Alert archive / California / Red Flag Warnings in 2018

Red Flag Warning 2, NWS San Diego, CA

February 9, 20184 counties in California

NWS San Diego, CA issued this red flag warning at Feb 9, 2018, 10:21 AM PST for 4 counties in California. It took effect at Feb 10, 2018, 10:00 PM PST. It was in force for 15 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
Feb 9, 2018, 10:21 AM PST (18:21 UTC)
In effect from
Feb 10, 2018, 10:00 PM PST
Expired
Feb 11, 2018, 1:00 PM PST
In force
15 hr
Issued by
NWS San Diego, CA

Counties Orange County, CA, Riverside County, CA, San Bernardino County, CA, San Diego County, CA

The radar

The Santa Ana Mts radar (KSOX), 88 km from the middle of the area, began a volume at 18:21 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 12:00Z, 6.4 hours before the alert went out and 124 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 12:00Z on 2018-02-09Temperature 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 12:00Z on 2018-02-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
3173 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

739 
WWUS86 KSGX 091821
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
1021 AM PST Fri Feb 9 2018

CAZ554-091930-
/O.CAN.KSGX.FW.A.0002.180211T0600Z-180211T2100Z/
Orange County Inland Areas-
1021 AM PST Fri Feb 9 2018

...FIRE WEATHER WATCH IS CANCELLED FOR INLAND ORANGE COUNTY
AREAS...

The National Weather Service in San Diego has cancelled the Fire 
Weather Watch. Gusty Santa Ana winds are likely Saturday night and
Sunday with gusts to 30 mph at times, however critical relative 
humidity values are no longer expected.

$$

CAZ248-255>257-265-100600-
/O.UPG.KSGX.FW.A.0002.180211T0600Z-180211T2100Z/
/O.NEW.KSGX.FW.W.0002.180211T0600Z-180211T2100Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger Districts Of
The San Bernardino National Forest-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San Bernardino
National Forest-Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-San Gorgonio Pass Near Banning-
1021 AM PST Fri Feb 9 2018

...RED FLAG WARNING IN EFFECT FROM 10 PM SATURDAY TO 1 PM PST
SUNDAY FOR STRONG SANTA ANA WINDS AND LOW HUMIDITY...

The National Weather Service in San Diego has issued a a Red Flag
Warning...which is in effect from 10 PM Saturday to 1 PM PST
Sunday. The Fire Weather Watch is no longer in effect. 

* WIND...Gusty north-northeast Santa Ana winds will develop
  Saturday evening and become strong overnight. The strongest
  gusts in coastal foothills and just below passes will reach 55  
  mph at times. 

* HUMIDITY...Relative humidity values will plummet Sunday into 
  the single digits.

* OUTLOOK...Conditions will quickly improve Sunday night as a low
  pressure system brings a humid onshore flow. 

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning should be avoided.

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.

&&

$$

jmb

weather.gov/sandiego
5 follow-up statements
448 
WWUS86 KSGX 101131
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
331 AM PST Sat Feb 10 2018

...RED FLAG WARNING FOR THE MOUNTAINS OF ORANGE...SAN
BERNARDINO...AND RIVERSIDE COUNTIES...THE INLAND EMPIRE...AND THE
SAN GORGONIO PASS FOR LATE TONIGHT THROUGH EARLY SUNDAY AFTERNOON
FOR STRONG GUSTY WINDS AND LOW HUMIDITY...

.Surface high pressure over the Great Basin will bring a period of
stronger and gusty north to northeast winds for late tonight
through Sunday morning along with low inland humidities. Winds
will diminish Sunday afternoon and humidities will recover rapidly
late Sunday night as onshore flow returns.

CAZ248-255>257-265-102245-
/O.CON.KSGX.FW.W.0002.180211T0600Z-180211T2100Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger Districts Of
The San Bernardino National Forest-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San Bernardino
National Forest-Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-San Gorgonio Pass Near Banning-
331 AM PST Sat Feb 10 2018

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING TO
1 PM PST SUNDAY FOR STRONG GUSTY WINDS AND LOW HUMIDITY...

