Alert archive / California / Red Flag Warnings in 2019

Red Flag Warning 6, NWS San Francisco Bay Area, CA

October 25, 20198 counties in California

NWS San Francisco Bay Area, CA issued this red flag warning at Oct 25, 2019, 10:35 AM PDT for 8 counties in California. It took effect at Oct 26, 2019, 8:00 PM PDT. It was in force for 39 hr. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Oct 25, 2019, 10:35 AM PDT (17:35 UTC)
In effect from
Oct 26, 2019, 8:00 PM PDT
Expired
Oct 28, 2019, 11:00 AM PDT
In force
39 hr
Issued by
NWS San Francisco Bay Area, CA

Counties Alameda County, CA, Contra Costa County, CA, Marin County, CA, Napa County, CA, San Mateo County, CA, Santa Clara County, CA, Santa Cruz County, CA, Sonoma County, CA

The radar

The San Francisco radar (KMUX), 77 km from the middle of the area, began a volume at 17:36 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Oct 27, 2:08 AM PDTNON-TSTM WND DMGSonoma, CATREE FELL DOWN ON APARTMENT BUILDING COMPLEX.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 5.6 hours before the alert went out and 8 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 12:00Z on 2019-10-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2019-10-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3787 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

448 
WWUS86 KMTR 251735
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
1035 AM PDT Fri Oct 25 2019

...Red Flag Warning Saturday night through Monday morning for 
dangerously strong offshore winds and critically low humidity...

.Confidence is high that another offshore wind event featuring
strong and dangerous winds and critically low humidity will 
impact the area from early Saturday night through Monday morning.
This event looks to be the strongest since the 2017 wine country 
fires and potentially a historic event given the strength and 
duration of the winds. The strongest winds are expected Saturday
night into Sunday morning. Stronger winds mixing to the lower
elevations will be a particular concern throughout Sunday.
Winds will gradually ease later Sunday, remaining locally gusty
across the higher elevations into Monday morning.

CAZ505>507-510-511-260400-
/O.UPG.KMTR.FW.A.0004.191027T0300Z-191028T1800Z/
/O.NEW.KMTR.FW.W.0006.191027T0300Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
1035 AM PDT Fri Oct 25 2019

...RED FLAG WARNING IN EFFECT FROM 8 PM SATURDAY TO 11 AM PDT
MONDAY FOR DANGEROUSLY STRONG OFFSHORE WINDS AND CRITICALLY LOW 
Humidity FOR FIRE WEATHER ZONES 505, 506, 507, 510, AND 511...

The National Weather Service in San Francisco has issued a Red
Flag Warning, which is in effect from 8 PM Saturday to 11 AM PDT
Monday. The Fire Weather Watch has been upgraded.

* HUMIDITY... Critically low daytime humidity with poor overnight
  recoveries. Locally lower humidity values are possible.
  Mountains/Hills...  Sat Night... 15-35%...
                      Sun Day...   10-20%...
                      Sun Night... 10-25%...
                      Mon Day...   10-20%...
 
  Valleys/Coast...    Sat Night... 30-55%...
                      Sun Day...   15-30%...
                      Sun Night... 25-45%...
                      Mon Day...   15-30%...

* WINDS...Strong and dangerous north to northeast winds are forecast 
  Saturday night into Sunday morning.  Winds are expected to reach 
  the lower elevations particularly by Sunday morning and through 
  the day Sunday. Offshore winds weaken but remain locally gusty 
  Sunday night into Monday.

  Mountains/Hills...  Sat Night... Sustained 30-55mph Gusts 60-80mph...
                      Sun Day...   Sustained 20-35mph Gusts 40-60mph...
                      Sun Night... Sustained 15-25mph Gusts 25-40mph...
                      Mon Day...   Sustained 5-15mph  Gusts 15-25mph...
 
  Valleys/Coast...    Sat Night... Sustained 5-15mph  Gusts 15-35mph...
                      Sun Day...   Sustained 15-25mph Gusts 30-50mph...
                      Sun Night... Sustained 5-10mph  Gusts 10-20mph...
                      Mon Day...   Light Winds...


* IMPACTS...Any fires that develop will likely spread rapidly.

* TIMING....Strongest winds throughout Saturday night into Sunday 
  morning. Winds gradually weaken through Sunday into Sunday night
  but remain locally gusty into Monday morning. 


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.

