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FXUS66 KMTR [Monterey CA] 192354 AFDMTR ∨

FXUS66 KMTR 192354
AFDMTR [HEAD]

National Weather Service San Francisco California 4:54pm PDT Sun Jul 19 2026 ∨

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
454 PM PDT SUN JUL 19 2026 [HEAD]

New aviation, marine. ∨

...NEW AVIATION, MARINE... [DISC]

Key Messages… updated at 1:48pm PDT Sun July 19 2026 ∨

.KEY MESSAGES...
UPDATED AT 148 PM PDT SUN JUL 19 2026 [DISC]

- near or slightly below normal temperatures and higher humidity through the first half of the upcoming week. ∨

 - NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES AND HIGHER HUMIDITY
THROUGH THE FIRST HALF OF THE UPCOMING WEEK. [DISC]

- the marine layer and mid to upper level cloud cover will continue to help keep temperatures cooler under building high pressure. ∨

 - THE MARINE LAYER AND MID TO UPPER LEVEL CLOUD COVER WILL
CONTINUE TO HELP KEEP TEMPERATURES COOLER UNDER BUILDING HIGH
PRESSURE. [DISC]

- approximately 5% chance of elevated showers with isolated thunderstorms Tuesday afternoon through Wednesday evening. ∨

 - APPROXIMATELY 5% CHANCE OF ELEVATED SHOWERS WITH ISOLATED
THUNDERSTORMS TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. [DISC]

Short term. Issued at 1:48pm PDT Sun July 19 2026 (this evening through Monday night) ∨

.SHORT TERM...
ISSUED AT 148 PM PDT SUN JUL 19 2026
(THIS EVENING THROUGH MONDAY NIGHT) [DISC]

Marine layer stratus has retreated back to the coastline as of early this afternoon. Increasing coverage of mid/high level clouds streaming northeast out ahead of an upper level low over the Eastern Pacific will continue this afternoon and tonight. Elevated showers can be seen on radar approaching our southern outer marine zones and will continue to remain well off shore for the remainder of today and this evening. However, after midnight, elevated shower activity is possible mainly for the Bay Area and the North Bay through mid-morning Monday. Poor lapse rates [The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of instability) and a steepening lapse rate implies that destabilization is occurring.] and thermal instability will limit the chances for thunderstorm activity. Along with the weak instability, very dry air between 700 mb-925 mb will likely result in little to no precipitation reaching the ground with only a trace to a few hundredths where any rainfall is measured. Temperatures on Monday will be similar to slightly cooler than today's values with the increased cloud coverage. ∨

MARINE LAYER STRATUS HAS RETREATED BACK TO THE COASTLINE AS OF EARLY
THIS AFTERNOON. INCREASING COVERAGE OF MID/HIGH LEVEL CLOUDS
STREAMING NORTHEAST OUT AHEAD OF AN UPPER LEVEL LOW OVER THE EPAC
WILL CONTINUE THIS AFTERNOON AND TONIGHT. ELEVATED SHOWERS CAN BE
SEEN ON RADAR APPROACHING OUR SOUTHERN OUTER MARINE ZONES AND WILL
CONTINUE TO REMAIN WELL OFF SHORE FOR THE REMAINDER OF TODAY AND
THIS EVENING. HOWEVER, AFTER MIDNIGHT, ELEVATED SHOWER ACTIVITY IS
POSSIBLE MAINLY FOR THE BAY AREA AND THE NORTH BAY THROUGH MID-
MORNING MONDAY. POOR LAPSE RATES AND THERMAL INSTABILITY WILL LIMIT
THE CHANCES FOR THUNDERSTORM ACTIVITY. ALONG WITH THE WEAK
INSTABILITY, VERY DRY AIR BETWEEN 700MB-925MB WILL LIKELY RESULT IN
LITTLE TO NO PRECIPITATION REACHING THE GROUND WITH ONLY A TRACE TO
A FEW HUNDREDTHS WHERE ANY RAINFALL IS MEASURED. TEMPERATURES ON
MONDAY WILL BE SIMILAR TO SLIGHTLY COOLER THAN TODAYS VALUES WITH
THE INCREASED CLOUD COVERAGE. [AVIA]

Expecting a typical stratus intrusion tonight into early Monday morning as onshore flow persists, with high clouds helping to limit some of the radiational stratus cloud top cooling that will result in less mist/drizzle coverage than we saw this morning, and mostly confined to coastal areas. ∨

EXPECTING A TYPICAL STRATUS INTRUSION TONIGHT INTO EARLY MONDAY
MORNING AS ONSHORE FLOW PERSISTS, WITH HIGH CLOUDS HELPING TO LIMIT
SOME OF THE RADIATIONAL STRATUS CLOUD TOP COOLING THAT WILL RESULT
IN LESS MIST/DRIZZLE COVERAGE THAN WE SAW THIS MORNING, AND MOSTLY
CONFINED TO COASTAL AREAS. [AVI2]

