Alert archive / California / Red Flag Warnings in 2021

Red Flag Warning 2, NWS San Diego, CA

January 18, 20214 counties in California

NWS San Diego, CA issued this red flag warning at Jan 18, 2021, 9:50 AM PST for 4 counties in California. It took effect at Jan 18, 2021, 10:00 PM PST. It was in force for 24 hr. 53 reports 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
Jan 18, 2021, 9:50 AM PST (17:50 UTC)
In effect from
Jan 18, 2021, 10:00 PM PST
Expired
Jan 19, 2021, 10:00 PM PST
In force
24 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 17:50 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
Jan 19, 4:00 AM PSTWILDFIRE4 Sw Mecca, CA72 FIRE BURNED 43 ACRES NEAR AVE 72 AND PIERCE ST, SOUTH OF OASIS. BEGAN DURING ONSET OF SANTA ANA WINDS.
Jan 19, 9:16 AM PSTNON-TSTM WND DMG4 Nw Fontana, CABIG RIG ON SIDE ON I-210. ANOTHER ON EDGE OF ROAD. NORTH WIND GUSTS 50 TO 60 MPH AT NEARBY SCE SITES.
Jan 19, 9:17 AM PSTNON-TSTM WND DMG4 Se Devore, CASEMI TRUCK OVERTURNED BLOCKING AT LEAST ONE LANE OF I-215 SOUTH OF PALM AVE DUE TO WINDS PER CHP. SCE WEATHER STATION NEARBY (SE600) REPORTED NNE WINDS GUSTING TO 56 MPH AT 0910 AM.
Jan 19, 9:26 AM PSTNON-TSTM WND DMG2 N Rancho Cucamonga, CASIGN DAMAGED AND HANGING BUT NOT ON FREEWAY. NORTH WINDS 45 TO 55 MPH AT THE TIME.
Jan 19, 9:29 AM PSTNON-TSTM WND DMG3 Sse Rancho Cucamonga, CASEMI OVERTURNED DUE TO HIGH WINDS AT I-15 AND I-10. WINDS ARE RAPIDLY INCREASING IN INLAND EMPIRE. SCE STATIONS NEARBY GUSTING TO AROUND 50 MPH.
Jan 19, 9:29 AM PSTNON-TSTM WND DMG4 Ene Rancho Cucamonga, CABIG RIG ON SIDE, CAB IN LANES BUT DETACHED TRAILER DOWN BANK AT I-210 AND I-15 SPLIT. WIND GUSTS OVER 50 MPH AT NEARBY SCE SITES SUCH AS SUMMIT AVE.
Jan 19, 10:23 AM PSTNON-TSTM WND DMG3 W Fontana, CAPOWERLINE DOWN ON ROAD. SCE WIND GUSTS 60 MPH JUST NORTH OF THIS AREA.
Jan 19, 10:28 AM PSTNON-TSTM WND DMG4 Nne Rialto, CAPOLE DAMAGE AND WIRES HANGING. WIND GUSTS 50 MPH PER SCE SITES.
Jan 19, 11:05 AM PSTNON-TSTM WND DMG6 Ene Ramona, CACHP REPORT OF A LARGE TREE DOWN ON HIGHWAY 78 AT RANCHO SANTA TERESA DRIVE. THIS LOCATION IS BETWEEN RAMONA AND SANTA YSABEL.
Jan 19, 11:25 AM PSTNON-TSTM WND DMG1 Sse Ramona, CACHP REPORT OF A TREE THAT FELL ON POWER LINES IN RAMONA ON HANSON LN. POWER LINES ARE DOWN ACROSS THE ROAD. WIND GUSTS OF 61 TO 64 MPH WERE OBSERVED ON A RIDGE JUST EAST OF THIS LOCATION, WHILE WIND GUSTS NEARBY AT A SIMILAR ELEVATION WERE AROUND 30 MPH.
Jan 19, 11:39 AM PSTNON-TSTM WND DMG2 Ene Ramona, CALARGE TREE DOWN BLOCKING THE EASTBOUND LANE OF HIGHWAY 78 AT RAMONA VIEW CT. NEARBY OBSERVATIONS REPORTED GUSTS AROUND 50 MPH, UP TO 67 MPH ON A RIDGE JUST SOUTH OF THIS LOCATION.
Jan 19, 11:57 AM PSTNON-TSTM WND DMG1 Nne Ramona, CASOCIAL MEDIA REPORT OF A TREE DOWN ON AQUA LANE NEAR THE RAMONA COMMUNITY CENTER. NEARBY WIND OBSERVATIONS SHOWED GUSTS OF 40 TO 45 MPH.
Jan 19, 12:00 PM PSTNON-TSTM WND DMG1 Nw Devore, CADEVORE HEIGHTS. PUBLIC SHARED PHOTO OF TREE DOWNED THAT LANDED AND BROKE A FENCE. WINDS ARE GUSTING 55 TO 65 MPH IN THIS AREA SINCE 7 AM.
Jan 19, 12:00 PM PSTNON-TSTM WND DMG3 Se Calimesa, CATREE FELL ON POWERLINE AND SPARKED FIRE. SCE STATIONS WIND GUSTS 45 MPH.
