Alert archive / California / Red Flag Warnings in 2020

Red Flag Warning 9, NWS San Francisco Bay Area, CA

October 19, 2020

NWS San Francisco Bay Area, CA issued this red flag warning at Oct 19, 2020, 10:57 AM PDT. It took effect at Oct 19, 2020, 11:00 PM PDT. It was in force for 33 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Oct 19, 2020, 10:57 AM PDT (17:57 UTC)
In effect from
Oct 19, 2020, 11:00 PM PDT
Expired
Oct 21, 2020, 8:00 AM PDT
In force
33 hr
Issued by
NWS San Francisco Bay Area, CA

The text

As transmitted.

076 
WWUS86 KMTR 191757
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco Bay Area
1057 AM PDT Mon Oct 19 2020

...Bursts of gusty offshore winds and dry conditions will develop
tonight and carry into the next several days... 

.These weather conditions, in combination with very dry fuels, 
will result in an increased risk of new wildfire starts and rapid 
wildfire spread. The first burst will primarily affect the North 
Bay Mountains Monday night through Wednesday morning. A lull in 
the offshore winds is expected from Wednesday morning through 
Wednesday evening, but drying will continue and carry over into 
the second burst. The culmination of offshore winds and very dry 
fuels, along with very dry conditions are possible from Wednesday 
night through Friday morning and has the potential to impact 
higher-terrain locations in the North Bay Mountains, along with 
locations in the East Bay Hills, the Diablo Range, and the Santa 
Cruz Mountains.

CAZ507-200500-
/O.UPG.KMTR.FW.A.0007.201020T0600Z-201021T1500Z/
/O.NEW.KMTR.FW.W.0009.201020T0600Z-201021T1500Z/
/O.NEW.KMTR.FW.A.0008.201022T0500Z-201023T1500Z/
North Bay Mountains-
1057 AM PDT Mon Oct 19 2020

...RED FLAG WARNING IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT
WEDNESDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE 
WEATHER ZONE 507... .

..FIRE WEATHER WATCH IN EFFECT FROM WEDNESDAY
EVENING THROUGH FRIDAY MORNING FOR THE POTENTIAL FOR GUSTY
OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONES 511 AND
512...

The National Weather Service in San Francisco has issued a Red 
Flag Warning...which is in effect from 11 PM this evening to 8 AM 
PDT Wednesday. a Fire Weather Watch has also been issued. This Fire
Weather Watch is in effect from Wednesday evening through Friday 
morning.



* WIND...North to northeast 10 to 25 mph with gusts up to 40 mph. Winds
  will be stronger overnight. Locally stronger winds are possible
  over the higher ridges and peaks. 

* HUMIDITY...Daytime humidities in the 20-30% range with poor
  overnight recoveries in the 12-20% range.

* HIGHEST THREAT...Mountains of Napa County and northeastern 
  Sonoma County.

* IMPACTS...Any fires that start will likely spread rapidly due 
  to the combination of dry fuels, gusty north- northeasterly 
  winds, and low humidities.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$

CAZ511-200500-
/O.NEW.KMTR.FW.A.0008.201022T0500Z-201023T1500Z/
East Bay Hills and the Diablo Range-
1057 AM PDT Mon Oct 19 2020

...FIRE WEATHER WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
FRIDAY MORNING FOR THE POTENTIAL FOR GUSTY OFFSHORE WINDS AND DRY
CONDITIONS FOR FIRE WEATHER ZONE 511...

The National Weather Service in San Francisco has issued a Fire 
Weather Watch...which is in effect from Wednesday evening through
Friday morning.


* AFFECTED AREA...FIRE WEATHER ZONE 511.

* WIND...North to northeast 20 to 30 mph with gusts up to 40 mph.
  Winds will be stronger overnight. Locally stronger winds are
  possible over the higher ridges and peak.