&&

$$

CAZ509-512-260400-
/O.UPG.KMTR.FW.A.0004.191027T1000Z-191028T1800Z/
/O.NEW.KMTR.FW.W.0006.191027T1000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
1035 AM PDT Fri Oct 25 2019

...RED FLAG WARNING IN EFFECT FROM 3 AM SUNDAY TO 11 AM PDT
MONDAY FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 
509 AND 512...

The National Weather Service in San Francisco has issued a Red
Flag Warning, which is in effect from 3 AM Sunday to 11 AM PDT
Monday. The Fire Weather Watch has been upgraded.

* WIND...Strong north to northeast winds will develop through
  Saturday night into Sunday, peaking early Sunday morning. 
  Sustained wind speeds of 15 to 30 mph with gusts 35 to 55 mph
  are possible.  Winds gradually weaken from Sunday morning through 
  Monday morning, but will remain locally gusty into early Monday.

* HUMIDITY... Critically low daytime humidity with poor overnight
  recoveries.
  Mountains/Hills...  Sat Night... 25-35%...
                      Sun Day...   15-25%...
                      Sun Night... 20-35%...
                      Mon Day...   15-30%...
 
  Valleys/Coast...    Sat Night... 45-60%...
                      Sun Day...   20-40%...
                      Sun Night... 25-45%...
                      Mon Day...   20-35%...

* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92.

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Strongest winds late Saturday night into Sunday morning.
  Winds gradually weaken through Sunday into Sunday night but 
  remain locally gusty into Monday morning. 


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.

&&

$$
7 follow-up statements
133 
WWUS86 KMTR 260354
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
854 PM PDT Fri Oct 25 2019

...Red Flag Warning Saturday night through Monday morning for
dangerously strong offshore winds and critically low humidity...

.Confidence is high that an offshore wind event featuring strong 
and dangerous winds and critically low humidity will impact the 
area from Saturday evening through Monday morning. This event 
looks to be the strongest since the 2017 wine country fires and 
potentially a historic event given the strength and duration of 
the winds. The strongest winds are expected Saturday night into 
Sunday morning. Stronger winds mixing to the lower elevations will
be a particular concern from late Saturday night through Sunday. 
Winds will gradually ease at lower elevations by late Sunday, but
remain locally gusty across the higher elevations on Sunday night
and into Monday morning.

CAZ505>507-510-511-261300-
/O.CON.KMTR.FW.W.0006.191027T0300Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
854 PM PDT Fri Oct 25 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 8 PM SATURDAY TO 11 AM
PDT MONDAY FOR DANGEROUSLY STRONG OFFSHORE WINDS AND CRITICALLY
LOW HUMIDITY FOR FIRE WEATHER ZONES 505, 506, 507, 510, AND 511...

* HUMIDITY... Critically low daytime humidity with poor overnight
  recoveries. Locally lower humidity values are possible.
  Mountains/Hills...  Sat Night... 15-35%...
                      Sun Day...   10-20%...
                      Sun Night... 10-25%...
                      Mon Day...   10-20%...
 
  Valleys/Coast...    Sat Night... 30-55%...
                      Sun Day...   15-30%...
                      Sun Night... 25-45%...
                      Mon Day...   15-30%...

* WINDS...Strong and dangerous north to northeast winds are forecast 
  Saturday night into Sunday morning.  Winds are expected to reach 
  the lower elevations particularly by Sunday morning and through 
  the day Sunday. Offshore winds weaken but remain locally gusty 
  Sunday night into Monday.

  Mountains/Hills...  Sat Night... Sustained 30-55mph Gusts 60-80mph...
                      Sun Day...   Sustained 20-35mph Gusts 40-60mph...
                      Sun Night... Sustained 15-25mph Gusts 25-40mph...
                      Mon Day...   Sustained 5-15mph  Gusts 15-25mph...
 
  Valleys/Coast...    Sat Night... Sustained 5-15mph  Gusts 15-35mph...
                      Sun Day...   Sustained 15-25mph Gusts 30-50mph...
                      Sun Night... Sustained 5-10mph  Gusts 10-20mph...
                      Mon Day...   Light Winds...


* IMPACTS...Any fires that develop will likely spread rapidly.

* TIMING....Strongest winds throughout Saturday night into Sunday 
  morning. Winds gradually weaken through Sunday into Sunday night
  but remain locally gusty into Monday morning.  

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.