Jan 19, 12:02 PM PSTNON-TSTM WND DMG5 W Pine Valley, CAREPORT OF OVERTURNED SEMI ON EASTBOUND I-8 JUST EAST OF HIGHWAY 79. WIND OBSERVATIONS IN THIS AREA SHOWED GUSTS OF 45 TO 55 MPH. GUSTS SLIGHTLY WEST OF THIS LOCATION WERE AS HIGH AS 66 MPH.
Jan 19, 12:04 PM PSTNON-TSTM WND DMG10 Nnw Aguanga, CATREE FELL ON ROADWAY. SAGE RD / E BENTON RD. WEBER VALLEY SCE GUST 44 MPH.
Jan 19, 12:10 PM PSTNON-TSTM WND GST 593 Wnw Riverside, CAMESONET STATION SE851 JURUPA VALLEY (SCE851).
Jan 19, 12:22 PM PSTNON-TSTM WND DMGDulzura, CAREPORT OF LARGE TREE LIMB DOWN ON HIGHWAY 94 NEAR LUCKY SIX TRUCK TRAIL IN DULZURA. WIND OBSERVATIONS NEARBY REPORTED GUSTS OF 45 TO 50 MPH.
Jan 19, 12:24 PM PSTNON-TSTM WND DMG1 Wsw Ramona, CACHP REPORT OF A TREE DOWN ON THE NORTHBOUND LANE OF HUNTER STREET NEAR RAYMOND AVE IN RAMONA. NEARBY OBSERVATIONS REPORTED WIND GUSTS AROUND 30 MPH.
Jan 19, 12:40 PM PSTNON-TSTM WND DMGRamona, CACHP REPORT OF A TRAFFIC SIGNAL DOWN OH HIGHWAY 67/MAIN ST AT 14TH ST IN RAMONA. WIND OBSERVATIONS NEARBY REPORTED GUSTS OF 35 TO 40 MPH.
Jan 19, 12:58 PM PSTNON-TSTM WND DMG4 Ese Ramona, CACHP REPORT OF A DOWNED TREE BLOCKING THE EASTBOUND LANES OF SAN VICENTE RD BETWEEN GUNN STAGE RD AND RAMONA OAKS RD IN SAN DIEGO COUNTRY ESTATES. WIND OBSERVATIONS NEARBY REPORTED GUSTS OF 40 TO 50 MPH.
Jan 19, 1:09 PM PSTNON-TSTM WND DMG2 Wnw Ramona, CACHP REPORT OF TREE DOWN BLOCKING BOTH LANES OF SUMMER GLEN RD NEAR OLIVE ST IN RAMONA. WINDS OBSERVATIONS NEARBY SHOWED GUSTS AROUND 40 MPH.
Jan 19, 1:10 PM PSTNON-TSTM WND DMG3 Ssw San Juan Capistra, CALARGE TREE DOWN ON ROADWAY. WIND GUST ON LIMITED WEATHER STATIONS AT 30 MPH.
Jan 19, 1:24 PM PSTNON-TSTM WND DMG2 Wsw Bonita, CATREE DOWN BLOCKING THE HILL RD IN BONITA. NEARBY WIND OBSERVATIONS OF 30 TO 40 MPH.
Jan 19, 1:24 PM PSTNON-TSTM WND DMG2 Wsw Bonita, CADOWNED TREE ON ROAD - THE HILL ROAD AND GREVILLEA ROAD IN CHULA VISTA. WINDS GUSTING TO 40 MPH NEARBY (MIGSD) AT TIME OF CHP REPORT.
Jan 19, 1:27 PM PSTNON-TSTM WND DMG4 Nw San Jacinto, CAOVERTURNED BIG RIG BLOCKING SEVERAL LANES PER CHP. WINDS GUSTING 50-60 MPH AT NEARBY SCE SITES AT THE TIME. SR79 & GILMAN SPRINGS RD.
Jan 19, 2:08 PM PSTNON-TSTM WND DMG6 S Riverside, CAPOWER POLE LEANING 45 DEGREES. ROAD CLOSURE IN WOODCREST. WASHINGTON ST / HERMOSA DR WITH EAST WIND GUSTS 35 MPH AT RAWS.
Jan 19, 3:30 PM PSTNON-TSTM WND GST 677 Ene Alpine, CAMESONET STATION NDCSD NORTH DESCANSO (SDGE).
Jan 19, 3:37 PM PSTNON-TSTM WND DMG5 Nw Pine Valley, CAFALLEN TREE BLOCKING LANE AT HWY 79 AND CAMINO DE TIERRA, PER CHP. WINDY GUSTING TO 46 MPH AT NEARBY SDGE DESCANSO WEATHER STATION.
Jan 19, 3:39 PM PSTNON-TSTM WND DMG4 Nne Rialto, CAPOWER POLE SNAPPED AND BROUGHT DOWN WIRES ON ROAD, BLATE ST AND OTONO CT, PER CHP. WINDS AT VARIOUS NEARBY STATIONS GUSTING TO AROUND 40 MPH AT THE TIME.
Jan 19, 3:40 PM PSTNON-TSTM WND GST 695 Ene Alpine, CAMESONET STATION VGDSD VIEJAS GRADE (SDGE) IMPACTS I-8.
Jan 19, 3:40 PM PSTNON-TSTM WND DMG2 Sse Yorba Linda, CALARGE TREE (PINE) DOWN ON ROAD. WIND GUSTS 40-45 MPH NEARBY. JUST NORTH OF HIGHWAY 91.
Jan 19, 3:47 PM PSTNON-TSTM WND DMG3 Nw Ramona, CADOWNED TREE BLOCKING LANES ON HWY 78 BY INDIAN OAKS RD, PER CHP. WINDS GUSTING 40-50 MPH IN VICINITY AT THE TIME.