* HUMIDITY...Daytime humidities in the 25-30% range with poor
  overnight recoveries in the 12-17% range.

* HIGHEST THREAT...The East Bay Hills.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$

CAZ512-200500-
/O.NEW.KMTR.FW.A.0008.201022T0800Z-201023T1500Z/
Santa Cruz Mountains-
1057 AM PDT Mon Oct 19 2020

...FIRE WEATHER WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
FRIDAY MORNING FOR FOR THE POTENTIAL FOR GUSTY
OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONE 512...

The National Weather Service in San Francisco has issued a Fire 
Weather Watch...which is in effect from late Wednesday night 
through Friday morning. 

* AFFECTED AREA...FIRE WEATHER ZONE 512.

* WIND...North to northeast 20 to 30 mph with gusts up to 40 mph.
  Winds will be stronger overnight. Locally stronger winds are
  possible over the higher ridges and peaks.

* HUMIDITY...Daytime humidities in the 25-35% range with overnight
  humidities dropping to the 15-20% range.

* HIGHEST THREAT...Locations with high fuels in the Santa Cruz
  Mountain Range.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$
4 follow-up statements
200 
WWUS86 KMTR 200613
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco Bay Area
1113 PM PDT Mon Oct 19 2020

...Dry conditions and bursts of gusty offshore winds forecast in
the hills of the San Francisco Bay Area over the next several 
days...

.Gusty, dry offshore winds and continued low humidity, in 
combination with very dry fuels, will result in an increased risk 
of new wildfire starts and rapid wildfire spread. The first burst 
of gusty northerly winds will primarily affect the North Bay 
Mountains Monday night through Wednesday morning. A lull in the 
offshore winds is expected from Wednesday morning through 
Wednesday evening, but drying will continue and carry over into 
the second burst from Wednesday night through Friday morning. This
second offshore wind event will impact not only the higher 
terrain locations in the North Bay Mountains, but also locations 
in the East Bay Hills, the Diablo Range, and the Santa Cruz 
Mountains.


CAZ507-201800-
/O.CON.KMTR.FW.W.0009.000000T0000Z-201021T1500Z/
/O.CON.KMTR.FW.A.0008.201022T0500Z-201023T1500Z/
North Bay Mountains-
1113 PM PDT Mon Oct 19 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 AM PDT WEDNESDAY
FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONE
507... 

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM WEDNESDAY EVENING 
THROUGH FRIDAY MORNING FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS
FOR FIRE WEATHER ZONE 507... 

* AFFECTED AREA...North Bay Mountains.

* WIND...Through Wednesday morning north to northeast 10 to 25 mph
  with gusts up to 40 mph. Winds will be strongest during the
  overnight hours. From Wednesday evening through Friday morning
  north to northeast 15 to 30 mph with gusts up to 50 mph. Locally
  stronger winds are possible over the higher ridges and peaks. 

* HUMIDITY...Daytime humidities in the 12-20 percent range with
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...Mountains of Napa County and northeastern 
  Sonoma County.

* IMPACTS...Any fires that start will likely spread rapidly due to
  the combination of dry fuels, gusty north-northeasterly winds, 
  and low humidities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$

CAZ511-201800-
/O.CON.KMTR.FW.A.0008.201022T0500Z-201023T1500Z/
East Bay Hills and the Diablo Range-
1113 PM PDT Mon Oct 19 2020

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM WEDNESDAY EVENING
THROUGH FRIDAY MORNING FOR THE POTENTIAL FOR GUSTY OFFSHORE WINDS
AND DRY CONDITIONS FOR FIRE WEATHER ZONE 511...

* AFFECTED AREA...East Bay Hills and Diablo Range.

* WIND...North to northeast 15 to 30 mph with gusts up to 40 mph.
  Winds will be strongest during the overnight hours. Locally 
  stronger winds are possible over the higher ridges and peak.

* HUMIDITY...Daytime humidities in the 12-18 percent range with 
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...The East Bay Hills.