&&

$$

CAZ509-512-261300-
/O.CON.KMTR.FW.W.0006.191027T1000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
854 PM PDT Fri Oct 25 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 3 AM SUNDAY TO 11 AM
PDT MONDAY FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER
ZONES 509 AND 512...

* WIND...Strong north to northeast winds will develop through
  Saturday night into Sunday, peaking early Sunday morning. 
  Sustained wind speeds of 15 to 30 mph with gusts 35 to 55 mph
  are possible.  Winds gradually weaken from Sunday morning through 
  Monday morning, but will remain locally gusty into early Monday.

* HUMIDITY... Critically low daytime humidity with poor overnight
  recoveries.
  Mountains/Hills...  Sat Night... 25-35%...
                      Sun Day...   15-25%...
                      Sun Night... 20-35%...
                      Mon Day...   15-30%...
 
  Valleys/Coast...    Sat Night... 45-60%...
                      Sun Day...   20-40%...
                      Sun Night... 25-45%...
                      Mon Day...   20-35%...

* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92.

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Strongest winds late Saturday night into Sunday morning.
  Winds gradually weaken through Sunday into Sunday night but 
  remain locally gusty into Monday morning.

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.

&&

$$
139 
WWUS86 KMTR 261242
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
542 AM PDT Sat Oct 26 2019

...Red Flag Warning tonight through Monday morning for
dangerously strong offshore winds and critically low humidity...

.Confidence is high that an offshore wind event featuring strong
and dangerous winds and critically low humidity will impact the
area from this evening through Monday morning. This event looks 
to be the strongest since the 2017 wine country fires and 
potentially a historic event given the strength and duration of 
the winds. The strongest winds are expected from tonight into 
Sunday morning. Stronger winds mixing to the lower elevations will
be a particular concern from late tonight through Sunday. Winds 
will gradually ease at lower elevations by late Sunday, but remain
locally gusty across the higher elevations on Sunday night and 
into Monday morning.

CAZ505>507-510-511-262300-
/O.CON.KMTR.FW.W.0006.191027T0300Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
542 AM PDT Sat Oct 26 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 8 PM THIS EVENING TO
11 AM PDT MONDAY FOR DANGEROUSLY STRONG OFFSHORE WINDS AND
CRITICALLY LOW HUMIDITY FOR FIRE WEATHER ZONES 505, 506, 507,
510, AND 511...

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries. Locally lower humidity values are 
  possible.

  Mountains/Hills...  Sat Night... 15-35%...
                      Sun Day...   10-20%...
                      Sun Night... 10-25%...
                      Mon Day...   10-20%...
 
  Valleys/Coast...    Sat Night... 30-55%...
                      Sun Day...   15-30%...
                      Sun Night... 25-45%...
                      Mon Day...   15-30%...


* WINDS...Strong and dangerous north to northeast winds are 
  forecast tonight into Sunday morning. Winds are 
  expected to reach the lower elevations particularly by Sunday 
  morning and through the day Sunday. Offshore winds weaken but 
  remain locally gusty Sunday night into Monday.
 
  Mountains/Hills...  Sat Night... Sustained 30-55mph Gusts 60-80mph...
                      Sun Day...   Sustained 20-35mph Gusts 40-60mph...
                      Sun Night... Sustained 15-25mph Gusts 25-40mph...
                      Mon Day...   Sustained 5-15mph  Gusts 15-25mph...
 
  Valleys/Coast...    Sat Night... Sustained 5-15mph  Gusts 15-35mph...
                      Sun Day...   Sustained 15-25mph Gusts 30-50mph...
                      Sun Night... Sustained 5-10mph  Gusts 10-20mph...
                      Mon Day...   Light Winds...

* IMPACTS...Any fires that develop will likely spread rapidly.

* TIMING....Strongest winds throughout tonight into 
  Sunday morning. Winds gradually weaken through Sunday into 
  Sunday night but remain locally gusty into Monday morning. 

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.

&&

$$

CAZ509-512-262300-
/O.CON.KMTR.FW.W.0006.191027T1000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
542 AM PDT Sat Oct 26 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 3 AM SUNDAY TO 11 AM
PDT MONDAY FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER
ZONES 509 AND 512...

* WIND...Strong north to northeast winds will develop tonight
  into Sunday, peaking early Sunday morning. Sustained wind 
  speeds of 15 to 30 mph with gusts 35 to 55 mph are possible. 
  Winds gradually weaken from Sunday morning through Monday 
  morning, but will remain locally gusty into early Monday. 

