Alert archive / California / Red Flag Warnings in 2007

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

November 22, 2007Riverside County, California

NWS San Francisco Bay Area, CA issued this red flag warning at Nov 22, 2007, 4:38 PM PST for Riverside County, California. It took effect at Nov 23, 2007, 12:00 AM PST. It was in force for 28 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
Nov 22, 2007, 4:38 PM PST (00:38 UTC)
In effect from
Nov 23, 2007, 12:00 AM PST
Expired
Nov 24, 2007, 4:00 AM PST
In force
28 hr
Issued by
NWS San Francisco Bay Area, CA

County Riverside County, CA

The radar

The San Diego radar (KNKX), 134 km from the middle of the area, began a volume at 00:41 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.

The nearest sounding before it

San Diego, CA (KNKX), launched 00:00Z, 0.6 hours before the alert went out and 154 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, San Diego, CA at 00:00Z on 2007-11-23Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 00:00Z on 2007-11-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -99 square meters per square second.19395878Sfc1 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
1015 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-99 m²/s²
0-3 km storm-relative helicity
-28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WWUS86 KMTR 230038
RFWMTR

RED FLAG WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
438 PM PST THU NOV 22 2007

CAZ207-230145-
/O.CAN.KMTR.FW.A.0004.071123T1200Z-071124T1200Z/
THE EAST BAY HILLS-
438 PM PST THU NOV 22 2007

...FIRE WEATHER WATCH IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS CANCELED THE
FIRE WEATHER WATCH. 

HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE PACIFIC NORTHWEST
AND NORTHERN GREAT BASIN TONIGHT AND FRIDAY...WHILE A WEAK TROUGH
OF LOW PRESSURE PERSISTS ALONG THE COAST. AS A RESULT...NORTHEAST
WINDS ARE EXPECTED TO INCREASE OVER THE EAST BAY HILLS LATE
TONIGHT AND FRIDAY...AND BRING LOW RELATIVE HUMIDITIES. HOWEVER...
FUEL MOISTURE VALUES APPEAR TO BE SUFFICIENT TO KEEP CONDITIONS
FROM REACHING CRITICAL LEVELS.

$$

CAZ265-231245-
/O.UPG.KMTR.FW.A.0004.071123T1200Z-071124T1200Z/
/O.NEW.KMTR.FW.W.0004.071123T0800Z-071124T1200Z/
NAPA COUNTY-
438 PM PST THU NOV 22 2007

...RED FLAG WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 4 AM PST
SATURDAY...
...FIRE WEATHER WATCH NO LONGER IN EFFECT...

THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A RED
FLAG WARNING...WHICH IS IN EFFECT FROM MIDNIGHT TONIGHT TO 4 AM
PST SATURDAY. THE FIRE WEATHER WATCH IS NO LONGER IN EFFECT. 

HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE PACIFIC NORTHWEST
AND NORTHERN GREAT BASIN TONIGHT AND FRIDAY...WHILE A WEAK TROUGH
OF LOW PRESSURE PERSISTS IN THE VICINITY OF THE COAST. AS A
RESULT...NORTHEAST WINDS WILL INCREASE OVER THE NAPA COUNTY HILLS
BEGINNING LATE TONIGHT...REACHING SPEEDS OF 20 TO 35 MPH WITH LOCAL
GUSTS TO 45 MPH ON FRIDAY. THESE STRONG WINDS ARE EXPECTED TO
CONTINUE THROUGH FRIDAY NIGHT. IN ADDITION...RELATIVE HUMIDITIES
WILL LOWER IN RESPONSE TO THE DRY NORTHEAST FLOW. THE COMBINATION
OF STRONG WINDS...VERY LOW RELATIVE HUMIDITIES AND RELATIVELY LOW
FUEL MOISTURE CONTENT WILL CREATE CRITICAL FIRE WEATHER CONDITIONS.

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 WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

$$
BLIER
6 follow-up statements
000 
WWUS86 KMTR 231231
RFWMTR

RED FLAG WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
431 AM PST FRI NOV 23 2007

CAZ265-240000-
/O.CON.KMTR.FW.W.0004.000000T0000Z-071124T1200Z/
NAPA COUNTY-
431 AM PST FRI NOV 23 2007

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 4 AM PST SATURDAY FOR 
GUSTY OFFSHORE WINDS AND DRY RELATIVE HUMIDITY VALUES...

HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE PACIFIC NORTHWEST
AND NORTHERN GREAT BASIN TODAY...WHILE A WEAK TROUGH OF LOW PRESSURE
PERSISTS IN THE VICINITY OF THE COAST. AS A RESULT...NORTHEAST
WINDS WILL INCREASE OVER THE NAPA COUNTY HILLS THIS MORNING REACHING
SPEEDS OF 20 TO 35 MPH WITH LOCAL GUSTS TO 45 MPH. THESE STRONG
WINDS ARE EXPECTED TO CONTINUE THROUGH TONIGHT. IN ADDITION...RELATIVE
HUMIDITIES WILL LOWER IN RESPONSE TO THE DRY NORTHEAST FLOW. THE
COMBINATION OF STRONG WINDS...VERY LOW RELATIVE HUMIDITIES AND
RELATIVELY LOW FUEL MOISTURE CONTENT WILL CREATE CRITICAL FIRE
WEATHER CONDITIONS.

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 WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

$$

ANDERSON
000 
WWUS86 KMTR 232359
RFWMTR

RED FLAG WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
359 PM PST FRI NOV 23 2007

CAZ265-240800-
/O.CON.KMTR.FW.W.0004.000000T0000Z-071124T1200Z/
NAPA COUNTY-
359 PM PST FRI NOV 23 2007

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 4 AM PST SATURDAY FOR 
MODERATE OFFSHORE WINDS AND EXTREMELY LOW OVERNIGHT RELATIVE 
HUMIDITIES...

THE OFFSHORE PRESSURE GRADIENT WILL GRADUALLY WEAKEN OVER THE COMING
HOURS...AND RESULT IN SOME REDUCTION IN WIND SPEEDS. NORTHEAST
WINDS OF 10 TO 20 MPH WITH LOCAL GUSTS TO 30 MPH ARE EXPECTED IN
THE HILLS OVERNIGHT. IN ADDITION...RELATIVE HUMIDITIES WILL REMAIN
EXTREMELY LOW...LESS THAN 20% AND LOCALLY AS LOW AS 10% THROUGH
THE OVERNIGHT HOURS. THE COMBINATION OF MODERATE AND LOCALLY GUSTY
WINDS...VERY LOW RELATIVE HUMIDITIES AND RELATIVELY LOW FUEL
MOISTURE CONTENT WILL CREATE CRITICAL FIRE WEATHER CONDITIONS.

A RED FLAG WARNING REMAINS IN EFFECT UNTIL 4 AM PST SATURDAY 
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 WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

$$
BLIER
000 
WWUS86 KMTR 240459
RFWMTR

RED FLAG WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
859 PM PST FRI NOV 23 2007

CAZ265-241200-
/O.CON.KMTR.FW.W.0004.000000T0000Z-071124T1200Z/
NAPA COUNTY-
859 PM PST FRI NOV 23 2007

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 4 AM PST SATURDAY FOR 
LOCALLY MODERATE OFFSHORE WINDS AND EXTREMELY LOW OVERNIGHT RELATIVE 
HUMIDITIES...

WIND SPEEDS IN THE HILLS ARE REDUCING AS THE OFFSHORE PRESSURE
GRADIENT CONTINUES TO GRADUALLY WEAKEN. NORTHEAST WINDS OF 10 TO
15 MPH WITH LOCAL GUSTS TO 25 MPH ARE EXPECTED IN THE HILLS
OVERNIGHT. HOWEVER...RELATIVE HUMIDITIES WILL REMAIN EXTREMELY
LOW...LESS THAN 20% AND LOCALLY AS LOW AS 10-12% THROUGH THE
OVERNIGHT HOURS. THE COMBINATION OF MODERATE AND LOCALLY GUSTY
WINDS...VERY LOW RELATIVE HUMIDITIES AND RELATIVELY LOW FUEL
MOISTURE CONTENT WILL CREATE CRITICAL FIRE WEATHER CONDITIONS.

