS TOWARDS
MODELS OVERDOING STRATUS COVERAGE TONIGHT GIVEN THE INCOMING DRIER
AIR MASS AND MORE COMPRESSED MARINE LAYER. THERE LOOKS TO BE A BRIEF
PERIOD BETWEEN 12Z TO 16Z AT MRY TOMORROW MORNING WHERE STRATUS
BECOMES MORE LIKELY BUT THIS LOOKS TO BE PATCHY IN NATURE AND
CONFIDENCE REMAINS LOW.
MARINE
(TONIGHT THROUGH NEXT SUNDAY)
ISSUED AT 526 PM PDT MON AUG 18 2025
NW BREEZES ALONG THE COAST WILL INCREASE TO FRESH THIS
AFTERNOON/EVENING AND AGAIN TUESDAY. BY MID-WEEK, A STRONGER
PRESSURE GRADIENT WILL BRING MORE WIDESPREAD FRESH NW WINDS
THROUGHOUT THE OUTER WATERS, BUILDING ROUGH SEAS BY THURSDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM-SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT TUESDAY FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT TUESDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 3 AM PDT WEDNESDAY FOR
PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 9 PM TUESDAY TO 3 AM PDT WEDNESDAY FOR
PIGEON PT TO PT PINOS 10-60 NM-PT ARENA TO PT REYES 10-60
NM.
SHORT TERM...JM
LONG TERM....JM
AVIATION...KENNEDY
MARINE...FLYNN
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