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries.

  Mountains/Hills...  Sat Night... 25-35%...
                      Sun Day...   15-25%...
                      Sun Night... 20-35%...
                      Mon Day...   15-30%...
 
  Valleys/Coast...    Sat Night... 45-60%...
                      Sun Day...   20-40%...
                      Sun Night... 25-45%...
                      Mon Day...   20-35%...
 
* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92. 

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Strongest winds late tonight into Sunday
  morning. Winds gradually weaken through Sunday into Sunday 
  night but remain locally gusty into Monday morning. 

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.

&&

$$
634 
WWUS86 KMTR 262040
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
140 PM PDT Sat Oct 26 2019

...Red Flag Warning tonight through Monday morning for
dangerously strong offshore winds and critically low humidity...

.Confidence is high that an offshore wind event featuring strong
and dangerous winds and critically low humidity will impact the
area from this evening through Monday morning. This event looks
to be the strongest since the 2017 wine country fires and
potentially a historic event given the strength and duration of
the winds. The strongest winds are expected from late tonight 
into Sunday morning. Stronger winds mixing to the lower elevations
will be a particular concern from late tonight through Sunday.
Winds will gradually ease at lower elevations by late Sunday, but
remain gusty across the higher elevations on Sunday night
and into Monday morning. Latest model runs suggest winds will be
stronger Sunday night than previously expected over the higher
terrain.

CAZ505>507-510-511-271300-
/O.CON.KMTR.FW.W.0006.191027T0300Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
140 PM PDT Sat Oct 26 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 8 PM THIS EVENING TO
11 AM PDT MONDAY FOR FOR DANGEROUSLY STRONG OFFSHORE WINDS AND
CRITICALLY LOW HUMIDITY FOR FIRE WEATHER ZONES 505, 506, 507, 510, 
AND 511...

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries. Locally lower humidity values are 
  possible. 

  Mountains/Hills...  
   Sat Night... 10-35%...
   Sun Day...   7-20%...
   Sun Night... 10-25%...
   Mon Day...   7-20%...

  Valleys/Coast...    
   Sat Night... 30-55%...                     
   Sun Day...   12-30%...
   Sun Night... 25-45%...
   Mon Day...   12-30%...

* WINDS...Strong and dangerous offshore winds begin late this 
  evening and become widespread by midnight.  Strongest winds 
  from 3am to 10am Sunday morning. Gusty winds are expected to
  reach the lower elevations particularly by Sunday morning 
  and through the day Sunday. Winds are forecast to ease
  somewhat through the day Sunday but remain strong and gusty
  through Sunday night.  Winds drastically cut off through 
  Monday morning.  

  Mountains/Hills...
   Sat Night... Sustained 30-55mph Gusts 60-80mph...
   Sun Day...   Sustained 20-35mph Gusts 40-60mph...
   Sun Night... Sustained 25-45mph Gusts 50-70mph...
   Mon Day...   Sustained 5-15mph  Gusts 15-25mph...

  Valleys/Coast...    
   Sat Night... Sustained 5-15mph  Gusts 15-35mph...
   Sun Day...   Sustained 15-25mph Gusts 30-50mph...
   Sun Night... Sustained 5-15mph  Gusts 10-25mph...
   Mon Day...   Light Winds...

* 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.

&&

$$

CAZ509-512-271300-
/O.CON.KMTR.FW.W.0006.191027T1000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
140 PM PDT Sat Oct 26 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 3 AM SUNDAY TO 11 AM
PDT MONDAY FOR FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER
ZONES 509 AND 512...

* WIND...Strong north to northeast winds will develop tonight 
  into Sunday, peaking early Sunday morning. Sustained wind 
  speeds of 15 to 30 mph with gusts 35 to 55 mph are possible. 
  Winds gradually weaken somewhat through the day Sunday, but
  will remain gusty overnight Sunday night into Monday.

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries.

  Mountains/Hills...
   Sat Night... 25-35%...                     
   Sun Day...   15-25%...
   Sun Night... 20-35%...
   Mon Day...   15-30%...

  Valleys/Coast... 
   Sat Night... 45-60%...                     
   Sun Day...   20-40%...
   Sun Night... 25-45%...
   Mon Day...   20-35%...

* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92. 