Long term. Issued at 1:48pm PDT Sun July 19 2026 (Tuesday through next Saturday) ∨

.LONG TERM...
ISSUED AT 148 PM PDT SUN JUL 19 2026
(TUESDAY THROUGH NEXT SATURDAY) [DISC]

Chances for another round of elevated showers with isolated thunderstorms is trending upward. Not currently reflected in the official forecast but subsequent updates may see increases in coverage and intensity by Tuesday afternoon into Wednesday, mainly across the North Bay and maybe as far south as the Bay Area. The main source continues to be the moisture associated with what will be the remnants of Elida moving north, well offshore of our area by the end of the day Wednesday. Increasing lift, better thermal instability and slightly improved mid-level lapse rates [The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of instability) and a steepening lapse rate implies that destabilization is occurring.] between 7–7.5°C/km by late Tuesday afternoon into Tuesday night will provide the best chances for elevated thunderstorms and potentially impactful dry lightning. A similar pocket of dry air from 700 mb-925 mb will continue to limit beneficial rainfall. A final wave of elevated instability will move into the North Bay once again late Wednesday afternoon into the evening hours with potentially improved thermal instability, however less lift and weaker lapse rates [The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of instability) and a steepening lapse rate implies that destabilization is occurring.], with dry air in the mid-levels continuing to limit precipitation reaching the ground. By Thursday into the weekend, the increased mid-level moisture shifts north and we begin to see drier air aloft with a gradual warming trend into the weekend. However, onshore flow will persist will persist through the extended forecast with typical no-sky-July conditions each night and morning. ∨

CHANCES FOR ANOTHER ROUND OF ELEVATED SHOWERS WITH ISOLATED
THUNDERSTORMS IS TRENDING UPWARD. NOT CURRENTLY REFLECTED IN THE
OFFICIAL FORECAST BUT SUBSEQUENT UPDATES MAY SEE INCREASES IN
COVERAGE AND INTENSITY BY TUESDAY AFTERNOON INTO WEDNESDAY, MAINLY
ACROSS THE NORTH BAY AND MAYBE AS FAR SOUTH AS THE BAY AREA. THE
MAIN SOURCE CONTINUES TO BE THE MOISTURE ASSOCIATED WITH WHAT WILL
BE THE REMNANTS OF ELIDA MOVING NORTH, WELL OFFSHORE OF OUR AREA BY
THE END OF THE DAY WEDNESDAY. INCREASING LIFT, BETTER THERMAL
INSTABILITY AND SLIGHTLY IMPROVED MID-LEVEL LAPSE RATES BETWEEN 7-
7.5 C/KM BY LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT WILL PROVIDE
THE BEST CHANCES FOR ELEVATED THUNDERSTORMS AND POTENTIALLY
IMPACTFUL DRY LIGHTNING. A SIMILAR POCKET OF DRY AIR FROM 700MB-
925MB WILL CONTINUE TO LIMIT BENEFICIAL RAINFALL. A FINAL WAVE OF
ELEVATED INSTABILITY WILL MOVE INTO THE NORTH BAY ONCE AGAIN LATE
WEDNESDAY AFTERNOON INTO THE EVENING HOURS WITH POTENTIALLY
IMPROVED THERMAL INSTABILITY, HOWEVER LESS LIFT AND WEAKER LAPSE
RATES, WITH DRY AIR IN THE MID-LEVELS CONTINUING TO LIMIT
PRECIPITATION REACHING THE GROUND. BY THURSDAY INTO THE WEEKEND,
THE INCREASED MID-LEVEL MOISTURE SHIFTS NORTH AND WE BEGIN TO SEE
DRIER AIR ALOFT WITH A GRADUAL WARMING TREND INTO THE WEEKEND.
HOWEVER, ONSHORE FLOW WILL PERSIST WILL PERSIST THROUGH THE
EXTENDED FORECAST WITH TYPICAL NO- SKY-JULY CONDITIONS EACH NIGHT
AND MORNING. [DISC]

Aviation. (00Z [5pm PDT] TAFs [Terminal Aerodrome Forecasts]) issued at 4:40pm PDT Sun July 19 2026 ∨

.AVIATION...
(00Z TAFS)
ISSUED AT 440 PM PDT SUN JUL 19 2026 [AVIA]

