824
FXUS66 KMTR 272322
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
422 PM PDT FRI MAR 27 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1010 AM PDT FRI MAR 27 2026
- ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE WEEKEND
- BENEFICIAL RAIN POSSIBLE NEXT WEEK
SHORT TERM
ISSUED AT 1010 AM PDT FRI MAR 27 2026
(THIS AFTERNOON THROUGH SATURDAY)
DESPITE THE HIGH CLOUDS MOVING IN FROM THE SOUTH, MAX
TEMPERATURES TODAY WILL CHALLENGE DAILY RECORDS. THE MORNING
SOUNDING FOUND 850 MB TEMPERATURES OF 16.75 C, AND A 500 MB HEIGHT
OF 5800M. THOSE BENCHMARKS ARE BOTH BETWEEN THE 90TH PERCENTILE
AND DAILY MAX FOR THIS DATE. IN ADDITION TO THE BACKGROUND
ATMOSPHERIC HEAT CONTENT, THERE ARE OFFSHORE WINDS HELPING KEEP
THE SURFACE WARM AND DRY VIA DOWNSLOPE FLOW AND ADIABATIC HEATING.
AS SUCH, A COUPLE DAILY RECORDS MAY FALL TODAY, BUT NOT NEARLY AS
WIDESPREAD OR HISTORIC AS LAST WEEK WHEN THE 850 MB TEMPERATE
REACHED A RIDICULOUS 22 C. DESPITE THE POSSIBLE RECORDS, THE HIGH
CLOUDS AND GENTLE BREEZE SHOULD HELP IT FEEL PLEASANT FOR MOST
THIS AFTERNOON.
BY SATURDAY THE SURFACE HIGH PRESSURE OVER THE ROCKIES WILL BE
REPLACED BY LOW PRESSURE MOVING IN FROM CANADA. THIS WILL EITHER
NEUTRALIZE THE OFFSHORE GRADIENT OR FLIP IT TO WEAK ONSHORE FLOW,
DEPENDING ON THE STRENGTH OF THE LOW PRESSURE. THIS CHANGE OPENS
THE DOOR FOR A SHALLOW MARINE LAYER TO CREEP IN, BRINGING LOW
CLOUDS AND POSSIBLY MORNING FOG TO THE COAST AND ADJACENT LOW-
LYING AREAS. THE ONSHORE WINDS WILL ALSO SUPPRESS THE
TEMPERATURES A BIT, BUT THE WARM LOW-MIDDLE ATMOSPHERE WILL ENSURE
TEMPERATURES STAY WELL ABOVE NORMAL.
LONG TERM
ISSUED AT 1010 AM PDT FRI MAR 27 2026
(SATURDAY NIGHT THROUGH NEXT THURSDAY)
AFTER A MINOR COOL-DOWN SATURDAY, NEAR RECORD WARMTH RETURNS ON
SUNDAY. SOME LIGHT OFFSHORE FLOW IS LIKELY TO RETURN, BUT THE
HIGH CLOUDS THAT ARE SUPPRESSING TEMPERATURES TODAY WILL BE
THINNER AND MORE SCATTERED. INLAND AREAS SHOULD REACH THE MID 80S,
WITH 70S ALONG THE COAST. MONDAY IS A TRANSITION DAY BEFORE
TEMPERATURES FINALLY RETURN TO NORMAL NEXT WEEK. ENSEMBLE
CLUSTERS AGREE THAT A TROUGH WILL MOVE IN AND USHER OUT THE
PERSISTENT RIDGE. THE DEPTH OF THIS TROUGH IS STILL IN QUESTION,
WITH SOME SOLUTIONS KEEPING THE MAJORITY OF THE PRECIPITATION IN
THE PACIFIC NORTHWEST AND OTHERS DIGGING DOWN TO CENTRAL
CALIFORNIA. SO WE KNOW THE TEMPERATURES WILL DROP, BUT THE
PRECIPITATION AMOUNT REMAINS IN QUESTION. OUR OFFICIAL FORECAST
HAS AROUND 1/4" IN THE INTERIOR AND UP TO 1" IN THE COASTAL
MOUNTAINS FROM TUESDAY THROUGH WEDNESDAY. THE DRY SCENARIO IS MORE
LIKE A TRACE IN THE LOW LANDS AND A FEW HUNDREDTHS IN THE COASTAL
MOUNTAINS, WHILE THE WET SCENARIO IS MORE LIKE 3/4" INLAND AND
2-3 INCHES IN THE COASTAL MOUNTAINS. THE REALITY CAN BE EITHER OF
THESE, OR OF COURSE SOMEWHERE IN THE MIDDLE. THERE IS EVEN A 20%
CHANCE THAT WE FALL OUTSIDE OF THAT WIDE RANGE, TO ONE SIDE OR THE
OTHER. THIS JUST HIGHLIGHTS THE REMAINING UNCERTAINTY WITH THIS
SYSTEM. DON'T BANK ON ANY DETERMINISTIC FORECAST JUST YET.