* IMPACTS...Any fires that start will likely spread rapidly due to
  the combination of dry fuels, gusty north-northeasterly winds,
  and low humidities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$

CAZ512-201800-
/O.CON.KMTR.FW.A.0008.201022T0800Z-201023T1500Z/
Santa Cruz Mountains-
1113 PM PDT Mon Oct 19 2020

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM LATE WEDNESDAY NIGHT
THROUGH FRIDAY MORNING FOR FOR THE POTENTIAL FOR GUSTY OFFSHORE
WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONE 512...

* AFFECTED AREA...Santa Cruz Mountains.

* WIND...North to northeast 10 to 20 mph with gusts up to 35 mph.
  Winds will be strongest during the overnight hours. Locally 
  stronger winds are possible over the higher ridges and peaks.

* HUMIDITY...Daytime humidities in the 12-20 percent range with 
  poor overnight recoveries in the 20-30 percent range. 

* HIGHEST THREAT...Locations with high fuel loads in the Santa
  Cruz Mountain Range. 

* IMPACTS...Any fires that start will likely spread rapidly due to
  the combination of dry fuels, gusty north-northeasterly winds,
  and low humidities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

&&

$$
019 
WWUS86 KMTR 201746
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco Bay Area
1046 AM PDT Tue Oct 20 2020

...Dry conditions and bursts of gusty offshore winds forecast in
the hills of the San Francisco Bay Area over the next several 
days...

.The continuation of gusty, dry offshore winds and low humidity, 
in combination with very dry fuels, will result in an increased 
risk of new wildfire starts and rapid wildfire spread. Gusty 
northerly winds will initially affect the North Bay Mountains and
East Bay Hills and Valleys late Wednesday evening and expand 
overnight into the Santa Cruz Mountains and portions of Coastal 
San Mateo County through Thursday morning. A lull in the offshore
winds is expected from late Thursday morning through Thursday 
evening, but another burst is expected overnight and into Friday
morning. 

CAZ507-210500-
/O.UPG.KMTR.FW.A.0008.201022T0500Z-201023T1500Z/
/O.NEW.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
/O.CON.KMTR.FW.W.0009.000000T0000Z-201021T1500Z/
North Bay Mountains-
1046 AM PDT Tue Oct 20 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 AM PDT WEDNESDAY
FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONE
507...
...RED FLAG WARNING IN EFFECT FROM 10 PM WEDNESDAY TO 8 AM PDT
FRIDAY FOR FIRE WEATHER ZONE 507...

The National Weather Service in San Francisco has issued a Red 
Flag Warning...which is in effect from 10 PM Wednesday to 8 AM 
PDT Friday. The Fire Weather Watch is no longer in effect. 



* AFFECTED AREA...North Bay Mountains.

* WIND...Through Wednesday evening north to northeast 10 to 25 
  mph with gusts up to 40 mph. Winds will be strongest during the 
  overnight hours. From Wednesday evening through Friday morning 
  north to northeast 15 to 30 mph with gusts up to 50 mph. Locally
  stronger winds are possible over the higher ridges and peaks.

* HUMIDITY...Daytime humidities in the 12-20 percent range with 
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...Mountains of Napa County and northeastern 
  Sonoma County.

* IMPACTS...Any fires that start will likely spread rapidly due
  to the combination of dry fuels, gusty north-northeasterly 
  winds, and low humidities. 


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ511-210500-
/O.UPG.KMTR.FW.A.0008.201022T0500Z-201023T1500Z/
/O.NEW.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
East Bay Hills and the Diablo Range-
1046 AM PDT Tue Oct 20 2020

...RED FLAG WARNING IN EFFECT FROM 10 PM WEDNESDAY TO 8 AM PDT
FRIDAY FOR FOR FIRE WEATHER ZONE 511...

