California, 2009

High Wind in California, May 12 to 13, 2009

May 12 to 13, 2009 · NWS LOX · 2 events in 2 counties and zones

A strong northerly pressure gradient produced another round of gusty north winds in the mountains of Ventura and Los Angeles counties. Wind gusts as high as 79 MPH were reported.

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS LOX wrote it up.

A strong northerly pressure gradient produced another round of gusty north winds in the mountains of Ventura and Los Angeles counties. Wind gusts as high as 79 MPH were reported.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Los Angeles, CA wrote its last area forecast discussion before the first event at May 12, 7:45 PM PST, 8 minutes earlier.

Area forecast discussion, May 12, 7:45 PM PST, 8 minutes before
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
845 PM PDT TUE MAY 12 2009

.UPDATE...WINDS ARE PICKING UP THROUGH THE I-5 CORRIDOR AND RIDING
NEAR DAMAGING LEVELS THIS EVENING. WHITAKER PEAK AND SANDBERG ARE
GUSTING INTO THE 50 MPH RANGE CURRENTLY WELL AHEAD THE MOST
FAVORABLE SURFACE PRESSURE AND 850 MB THERMAL GRADIENTS. WHILE
WINDS ACROSS SOUTHERN SANTA BARBARA COUNTY HAVE BEEN
LIGHTER...KSBA-KSMX SURFACE PRESSURE GRADIENTS...NEAR 4.1 MB OUT
OF THE NORTH...CONTINUE TO TREND OFFSHORE FOR SOUTHERN SANTA
BARBARA COUNTY. IN ADDITION...THE WINDS WILL STRENGTHEN LATER
TONIGHT WHEN THE BEST WINDS ALOFT AND 850 MB THERMAL GRADIENTS
TIGHTEN ACROSS THE AREA. THE WINDS WILL LIKELY SWITCH TO THE
NORTHEAST OVER SOUTHERN SANTA BARBARA COUNTY AND INCREASE TO
WARNING LEVELS. WARNINGS WILL BE LEFT IN TACT AT THIS POINT AND
THE ADVISORY WILL BE ALLOWED TO EXPIRE FOR THE CENTRAL COAST.

WITH THE NORTHERLY GRADIENT DEVELOPING...A WARMING TREND WILL
DEVELOP OVER THE AREA AS THE MARINE LAYER INVERSION THINS TONIGHT.
THE MARINE DEPTH HAS THINNED TO AROUND 1100 FEET FROM THE LATEST
KLAX ACARS SOUNDINGS. BASED UPON THE LATEST NAM-WRF AND 13-KM RUC
SOLUTIONS...BOTH MODEL SOLUTIONS ARE INDICATING THAT THE MARINE
LAYER MAY CREEP BACK INTO THE VENTURA COUNTY COASTAL PLAIN. AN
UPDATE WILL OCCUR TO BRING THE MARINE LAYER SLIGHTLY MORE NORTH
THAN THE CURRENT PACKAGE.

WEDNESDAY AND WEDNESDAY NIGHT LOOKS TO CONTINUE TO BE WINDY FOR
THE SAME AREAS...WITH THE POTENTIAL FOR DAMAGING GUSTS. THE NAM-
WRF IS STARTING TO TREND WEAKER WITH THE THERMAL PATTERN...BUT
THE MODEL SOLUTION IS TRENDING STRONGER WITH THE SURFACE PRESSURE
PATTERN. WITH STILL 40 TO 45 KNOTS WINDS PRESENT AT 850 MB IN THE
NAM-WRF...CONFIDENCE STILL EXISTS FOR THE POTENTIAL FOR DAMAGING
WINDS GUSTS INTO THURSDAY. UPDATES TO THE WIND HEADLINES WILL BE
OUT SHORTLY.

&&

.PREV DISCUSSION... /ISSUED 510 PM PDT TUE MAY 12 2009/

SHORT TERM...AN UPPER RIDGE SW OF THE FORECAST AREA WILL KEEP A
BROAD W TO WNW FLOW ALOFT OVER THE REGION THRU THU. THE UPPER
RIDGE WILL BUILD NORTHWARD OFF THE COAST BY FRI WHICH WILL TURN
THE UPPER LEVEL FLOW MORE NORTHERLY. DRY WEATHER WITH MOSTLY CLEAR
SKIES IS FORECAST TO CONTINUE OVER THE FORECAST AREA THRU
FRI...ALTHO PATCHY LOW CLOUDS AND FOG MAY AFFECT THE CENTRAL COAST
AND L.A. COUNTY COAST AT TIMES. A DECENT NORTHERLY GRADIENT WILL
PERSIST WITH GUSTY NW TO N WINDS PERSISTING IN THE MOUNTAINS AND
SBA S COAST MAINLY EACH AFTERNOON AND EVENING THRU THU NIGHT.
STRONG AND GUSTY W TO NW WINDS WILL ALSO PREVAIL AFTERNOONS AND
EVENING THRU THU NIGHT FOR THE ANTELOPE VALLEY AND ALONG THE
CENTRAL COAST. IT LOOKS LIKE WIND ADVISORIES OR HIGH WIND WARNINGS
WILL BE NEEDED OVER THIS REGION AT TIMES THRU THU NIGHT.