WHATEVER HAPPENS MID WEEK, IT DOES LOOK LIKE THE PATTERN WILL
STABILIZE LATE WEEK BEFORE ANOTHER RIDGE BUILDS IN THE FOLLOWING
WEEK.
AVIATION
(00Z TAFS)
ISSUED AT 422 PM PDT FRI MAR 27 2026
VFR WITH HIGH CLOUDS ACROSS THE REGION. BREEZY ONSHORE WINDS
CONTINUE ACROSS THE COASTAL REGIONS, WITH THE LINGERING OFFSHORE
PUSH KEEPING WINDS LIGHT IN THE INTERIOR. WINDS TURN LIGHT OVERNIGHT
WITH A MODERATE-HIGH CONFIDENCE OF A SURGE OF STRATUS COMING INTO
THE IMMEDIATE COASTAL REGIONS AFTER MIDNIGHT, WITH SOME INTRUSION
INTO THE SONOMA COUNTY VALLEYS, EAST BAY, AND THE MONTEREY BAY
REGION. PATCHY FOG IS POSSIBLE IN THE COASTAL REGIONS AND THE SONOMA
COUNTY VALLEYS. HIGH RESOLUTION MODELS HAVE FOG DEVELOPING AROUND 09-
10Z. BESIDES STS, HAVE REFASHIONED THE PREVIOUS TEMPO GROUPS INTO
PREVAILING FORECASTS FOR FOG, BUT THIS IS A LOW TO MODERATE
CONFIDENCE FORECAST AT THIS TIME. STRATUS RETREATS AND LIFTS THROUGH
SATURDAY MORNING, WITH PATCHY STRATUS PERSISTING AT THE IMMEDIATE
COAST WHILE THE ONSHORE WINDS RESUME.
VICINITY OF SFO... VFR WITH THIN HIGH CLOUDS THROUGH THE TAF PERIOD.
BREEZY WEST-NORTHWEST WINDS CONTINUE THROUGH THE EVENING HOURS.
WINDS GRADUALLY DIMINISH IN THE LATE EVENING WITH LIGHT WINDS
SATURDAY MORNING, BEFORE THE BREEZY WEST-NORTHWEST WINDS RESUME
DURING THE AFTERNOON. VERY LOW CONFIDENCE OF STRATUS IMPACTS TO
NIGHT AT THE TERMINAL, WITH MODERATE CONFIDENCE OF IMPACTS TO THE
BERKELEY AREA AND LOWER CONFIDENCE AT OAK.
SFO BRIDGE APPROACH... SIMILAR TO SFO.
MONTEREY BAY TERMINALS... VFR CONDITIONS WITH BREEZY NORTHWEST WINDS
THROUGH THE REST OF THE DAY. MODERATE TO HIGH CONFIDENCE THAT A
SURGE OF STRATUS WILL IMPACT THE REGION AFTER MIDNIGHT WITH PATCHY
FOG LIKELY. MOST RECENT HIGH RESOLUTION MODEL OUTPUT HAS THE FOG
ARRIVING AROUND 09-10Z. HAVE REFASHIONED THE PREVIOUS TEMPO GROUPS
INTO PREVAILING FORECASTS FOR FOG, BUT THIS IS A LOW TO MODERATE
CONFIDENCE FORECAST AT THIS TIME. SATURDAY MORNING, CEILINGS LIFT
AND LATER DISSIPATE AS BREEZY NORTHWEST WINDS RESUME.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 422 PM PDT FRI MAR 27 2026
HIGH PRESSURE OVER THE EASTERN PACIFIC CONTINUES TO DOMINATE THE
PATTERN, PRODUCING A MODERATE TO FRESH NW BREEZE AND MODERATE SEAS
THROUGH THE WEEKEND. CONDITIONS WILL BE SLIGHTLY HEAVIER ON
SATURDAY ACROSS THE NW WATERS, WITH A FRESH TO STRONG NW BREEZE
AND ROUGH SEAS TO 8 FT.
