156
FXUS66 KMTR 200537
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1037 PM PDT TUE MAY 19 2026
..NEW SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 1036 PM PDT TUE MAY 19 2026
- DIURNALLY DRIVEN WINDS, WITH ONSHORE WINDS DURING THE AFTERNOON
AND EARLY EVENING.
- ABOVE NORMAL TEMPERATURES CONTINUE THROUGH MIDWEEK WITH SEASONAL
TEMPERATURES RETURNING LATE WEEK.
- WARM AND DRY WEATHER THROUGH THURSDAY LEADS TO ELEVATED FIRE
WEATHER CONCERNS FOR THE INTERIOR BAY AREA AND CENTRAL COAST.
SHORT TERM
ISSUED AT 1036 PM PDT TUE MAY 19 2026
(TONIGHT THROUGH THURSDAY)
LITTLE CHANGE IN THE FORECAST AS HIGH PRESSURE SLOWLY CREEPS INTO
NORTHERN CALIFORNIA TODAY. SATELLITE IMAGERY THIS EVENING SHOWS
HIGH CLOUDS SLIDING DOWN THE WEST COAST, WITH MUCH OF THE BAY AREA
LIKELY SEEING SOME CIRRUS. WITH THE CURRENT DATA, TEMPERATURES
LOOK TO BE ON TRACK; HOWEVER, IF WE'RE NOT ABLE TO GET RADIATIONAL
COOLING, OUR TEMPERATURES FOR TONIGHT MIGHT BE LOW/COOL. THIS
WOULD BE BECAUSE THE CLOUDS ACT AS BLANKET, ALLOWING LESS HEAT TO
ESCAPE AT NIGHT. IT'LL BE SOMETHING TO KEEP AN EYE ON OVER THE
NEXT FEW HOURS.
IN TERMS OF WEDNESDAY, IF YOU GUESSED, "NO PATTERN CHANGE. HA, THIS
MEANS ANOTHER DAY OF WARMER WEATHER", YOU'D BE CORRECT! A POTENTIAL
FLY IN THE OINTMENT IS IF THE MARINE LAYER ATTEMPTS TO MANIFEST
AROUND 500 FEET. THIS MIGHT KEEP TEMPERATURES A FEW DEGREES COOLER
ALONG THE IMMEDIATE COAST, BUT ELSEWHERE TEMPERATURES SHOULD BE
SIMILAR TO TUESDAY, PERHAPS A FEW DEGREES HIGHER.
LONG TERM
ISSUED AT 1036 PM PDT TUE MAY 19 2026
(THURSDAY NIGHT THROUGH NEXT TUESDAY)
NO MAJOR CHANGES TO THE EXTENDED FORECAST. UPPER LEVEL TROUGHING
LOOKS TO KEEP HOLD OVER THE WESTERN US, WHILE THE PACIFIC HIGH
PUSHES EVEN MORE INTO NORTHERN CALIFORNIA ON THURSDAY. WITH THE HIGH
BEING A BIT MORE PRONOUNCED, ANOTHER WARM DAY WILL BE ON TAP.
AFTER THAT, GUIDANCE HAS FLOW BECOMING QUASI-ZONAL FOR A BRIEF
PERIOD BEFORE TROUGHING RETURNS ON FRIDAY. THE MARINE LAYER LOOKS
TO BE AROUND 500FT ON THURSDAY, DEEPENING TO AROUND 1000FT BY
FRIDAY AND THEN LASTING THROUGH THE WEEKEND. WITH ONSHORE FLOW, A
DEEPER MARINE LAYER, AND TROUGHING THROUGH THE WEEKEND THE NBM'S
TEMPERATURES ARE BIT TOO WARM. OPTED TO START TRENDING TOWARDS
SLIGHTLY COOLER TEMPERATURES GIVEN THE ENSEMBLES AND CLUSTER
ANALYSIS. BUT THERE IS A CHANCE RIDGING WINS OUT AND TEMPERATURES
MIGHT WARMER. DEFINITELY SOMETHING TO KEEP AN EYE ON OVER THE NEXT
FEW DAYS.
AVIATION
(06Z TAFS)
ISSUED AT 926 PM PDT TUE MAY 19 2026
CURRENTLY VFR AT ALL TERMINALS WITH THE EXCEPTION OF MVFR AT HAF.
WINDS MAY BECOME CALM AND/OR LIGHT AND VARIABLE OVERNIGHT. LOW TO
MODERATE CONFIDENCE IN IFR CONDITIONS DEVELOPING AT TERMINALS
TONIGHT - THE MOST LIKELY TIMEFRAME IS 12Z TO 16Z. COASTAL
TERMINALS WILL BE AT GREATEST RISK WITH RISK DECREASING FOR
BAYSHORE AND INTERIOR TERMINALS, RESPECTIVELY. HIGHER CONFIDENCE
IN IFR CONDITIONS RETURNING TOMORROW NIGHT.
VICINITY OF SFO...CURRENTLY VFR WITH NORTHWESTERLY FLOW. MODERATE
TO HIGH CONFIDENCE IN VFR AND DIURNAL WINDS PREVAILING THROUGH
THE TAF PERIOD. LOW PROBABILITY FOR SUB-VFR CONDITIONS TO DEVELOP
AT THE TERMINAL TONIGHT AS THE COMPRESSED MARINE LAYER WILL BE
UNABLE TO PENETRATE THE SAN BRUNO GAP. REASONABLE WORST CASE
SCENARIO IS STRATUS SNEAKS THROUGH THE GOLDEN GATE GAP AND BRINGS
FEW/SCT TO THE NORTH SIDE OF THE TERMINAL.
SFO BRIDGE APPROACH...THE SAN MATEO BRIDGE APPROACH HAS A LOWER
PROBABILITY OF SUB-VFR CONDITIONS.
MONTEREY BAY TERMINALS...CURRENTLY VFR AND CALM AT MRY AND VFR WITH
NORTHERLY FLOW AT SNS. CONFIDENCE HAS INCREASED IN SUB-VFR
CONDITIONS DEVELOPING AT THE TERMINALS TONIGHT, ESPECIALLY FOR
MRY. CEILINGS WILL LIKELY BE ON THE CUSP OF IFR/LIFR.
MARINE
(TONIGHT THROUGH NEXT MONDAY)
ISSUED AT 926 PM PDT TUE MAY 19 2026
HAZARDOUS CONDITIONS FOR SMALL CRAFT WILL CONTINUE THROUGH
WEDNESDAY FOR THE NORTHERN OUTERS DUE TO ROUGH SEAS AND STRONG
NORTHERLY BREEZES. ELSEWHERE, MODERATE TO FRESH NORTHWESTERLY
BREEZES AND MODERATE SEAS WILL PREVAIL. CONDITIONS IMPROVE INTO
THE WEEKEND AS SEAS AND NORTHWESTERLY BREEZES BECOME MODERATE.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 PM PDT THURSDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...KR
LONG TERM....KR
AVIATION...SARMENT
MARINE...SARMENT
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