917
FXUS66 KMTR 041914
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1214 PM PDT SUN OCT 4 2026
..NEW SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 1213 PM PDT SUN OCT 4 2026
- WARM TO HOT CONDITIONS ACROSS THE REGION THROUGH MID-WEEK
- HAZARDOUS HEAT CONDITIONS EXPECTED TO PERSIST INLAND, NEVER
LEAVE CHILDREN OR PETS IN UNATTENDED VEHICLES!
- ELEVATED FIRE WEATHER CONDITIONS PERSIST IN THE INTERIOR
THROUGH THURSDAY
SHORT TERM
ISSUED AT 1213 PM PDT SUN OCT 4 2026
(THIS EVENING THROUGH MONDAY NIGHT)
IT'S HOT. A PERSISTENT RIDGE OVER THE WESTERN UNITED STATES KEEPS
THE AREA MUCH ABOVE THE SEASONAL AVERAGE (15 TO 25 DEGREES ABOVE
SEASONAL AVERAGE AWAY FROM THE IMMEDIATE COAST). AS OF 11 AM TODAY
TEMPERATURES ACROSS THE REGION RANGED FROM THE 80S INTO THE LOWER
90S INLAND, THE 70S TO THE LOWER 80S CLOSE TO THE BAYS, AND THE
MIDDLE 60S TO THE MIDDLE 70S FOR THE PACIFIC COAST. THERE ARE SOME
HIGH CLOUDS FLOWING ABOVE THE SF BAY AREA, BUT THEY DO NOT SEEM TO
BE IMPACTING THE HEAT LEVELS. HIGH TEMPERATURES TODAY AND MONDAY
WILL BE RATHER SIMILAR IN THE INLAND VALLEYS, RANGING FROM THE
MIDDLE 90S TO NEAR 104. CLOSER TO THE BAYS, TODAY'S HIGHS WILL BE IN
THE MIDDLE 80S TO THE MIDDLE 90S WHILE LOCATIONS ALONG THE PACIFIC
COAST RISE INTO THE 70S. ACROSS THE HIGHER ELEVATIONS AND SOME
NEARBY VALLEYS, ESPECIALLY IN THE EAST AND SOUTH BAYS, MILD
OVERNIGHT LOWS IN THE UPPER 60S TO MIDDLE 70S WILL LIMIT THE
ABILITY TO RECOVER OVERNIGHT. FOR MONDAY, THESE TEMPERATURES ARE A
LITTLE UNCERTAIN OWING TO POTENTIAL IMPACTS FROM A SHALLOW MARINE
LAYER OR A MARGINALLY STRONGER ONSHORE FLOW THAN THE CURRENT
FORECAST, BUT HIGHS SHOULD REMAIN IN THE 70S AND 80S. IF CONFIDENCE
IN HIGHS TOWARDS THE HIGHER PART OF THAT RANGE INCREASES, THE HEAT
ADVISORY FOR OUR COASTAL REGIONS MAY NEED TO BE EXTENDED.
DUE TO THE HAZARDOUS HEAT LEVELS, A HEAT ADVISORY IS IN EFFECT FOR
COASTAL LOCATIONS THROUGH 10 PM TONIGHT, WHILE INLAND AND BAYSHORE
AREAS REMAINS UNDER THE ADVISORY THROUGH WEDNESDAY. WIDESPREAD
MODERATE HEATRISK BLANKETS THE REGION, CORRESPONDING TO A MODERATE
RISK OF HEAT-RELATED ILLNESSES FOR SENSITIVE POPULATIONS, INCLUDING
CHILDREN, THE ELDERLY, PREGNANT WOMEN, PEOPLE WITH CHRONIC
ILLNESSES, AND PEOPLE WHO WORK OR LIVE OUTDOORS WITHOUT ACCESS TO
ADEQUATE COOLING OR HYDRATION. IN ADDITION, MANY OF THE HIGHER
ELEVATIONS IN ADDITION TO THE EAST BAY, SOUTH BAY, AND THE CARMEL,
HOLLISTER, AND NORTHERN SALINAS VALLEYS SEE MAJOR HEATRISK,
CORRESPONDING TO A HIGH RISK FOR HEAT-RELATED ILLNESSES FOR ANYONE
WITHOUT HYDRATION OR COOLING. FOLLOW THESE TIPS TO AVOID HEAT
EXHAUSTION AND HEATSTROKE:
* STAY HYDRATED AND DRINK PLENTY OF FLUIDS.
* WEAR LIGHTWEIGHT, LIGHT-COLORED CLOTHING.
* REDUCE TIME SPENT OUTDOORS OR STAY IN THE SHADE.
* NEVER LEAVE PEOPLE OR PETS UNATTENDED IN VEHICLES.
* USE SUNSCREEN IF GOING TO THE COAST OR THE POOL.
