094
FXUS66 KMTR 220702
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1202 AM PDT TUE SEP 22 2026
..NEW SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 1201 AM PDT TUE SEP 22 2026
- WARMING TREND BEGINS TODAY THROUGH THURSDAY
- COOLER CONDITIONS FRIDAY INTO THE WEEKEND
SHORT TERM
ISSUED AT 1201 AM PDT TUE SEP 22 2026
(TODAY AND TONIGHT)
EXTENSIVE STRATUS HAS FLOWED INTO THE NORTH BAY VALLEYS, MONTEREY
BAY REGION, SALINAS VALLEY, HOLLISTER AREA, AND THE EAST BAY WEST OF
THE BERKELEY HILLS. ACROSS THE REST OF THE SF BAY AREA, PATCHES OF
STRATUS HAVE DEVELOPED NEAR LIVERMORE AND NORTH OF SAN JOSE, WITH
FURTHER EXPANSION EXPECTED THROUGH THE PRE-DAWN HOURS. THE CLOUD
DECK RETREATS BACK TO THE IMMEDIATE COAST LATE THIS MORNING INTO THE
EARLY AFTERNOON, BUT BY THE TIME IT DEVELOPS AGAIN TONIGHT, THE
MARINE LAYER WILL BE COMPRESSED, LEADING TO UNCERTAINTY OVER JUST
HOW FAR INLAND THE CLOUDS WILL GO.
THE CUT-OFF LOW THAT GAVE US THE LAST COUPLE DAYS OF COOLER
TEMPERATURES IS MOVING ACROSS THE STATE WITH THE CENTER CRAWLING
THROUGH THE MOJAVE DESERT INTO THE GREAT BASIN. THIS ALLOWS FOR MORE
ZONAL FLOW TO COME INTO THE STATE AND A WARMING TREND TO BEGIN
TODAY, WITH HIGH TEMPERATURES IN THE UPPER 70S TO THE MIDDLE 80S
ACROSS THE INLAND VALLEYS, INTO THE UPPER 80S IN THE FAR INTERIOR
REGIONS OF THE NORTH BAY AND SOUTHERN MONTEREY COUNTY, THE MIDDLE
60S TO THE MIDDLE 70S CLOSE TO THE BAYS, AND THE LOWER TO MIDDLE 60S
ALONG THE IMMEDIATE COAST. A BREEZY ONSHORE WIND WILL DEVELOP IN THE
AFTERNOON AND EVENING HOURS, WITH THE STRONGEST GUSTS OF 20 TO 30
MILES PER HOUR ALONG THE COAST, THROUGH FAVORED GAPS AND PASSES, AND
WITHIN THE NORTHERN SALINAS VALLEY.
AS A QUICK SIDE NOTE, TODAY WILL MARK THE AUTUMNAL EQUINOX AND THE
START OF ASTRONOMICAL FALL. AT 505 PM PACIFIC TIME, THE SUN'S
APPARENT PATH ON THE EARTH CROSSES THE EQUATOR, GIVING US 12 HOURS
EACH OF SUNLIGHT AND NIGHTTIME.
LONG TERM
ISSUED AT 1201 AM PDT TUE SEP 22 2026
(WEDNESDAY THROUGH MONDAY)
SLIGHT RIDGING WILL DEVELOP OVER CALIFORNIA OVER THE NEXT COUPLE OF
DAYS, AND WHILE THE RIDGE AXIS QUICKLY MOVES INTO THE INTERMOUNTAIN
WEST, THE RIDGE INFLUENCE WILL ALLOW FOR FURTHER WARMING WEDNESDAY
AND THURSDAY. HIGH TEMPERATURES WARM INTO THE MIDDLE 80S TO THE
MIDDLE 90S IN THE INLAND VALLEYS, THE MIDDLE 70S TO THE MIDDLE 80S
CLOSE TO THE BAYS, AND THE MIDDLE 60S TO THE LOWER 70S ALONG THE
PACIFIC COAST. POCKETS OF MODERATE HEATRISK ARE SCATTERED ACROSS THE
INTERIOR REGIONS, PARTICULARLY NEAR SAN JOSE, THE INTERIOR EAST BAY,
AND THE SANTA LUCIA RANGE. THESE POCKETS ARE NOT EXPANSIVE ENOUGH TO
MERIT A HEAT ADVISORY.
BY FRIDAY, A DEVELOPING TROUGH IN THE EASTERN PACIFIC COMES INTO THE
WEST COAST, AND A COOLING TREND WILL CAUSE TEMPERATURES TO DIP NEAR
AND BELOW SEASONAL AVERAGES. WEEKEND HIGHS RANGE FROM THE MIDDLE 70S
TO THE MIDDLE 80S IN THE INLAND VALLEYS AND THE MIDDLE 60S TO THE
MIDDLE 70S CLOSE TO THE BAYS. TEMPERATURES WILL RECOVER EARLY NEXT
WEEK AS THE TROUGH FLATTENS AND ENSEMBLE MODEL CLUSTER ANALYSIS
HINTS AT A RIDGE DEVELOPING SOMEWHERE WITHIN THE WESTERN UNITED
STATES, ALTHOUGH THE EXACT IMPACTS ARE NOT CERTAIN AT THIS POINT.
