Alert archive / California / Red Flag Warnings in 2018

Red Flag Warning 4, NWS San Francisco Bay Area, CA

September 24, 2018

NWS San Francisco Bay Area, CA issued this red flag warning at Sep 24, 2018, 3:21 AM PDT. It was in force for 38 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
Sep 24, 2018, 3:21 AM PDT (10:21 UTC)
Expired
Sep 25, 2018, 5:00 PM PDT
In force
38 hr
Issued by
NWS San Francisco Bay Area, CA

The text

As transmitted.

942 
WWUS86 KMTR 241021
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
321 AM PDT Mon Sep 24 2018

...Red Flag Warning in effect through Tuesday afternoon for
low humidity and dry offshore winds for the North and East Bay
Hills...

.A very dry airmass with light to moderate offshore winds will
continue today through at least Tuesday and possibly midweek. The
combination of these weather conditions with very dry fuels will
create critical fire weather conditions through at least Tuesday
afternoon.

CAZ507-242100-
/O.NEW.KMTR.FW.W.0004.180924T1021Z-180926T0000Z/
North Bay Mountains-
321 AM PDT Mon Sep 24 2018

...RED FLAG WARNING IN EFFECT UNTIL 5 PM PDT TUESDAY FOR LOW
HUMIDITY AND OFFSHORE WINDS FOR THE NORTH BAY MOUNTAINS...

The National Weather Service in San Francisco has issued a Red
Flag Warning, which is in effect until 5 PM PDT Tuesday. 

* AFFECTED AREA...The North Bay Mountains. Fire weather zone 507
  which includes all locations above 1000 feet in Napa, Sonoma and
  Marin Counties.

* WIND...North to Northeast winds 5 to 15 mph today but increasing
  Monday night into Tuesday 10 to 20 mph with gusts to 35 mph.

* HUMIDITY...5 to 15% with little or no night time recovery
  through midweek.

* HIGHEST THREAT...The next burst of moderate winds is forecast to
  arrive during the overnight hours of Monday into early Tuesday
  morning across the Napa hills.

* 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.

&&

$$

CAZ511-242100-
/O.NEW.KMTR.FW.W.0004.180924T1021Z-180926T0000Z/
East Bay Hills and the Diablo Range-
321 AM PDT Mon Sep 24 2018

...RED FLAG WARNING IN EFFECT UNTIL 5 PM PDT TUESDAY FOR LOW
HUMIDITY AND DRY OFFSHORE WINDS FOR THE EAST BAY HILLS...

The National Weather Service in San Francisco has issued a Red
Flag Warning, which is in effect until 5 PM PDT Tuesday. 

* AFFECTED AREA...The East Bay Hills. Fire weather zone 511 which
  includes all locations above 1000 feet for the East Bay and
  Diablo Range of Santa Clara county including Mt Hamilton.

* WIND...Northeast winds 5 to 15 mph today but increasing 10 to 20
  mph with gusts to 35 mph tonight into early Tuesday morning.

* HUMIDITY...5 to 15% and locally lower with little or no night
  time recovery through midweek.

* 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.

&&

$$
3 follow-up statements
864 
WWUS86 KMTR 242022
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
122 PM PDT Mon Sep 24 2018

...Red Flag Warning in effect through Tuesday afternoon for low
humidity and dry offshore winds for the North Bay Mountains and 
East Bay Hills...

.A very dry airmass with light to moderate offshore winds will
continue today through at least Tuesday and possibly midweek. The
combination of these weather conditions with very dry fuels will
create critical fire weather conditions through at least Tuesday
afternoon.

CAZ507-250500-
/O.CON.KMTR.FW.W.0004.000000T0000Z-180926T0000Z/
North Bay Mountains-
122 PM PDT Mon Sep 24 2018

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 PM PDT TUESDAY FOR
LOW HUMIDITY AND OFFSHORE WINDS FOR THE NORTH BAY MOUNTAINS...

* AFFECTED AREA...The North Bay Mountains. Fire weather zone 507 
  which includes all locations above 1000 feet in Napa, Sonoma 
  and Marin Counties. 