* WIND...Areas of north to northeast winds 20 to 30 mph with gusts
  to 50 mph. Isolated gusts to 65 mph in the Inland Empire below
  the Cajon Pass and along and near the coastal slopes of the
  Santa Ana mountains.

* TIMING...The winds will develop late this evening...strengthen
  into Sunday morning...then diminish Sunday afternoon.

* LOCATION...Strongest winds along lower coastal mountain slopes
  and below passes and canyons. 

* HUMIDITY...Falling to 15 to 20 percent late tonight...and 5 to
  10 percent Sunday.

* OUTLOOK...Winds will diminish Sunday afternoon and a return of
  onshore flow will bring a rapid recovery of humidities late
  Sunday night along with a slight chance of showers.

* IMPACTS...Any fires that develop will likely spread rapidly.
  Outdoor burning should be avoided. The winds will make driving
  difficult...especially for motorists with high profile vehicles.
  Watch for broken tree limbs and other debris. 

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.

&&

$$

17
490 
WWUS86 KSGX 102129
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
129 PM PST Sat Feb 10 2018

...RED FLAG WARNING FOR THE MOUNTAINS OF ORANGE...SAN
BERNARDINO...AND RIVERSIDE COUNTIES...THE INLAND EMPIRE...AND THE
SAN GORGONIO PASS FOR LATE TONIGHT THROUGH EARLY SUNDAY AFTERNOON
FOR STRONG GUSTY WINDS AND LOW HUMIDITY...

CAZ248-255>257-265-110600-
/O.CON.KSGX.FW.W.0002.180211T0600Z-180211T2100Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger Districts Of
The San Bernardino National Forest-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San Bernardino
National Forest-Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-San Gorgonio Pass Near Banning-
129 PM PST Sat Feb 10 2018

...RED FLAG WARNING FOR THE MOUNTAINS OF ORANGE...SAN
BERNARDINO...AND RIVERSIDE COUNTIES...THE INLAND EMPIRE...AND THE
SAN GORGONIO PASS REMAINS IN EFFECT FROM 10 PM THIS EVENING TO
1 PM PST SUNDAY FOR STRONG GUSTY WINDS AND LOW HUMIDITY...

* WIND...Areas of north to northeast winds 20 to 30 mph with gusts
  to 50 mph. Isolated gusts to 60 mph in the Inland Empire below 
  the Cajon Pass and along and near the coastal slopes of the 
  Santa Ana mountains. 

* TIMING...The winds will develop late this evening...
  strengthen into Sunday morning...then diminish Sunday 
  afternoon. 

* LOCATION...Strongest winds along lower coastal mountain 
  slopes and below passes and canyons. 

* HUMIDITY...Falling to 15 to 20 percent late tonight...and 5 
  to 10 percent Sunday. 

* OUTLOOK...Winds will diminish Sunday afternoon and a return of
  onshore flow will bring a rapid humidity recovery Sunday night. 

* IMPACTS...Any fires that develop will likely spread rapidly.
  Outdoor burning should be avoided. The winds will make driving 
  difficult...especially for motorists with high profile vehicles.
  Watch for broken tree limbs and other debris. 

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...can contribute to extreme 
fire behavior.

&&

$$
552 
WWUS86 KSGX 110548
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
948 PM PST Sat Feb 10 2018

...RED FLAG WARNING FOR THE MOUNTAINS OF ORANGE...SAN 
BERNARDINO...AND RIVERSIDE COUNTIES...THE INLAND EMPIRE...AND THE 
SAN GORGONIO PASS THROUGH 1 PM SUNDAY...

.Surface high pressure building over the Great Basin will bring a
period of stronger and gusty north to northeast winds tonight through
Sunday morning along with low humidities. Winds will diminish 
Sunday afternoon and humidities will recover rapidly late Sunday 
night as onshore flow returns.

CAZ248-255>257-265-111400-
/O.CON.KSGX.FW.W.0002.180211T0600Z-180211T2100Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger Districts Of
The San Bernardino National Forest-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San Bernardino
National Forest-Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-San Gorgonio Pass Near Banning-
948 PM PST Sat Feb 10 2018

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 1 PM PST SUNDAY...