The National Weather Service in San Francisco has issued a Red 
Flag Warning...which is in effect from 10 PM Wednesday to 8 AM 
PDT Friday. The Fire Weather Watch is no longer in effect. 


* WIND...North to northeast 15 to 30 mph with gusts up to 40 
  mph. Winds will be strongest during the overnight hours. 
  Locally stronger winds are possible over the higher ridges and 
  peaks. 

* HUMIDITY...Daytime humidities in the 12-18 percent range with 
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...The East Bay Hills.

* IMPACTS...Any fires that start will likely spread rapidly due
  to the combination of dry fuels, gusty north-northeasterly 
  winds, and low humidities. 


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ512-210500-
/O.UPG.KMTR.FW.A.0008.201022T0800Z-201023T1500Z/
/O.NEW.KMTR.FW.W.0010.201022T0800Z-201023T1500Z/
Santa Cruz Mountains-
1046 AM PDT Tue Oct 20 2020

...RED FLAG WARNING IN EFFECT FROM 1 AM THURSDAY TO 8 AM PDT
FRIDAY FOR FIRE WEATHER ZONE 512...

The national weather service in San Francisco has issued a Red 
Flag Warning...which is in effect from 1 AM Thursday to 8 AM PDT 
Friday. The Fire Weather Watch is no longer in effect. 


* WIND...North to northeast 10 to 20 mph with gusts up to 35 
  mph. Winds will be strongest during the overnight hours. 
  Locally stronger winds are possible over the higher ridges and 
  peaks. 

* HUMIDITY...Daytime humidities in the 12-20 percent range with 
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...Locations with high fuel loads in the Santa
  Cruz Mountains.

* IMPACTS...Any fires that start will likely spread rapidly due
  to the combination of dry fuels, gusty north-northeasterly 
  winds, and low humidities. 


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ510-210500-
/O.NEW.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
East Bay Interior Valleys-
1046 AM PDT Tue Oct 20 2020

...RED FLAG WARNING IN EFFECT FROM 10 PM WEDNESDAY TO 8 AM PDT
FRIDAY FOR FIRE WEATHER ZONE 510...

The National Weather Service in San Francisco has issued a Red 
Flag Warning...which is in effect from 10 PM Wednesday to 8 AM 
PDT Friday.


* AFFECTED AREA...FIRE WEATHER ZONE 510.

* WIND...North to northeast 10 to 20 mph with gusts up to 35 mph.
  Winds will be strongest during the overnight hours. Locally 
  stronger winds are possible as winds from the higher ridges and 
  peaks mix down to the valley floors.

* HUMIDITY...Daytime humidities in the 30-35 percent range but
  falling quickly overnight. Poor overnight recoveries expected,
  with widespread humidities in the 15-20 percent range.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ509-210500-
/O.NEW.KMTR.FW.W.0010.201022T0800Z-201023T1500Z/
San Francisco Peninsula Coast-
1046 AM PDT Tue Oct 20 2020

...RED FLAG WARNING IN EFFECT FROM 1 AM THURSDAY TO 8 AM PDT
FRIDAY FOR FIRE WEATHER ZONE 509...

The National Weather Service in San Francisco has issued a Red 
Flag Warning...which is in effect from 1 AM Thursday to 8 AM PDT 
Friday.


* AFFECTED AREA...FIRE WEATHER ZONE 509.

* WIND...North to northeast 15 to 20 mph with gusts up to 40 mph.
  Winds will be strongest during the overnight hours. Locally
  stronger winds are possible over the higher ridges, peaks, and
  passages that lead to the shoreline.

* HUMIDITY...Daytime humidities gradually falling to the 15-30
  percent range, even down to the coast. Poor overnight humidity 
  recoveries in the 12-20 percent range.

* HIGHEST THREAT...is located from Half Moon Bay southward as dry
  winds from the mountains race down to the coast.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$
706 
WWUS86 KMTR 210405
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco Bay Area
905 PM PDT Tue Oct 20 2020

...Dry conditions and bursts of gusty offshore winds forecast in
the hills of the San Francisco Bay Area over the next several 
days...

