601
FXUS66 KMTR 191757
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1057 AM PDT TUE AUG 19 2025
..NEW AVIATION
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
UPDATE
ISSUED AT 908 AM PDT TUE AUG 19 2025
A NARROW BAND OF CLOUDS WAS ABLE TO FORM ALONG THE COAST JUST
AFTER SUNRISE, BUT THEY ARE MIXING OUT NOW WITH CLEAR SKIES AND
NICE WARM TEMPERATURES EXPECTED THROUGH THE REST OF THE DAY.
SHORT TERM
ISSUED AT 108 AM PDT TUE AUG 19 2025
(TODAY AND TONIGHT)
SATELLITE SHOWS IT'S CLEAR EXCEPT FOR A PATCH OR TWO OF COASTAL
STRATUS AND FOG. EXCEPT FOR PATCHY COASTAL STRATUS AND FOG, A SUNNY
DAY IS FORECAST TODAY. FORECAST HIGHS TODAY WILL BE WITHIN A FEW
DEGREES OF NORMAL MID AUGUST HIGH TEMPERATURES, IN THE UPPER 60S
TO LOWER 70S NEAREST THE COAST AND BAYS AND AS WARM TO HOT AS THE
MID 80S TO LOWER 90S FARTHEST INLAND.
LONG TERM
ISSUED AT 108 AM PDT TUE AUG 19 2025
(WEDNESDAY THROUGH MONDAY)
A STRONG HIGH PRESSURE SYSTEM NEAR THE FOUR CORNERS WILL PLACE
OUR FORECAST AREA UNDER INCREASING 500 MB HIGH PRESSURE WITH
INCREASING 925-500 MB THERMAL RIDGING THROUGH MID TO LATE WEEK.
WIND FLOW IN THE LOWER ATMOSPHERE WILL BE TEMPORARILY NORTHERLY BY
MID WEEK AND THE MARINE LAYER WILL BECOME COMPRESSED TO NEAR SEA
LEVEL. HIGHS WILL WARM TO ABOVE NORMAL FOR LATE AUGUST SINCE 850
MB TEMPS WILL BE ABOVE THE 90TH PERCENTILE. FORECAST HIGHS IN THE
HOTTEST SPOTS FARTHEST INLAND E.G. MAY APPROACH 100F TO 102F. IN
GENERAL THE 500 MB PATTERN ACROSS THE SOUTHWEST U.S. AND CENTRAL/EASTERN
PACIFIC WILL BE STATIONARY TO SLIGHTLY RETROGRESSIVE, KEEPING OUR
FORECAST AREA UNDER THE WESTERN PORTION OF THE FOUR CORNERS 500 MB
HIGH PRESSURE SYSTEM.
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
(18Z TAFS)
ISSUED AT 1041 AM PDT TUE AUG 19 2025
VFR WILL PERSIST THROUGH THE REMAINDER OF THE DAY AND EVENING WITH
VERY DRY AIR ABOVE A COMPRESSED MARINE LAYER. TERRAIN INDUCED
STRATUS PRODUCED A SHORT PERIOD OF MVFR CEILINGS EARLIER THIS
MORNING ACROSS THE BAY AREA TERMINALS. THERE IS LOW CONFIDENCE IN
STRATUS MAKING IT FAR ENOUGH INLAND LATE TONIGHT INTO EARLY
WEDNESDAY MORNING TO IMPACT OUR TERMINALS.
VICINITY OF SFO...VFR WILL PERSIST THROUGH THE REMAINDER OF TODAY
AND TONIGHT WITH A CHANCE OF MVFR/IFR CEILINGS DEVELOPING LATE IN
THE OVERNIGHT HOURS INTO EARLY MORNING WEDNESDAY. OTHERWISE EXPECT
VFR WITH LIGHT ONSHORE FLOOR.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR IS EXPECTED THROUGH THE REMAINDER OF
TODAY AND TONIGHT WITH LOW CONFIDENCE IN MVFR/IFR CEILINGS
DEVELOPING DURING THE OVERNIGHT HOURS INTO EARLY WEDNESDAY
MORNING, CLEARING OUT BY MID-MORNING.
MARINE
(TODAY THROUGH SUNDAY)
ISSUED AT 908 AM PDT TUE AUG 19 2025
MODERATE SEAS WILL PERSIST TODAY AND BECOME ROUGH BY WEDNESDAY
WITH MODERATE TO STRONG NORTHWESTERLY BREEZES, ESPECIALLY ACROSS
THE OUTER WATERS AND COASTAL JET REGIONS NEAR POINT SURE AND POINT
REYES. EXPECT WIDESPREAD HAZARDOUS CONDITIONS FOR SMALL CRAFT
TODAY INTO WEDNESDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR MRY BAY-PT REYES TO PIGEON PT 0-10 NM-SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT
THURSDAY FOR PIGEON PT TO PT PINOS 10-60 NM-PT ARENA TO PT
REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PIGEON PT
TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT WEDNESDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...CANEPA
LONG TERM....CANEPA
AVIATION...JM
MARINE...JM
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