VFR [Visual Flight Rules] with IFR [Instrument Flight Rules]-LIFR [Low Instrument Flight Rules] stratus to return overnight. The marine layer is expected to compress tonight which will lead both to lowered ceiling heights and a smaller inland extent. Confidence in stratus reaching SJC [San Jose CA] is slightly higher than it was this morning while stratus chances for Livermore remain minimal. Have kept higher chances for IFR [Instrument Flight Rules] in at OAK [Oakland CA]/SFO [San Francisco CA] with confidence increasing. Patchy fog is possible along the coast tonight with LIFR [Low Instrument Flight Rules] ceilings and reductions in visibility possible. Diurnally breezy onshore winds continue in the afternoon/evening. ∨

VFR WITH IFR-LIFR STRATUS TO RETURN OVERNIGHT. THE MARINE LAYER IS
EXPECTED TO COMPRESS TONIGHT WHICH WILL LEAD BOTH TO LOWERED
CEILING HEIGHTS AND A SMALLER INLAND EXTENT. CONFIDENCE IN STRATUS
REACHING SJC IS SLIGHTLY HIGHER THAN IT WAS THIS MORNING WHILE
STRATUS CHANCES FOR LVK REMAIN MINIMAL. HAVE KEPT HIGHER CHANCES
FOR IFR IN AT OAK/SFO WITH CONFIDENCE INCREASING. PATCHY FOG IS
POSSIBLE ALONG THE COAST TONIGHT WITH LIFR CIGS AND REDUCTIONS IN
VISIBILITY POSSIBLE. DIURNALLY BREEZY ONSHORE WINDS CONTINUE IN
THE AFTERNOON/EVENING. [AVI2]

Vicinity of SFO [San Francisco CA]… VFR [Visual Flight Rules] with MVFR [Marginal Visual Flight Rules]-IFR [Instrument Flight Rules] stratus to return overnight. Moderate confidence of timing of stratus return. Satellite imagery shows a less expansive stratus layer than last night which increases confidence in a later stratus arrival (~07Z [12am PDT]). MVFR [Marginal Visual Flight Rules] ceilings are the most likely scenario but cannot rule out patchy IFR [Instrument Flight Rules] ceilings given the compressing of the marine layer. Conditions improve by late morning with some potential for stratus to return again late tomorrow evening. ∨

VICINITY OF SFO...VFR WITH MVFR-IFR STRATUS TO RETURN OVERNIGHT.
MODERATE CONFIDENCE OF TIMING OF STRATUS RETURN. SATELLITE IMAGERY
SHOWS A LESS EXPANSIVE STRATUS LAYER THAN LAST NIGHT WHICH
INCREASES CONFIDENCE IN A LATER STRATUS ARRIVAL (~07Z). MVFR CIGS
ARE THE MOST LIKELY SCENARIO BUT CANNOT RULE OUT PATCHY IFR CIGS
GIVEN THE COMPRESSING OF THE MARINE LAYER. CONDITIONS IMPROVE BY
LATE MORNING WITH SOME POTENTIAL FOR STRATUS TO RETURN AGAIN LATE
TOMORROW EVENING. [AVI2]

SFO [San Francisco CA] bridge approach… similar to SFO [San Francisco CA]. ∨

SFO BRIDGE APPROACH...SIMILAR TO SFO. [AVI2]

Monterey Bay terminals… VFR [Visual Flight Rules] with stratus expected to build in over the next few hours. IFR [Instrument Flight Rules]-LIFR [Low Instrument Flight Rules] ceilings are expected tonight with ceilings to gradually lower early tomorrow morning. There is some potential for fog and reductions in visibility due to the compressing of the marine layer. Moderate confidence in clearing between 17–19Z [10am–12pm PDT] with a few models indicating stratus could linger longer at MRY [Monterey CA]. ∨

MONTEREY BAY TERMINALS...VFR WITH STRATUS EXPECTED TO BUILD IN
OVER THE NEXT FEW HOURS. IFR-LIFR CIGS ARE EXPECTED TONIGHT WITH
CIGS TO GRADUALLY LOWER EARLY TOMORROW MORNING. THERE IS SOME
POTENTIAL FOR FOG AND REDUCTIONS IN VISIBILITY DUE TO THE
COMPRESSING OF THE MARINE LAYER. MODERATE CONFIDENCE IN CLEARING
BETWEEN 17-19Z WITH A FEW MODELS INDICATING STRATUS COULD LINGER
LONGER AT MRY. [AVI2]

Marine. (tonight through next Friday) issued at 4:40pm PDT Sun July 19 2026 ∨

.MARINE...
(TONIGHT THROUGH NEXT FRIDAY)
ISSUED AT 440 PM PDT SUN JUL 19 2026 [AVIA]

Gentle to moderate northwesterly breezes will persist through the upcoming workweek with slight to moderate seas. As tropical cyclone activity continues across the eastern Pacific, long period southerly swell is forecast. Southerly swell heights are anticipated to remain in the slight category but mixed seas may result in hazardous boating conditions through the week. Additionally, there are non-zero chances for high based showers which could result in pockets of gusty outflow winds and subsequent steep seas tonight through mid-week. ∨