Jan 19, 4:28 PM PSTNON-TSTM WND DMG5 Wnw Pine Valley, CALARGE TREE DOWN IN ROADWAY, HWY 79 AT VIEJAS BLVD. NEARBY OBSERVATION REPORTS GUSTS TO 56 MPH.
Jan 19, 4:45 PM PSTNON-TSTM WND DMG4 Nw San Jacinto, CAANOTHER SEMI OVERTURNED BY WIND. CHP REQUESTING MORE SIGNAGE TO ALERT HIGH PROFILE VEHICLES. EARLY HAD A SIG ALERT ON HIGHWAY 79. SCE SITE AT RAMONA AND 79 IS GUSTING 62 TO 71 MPH PAST 2 HOURS.
Jan 19, 4:50 PM PSTNON-TSTM WND GST 656 Se Alpine, CAMESONET STATION JVRSD JAPATUL VALLEY (SDGE).
Jan 19, 5:10 PM PSTNON-TSTM WND GST 829 Ssw Julian, CAMESONET STATION SILSD SILL HILL (SDGE) - NORMALLY THE WINDIEST LOCATION IN SAN DIEGO COUNTY.
Jan 19, 5:40 PM PSTNON-TSTM WND GST 713 Nw San Jacinto, CAMESONET STATION SE657 SAN JACINTO (SCE657). SEVERAL SEMIS OVERTURNED ON HIGHWAY 79 INCLUDING A 2 SIG ALERT ISSUED.
Jan 19, 5:52 PM PSTNON-TSTM WND GST 765 E Alpine, CAMESONET STATION ANEC1 ALPINE RAWS. THIS IS A HIGH WIND GUST EVEN FOR THIS LOCATION. IMPACTS I-8.
Jan 19, 5:53 PM PSTNON-TSTM WND GST 531 Ese Ontario, CAASOS STATION KONT ONTARIO AIRPORT.
Jan 19, 6:00 PM PSTNON-TSTM WND GST 613 N Yorba Linda, CAMESONET STATION SE122 OLINDA VILLAGE 1 (SCE122) - TREE DAMAGE REPORTED IN YORBA LINDA.
Jan 19, 6:00 PM PSTNON-TSTM WND GST 705 Sw Devore, CAMESONET STATION SE157 FONTANA (SCE157) - SEVERAL SEMIS OVERTURNED ON I-10 AND I-15 TUESDAY MORNING AND EARLY EVENING.
Jan 19, 6:00 PM PSTNON-TSTM WND GST 834 N Rancho Cucamonga, CAMESONET STATION SE216 DEER CANYON (SCE216). SEVERAL SEMIS OVERTURNED ON I-15 TO 210.
Jan 19, 6:10 PM PSTNON-TSTM WND DMG5 Sw Devore, CA2 BIG RIGS FLIPPED BY WIND AND ON ITS SIDE ON I-15 NORTH OF I-210. LYTLE CREEK SCE WIND GUSTS 55 TO 70 MPH PAST HOUR. I-15 SOUTH AT DUNCAN CANYON RD AND AT I-15 NORTH AT SIERRA AVE.
Jan 19, 6:14 PM PSTNON-TSTM WND DMG5 S Mt Baldy, CAAT LEAST 2 TREES DOWNED AT 2343 PARK BLVD. DEER CANYON SCE REACHED 78 MPH. OTHER SITES 50-60 MPH PAST HOUR. WEST POINT SCE GUSTING TO 50 MPH NEAR THIS LOCATION NORTH OF I-210. SAN ANTONIO HEIGHTS.
Jan 19, 6:20 PM PSTNON-TSTM WND DMG3 Nw Fontana, CAWIND BLEW MOTORCYCLE INTO BARRIER ON I-210 WEST. SCE SUMMIT AVE GUST TO 59 MPH.
Jan 19, 6:20 PM PSTNON-TSTM WND DMG4 E Ramona, CAMEDIUM SIZE TREE DOWN IN ROAD. GUNN STAGE RD AND WATT RD. WIND GUSTS 45 TO 55 MPH ON SEVERAL SDGE SITES IN SAN DIEGO COUNTY ESTATES.
Jan 19, 6:45 PM PSTNON-TSTM WND GST 899 Wnw Santa Ysabel, CAMESONET STATION HP016 BIG BLACK MOUNTAIN (HPWREN) AT 4000 FEET.
Jan 19, 7:00 PM PSTNON-TSTM WND GST 694 Nnw Rancho Cucamonga, CAMESONET STATION SE217 RANCHO CUCAMONGA (SCE217).
Jan 19, 7:00 PM PSTNON-TSTM WND GST 782 E Ramona, CAMESONET STATION SOSSD SIMON OPEN SPACE NEAR SAN DIEGO ESTATES AND JUST EAST OF RAMONA.
Jan 19, 7:08 PM PSTNON-TSTM WND GST 685 Ene Yorba Linda, CAMESONET STATION CQHC1 CHINO HILLS RAWS.
Jan 19, 7:50 PM PSTNON-TSTM WND DMG4 Ssw Devore, CASIG ALERT AT 825 PM FOR ALL LANES CLOSED I15 SOUTH AT SIERRA AVE. SEMI OVERTURNED BY WIND THEN HIT BY VEHICLES. DRIVER BROKE WINDOW TO GET OUT. WIND GUSTS 50 TO 55 MPH AT SCE SITES.
Jan 19, 8:00 PM PSTSNOW 34 S Big Bear City, CABIG BEAR RESORT REPORTED 3 TO 5 INCHES NEW SNOW. BIG BEAR YARD 3 INCHES FROM 2 TO 6 PM. SEVERAL SPIN OUTS AND CHAIN CONTROL WAS SET UP ON HIGHWAY 38 AND 18.