LONG TERM...MEDIUM RANGE MODELS IN GENERAL AGREEMENT AT LEAST
THRU THE WEEKEND WITH THE UPPER RIDGE EXPECTED TO BUILD INLAND
OVER CA AND INTO THE CENTRAL GREAT BASIN SAT THRU SUN. THE UPPER
RIDGE WILL BRING WEAK OFFSHORE FLOW NIGHT AND MORNING HOURS AND
MUCH ABOVE NORMAL TEMPS TO THE FORECAST AREA FOR INLAND AREAS.
HIGHS ARE EXPECTED TO SOAR WELL INTO THE 90S TO NEAR 100 SAT AND
SUN FOR THE VALLEYS...FOOTHILLS AND LOWER MOUNTAIN ELEVATIONS.
TEMPS WILL BE COOLER BUT STILL NEAR OR A FEW DEGREES ABOVE NORMAL
FOR THE COAST DURING THE PERIOD. THE EC THEN BUILDS THE UPPER HI
INTO OREGON MON AND TUE WHILE THE GFS BREAKS DOWN THE UPPER RIDGE
AS AN UPPER TROF MOVES INTO THE PAC NW. AT THE SAME TIME THE GFS
FORECASTS AN UPPER LOW TO DEVELOP WELL SW OF THE DISTRICT MON AND
APPROACH THE REGION BY TUE. LEANED MORE TOWARD THE GFS SOLUTION
BUT OVERALL DRY CONDITIONS SHOULD PERSIST FOR EITHER
SOLUTION...WITH SOME MID AND HI LEVEL MOISTURE POSSIBLY MOVING IN
BY TUE FOR PARTLY CLOUDY SKIES. TEMPS SHOULD REMAIN WELL ABOVE
NORMAL MON THEN FALL TO NEAR NORMAL OR SLIGHTLY ABOVE NORMAL FOR
TUE.

&&

.AVIATION...13/0010Z.
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD AT SITES NORTH OF
KOXR. SOUTH OF KOXR...IFR TO MVFR CONDITIONS ARE EXPECTED AT THE
COASTAL TERMINALS AFTER 07Z TONIGHT. VFR CONDITIONS SHOULD REDEVELOP
AT COASTAL TERMINALS BETWEEN 16Z AND 18Z WEDNESDAY. THERE IS A
CHANCE LIFR TO IFR CONDITIONS AT KBUR...WITH A SLIGHT CHANCE AT KSBA
AND KVNY. OTHERWISE...MODERATE TO STRONG LOW-LEVEL WIND SHEAR ISSUES
WILL AFFECT KSBA...KBUR...AND KVNY THIS EVENING.

KLAX...VFR CONDITIONS ARE EXPECTED THROUGH 07Z TONIGHT WITH IFR TO
MVFR CONDITIONS SPREADING INLAND. VFR CONDITIONS SHOULD REDEVELOP
BETWEEN 16Z AND 18Z WEDNESDAY.

KBUR...VFR CONDITIONS WITH MODERATE LOW-LEVEL WIND SHEAR AND
TURBULENCE ARE EXPECTED THROUGH 11Z TONIGHT. MVFR CONDITIONS SHOULD
DEVELOP BETWEEN 12Z AND 18Z ON WEDNESDAY...WITH VFR CONDITIONS
REDEVELOPING.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
RED FLAG WARNING (SEE LAXRFWLOX).
GALE WARNING (SEE LAXMWWLOX).
WIND ADVISORY (SEE LAXNPWLOX).

&&

HALL/SIRARD

WWW.WEATHER.GOV/LOSANGELES
Hazardous weather outlook, May 12, 1:06 PM PST, 6 hours 47 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
206 PM PDT TUE MAY 12 2009

CAZ034>041-044>046-051>054-059-087-088-547-548-131300-
SAN LUIS OBISPO COUNTY CENTRAL COAST-
SANTA BARBARA COUNTY CENTRAL COAST-SANTA YNEZ VALLEY-
SAN LUIS OBISPO COUNTY INTERIOR VALLEYS-CUYAMA VALLEY-
SANTA BARBARA COUNTY SOUTH COAST-VENTURA COUNTY COAST-
LOS ANGELES COUNTY COAST INCLUDING DOWNTOWN LOS ANGELES-
VENTURA COUNTY INTERIOR VALLEYS-VENTURA COUNTY COASTAL VALLEYS-
SANTA MONICA MOUNTAINS RECREATIONAL AREA-
SAN LUIS OBISPO COUNTY MOUNTAINS-
SANTA BARBARA COUNTY MOUNTAINS-VENTURA COUNTY MOUNTAINS-
LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE-
ANTELOPE VALLEY-CATALINA ISLAND-SANTA CLARITA VALLEY-
LOS ANGELES COUNTY SAN FERNANDO VALLEY-
LOS ANGELES COUNTY SAN GABRIEL VALLEY-
206 PM PDT TUE MAY 12 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE... THROUGH TONIGHT