GENTLE TO MODERATE NORTHWESTERLY BREEZES WILL PERSIST THROUGH THE
UPCOMING WORKWEEK WITH SLIGHT TO MODERATE SEAS. AS TROPICAL
CYCLONE ACTIVITY CONTINUES ACROSS THE EASTERN PACIFIC, LONG PERIOD
SOUTHERLY SWELL IS FORECAST. SOUTHERLY SWELL HEIGHTS ARE
ANTICIPATED TO REMAIN IN THE SLIGHT CATEGORY BUT MIXED SEAS MAY
RESULT IN HAZARDOUS BOATING CONDITIONS THROUGH THE WEEK.
ADDITIONALLY, THERE ARE NON-ZERO CHANCES FOR HIGH BASED SHOWERS
WHICH COULD RESULT IN POCKETS OF GUSTY OUTFLOW WINDS AND
SUBSEQUENT STEEP SEAS TONIGHT THROUGH MID-WEEK. [AVI2]

Fire weather. Issued at 1:48pm PDT Sun July 19 2026 ∨

.FIRE WEATHER...
ISSUED AT 148 PM PDT SUN JUL 19 2026 [AVIA]

Near to slightly cooler than normal temperatures will continue through the week with typical diurnal intrusion of the marine layer each night and retreat to the coast each morning as onshore flow persists. However, above 1500–2000 ft we'll see relatively weak thermal belting the first half of the week with continued warm overnights and poor RH [Relative Humidity] recovery at higher elevations. ∨

NEAR TO SLIGHTLY COOLER THAN NORMAL TEMPERATURES WILL CONTINUE
THROUGH THE WEEK WITH TYPICAL DIURNAL INTRUSION OF THE MARINE LAYER
EACH NIGHT AND RETREAT TO THE COAST EACH MORNING AS ONSHORE FLOW
PERSISTS. HOWEVER, ABOVE 1500-2000FT WE`LL SEE RELATIVELY WEAK
THERMAL BELTING THE FIRST HALF OF THE WEEK WITH CONTINUED WARM
OVERNIGHTS AND POOR RH RECOVERY AT HIGHER ELEVATIONS. [AVI2]

Guidance is trending toward an increasing potential for elevated showers and isolated thunderstorms Tuesday afternoon through Wednesday evening. Chances are below 5% in the official forecast but may increase in subsequent updates tonight and Monday. The primary concern is dry lightning strikes across the North Bay, with lesser chances farther south into the Bay Area. ∨

GUIDANCE IS TRENDING TOWARD AN INCREASING POTENTIAL FOR ELEVATED
SHOWERS AND ISOLATED THUNDERSTORMS TUESDAY AFTERNOON THROUGH
WEDNESDAY EVENING. CHANCES ARE BELOW 5% IN THE OFFICIAL FORECAST BUT
MAY INCREASE IN SUBSEQUENT UPDATES TONIGHT AND MONDAY. THE
PRIMARY CONCERN IS DRY LIGHTNING STRIKES ACROSS THE NORTH BAY,
WITH LESSER CHANCES FARTHER SOUTH INTO THE BAY AREA. [AVI2]

MTR Watches/Warnings/Advisories

California: none.
Pacific Ocean: none. ∨

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE. [WARN]

Short term…JM long term…JM aviation…Kennedy marine…bain ∨

SHORT TERM...JM
LONG TERM....JM
AVIATION...KENNEDY
MARINE...BAIN [WRN2]

VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO [LINK]

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WWW.YOUTUBE.COM/NWSBAYAREA [DISC]