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Strongest winds late tonight into Sunday morning. 
  Winds gradually weaken somewhat through the day Sunday, but
  will remain gusty overnight Sunday night into Monday.

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.

&&

$$
499 
WWUS86 KMTR 271305
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
605 AM PDT Sun Oct 27 2019

...Red Flag Warning through Monday morning for dangerously strong
offshore winds and critically low humidity...

.The offshore wind event featuring strong and dangerous winds and
critically low humidity will continue to impact the area through 
Monday morning. This event may be the strongest since the 
2017 wine country fires and potentially a historic event given the
strength and duration of the winds. The strongest winds in the
higher terrain are expected to continue through the morning hours
today before weakening somewhat. Stronger winds mixing to the 
lower elevations will be a particular concern through the day. 
Winds will gradually ease at lower elevations by late today, but 
remain gusty across the higher elevations tonight and into Monday
morning. 

CAZ505>507-510-511-280000-
/O.CON.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
605 AM PDT Sun Oct 27 2019

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT MONDAY FOR
FOR DANGEROUSLY STRONG OFFSHORE WINDS AND CRITICALLY LOW HUMIDITY
FOR FIRE WEATHER ZONES 505, 506, 507, 510, AND 511...

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries. Locally lower humidity values are 
  possible. 

  Mountains/Hills...
    Sun Day...   7-20%...    
    Sun Night... 10-25%...
    Mon Day...   7-20%...

  Valleys/Coast...
    Sun Day...   12-30%...
    Sun Night... 25-45%...
    Mon Day...   12-30%...

* WINDS...Strongest winds will continue until mid morning. Gusty
  winds are expected to reach the lower elevations particularly 
  through the day Sunday. Winds are forecast to ease somewhat 
  through the day today but remain strong and gusty through
  the night. Winds drastically cut off through Monday morning. 

  Mountains/Hills...
    Sun Morning... Sustained 30-55mph Gusts 60-80mph...
    Sun Day...     Sustained 20-35mph Gusts 40-60mph...  
    Sun Night...   Sustained 25-45mph Gusts 50-70mph...
    Mon Day...     Sustained 5-15mph  Gusts 15-25mph...

  Valleys/Coast...
    Sun Day...   Sustained 15-25mph Gusts 30-50mph...     
    Sun Night... Sustained 5-15mph  Gusts 10-25mph...
    Mon Day...   Light Winds...

* 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.

&&

$$

CAZ509-512-280000-
/O.CON.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
605 AM PDT Sun Oct 27 2019

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT MONDAY FOR
FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 509 AND
512...

* WIND...Strong north to northeast winds will continue today
  peaking early this morning. Sustained wind speeds of 15 
  to 30 mph with gusts 35 to 55 mph are possible. Winds 
  gradually weaken somewhat through the day today, but 
  will remain gusty overnight into Monday. 

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries.

  Mountains/Hills...
    Sun Day...   15-25%...
    Sun Night... 20-35%...
    Mon Day...   15-30%...

  Valleys/Coast...
    Sun Day...   20-40%...
    Sun Night... 25-45%...
    Mon Day...   20-35%...

* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92. 

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Strongest winds late until mid morning. 
  Winds gradually weaken somewhat through the day today, but 
  will remain gusty overnight into Monday.

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.

&&

$$
389 
WWUS86 KMTR 272358
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
458 PM PDT Sun Oct 27 2019

...Red Flag Warning through Monday morning for dangerously strong
offshore winds and critically low humidity...

.The offshore wind event featuring strong and dangerous winds and
critically low humidity will continue to impact the area through
Monday morning. This event has been the strongest since the 2017 
wine country fires and is potentially a historic event given the 
strength and duration of the winds. Strong and gusty winds in the
higher terrain are expected to continue through much of tonight, 
and then diminish quickly on Monday morning. At lower elevations, 
winds will gradually ease by midnight tonight.

Another burst of dry offshore winds is forecast to occur from 
midday Tuesday through Wednesday morning across the same areas 
that are being impacted by the current offshore wind event. The 
upcoming offshore wind event is not expected to be as strong, or 
last as long, as the current event, but will still likely generate
critical fire weather conditions. 

CAZ505>507-510-511-281300-
/O.CON.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
458 PM PDT Sun Oct 27 2019

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT MONDAY FOR
FOR DANGEROUSLY STRONG OFFSHORE WINDS AND CRITICALLY LOW HUMIDITY
FOR FIRE WEATHER ZONES 505, 506, 507, 510, AND 511...