AVIATION
(06Z TAFS)
ISSUED AT 1021 PM PDT MON SEP 21 2026
EXTENSIVE MVFR-IFR STRATUS HAS FLOWED INTO THE NORTH BAY AND THE
MONTEREY BAY REGION, AND CONTINUES TO DEVELOP IN THE SF BAY REGION.
A DEEP MARINE LAYER SHOULD ALLOW MANY OF THE INLAND VALLEYS TO SEE
CEILINGS OVERNIGHT BEFORE THE STRATUS RETREATS BACK TO THE IMMEDIATE
COAST LATE TUESDAY MORNING. LOW TO MODERATE CONFIDENCE IN TEMPORARY
SCATTERINGS AT HAF AND MRY AROUND THE 19-22Z TIMEFRAME. GENTLE TO
MODERATE ONSHORE WINDS WILL DEVELOP TUESDAY AFTERNOON AND EVENING.
STRATUS FORECASTS FOR TUESDAY NIGHT INTO WEDNESDAY MORNING ARE LOWER
CONFIDENCE, PARTICULARLY AWAY FROM THE IMMEDIATE COAST, AS A
COMPRESSING MARINE LAYER SHOULD KEEP STRATUS AWAY FROM MANY INLAND
REGIONS BUT LOWER CEILINGS AND VISIBILITIES WHERE IT DOES FORM.
VICINITY OF SFO... A TRICKY FORECAST FOR THE NEXT SEVERAL HOURS AS
THE STRATUS FEED THROUGH THE GOLDEN GATE GETS DEFLECTED TO THE
NORTH, LEAVING THE TERMINAL AREA VFR. HIGH RESOLUTION MODEL OUTPUT
HAS THE TERMINAL GETTING MVFR CEILINGS IMMINENTLY, BUT THE MODELS
HAVE NOT CAPTURED THE CURRENT SITUATION WELL AND HAVE KEPT THE
TERMINAL VFR FOR THE TIME BEING. IF STRATUS FORMS OVER SFO EXPECT
THE CLOUDS TO SCATTER OUT LATE TUESDAY MORNING, WITH A MODERATE WEST
BREEZE DEVELOPING IN THE AFTERNOON AND EVENING HOURS. LOW CONFIDENCE
OF STRATUS RETURNING TUESDAY NIGHT, WHICH MOST OF THE HIGH
RESOLUTION GUIDANCE HAS BACKED AWAY FROM AND MAY BE IMPACTED BY A
COMPRESSING MARINE LAYER.
SFO BRIDGE APPROACH... MVFR STRATUS MAY ARRIVE BEFORE OR AFTER IT
GETS TO THE TERMINAL TONIGHT, DEPENDING ON HOW EXACTLY THE STRATUS
DEVELOPS WITH SF BAY. OTHERWISE SIMILAR TO SFO.
MONTEREY BAY TERMINALS... MVFR CEILINGS AT PRESENT WITH IFR
CONDITIONS EXPECTED LATER TONIGHT. STRATUS WILL SCATTER OUT TUESDAY
LATE MORNING TO THE EARLY AFTERNOON, WITH MODERATE CONFIDENCE IN A
BRIEF SCATTERING PERIOD AT MRY NEAR 19-22Z. STRATUS IS EXPECTED TO
RETURN TO MRY LATE IN THE AFTERNOON AND PERSIST INTO THE EVENING. AT
SNS, CONFIDENCE IS LOWER AS THE COMPRESSING MARINE LAYER MAY KEEP
THE DECK AWAY, BUT ON THE FLIP SIDE, THE COMPRESSION COULD ALSO
LOWER CEILINGS AND VISIBILITIES AT MRY ON TUESDAY NIGHT.
MARINE
(TONIGHT THROUGH NEXT SUNDAY)
ISSUED AT 826 PM PDT MON SEP 21 2026
MODERATE TO FRESH NORTHWEST BREEZES PERSIST OVERNIGHT WITH
LOCALLY STRONGER WINDS NORTH OF POINT REYES. BY TUESDAY AFTERNOON,
WIDESPREAD STRONG NORTHWEST WINDS PREVAIL ACROSS THE COASTAL
WATERS, ALLOWING FOR SEAS TO BUILD FROM MODERATE TO ROUGH.
NORTHWEST WINDS AND SEAS REMAIN ELEVATED THROUGH THE WEEK WITH A
BRIEF PERIOD OF IMPROVED CONDITIONS WEDNESDAY NIGHT INTO THURSDAY.
BY FRIDAY, WINDS INCREASE WITH BUILDING ROUGH SEAS.
FIRE WEATHER
ISSUED AT 423 AM PDT MON SEP 21 2026
AN UPPER-LEVEL LOW WILL SUPPORT NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES, INCREASED DIURNAL WINDS, A DEEP (2,500') MARINE
LAYER. WARMING AND DRYING TREND KICKS OFF TUESDAY WITH
TEMPERATURES UP TO 10 DEGREES ABOVE NORMAL AND AREAS OF MODERATE
HEATRISK WEDNESDAY AND THURSDAY. THE MARINE LAYER WILL COMPRESS
BELOW 1,000 FEET DURING THIS WARM-UP WITH NOCTURNAL DRYING
EXPECTED ABOVE IT.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT
WEDNESDAY FOR PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM PDT
WEDNESDAY FOR PIGEON PT TO PT PINOS 10-60 NM.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...DIALH
MARINE...DIALH
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