Weather NWS glossary About NWS point forecasts Hourly Weather Graph Long-range forecast Radar Satellite Max Temps Graphical Forecast	Area Forecast Discussion FXUS66 KMTR [Monterey CA] 192354 AFDMTR ∨ FXUS66 KMTR 192354 AFDMTR [HEAD] National Weather Service San Francisco California 4:54pm PDT Sun Jul 19 2026 ∨ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO CA 454 PM PDT SUN JUL 19 2026 [HEAD] New aviation, marine. ∨ ...NEW AVIATION, MARINE... [DISC] Key Messages… updated at 1:48pm PDT Sun July 19 2026 ∨ .KEY MESSAGES... UPDATED AT 148 PM PDT SUN JUL 19 2026 [DISC] - near or slightly below normal temperatures and higher humidity through the first half of the upcoming week. ∨ - NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES AND HIGHER HUMIDITY THROUGH THE FIRST HALF OF THE UPCOMING WEEK. [DISC] - the marine layer and mid to upper level cloud cover will continue to help keep temperatures cooler under building high pressure. ∨ - THE MARINE LAYER AND MID TO UPPER LEVEL CLOUD COVER WILL CONTINUE TO HELP KEEP TEMPERATURES COOLER UNDER BUILDING HIGH PRESSURE. [DISC] - approximately 5% chance of elevated showers with isolated thunderstorms Tuesday afternoon through Wednesday evening. ∨ - APPROXIMATELY 5% CHANCE OF ELEVATED SHOWERS WITH ISOLATED THUNDERSTORMS TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. [DISC] Short term. Issued at 1:48pm PDT Sun July 19 2026 (this evening through Monday night) ∨ .SHORT TERM... ISSUED AT 148 PM PDT SUN JUL 19 2026 (THIS EVENING THROUGH MONDAY NIGHT) [DISC] Marine layer stratus has retreated back to the coastline as of early this afternoon. Increasing coverage of mid/high level clouds streaming northeast out ahead of an upper level low over the Eastern Pacific will continue this afternoon and tonight. Elevated showers can be seen on radar approaching our southern outer marine zones and will continue to remain well off shore for the remainder of today and this evening. However, after midnight, elevated shower activity is possible mainly for the Bay Area and the North Bay through mid-morning Monday. Poor lapse rates [The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of instability) and a steepening lapse rate implies that destabilization is occurring.] and thermal instability will limit the chances for thunderstorm activity. Along with the weak instability, very dry air between 700 mb-925 mb will likely result in little to no precipitation reaching the ground with only a trace to a few hundredths where any rainfall is measured. Temperatures on Monday will be similar to slightly cooler than today's values with the increased cloud coverage. ∨ MARINE LAYER STRATUS HAS RETREATED BACK TO THE COASTLINE AS OF EARLY THIS AFTERNOON. INCREASING COVERAGE OF MID/HIGH LEVEL CLOUDS STREAMING NORTHEAST OUT AHEAD OF AN UPPER LEVEL LOW OVER THE EPAC WILL CONTINUE THIS AFTERNOON AND TONIGHT. ELEVATED SHOWERS CAN BE SEEN ON RADAR APPROACHING OUR SOUTHERN OUTER MARINE ZONES AND WILL CONTINUE TO REMAIN WELL OFF SHORE FOR THE REMAINDER OF TODAY AND THIS EVENING. HOWEVER, AFTER MIDNIGHT, ELEVATED SHOWER ACTIVITY IS POSSIBLE MAINLY FOR THE BAY AREA AND THE NORTH BAY THROUGH MID- MORNING MONDAY. POOR LAPSE RATES AND THERMAL INSTABILITY WILL LIMIT THE CHANCES FOR THUNDERSTORM ACTIVITY. ALONG WITH THE WEAK INSTABILITY, VERY DRY AIR BETWEEN 700MB-925MB WILL LIKELY RESULT IN LITTLE TO NO PRECIPITATION REACHING THE GROUND WITH ONLY A TRACE TO A FEW HUNDREDTHS WHERE ANY RAINFALL IS MEASURED. TEMPERATURES ON MONDAY WILL BE SIMILAR TO SLIGHTLY COOLER THAN TODAYS VALUES WITH THE INCREASED CLOUD COVERAGE. [AVIA] Expecting a typical stratus intrusion tonight into early Monday morning as onshore flow persists, with high clouds helping to limit some of the radiational stratus cloud top cooling that will result in less mist/drizzle coverage than we saw this morning, and mostly confined to coastal areas. ∨ EXPECTING A TYPICAL STRATUS INTRUSION TONIGHT INTO EARLY MONDAY MORNING AS ONSHORE FLOW PERSISTS, WITH HIGH CLOUDS HELPING TO LIMIT SOME OF THE RADIATIONAL STRATUS CLOUD TOP COOLING THAT WILL RESULT IN LESS MIST/DRIZZLE COVERAGE THAN WE SAW THIS MORNING, AND MOSTLY CONFINED TO COASTAL AREAS. [AVI2] Long term. Issued