LONG TERM
ISSUED AT 1213 PM PDT SUN OCT 4 2026
(TUESDAY THROUGH NEXT SATURDAY)
THE RIDGING PERSISTS FOR THE NEXT FEW DAYS AND AS PREVIOUSLY
MENTIONED, THE HEAT ADVISORY EXTENDS TO WEDNESDAY NIGHT FOR THE
INLAND AND BAYSHORE REGIONS. TEMPERATURES ACROSS THE INLAND VALLEYS
REMAIN IN THE MIDDLE 90S TO NEAR 105 THROUGH WEDNESDAY. ALONG THE
PACIFIC, WE CONTINUE TO MONITOR HOW THE FORECAST TRENDS EVOLVE AS
IMPACTS FROM A SHALLOW MARINE LAYER OR STRONGER ONSHORE FLOW THAN
THE CURRENT FORECAST MAY SIGNIFICANTLY IMPACT THE IMMEDIATE COAST.
A PATTERN CHANGE WILL BEGIN THURSDAY AS THE RIDGE FLATTENS AND
TROUGHING DEVELOPS IN THE NORTHEASTERN PACIFIC AND MOVES INTO
SOUTHWESTERN CANADA AND THE WESTERN UNITED STATES. THIS WILL START A
COOLING TREND WITH MOST LOCATIONS DROPPING OUT OF MODERATE HEATRISK
BY FRIDAY. ENSEMBLE MODEL CLUSTER ANALYSIS HINTS AT SIGNIFICANT
UNCERTAINTY FOR THE UPCOMING WEEKEND AND THE EARLY PART OF THE
UPCOMING WEEK REGARDING THE STRENGTH OF THE TROUGH AND HOW LONG IT
COULD PERSIST.
AVIATION
(18Z TAFS)
ISSUED AT 1029 AM PDT SUN OCT 4 2026
VFR CONDITIONS REGIONWIDE THROUGHOUT MUCH OF THE DAY WITH LIGHT
ONSHORE WINDS FORECAST TO RETURN BY MID-AFTERNOON. WINDS BEGIN TO
DIMINISH AFTER SUNSET AND MORE SO INTO MONDAY MORNING. THE
GREATEST POTENTIAL FOR LOW CEILINGS AND/OR FOG TO OCCUR MONDAY
MORNING WILL BE AT COASTAL SITES (MRY, HAF, AND TO A LESSER EXTENT
SNS) AS HIGH CLOUD COVER IS FORECAST TO DIMINISH THROUGHOUT THE
DAY. HOWEVER, CONFIDENCE IS LOW-TO-MODERATE FOR FOG DEVELOPMENT IN
THESE LOCATIONS.
VICINITY OF SFO...VFR. WEAK OFFSHORE WINDS CURRENTLY WITH WEAK TO
MODERATE ONSHORE FLOW EXPECTED BY MID-AFTERNOON. WINDS EASE
OVERNIGHT AND INTO EARLY MONDAY MORNING WITH GENERALLY HIGH
CONFIDENCE OF VFR CONDITIONS PERSISTING THROUGH THE TAF PERIOD.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR. LIGHT DRAINAGE WINDS CURRENTLY AT
SNS WILL SHIFT ONSHORE BY EARLY AFTERNOON AND PREVAIL BEFORE
EASING AFTER SUNSET. THE GREATEST POTENTIAL FOR SUB-IFR CONDITIONS
WILL BE AT MRY EARLY MONDAY MORNING, LESS CONFIDENCE FOR SNS. ANY
LOW CLOUDS AND/OR FOG THAT DOES DEVELOP IS LIKELY TO DISSIPATE BY
16Z MONDAY.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 833 AM PDT SUN OCT 4 2026
NORTHWESTERLY BREEZES WILL REMAIN GENTLE TO MODERATE INTO
MIDWEEK, ALLOWING FOR SLIGHT TO MODERATE WAVE HEIGHTS TO PERSIST.
FIRE WEATHER
ISSUED AT 405 AM PDT SUN OCT 4 2026
HOT AND DRY CONDITIONS WILL CONTINUE THROUGH THURSDAY, WHICH WILL
BE ACCOMPANIED WITH WEAK OFFSHORE FLOW. POOR TO VERY POOR
OVERNIGHT RECOVERY IS EXPECTED FOR THE THERMAL BELTS, GENERALLY
FOR ELEVATIONS ABOVE 1000-1500 FEET, LEADING TO ELEVATED FIRE
WEATHER CONDITIONS. THE MARINE LAYER IS EXPECTED TO BE CONFINED TO
THE IMMEDIATE COAST AND AROUND 500 FEET. IF WORKING IN THE
THERMAL BELTS, MODERATE TO EXTREME HEATRISK IS FORECAST THIS WEEK,
WITH TEMPERATURE AND HEATRISK TRENDS IMPROVING LATE WEEK. A
PATTERN CHANGE IS EXPECTED LATE IN THE WEEK OR OVER THE WEEKEND.
COOLER WEATHER AND THE POTENTIAL FOR IMPROVED RH RECOVERY IS
FORECAST OR FRIDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...HEAT ADVISORY UNTIL 10 PM PDT THIS EVENING FOR CAZ006-502-505-
509-528>530.
HEAT ADVISORY UNTIL 10 PM PDT WEDNESDAY FOR CAZ503-504-506-508-
510-512>518.
PZ...NONE.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...RGASS
MARINE...RGASS
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