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries. Locally lower humidity values are 
  possible. 

  Mountains/Hills...
    Sun Day...   7-20%...    
    Sun Night... 10-25%...
    Mon Day...   7-20%...

  Valleys/Coast...
    Sun Day...   12-30%...
    Sun Night... 25-45%...
    Mon Day...   12-30%...

* WINDS...Strong winds will continue in all areas through early
  Sunday evening. Winds are forecast to ease in the valleys by late 
  Sunday evening but remain strong and gusty in the hills, and
  locally near the ocean, through Sunday night. Winds will
  decrease significantly in all areas by late Monday morning.

 Mountains/Hills...
    Sun Day...     Sustained 20-35mph Gusts 40-60mph...  
    Sun Night...   Sustained 25-45mph Gusts 50-70mph...
    Mon Day...     Sustained 5-15mph  Gusts 15-25mph...

  Valleys/Coast...
    Sun Day...   Sustained 15-25mph Gusts 30-50mph...     
    Sun Night... Sustained 5-15mph  Gusts 10-25mph...
    Mon Day...   Light Winds...

* 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.

&&

$$

CAZ509-512-281300-
/O.CON.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
458 PM PDT Sun Oct 27 2019

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT MONDAY FOR
FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONES 509 AND
512...

* WIND...Strong north to northeast winds will continue  
  through this evening. Sustained wind speeds of 15 to 30 
  mph with gusts 35 to 55 mph are possible. Winds gradually 
  weaken late tonight, and then decrease significantly on 
  Monday morning.

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries.

 Mountains/Hills...
    Sun Day...   15-25%...
    Sun Night... 20-35%...
    Mon Day...   15-30%...

  Valleys/Coast...
    Sun Day...   20-40%...
    Sun Night... 25-45%...
    Mon Day...   20-35%...

* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92. 

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Strongest winds late until mid morning. Winds 
  gradually weaken somewhat through the day today, but will 
  remain gusty overnight into Monday.

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.

&&

$$
432 
WWUS86 KMTR 281446
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
746 AM PDT Mon Oct 28 2019

...Red Flag Warning through Monday morning for gusty offshore 
winds and critically low humidity...

.The offshore wind event featuring gusty winds and critically low
humidity will continue to impact the area through Monday morning.


Another burst of dry offshore winds is forecast to occur from
midday Tuesday through Wednesday morning across the same areas
that are being impacted by the current offshore wind event. The
upcoming offshore wind event is not expected to be as strong, or
last as long, as the current event, but will still likely
generate critical fire weather conditions.

CAZ505>507-510-511-281800-
/O.CON.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
746 AM PDT Mon Oct 28 2019

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT THIS
MORNING FOR FOR DANGEROUSLY STRONG OFFSHORE WINDS AND CRITICALLY
LOW HUMIDITY FOR FIRE WEATHER ZONES 505, 506, 507, 510, AND 511...

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries. Locally lower humidity values are 
  possible. 

 Mountains/Hills... Mon Day... 7-20%...

 Valleys/Coast...   Mon Day... 12-30%...

* WINDS... Winds will decrease significantly in all areas by late
  Monday morning. 

 Mountains/Hills... Mon Day... Sustained 5-15mph Gusts 15-25mph...

 Valleys/Coast...   Mon Day... Light Winds...

* IMPACTS...Any fires that develop will likely spread rapidly.

* TIMING...Winds decreasing Monday.

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.

&&

$$

CAZ509-512-281800-
/O.CON.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
746 AM PDT Mon Oct 28 2019

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT THIS
MORNING FOR FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER
ZONES 509 AND 512...

* WIND...Winds decrease significantly on Monday morning. 

* HUMIDITY... Critically low daytime humidity with poor 
  overnight recoveries.

 Mountains/Hills... Mon Day... 15-30%...

 Valleys/Coast...   Mon Day... 20-35%...

* HIGHEST THREAT...Highway 1 corridor from south of Pacifica to 
  near Davenport including Half Moon Bay and coastal areas east 
  of Highway 1...and Santa Cruz mountains above 1500 feet 
  including locations along Highway 9 and 92. 

* IMPACTS...any fires that develop will likely spread rapidly.

* TIMING...Winds decreasing Monday.

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.

&&

$$
674 
WWUS86 KMTR 281748
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
1048 AM PDT Mon Oct 28 2019

...Red Flag Warning will expire at 11 AM...