at 1:48pm PDT Sun July 19 2026 (Tuesday through next Saturday) ∨ .LONG TERM... ISSUED AT 148 PM PDT SUN JUL 19 2026 (TUESDAY THROUGH NEXT SATURDAY) [DISC] Chances for another round of elevated showers with isolated thunderstorms is trending upward. Not currently reflected in the official forecast but subsequent updates may see increases in coverage and intensity by Tuesday afternoon into Wednesday, mainly across the North Bay and maybe as far south as the Bay Area. The main source continues to be the moisture associated with what will be the remnants of Elida moving north, well offshore of our area by the end of the day Wednesday. Increasing lift, better thermal instability and slightly improved mid-level lapse rates [The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of instability) and a steepening lapse rate implies that destabilization is occurring.] between 7–7.5°C/km by late Tuesday afternoon into Tuesday night will provide the best chances for elevated thunderstorms and potentially impactful dry lightning. A similar pocket of dry air from 700 mb-925 mb will continue to limit beneficial rainfall. A final wave of elevated instability will move into the North Bay once again late Wednesday afternoon into the evening hours with potentially improved thermal instability, however less lift and weaker lapse rates [The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of instability) and a steepening lapse rate implies that destabilization is occurring.], with dry air in the mid-levels continuing to limit precipitation reaching the ground. By Thursday into the weekend, the increased mid-level moisture shifts north and we begin to see drier air aloft with a gradual warming trend into the weekend. However, onshore flow will persist will persist through the extended forecast with typical no-sky-July conditions each night and morning. ∨ CHANCES FOR ANOTHER ROUND OF ELEVATED SHOWERS WITH ISOLATED THUNDERSTORMS IS TRENDING UPWARD. NOT CURRENTLY REFLECTED IN THE OFFICIAL FORECAST BUT SUBSEQUENT UPDATES MAY SEE INCREASES IN COVERAGE AND INTENSITY BY TUESDAY AFTERNOON INTO WEDNESDAY, MAINLY ACROSS THE NORTH BAY AND MAYBE AS FAR SOUTH AS THE BAY AREA. THE MAIN SOURCE CONTINUES TO BE THE MOISTURE ASSOCIATED WITH WHAT WILL BE THE REMNANTS OF ELIDA MOVING NORTH, WELL OFFSHORE OF OUR AREA BY THE END OF THE DAY WEDNESDAY. INCREASING LIFT, BETTER THERMAL INSTABILITY AND SLIGHTLY IMPROVED MID-LEVEL LAPSE RATES BETWEEN 7- 7.5 C/KM BY LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT WILL PROVIDE THE BEST CHANCES FOR ELEVATED THUNDERSTORMS AND POTENTIALLY IMPACTFUL DRY LIGHTNING. A SIMILAR POCKET OF DRY AIR FROM 700MB- 925MB WILL CONTINUE TO LIMIT BENEFICIAL RAINFALL. A FINAL WAVE OF ELEVATED INSTABILITY WILL MOVE INTO THE NORTH BAY ONCE AGAIN LATE WEDNESDAY AFTERNOON INTO THE EVENING HOURS WITH POTENTIALLY IMPROVED THERMAL INSTABILITY, HOWEVER LESS LIFT AND WEAKER LAPSE RATES, WITH DRY AIR IN THE MID-LEVELS CONTINUING TO LIMIT PRECIPITATION REACHING THE GROUND. BY THURSDAY INTO THE WEEKEND, THE INCREASED MID-LEVEL MOISTURE SHIFTS NORTH AND WE BEGIN TO SEE DRIER AIR ALOFT WITH A GRADUAL WARMING TREND INTO THE WEEKEND. HOWEVER, ONSHORE FLOW WILL PERSIST WILL PERSIST THROUGH THE EXTENDED FORECAST WITH TYPICAL NO- SKY-JULY CONDITIONS EACH NIGHT AND MORNING. [DISC] Aviation. (00Z [5pm PDT] TAFs [Terminal Aerodrome Forecasts]) issued at 4:40pm PDT Sun July 19 2026 ∨ .AVIATION... (00Z TAFS) ISSUED AT 440 PM PDT SUN JUL 19 2026 [AVIA] VFR [Visual Flight Rules] with IFR [Instrument Flight Rules]-LIFR [Low Instrument Flight Rules] stratus to return overnight. The marine layer is expected to compress tonight which will lead both to lowered ceiling heights and a smaller inland extent. Confidence in stratus reaching SJC [San Jose CA] is slightly higher than it was this morning while stratus chances for Livermore remain minimal. Have kept higher chances for IFR [Instrument Flight Rules] in at OAK [Oakland CA]/SFO [San Francisco CA] with confidence increasing. Patchy fog is possible along the coast tonight with LIFR [Low Instrument Flight Rules] ceilings and reductions in visibility possible. Diurnally breezy onshore winds continue in the