FIRE WEATHER
ISSUED AT 1010 AM PDT FRI MAR 27 2026
IN ADDITION TO THE HEAT, THE AIR IS ALSO DRY THANKS TO SOME
OFFSHORE WINDS SUPPORTED BY THE GRADIENT BETWEEN HIGH PRESSURE
OVER THE ROCKIES AND A THERMAL TROUGH OVER THE COAST. THE SFO-WMC
GRADIENT HAS BEEN AROUND -10 MB FOR THE LAST 12 HOURS. WINDS WERE
GUSTING TO 30-45 MPH ACROSS HIGHER ELEVATIONS OF THE NORTH AND
EAST BAY, ENHANCED BY SOME MOUNTAIN WAVE ACTIVITY. THE RELATIVE
HUMIDITY IN THESE AREAS WAS IN THE TEENS OVERNIGHT, WHICH IS WHEN
YOU WOULD TYPICALLY EXPECT THE HIGHEST RH OF THE DAY. THE SOUNDING
FOUND AN INCREDIBLY DRY POCKET OF AIR BETWEEN 850 AND 700 MB,
WHERE THE AVERAGE RH IS ONLY 2%. THE COMBINED HOT, DRY, AND WINDY
CONDITIONS ARE MORE THAN ENOUGH TO REACH RED FLAG CRITERIA IN THE
NORTH AND EAST BAY MOUNTAINS TODAY, BUT WE STILL NEED THE ANNUAL
GRASSES TO CURE BEFORE THAT'S AN OPTION.
TYPICALLY THE GRASS CURES AND TURNS BROWN IN THE SUMMER, BUT THIS
YEAR IS AHEAD OF SCHEDULE. DOWNTOWN SAN FRANCISCO IS CURRENTLY
REPORTING THE WARMEST MARCH ON RECORD (BY A HEALTHY 1.5F IN TERMS
OF AVERAGE TEMPERATURE THROUGH MARCH 26TH) AND THE DRIEST MARCH
SINCE 1923 (ONLY 0.06" OF RAIN SO FAR, NORMAL FOR MARCH IS 3.15").
TO GET A SENSE OF THE LIVE FUEL MOISTURE I COMPARED HISTORICAL
POLAR ORBITING SATELLITE IMAGES FROM PAST YEARS (SEARCH "NASA
WORLDVIEW" TO SEE FOR YOURSELF). WE ARE SOMEWHERE BETWEEN A NORMAL
APRIL AND MAY IN TERMS OF BROWNNESS. FOR DEAD FUEL MOISTURE IT'S
EVEN MORE STARK. THE ENERGY RELEASE COMPONENTS ARE SETTING RECORDS
ACROSS THE CWA, WITH THE MID COAST TO MENDOCINO ERC NEAR THE
AVERAGE FOR EARLY JULY, AND DIABLO-SANTA CRUZ NEAR THE AVERAGE
FOR MID-JULY. THE BAY AREA MARINE ERC IS ACTUALLY ABOVE THE
AVERAGE FOR ANY TIME OF YEAR, AND EVEN CROSSED THE ANNUALIZED 97TH
PERCENTILE. WHILE THE HILLS STILL HAVE MORE GREEN THAN BROWN AND
WE'RE NOT EXPECTING LARGE WILDFIRES ANYTIME SOON, THE ANTECEDENT
CONDITIONS ARE SET UP FOR AN ACTIVE YEAR.
CLIMATE
ISSUED AT 301 AM PDT FRI MAR 27 2026
HERE ARE THE RECORD HIGH TEMPERATURES AT THE LONG TERM SITES FOR
MARCH 27TH AND MARCH 29TH.
LOCATION MARCH 27TH MARCH 29TH
SANTA ROSA 87 IN 1930 86 IN 2018
SAN RAFAEL 82 IN 1969, 1951 85 IN 2018
KENTFIELD 90 IN 1923 84 IN 1935
NAPA 86 IN 1930 83 IN 2018, 1968
RICHMOND 82 IN 1952 79 IN 1968
LIVERMORE 82 IN 1969, 1930 85 IN 2015
SAN FRANCISCO 84 IN 1923 81 IN 2018
SFO AIRPORT 77 IN 2021, 1986 81 IN 2018
REDWOOD CITY 83 IN 1969 85 IN 2018, 1968
HALF MOON BAY 76 IN 1952 77 IN 2004
OAKLAND 79 IN 1986 79 IN 2003
SAN JOSE 85 IN 1923 82 IN 2018
SALINAS AIRPORT 80 IN 1969, 1952 86 IN 2018
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 AM PDT SUNDAY
FOR PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...DIALH
MARINE...RGASS
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