.Conditions will continue to gradually improve as the strongest 
winds subside. Despite the weakening winds, breezy to gusty winds
will still be possible over the higher peaks today. Additionally,
relative humidity readings will remain low. The combination of
lingering gusts and low humidity will result in near critical fire
weather conditions.

CAZ505>507-510-511-281900-
/O.EXP.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
Coastal North Bay Including Point Reyes National Seashore-
North Bay Interior Valleys-North Bay Mountains-
East Bay Interior Valleys-East Bay Hills and the Diablo Range-
1048 AM PDT Mon Oct 28 2019

...RED FLAG WARNING WILL EXPIRE AT 11 AM PDT THIS MORNING FOR 
FIRE WEATHER ZONES 505, 506, 507, 510, AND 511...

The National Weather Service in Monterey will allow the Red Flag 
Warning to expire at 1100 AM this morning.

$$

CAZ509-512-281900-
/O.EXP.KMTR.FW.W.0006.000000T0000Z-191028T1800Z/
San Francisco Peninsula Coast-Santa Cruz Mountains-
1048 AM PDT Mon Oct 28 2019

...RED FLAG WARNING WILL EXPIRE AT 11 AM PDT THIS MORNING FIRE 
WEATHER ZONES 509 AND 512...

The National Weather Service in Monterey will allow the Red Flag 
Warning to expire at 1100 AM this morning.

$$

What forecasters said that day

The local office's own words before this red flag warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this red flag warning went out at Oct 25, 10:30 AM PDT, 5 minutes earlier.

Area forecast discussion, Oct 25, 10:30 AM PDT, 5 minutes before
Area Forecast Discussion
National Weather Service San Francisco Bay Area
1030 AM PDT Fri Oct 25 2019

.SYNOPSIS..High pressure over the region will result in continued
above normal temperatures and dry conditions. While temperatures
cool slightly over the weekend, a stronger offshore flow event is
forecast to occur late this weekend. Critical fire weather
conditions and potentially damaging winds will be possible over
portions of the San Francisco Bay Area from late Saturday through
Monday morning.

&&

.DISCUSSION...as of 10:21 AM PDT Friday...Forecast remains on
track this morning. A heat advisory has been issued for portions
of the area, including the Bay Shoreline, SF Peninsula coast,
Monterey Bay coastline, Santa Clara Valley, and North Salinas
Valley. Temperatures in these areas will be into the 90s again.
This creates a concern with people reaching to the ocean to escape
the heat due to the ocean water temps being in the mid 50s.

The main wind event remains on track for the weekend. The fire
weather watch and high wind watch are both being upgraded to
warnings at this time.

&&

.PREV DISCUSSION...as of 3:53 AM PDT Friday...Satellite imagery shows
an area of high clouds rotating over Central California. The fog
imagery reveals the heat signatures of California fires. Current
temperature trends are interesting - those in the North Bay are
running as many as 25 degrees cooler than 24 hours ago, in the
lower 50s, and areas in the Monterey County are 8 degrees warmer,
in the 60s! It's still 64 degrees in Monterey.

Another hot day is expected today with highs mainly in
the 80s and 90s, although temperatures should be a few degrees
cooler than Thursday's highs. Further cooling is expected over
the weekend as the upper level ridge weakens as a trough deepens
over the Great Basin. This coupling will bring another offshore
wind event late Saturday into Monday. This event is expected to be
the strongest one of the season with strong and gusty winds not
only being confined to the higher terrain, but even mixing down to
the valleys and coast. A High Wind Watch has been issued for the
entire North Bay region, East Bay Hills, interior valleys and the
Diablo Range, Santa Cruz Mountains and San Francisco Peninsula
Coast from late Saturday through Monday morning.

Even though cooler temperatures (near normal) will translate to
higher relative humidities, the strong winds will be more than
enough to push fire weather conditions to critical once again.
Thus, a Fire Weather Watch is in effect from Saturday night
through Monday morning for dangerously strong offshore winds.

Winds will will begin to taper off on Monday, and temperatures
will remain seasonably cool, especially overnights. Low temps in
the inland valley areas are forecast to drop to the upper 30s to
lower 40s in sheltered areas. Looking out in the extended, the
blocking ridge is forecast to remain over the Eastern Pacific,
thus no rain in sight through 10 days.