.The overarching weather pattern prevails around the Bay Area,
providing an increased risk of new wildfire starts and rapid 
wildfire spread this evening and through the end of the week. 
Gusty northerly winds and dry conditions provide the threat of new
wildfire starts through Wednesday morning. After a brief lull,
wind gusts will strengthen again on Wednesday evening over
affecting the North Bay Mountains, East Bay Hills and Valleys, 
and expand in the early Thursday morning timeframe over the Santa
Cruz Mountains and portions of San Mateo coast. Winds will once
again weaken in the afternoon before another round of gustier
offshore winds expected overnight Thursday into Friday morning.


CAZ507-211200-
/O.CON.KMTR.FW.W.0009.000000T0000Z-201021T1500Z/
/O.CON.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
North Bay Mountains-
905 PM PDT Tue Oct 20 2020

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 AM PDT WEDNESDAY
FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONE
507...
...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM WEDNESDAY 
TO 8 AM PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS 
FOR FIRE WEATHER ZONE 507...

* AFFECTED AREA...FIRE WEATHER ZONE 507 including the North Bay 
  Mountains.

* WIND...Through Wednesday evening north to northeast 10 to 25 
  mph with gusts up to 40 mph. Winds will be strongest during 
  the overnight hours. From Wednesday evening through Friday 
  morning north to northeast 15 to 30 mph with gusts up to 50 
  mph. Locally stronger winds are possible over the higher 
  ridges and peaks. 

* HUMIDITY...Daytime humidities in the 12-20 percent range with 
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...Mountains of Napa County and northeastern 
  Sonoma County.

* IMPACTS...Any fires that start will likely spread rapidly due 
  to the combination of dry fuels, gusty north-northeasterly 
  winds, and low humidities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ510-511-211200-
/O.CON.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
905 PM PDT Tue Oct 20 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM WEDNESDAY TO
8 AM PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR 
FIRE WEATHER ZONES 510 AND 511...

* AFFECTED AREA...FIRE WEATHER ZONES 510 AND 511 including the 
  East Bay Hills and the Diablo Range and the East Bay Interior 
  Valleys
  

* WIND...North to northeast 10 to 20 mph with gusts up to 35 
  mph. Winds will be strongest during the overnight hours. 
  Locally stronger winds are possible as winds from the higher 
  ridges and peaks mix down to the valley floors.

* HUMIDITY...Daytime humidities in the 30-35 percent range but 
  falling quickly overnight. Poor overnight recoveries 
  expected, with widespread humidities in the 15-20 percent 
  range.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ509-512-211200-
/O.CON.KMTR.FW.W.0010.201022T0800Z-201023T1500Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
905 PM PDT Tue Oct 20 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 AM THURSDAY TO 8 AM
PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE 
WEATHER ZONES 509 AND 512...

* AFFECTED AREA...FIRE WEATHER ZONES 509 AND 512 including the
  Santa Cruz Mountains and the San Mateo Coastline 

* WIND...North to northeast 15 to 20 mph with gusts up to 40 
  mph. Winds will be strongest during the overnight hours. 
  Locally stronger winds are possible over the higher ridges, 
  peaks, and passages that lead to the shoreline.

* HUMIDITY...Daytime humidities gradually falling to the 12-20
  percent range, even down to the coast. Poor overnight humidity
  recoveries in the 20-30 percent range.

* HIGHEST THREAT...is located from Half Moon Bay southward as 
  dry winds from the mountains race down to the coast. 

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$
091 
WWUS86 KMTR 211459
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco Bay Area
759 AM PDT Wed Oct 21 2020

...Dry conditions and bursts of gusty offshore winds forecast in 
the hills of the San Francisco Bay Area over the next several 
days...