A RED FLAG WARNING REMAINS IN EFFECT UNTIL 4 AM PST SATURDAY 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 WILL CREATE
EXPLOSIVE FIRE GROWTH POTENTIAL.

$$
BLIER
000 
WWUS86 KMTR 241211
RFWMTR

RED FLAG WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
411 AM PST SAT NOV 24 2007

CAZ265-242000-
/O.EXP.KMTR.FW.W.0004.000000T0000Z-071124T1200Z/
/O.NEW.KMTR.FW.W.0005.071124T1211Z-071124T2100Z/
NAPA COUNTY-
411 AM PST SAT NOV 24 2007

...RED FLAG WARNING IN EFFECT UNTIL 1 PM PST THIS AFTERNOON...
...RED FLAG WARNING HAS EXPIRED...

A COMBINATION OF VERY LOW HUMIDITIES AND LOCALLY BREEZY WINDS HAVE
CAUSED RED FLAG CONDITIONS TO CONTINUE THIS MORNING. THE OFFSHORE
FLOW WAS WEAKENING THIS MORNING AND WILL CONTINUE TO DO SO
THROUGHOUT THE DAY. THIS WILL CAUSE THE WINDS TO BE MAINLY LIGHT
FROM THIS AFTERNOON INTO SUNDAY WITH SLIGHT IMPROVEMENTS IN
HUMIDITY EXPECTED.

A RED FLAG WARNING REMAINS IN EFFECT UNTIL NOON PST SATURDAY 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 WILL CREATE
EXPLOSIVE FIRE GROWTH POTENTIAL.


$$
000 
WWUS86 KMTR 241211 CCA
RFWMTR

RED FLAG WARNING...CORRECTED
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
411 AM PST SAT NOV 24 2007

CAZ265-242000-
/O.EXP.KMTR.FW.W.0004.000000T0000Z-071124T1200Z/
/O.NEW.KMTR.FW.W.0005.071124T1211Z-071124T2100Z/
NAPA COUNTY-
411 AM PST SAT NOV 24 2007

...RED FLAG WARNING IN EFFECT UNTIL NOON PST THIS AFTERNOON...

A COMBINATION OF VERY LOW HUMIDITIES AND LOCALLY BREEZY WINDS HAVE
CAUSED RED FLAG CONDITIONS TO CONTINUE THIS MORNING. THE OFFSHORE
FLOW WAS WEAKENING THIS MORNING AND WILL CONTINUE TO DO SO
THROUGHOUT THE DAY. THIS WILL CAUSE THE WINDS TO BE MAINLY LIGHT
FROM THIS AFTERNOON INTO SUNDAY WITH SLIGHT IMPROVEMENTS IN
HUMIDITY EXPECTED.

A RED FLAG WARNING REMAINS IN EFFECT UNTIL NOON PST SATURDAY 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 WILL CREATE
EXPLOSIVE FIRE GROWTH POTENTIAL.


$$
000 
WWUS86 KMTR 241259 CCB
RFWMTR

RED FLAG WARNING...CORRECTED
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
411 AM PST SAT NOV 24 2007

CAZ265-242000-
/O.EXP.KMTR.FW.W.0004.000000T0000Z-071124T1200Z/
/O.NEW.KMTR.FW.W.0005.071124T1211Z-071124T2100Z/
NAPA COUNTY-
411 AM PST SAT NOV 24 2007

...RED FLAG WARNING IN EFFECT UNTIL NOON PST THIS AFTERNOON...

A COMBINATION OF VERY LOW HUMIDITIES AND LOCALLY BREEZY WINDS HAVE
CAUSED RED FLAG CONDITIONS TO CONTINUE THIS MORNING. THE OFFSHORE
FLOW WAS WEAKENING THIS MORNING AND WILL CONTINUE TO DO SO
THROUGHOUT THE DAY. THIS WILL CAUSE THE WINDS TO BE MAINLY LIGHT
FROM THIS AFTERNOON INTO SUNDAY WITH SLIGHT IMPROVEMENTS IN
HUMIDITY EXPECTED.

A RED FLAG WARNING REMAINS IN EFFECT UNTIL NOON PST SATURDAY A
RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS ARE 
EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF LOCALLY 
BREEZY WINDS AND VERY LOW RELATIVE HUMIDITIES WILL CREATE FIRE 
GROWTH POTENTIAL.


$$

Nearby

Red Flag Warnings in California, 2007Every red flag warning in 2007

Sources

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