* WIND...North to Northeast winds 5 to 15 mph today but
  increasing Monday night into Tuesday 10 to 20 mph with gusts 
  to 35 mph.

* HUMIDITY...5 to 15% with little or no night time recovery 
  through midweek.

* HIGHEST THREAT...The next burst of moderate winds is forecast
  to arrive during the overnight hours of Monday into early 
  Tuesday morning across the Napa hills. 

* 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.

&&

$$

CAZ511-250500-
/O.CON.KMTR.FW.W.0004.000000T0000Z-180926T0000Z/
East Bay Hills and the Diablo Range-
122 PM PDT Mon Sep 24 2018

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 PM PDT TUESDAY FOR
LOW HUMIDITY AND DRY OFFSHORE WINDS FOR THE EAST BAY HILLS...

* AFFECTED AREA...The East Bay Hills. Fire weather zone 511 
  which includes all locations above 1000 feet for the East Bay 
  and Diablo Range of Santa Clara county including Mt Hamilton. 

* WIND...Northeast winds 5 to 15 mph today but increasing 10 to
  20 mph with gusts to 35 mph tonight into early Tuesday 
  morning. 

* HUMIDITY...5 to 15% and locally lower with little or no night 
  time recovery through midweek.

* 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.

&&

$$
573 
WWUS86 KMTR 251027
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
327 AM PDT Tue Sep 25 2018

...Red Flag Warning in effect through 5 pm Tuesday for low 
humidity and dry offshore winds for the North Bay Mountains and 
East Bay Hills...

.A very dry airmass with light to moderate offshore winds will
continue through this afternoon.

CAZ507-252200-
/O.CON.KMTR.FW.W.0004.000000T0000Z-180926T0000Z/
North Bay Mountains-
327 AM PDT Tue Sep 25 2018

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 PM PDT THIS
AFTERNOON FOR LOW HUMIDITY AND OFFSHORE WINDS FOR THE NORTH BAY
MOUNTAINS...

* AFFECTED AREA...The North Bay Mountains. Fire weather zone 507 
  which includes all locations above 1000 feet in Napa, Sonoma 
  and Marin Counties. 

* WIND...Northeast winds 5 to 15 mph with gusts 20 to 30 mph.

* HUMIDITY...9 to 19%.

* HIGHEST THREAT...The hills of Napa and northeast Sonoma county
  above 1000 feet.

* 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.

&&

$$

CAZ511-252200-
/O.CON.KMTR.FW.W.0004.000000T0000Z-180926T0000Z/
East Bay Hills and the Diablo Range-
327 AM PDT Tue Sep 25 2018

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 5 PM PDT THIS
AFTERNOON FOR LOW HUMIDITY AND DRY OFFSHORE WINDS FOR THE EAST
BAY HILLS...

* AFFECTED AREA...The East Bay Hills. Fire weather zone 511 
  which includes all locations above 1000 feet for the East Bay 
  and Diablo Range of Santa Clara county including Mt Hamilton. 

* WIND...Northeast winds 5 to 15 mph with gusts 20 to 30 mph.

* HUMIDITY...9 to 19%.

* 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.

&&

$$
670 
WWUS86 KMTR 260011
RFWMTR

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Francisco CA
511 PM PDT Tue Sep 25 2018

CAZ507-511-260115-
/O.EXP.KMTR.FW.W.0004.000000T0000Z-180926T0000Z/
North Bay Mountains-East Bay Hills and the Diablo Range-
511 PM PDT Tue Sep 25 2018

...RED FLAG WARNING HAS EXPIRED FOR LOW HUMIDITY AND DRY OFFSHORE
WINDS FOR THE NORTH AND EAST BAY HILLS ABOVE 1000 FEET.

Low relative humidities will persist through tonight. However, 
wind speeds have been trending lighter and are forecast to remain
below Red Flag Warning criteria. Nonetheless, precautions should 
still be taken given the critically dry weather and fuel 
conditions across this region. 

$$

Nearby

Red Flag Warnings in California, 2018Every red flag warning in 2018

Sources

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