&&

.AVIATION...as of 4:54 AM PDT Friday...VFR. Light offshore flow
will continue to bring mostly clear skies. The Kincade Fire in
Sonoma County is forecast by the HRRR model to bring smoke to
much of the Bay Area. At KSTS, smoke is being reported with
visibility currently at 9 miles. The smoke could reduce
visibilities at times today, especially as northwest winds develop
this afternoon and transport smoke into the Bay Area. Light
offshore winds this morning will become light onshore this
afternoon.

Vicinity of KSFO...VFR. Light east winds will continue through mid
afternoon. Onshore winds expected to return late this afternoon.
Smoke could occasionally reduce visibility much of the day.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Southeast winds will continue
through the morning with onshore winds returning early to mid
afternoon. Smoke could drift near the terminals late this
afternoon and evening but confidence on coverage is low.

&&

.FIRE WEATHER...as of 9:24 PM PDT Thursday...While wind speeds
have diminish across the region through the day, a very dry air
mass remains in place this evening with light to occasionally
moderate offshore flow. This will lead to poor to moderate at best
humidity recoveries overnight which is not good for ongoing fires
over the region. All this is leading up to an even stronger
offshore wind event beginning Saturday and lasting until Monday
morning. Thus, a Fire Weather Watch has been issued for the entire
North Bay, East Bay Hills, interior valleys and the Diablo Range,
Santa Cruz Mountains and San Francisco Peninsula Coast.

Now for the details...confidence continues to increase with the
development of a very strong offshore flow gradient late this
weekend. The forecast models put this on par, strength wise, with
the 2017 offshore event that resulted in the deadly and devastating
North Bay/Wine Country Fires. 925 MB winds of 40-45kt will develop
first over Napa County late Saturday night and spread south and west
into Sunday morning. The local MTR WRF model shows winds peaking
early Sunday morning with 925 MB winds approaching 60kt over the
higher peaks of the North Bay region. Given better upper level
support, these stronger winds will have the potential to downslope
on the lee side of the mountains, thus mixing strong and gusty winds
into the valley floor and even to the coast early Sunday morning.
Thus, cannot rule out frequent wind gusts of 45 to 55 mph across the
aforementioned areas with gusts of up to 65 to 75 mph in the
region's highest ridges and peaks. Relative humidity values will
also plummet as these winds develop and mix down to the surface late
Saturday night into Sunday. This will make any ongoing fire fighting
efforts very difficult and will allow for any new fire starts to
spread rapidly. Winds will diminish slightly in the valley and
coastal locations late Sunday, yet critically dry conditions will
likely persist and gusty winds will continue in the higher
elevations. Please continue to monitor the latest forecast
information regarding the forecast critical fire weather conditions
and potentially damaging winds.

&&

.MARINE...as of 10:21 AM PDT Friday...Weak easterly winds Friday
will switch to northwesterly late tonight as high pressure
rebuilds over the northeastern Pacific. Winds will remain from the
northwest and strengthen on Saturday.  A larger northwest swell
will arrive this weekend. A light  southerly swell will persist
through the forecast period. Gale-  force winds are possible
across the northern outer waters Saturday night. Additionally,
gale force winds are possible along the  coastal waters north of
Pigeon Point late Saturday night and  Sunday due to strong
developing offshore winds.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
 .Tday...Heat Advisory...Bay Shoreline, SF Peninsula coast,
Monterey Coast, Santa Clara Valley, and North Salinas Valley.

&&

PUBLIC FORECAST: BFG?Sims
AVIATION: ST
MARINE: ST
FIRE WEATHER: RGass

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The office that day

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

IssuedProductOfficeCountiesLasted
Oct 24, 7:19 PM PDTHigh Wind WatchMTRAlameda, Contra Costa, Marin, Napa, San Mateo, Santa Clara and 2 more16 hr
Oct 25, 3:00 AM PDTGale WatchMTR19 hr
Oct 25, 7:21 AM PDTHeat AdvisoryMTRAlameda, Contra Costa, Monterey, San Benito, City and County of San Francisco, San Mateo and 2 more12 hr
Oct 25, 11:12 AM PDTHigh Wind WarningMTR63 hr
Oct 25, 11:12 AM PDTWind AdvisoryMTRAlameda, Contra Costa, Marin, Napa, City and County of San Francisco, San Mateo and 3 more66 hr

Nearby

Red Flag Warnings in California, 2019Every red flag warning in 2019

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.