VERY STRONG WINDS WILL CERATE HAZARDS IN THE MOUNTAINS AND DESERTS
THROUGH TONIGHT. ADDITIONALLY THE WINDS WILL CREATE HAZARDOUS
AREAS OF QUARTER MILE VISIBILITIES IN BLOWING SAND AND DUST. STRONG
AND DAMAGING WINDS ARE EXPECTED IN THE SANTA BARBARA COUNTY
MOUNTAINS AND SOUTH COAST TONIGHT. GUSTY WINDS WILL AFFECT THE
CENTRAL COAST THIS AFTERNOON AND EVENING. DANGEROUS FIRE WEATHER
CONDITIONS WILL AFFECT THE SANTA YNEZ RANGE AND THE SOUTH COAST OF
SANTA BARBARA COUNTY FROM LATE TODAY THROUGH TONIGHT DUE TO GUSTY
WINDS AND LOW RELATIVE HUMIDITY. MARINERS WILL FACE A HAZARDOUS GALE
ACROSS ALL THE OUTER WATERS AT LEAST THROUGH TONIGHT.

* HIGH WIND WARNING..........SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

* RED FLAG WARNING...........SEE WWUS86 KLOX - RFWLOX FOR DETAILS *

* WIND ADVISORY..............SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

* GALE WARNING...............SEE WHUS76 KLOX - MWWLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

DANGEROUS WIND GUSTS TO NEAR 60 MILES PER HOUR WILL BE POSSIBLE AT
TIMES IN THE MOUNTAINS...THE SANTA BARBARA COUNTY SOUTH COAST...AND
ANTELOPE VALLEY THROUGH THURSDAY EVENING OTHERWISE ADVISORY LEVEL
WINDS CAN BE EXPECTED BELOW AND THROUGH PASSES AND CANYONS. LOW
HUMIDITIES WILL COMBINE WITH THE WINDS TO PRODUCE DANGEROUS FIRE
WEATHER CONDITIONS FOR THE SANTA BARBARA COUNTY MOUNTAINS AND SOUTH
COAST THROUGH THURSDAY MORNING. MARINERS WILL FACE A HAZARDOUS GALE
ACROSS ALL THE OUTER WATERS. SIGNIFICANT HEAT WILL AFFECT THE AREA
OVER THE WEEKEND.

* RED FLAG WARNING...........SEE WWUS86 KLOX - RFWLOX FOR DETAILS *

* WIND ADVISORY..............SEE WWUS76 KLOX - NPWLOX FOR DETAILS *

* GALE WARNING...............SEE WHUS76 KLOX - MWWLOX FOR DETAILS *

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

SIRARD

In the hours before

Local storm report, May 12, 5:02 PM PST, 2 hours 51 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OXNARD CA
602 PM PDT TUE MAY 12 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1252 AM     NON-TSTM WND GST 6 NE PYRAMID LAKE       34.74N 118.72W
05/12/2009  M61.00 MPH       LOS ANGELES        CA   ASOS

            SUSTAINED NORTHWEST WINDS 40 MPH AT SANDBERG...ELEVATION
            4521 FEET.

1137 AM     NON-TSTM WND GST 6 SSW CASTAIC LAKE      34.57N 118.74W
05/12/2009  M57.00 MPH       LOS ANGELES        CA   OTHER FEDERAL

            SUSTAINED NORTHWEST WINDS OF 25 MPH AT WHITAKER
            PEAK...ELEVATION 4120 FEET.

0438 PM     NON-TSTM WND GST 12 WNW LANCASTER        34.73N 118.38W
05/12/2009  M58.00 MPH       LOS ANGELES        CA   OTHER FEDERAL

            SUSTAINED WEST WINDS 26 MPH AT POPPY PARK...2760 FEET.

&&

HALL

Event by event

2 high wind. Local standard time, as filed.

High Wind, Los Angeles County Mountains Excluding the Santa Monica Range

When
May 12, 7:53 PM PST to May 13, 5:53 AM PST
Where
Los Angeles County Mountains Excluding the Santa Monica Range forecast zone
Measured
69 kt (79 mph) measured gust
Reported by
Mesonet

Gusty north winds were reported in the mountains of Los Angeles county. The RAWS sensor at Whitaker Peak reported a wind gust of 79 MPH while the Warm Springs RAWS sensor reported wind gusts to 59 MPH. The Sandberg ASOS reported wind gusts to 61 MPH.

High Wind, Ventura County Mountains

When
May 12, 7:53 PM PST to May 13, 5:53 AM PST
Where
Ventura County Mountains forecast zone
Measured
69 kt (79 mph) measured gust
Reported by
Mesonet

Gusty north winds were reported in the mountains of Ventura county. Wind gusts between 58 and 75 MPH were reported.

What these are

High Wind
Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in California in 2009Every state in 2009This day in weather historyWarnings in California, May 2009

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 169366, 169367.