afternoon/evening. ∨ VFR WITH IFR-LIFR STRATUS TO RETURN OVERNIGHT. THE MARINE LAYER IS EXPECTED TO COMPRESS TONIGHT WHICH WILL LEAD BOTH TO LOWERED CEILING HEIGHTS AND A SMALLER INLAND EXTENT. CONFIDENCE IN STRATUS REACHING SJC IS SLIGHTLY HIGHER THAN IT WAS THIS MORNING WHILE STRATUS CHANCES FOR LVK REMAIN MINIMAL. HAVE KEPT HIGHER CHANCES FOR IFR IN AT OAK/SFO WITH CONFIDENCE INCREASING. PATCHY FOG IS POSSIBLE ALONG THE COAST TONIGHT WITH LIFR CIGS AND REDUCTIONS IN VISIBILITY POSSIBLE. DIURNALLY BREEZY ONSHORE WINDS CONTINUE IN THE AFTERNOON/EVENING. [AVI2] Vicinity of SFO [San Francisco CA]… VFR [Visual Flight Rules] with MVFR [Marginal Visual Flight Rules]-IFR [Instrument Flight Rules] stratus to return overnight. Moderate confidence of timing of stratus return. Satellite imagery shows a less expansive stratus layer than last night which increases confidence in a later stratus arrival (~07Z [12am PDT]). MVFR [Marginal Visual Flight Rules] ceilings are the most likely scenario but cannot rule out patchy IFR [Instrument Flight Rules] ceilings given the compressing of the marine layer. Conditions improve by late morning with some potential for stratus to return again late tomorrow evening. ∨ VICINITY OF SFO...VFR WITH MVFR-IFR STRATUS TO RETURN OVERNIGHT. MODERATE CONFIDENCE OF TIMING OF STRATUS RETURN. SATELLITE IMAGERY SHOWS A LESS EXPANSIVE STRATUS LAYER THAN LAST NIGHT WHICH INCREASES CONFIDENCE IN A LATER STRATUS ARRIVAL (~07Z). MVFR CIGS ARE THE MOST LIKELY SCENARIO BUT CANNOT RULE OUT PATCHY IFR CIGS GIVEN THE COMPRESSING OF THE MARINE LAYER. CONDITIONS IMPROVE BY LATE MORNING WITH SOME POTENTIAL FOR STRATUS TO RETURN AGAIN LATE TOMORROW EVENING. [AVI2] SFO [San Francisco CA] bridge approach… similar to SFO [San Francisco CA]. ∨ SFO BRIDGE APPROACH...SIMILAR TO SFO. [AVI2] Monterey Bay terminals… VFR [Visual Flight Rules] with stratus expected to build in over the next few hours. IFR [Instrument Flight Rules]-LIFR [Low Instrument Flight Rules] ceilings are expected tonight with ceilings to gradually lower early tomorrow morning. There is some potential for fog and reductions in visibility due to the compressing of the marine layer. Moderate confidence in clearing between 17–19Z [10am–12pm PDT] with a few models indicating stratus could linger longer at MRY [Monterey CA]. ∨ MONTEREY BAY TERMINALS...VFR WITH STRATUS EXPECTED TO BUILD IN OVER THE NEXT FEW HOURS. IFR-LIFR CIGS ARE EXPECTED TONIGHT WITH CIGS TO GRADUALLY LOWER EARLY TOMORROW MORNING. THERE IS SOME POTENTIAL FOR FOG AND REDUCTIONS IN VISIBILITY DUE TO THE COMPRESSING OF THE MARINE LAYER. MODERATE CONFIDENCE IN CLEARING BETWEEN 17-19Z WITH A FEW MODELS INDICATING STRATUS COULD LINGER LONGER AT MRY. [AVI2] Marine. (tonight through next Friday) issued at 4:40pm PDT Sun July 19 2026 ∨ .MARINE... (TONIGHT THROUGH NEXT FRIDAY) ISSUED AT 440 PM PDT SUN JUL 19 2026 [AVIA] Gentle to moderate northwesterly breezes will persist through the upcoming workweek with slight to moderate seas. As tropical cyclone activity continues across the eastern Pacific, long period southerly swell is forecast. Southerly swell heights are anticipated to remain in the slight category but mixed seas may result in hazardous boating conditions through the week. Additionally, there are non-zero chances for high based showers which could result in pockets of gusty outflow winds and subsequent steep seas tonight through mid-week. ∨ GENTLE TO MODERATE NORTHWESTERLY BREEZES WILL PERSIST THROUGH THE UPCOMING WORKWEEK WITH SLIGHT TO MODERATE SEAS. AS TROPICAL CYCLONE ACTIVITY CONTINUES ACROSS THE EASTERN PACIFIC, LONG PERIOD SOUTHERLY SWELL IS FORECAST. SOUTHERLY SWELL HEIGHTS ARE ANTICIPATED TO REMAIN IN THE SLIGHT CATEGORY BUT MIXED SEAS MAY RESULT IN HAZARDOUS BOATING CONDITIONS THROUGH THE WEEK. ADDITIONALLY, THERE ARE NON-ZERO CHANCES FOR HIGH BASED SHOWERS WHICH COULD RESULT IN POCKETS OF GUSTY OUTFLOW WINDS AND SUBSEQUENT STEEP SEAS TONIGHT THROUGH MID-WEEK. [AVI2] Fire weather. Issued at 1:48pm PDT Sun July 19 2026 ∨ .FIRE WEATHER... ISSUED AT 148 PM PDT SUN JUL 19 2026 [AVIA] Near to slightly cooler than normal temperatures will continue through the week with typical diurnal intrusion of the