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

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 5.8 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 2021-01-18Temperature 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 2021-01-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.193958Sfc1 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
3778 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

777 
WWUS86 KSGX 181750
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
950 AM PST Mon Jan 18 2021

CAZ248-257-554-190200-
/O.UPG.KSGX.FW.A.0001.210119T1400Z-210120T0400Z/
/O.NEW.KSGX.FW.W.0002.210119T0600Z-210120T0600Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-Orange County Inland Areas-
950 AM PST Mon Jan 18 2021

...RED FLAG WARNING IN EFFECT FROM 10 PM THIS EVENING TO 10 PM
PST TUESDAY FOR STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND
EMPIRE, SANTA ANA MOUNTAINS, AND INLAND ORANGE COUNTY...

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

* WIND...Areas of northeast winds 25 to 35 mph with gusts 50 mph.
  Isolated gusts to 70 mph in the Inland Empire below the Cajon 
  and San Gorgonio Passes, and near the coastal foothills of the 
  Santa Ana Mountains. 

* HUMIDITY...15 to 20 percent.

* TIMING...The strongest winds will be from late tonight into 
  Tuesday with the lowest humidity on Tuesday.

* OUTLOOK...Humidity will increase somewhat Tuesday night and 
  Wednesday with the winds more easterly and not quite as 
  strong for Tuesday night into Wednesday.

* IMPACTS...Any fires that develop will likely spread rapidly.
  Outdoor burning is not recommended.

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.