* WIND...Areas of north to northeast winds 20 to 30 mph with 
  gusts to 50 mph. Isolated gusts to 60 mph in the Inland Empire 
  below the Cajon Pass and along and near the coastal slopes of 
  the Santa Ana mountains. 

* TIMING...Tonight and through 1 PM Sunday. Winds diminishing 
  Sunday afternoon.

* LOCATION...Strongest winds along lower coastal mountain 
  slopes and below passes and canyons.

* HUMIDITY...Falling to 15 to 20 percent late tonight...and 5 
  to 10 percent Sunday.

* OUTLOOK...Northeast winds will diminish Sunday afternoon and a 
  return of onshore flow will bring a rapid humidity recovery 
  Sunday night. 

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning should be avoided. The winds will make 
  driving difficult...especially for motorists with high 
  profile vehicles. Watch for broken tree limbs and other 
  debris. 

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...can contribute to extreme
fire behavior.

&&

$$

Moede
702 
WWUS86 KSGX 111139
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
339 AM PST Sun Feb 11 2018

...RED FLAG WARNING FOR THE MOUNTAINS OF ORANGE...SAN
BERNARDINO...AND RIVERSIDE COUNTIES...THE INLAND EMPIRE...AND THE
SAN GORGONIO PASS THROUGH 1 PM TODAY...

.Moderate offshore flow will bring gusty north to northeast winds
and low humidities through this morning along and near coastal
mountain slopes of San Bernardino...Riverside...and Orange
Counties with critical fire weather conditions. Onshore flow will
return during the afternoon with humidities beginning to recover
by late afternoon. Humidities will recover more rapidly tonight 
as onshore flow strengthens. 

CAZ248-255>257-265-112100-
/O.CON.KSGX.FW.W.0002.000000T0000Z-180211T2100Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger Districts Of
The San Bernardino National Forest-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San Bernardino
National Forest-Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-San Gorgonio Pass Near Banning-
339 AM PST Sun Feb 11 2018

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 1 PM PST THIS
AFTERNOON FOR STRONG GUSTY WINDS AND LOW HUMIDITY...

* WIND...Areas of north to northeast winds 20 to 30 mph with gusts
  to 45 mph. Isolated gusts to 55 mph in the Inland Empire below 
  the Cajon Pass and along and near the coastal slopes of the 
  Santa Ana mountains. 

* TIMING...Strongest winds from after sunrise through mid morning
  with with lowest humidities after mid morning.

* LOCATION...Strongest winds along lower coastal mountain 
  slopes and below passes and canyons.

* HUMIDITY...Falling to 15 to 25 percent around sunrise...and
  around 10 percent by late morning.

* OUTLOOK...Northeast winds will diminish by early this afternoon.
  Weak onshore flow will develop during afternoon with humidities
  beginning to recover by late afternoon.

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning should be avoided. The winds will make 
  driving difficult...especially for motorists with high 
  profile vehicles. Watch for broken tree limbs and other 
  debris. 

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...can contribute to extreme
fire behavior.

&&

$$

17
347 
WWUS86 KSGX 112053
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
1253 PM PST Sun Feb 11 2018


CAZ248-255>257-265-112200-
/O.EXP.KSGX.FW.W.0002.000000T0000Z-180211T2100Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
San Bernardino County Mountains-
Including The Mountain Top And Front Country Ranger Districts Of
The San Bernardino National Forest-Riverside County Mountains-
Including The San Jacinto Ranger District Of The San Bernardino
National Forest-Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-San Gorgonio Pass Near Banning-
1253 PM PST Sun Feb 11 2018

...RED FLAG WARNING WILL EXPIRE AT 1 PM PST THIS AFTERNOON FOR
STRONG GUSTY WINDS AND LOW HUMIDITY...

Reporting stations across the forecast area are no longer 
reporting critical fire weather conditions. Relative humidity 
will remain low through late afternoon, but winds will continue 
to subside. A Wind Advisory has been issued for the San Bernardino
Mts and high desert areas for later this evening due to 
increasing south winds, which will bring much higher humidity 
overnight.

$$

jad

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.