marine layer each night and retreat to the coast each morning as onshore flow persists. However, above 1500–2000 ft we'll see relatively weak thermal belting the first half of the week with continued warm overnights and poor RH [Relative Humidity] recovery at higher elevations. ∨ NEAR TO SLIGHTLY COOLER THAN NORMAL TEMPERATURES WILL CONTINUE THROUGH THE WEEK WITH TYPICAL DIURNAL INTRUSION OF THE MARINE LAYER EACH NIGHT AND RETREAT TO THE COAST EACH MORNING AS ONSHORE FLOW PERSISTS. HOWEVER, ABOVE 1500-2000FT WE`LL SEE RELATIVELY WEAK THERMAL BELTING THE FIRST HALF OF THE WEEK WITH CONTINUED WARM OVERNIGHTS AND POOR RH RECOVERY AT HIGHER ELEVATIONS. [AVI2] Guidance is trending toward an increasing potential for elevated showers and isolated thunderstorms Tuesday afternoon through Wednesday evening. Chances are below 5% in the official forecast but may increase in subsequent updates tonight and Monday. The primary concern is dry lightning strikes across the North Bay, with lesser chances farther south into the Bay Area. ∨ GUIDANCE IS TRENDING TOWARD AN INCREASING POTENTIAL FOR ELEVATED SHOWERS AND ISOLATED THUNDERSTORMS TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. CHANCES ARE BELOW 5% IN THE OFFICIAL FORECAST BUT MAY INCREASE IN SUBSEQUENT UPDATES TONIGHT AND MONDAY. THE PRIMARY CONCERN IS DRY LIGHTNING STRIKES ACROSS THE NORTH BAY, WITH LESSER CHANCES FARTHER SOUTH INTO THE BAY AREA. [AVI2] MTR Watches/Warnings/Advisories California: none. Pacific Ocean: none. ∨ .MTR WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. [WARN] Short term…JM long term…JM aviation…Kennedy marine…bain ∨ SHORT TERM...JM LONG TERM....JM AVIATION...KENNEDY MARINE...BAIN [WRN2] VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO [LINK] Follow us on Facebook, x, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea ∨ FOLLOW US ON FACEBOOK, X, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA X.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA [DISC]	Point Forecast Half Moon Bay CA 19 Jul 08:15pm PDT Tonight Patchy fog after 2am. Otherwise, cloudy, with a low around 55°. Calm wind. Monday Patchy fog before 8am. Otherwise, mostly cloudy, with a high near 66°. Calm wind becoming WSW 5 to 7 mph in the morning. Monday Night Patchy fog between 11pm and 4am. Otherwise, mostly cloudy, with a low around 55°. West wind around 5 mph becoming calm in the evening. Tuesday Partly sunny, with a high near 72°. Calm wind becoming west 5 to 7 mph in the afternoon. Tuesday Night Patchy fog after 2am. Otherwise, mostly cloudy, with a low around 58°. West wind 5 to 7 mph becoming calm in the evening. Wednesday Patchy fog before 8am. Otherwise, partly sunny, with a high near 69°. Wednesday Night Mostly cloudy, with a low around 55°. Thursday Mostly cloudy, with a high near 65°. Thursday Night Mostly cloudy, with a low around 54°. Friday Partly sunny, with a high near 64°. Friday Night Mostly cloudy, with a low around 53°. Saturday Partly sunny, with a high near 64°. Saturday Night Mostly cloudy, with a low around 53°. Sunday Mostly sunny, with a high near 64°. Tonight Patchy fog after 2am. Otherwise, cloudy, with a low around 55. Calm wind. Monday Patchy fog before 8am. Otherwise, mostly cloudy, with a high near 66. Calm wind becoming west southwest 5 to 7 mph in the morning. Monday Night Patchy fog between 11pm and 4am. Otherwise, mostly cloudy, with a low around 55. West wind around 5 mph becoming calm in the evening. Tuesday Partly sunny, with a high near 72. Calm wind becoming west 5 to 7 mph in the afternoon. Tuesday Night Patchy fog after 2am. Otherwise, mostly cloudy, with a low around 58. West wind 5 to 7 mph becoming calm in the evening. Wednesday Patchy fog before 8am. Otherwise, partly sunny, with a high near 69. Wednesday Night Mostly cloudy, with a low around 55. Thursday Mostly cloudy, with a high near 65. Thursday Night Mostly cloudy, with a low around 54. Friday Partly sunny, with a high near 64. Friday Night Mostly cloudy, with a low around 53. Saturday Partly sunny, with a high near 64. Saturday Night Mostly cloudy, with a low around 53. Sunday Mostly sunny, with a high near 64.
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