&&

$$

APR
4 follow-up statements
767 
WWUS86 KSGX 190526
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
926 PM PST Mon Jan 18 2021
FOR STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND
EMPIRE, SANTA ANA MOUNTAINS, AND INLAND ORANGE COUNTY...

CAZ248-257-554-191330-
/O.CON.KSGX.FW.W.0002.210119T0600Z-210120T0600Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-Orange County Inland Areas-
926 PM PST Mon Jan 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 PM PST TUESDAY FOR
STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND EMPIRE, SANTA 
ANA MOUNTAINS, AND INLAND ORANGE COUNTY...

* WIND...Areas of northeast winds 25 to 35 mph with gusts 50 
  mph.Isolated gusts to 70 mph in the Inland Empire below the 
  Cajon and San Gorgonio Passes, and near the coastal foothills 
  of the Santa Ana Mountains. 

* HUMIDITY...15 to 20 percent.

* TIMING...The strongest winds will be from late tonight into 
  Tuesday with the lowest humidity on Tuesday.

* OUTLOOK...Humidity will increase somewhat Tuesday night and 
  Wednesday with the winds more easterly and not quite as 
  strong for Tuesday night into Wednesday.

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended.

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.

&&

$$
431 
WWUS86 KSGX 191249
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
449 AM PST Tue Jan 19 2021

FOR STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND EMPIRE,
SANTA ANA MOUNTAINS, AND INLAND ORANGE COUNTY...

CAZ248-257-554-192330-
/O.CON.KSGX.FW.W.0002.000000T0000Z-210120T0600Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-Orange County Inland Areas-
449 AM PST Tue Jan 19 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 PM PST THIS
EVENING FOR STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND 
EMPIRE...SANTA ANA MOUNTAIN...AND INLAND ORANGE COUNTY...

* WIND...Areas of northeast winds 25 to 35 mph with gusts to 55
  mph. Isolated gusts to 75 mph in the Inland Empire below the 
  Cajon and San Gorgonio Passes, and near the coastal foothills of
  the Santa Ana Mountains. 

* HUMIDITY...Lowest humidity of 15 to 20 percent.

* TIMING...The strongest winds and lowest humidity will be from
  late morning through the afternoon. 

* OUTLOOK...Humidity will increase tonight and Wednesday with the
  winds more easterly and not quite as strong for tonight and 
  Wednesday.

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended.

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
945 
WWUS86 KSGX 192249
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
249 PM PST Tue Jan 19 2021

CAZ248-257-554-200600-
/O.CON.KSGX.FW.W.0002.000000T0000Z-210120T0600Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-Orange County Inland Areas-
249 PM PST Tue Jan 19 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 PM PST THIS
EVENING FOR STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND
EMPIRE...SANTA ANA MOUNTAIN...AND INLAND ORANGE COUNTY...

* WIND...Areas of northeast winds 25 to 35 mph with gusts to 55 
  mph. Isolated gusts to 75 mph in the Inland Empire below the 
  Cajon and San Gorgonio Passes, and near the coastal foothills 
  of the Santa Ana Mountains. 

* HUMIDITY...Lowest humidity of 15 to 20 percent.

* TIMING...The strongest winds will occur through early this
  evening.

* OUTLOOK...Humidity will increase tonight and Wednesday with 
  the winds more easterly and not quite as strong for tonight 
  and Wednesday.

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended.

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.

&&

$$
Gregoria
770 
WWUS86 KSGX 200540
RFWSGX

URGENT - FIRE WEATHER MESSAGE
National Weather Service San Diego CA
940 PM PST Tue Jan 19 2021

CAZ248-257-554-200645-
/O.EXP.KSGX.FW.W.0002.000000T0000Z-210120T0600Z/
San Bernardino and Riverside County Valleys - The Inland Empire-
Santa Ana Mountains-
Including The Trabuco Ranger District of the Cleveland National
Forest-Orange County Inland Areas-
940 PM PST Tue Jan 19 2021

...RED FLAG WARNING WILL EXPIRE AT 10 PM PST THIS EVENING FOR
STRONG GUSTY WINDS AND LOW HUMIDITY FOR THE INLAND
EMPIRE...SANTA ANA MOUNTAINS...AND INLAND ORANGE COUNTY...

Relative humidity has risen well above critical levels, but strong
and gusty northeast winds will continue through Wednesday.

$$
10

The office that day

Everything else NWS San Diego, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 18, 12:40 PM PSTSmall Craft AdvisorySGX57 hr
Jan 18, 12:42 PM PSTHigh Wind WarningSGXOrange, Riverside, San Bernardino, San Diego57 hr

Nearby

Red Flag Warnings in California, 2021Every red flag warning in 2021

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.