.The overarching weather pattern prevails around the Bay Area,
providing a continued risk of new wildfire starts and rapid 
wildfire spread this evening and through the end of the week. 
Gusty northerly winds and dry conditions provide the threat of new
wildfire starts through Friday morning. After a brief lull during
the day today, wind gusts will strengthen again on Wednesday 
evening affecting the North Bay Mountains, East Bay Hills and 
Valleys, and expand in the early Thursday morning timeframe over 
the Santa Cruz Mountains and portions of San Mateo coast. Winds 
will once again weaken in the afternoon before another round of 
gustier offshore winds take hold overnight Thursday into Friday 
morning.

CAZ507-220400-
/O.EXP.KMTR.FW.W.0009.000000T0000Z-201021T1500Z/
/O.CON.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
North Bay Mountains-
759 AM PDT Wed Oct 21 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING TO
8 AM PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR 
FIRE WEATHER ZONE 507... 
...RED FLAG WARNING WILL EXPIRE AT 8 AM PDT THIS MORNING FOR 
GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE WEATHER ZONE 
507...

* WIND...Wednesday evening through Friday morning north to 
  northeast 15 to 30 mph with gusts up to 50 mph. Locally stronger
  winds are possible over the higher ridges and peaks. 

* HUMIDITY...Daytime humidities in the 12-20 percent range with 
  poor overnight recoveries in the 20-30 percent range.

* HIGHEST THREAT...Mountains of Napa County and northeastern 
  Sonoma County.

* IMPACTS...Any fires that start will likely spread rapidly due 
  to the combination of dry fuels, gusty north-northeasterly 
  winds, and low humidities.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ510-511-220400-
/O.CON.KMTR.FW.W.0010.201022T0500Z-201023T1500Z/
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
759 AM PDT Wed Oct 21 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING TO
8 AM PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR 
FIRE WEATHER ZONES 510 AND 511...

* AFFECTED AREA...FIRE WEATHER ZONES 510 AND 511 including the 
  East Bay Hills and the Diablo Range and the East Bay Interior 
  Valleys 

* WIND...North to northeast 10 to 20 mph with gusts up to 35 
  mph. Winds will be strongest during the overnight hours. 
  Locally stronger winds are possible as winds from the higher 
  ridges and peaks mix down to the valley floors.

* HUMIDITY...Daytime humidities in the 30-35 percent range but 
  falling quickly overnight. Poor overnight recoveries 
  expected, with widespread humidities in the 15-20 percent 
  range. 

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

CAZ509-512-220400-
/O.CON.KMTR.FW.W.0010.201022T0800Z-201023T1500Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
759 AM PDT Wed Oct 21 2020

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 AM THURSDAY TO 8 AM
PDT FRIDAY FOR GUSTY OFFSHORE WINDS AND DRY CONDITIONS FOR FIRE 
WEATHER ZONES 509 AND 512...

* AFFECTED AREA...FIRE WEATHER ZONES 509 AND 512 including the
  Santa Cruz Mountains and the San Mateo Coastline. 

* WIND...North to northeast 15 to 20 mph with gusts up to 40 
  mph. Winds will be strongest during the overnight hours. 
  Locally stronger winds are possible over the higher ridges, 
  peaks, and passages that lead to the shoreline.

* HUMIDITY...Daytime humidities gradually falling to the 12-20 
  percent range, even down to the coast. Poor overnight 
  humidity recoveries in the 20-30 percent range.

* HIGHEST THREAT...is located from Half Moon Bay southward as 
  dry winds from the mountains race down to the coast.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 19, 10:57 AM PDTFire Weather WatchMTRSan Mateo, Santa Clara, Santa Cruz24 hr
Oct 19, 2:41 PM PDTGale WatchMTR12 hr
Oct 19, 2:41 PM PDTSmall Craft AdvisoryMTR36 hr

Nearby

Red Flag Warnings in California, 2020Every red flag warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text.