Heat and High Wind in California, May 12 to 16, 2009

Name: Heat and High Wind in California, May 12 to 16, 2009
Start: 2009-05-12T16:47
End: 2009-05-16T20:00
Location: California

May 12 to 16, 2009 · NWS HNX · 5 events in 5 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 5

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 HNX wrote it up.

Temperatures slowly warmed through May 6th, then the central and southern San Joaquin Valley cooled a few degrees on the 7th as a push of marine air filled the Valley. This pool of marine air rapidly mixed out, and Fresno had a high of 90 degrees on May 9th. Temperatures then leveled off for a couple of days, before the next low-pressure system brought cooling to interior central California on the 12th. This low-pressure trough also brought strong winds to the Kern County desert, with gusts to 47 mph at Edwards AFB during the afternoon of May 12th, and gusts as high as 73 mph at Mojave that evening.

Weak high pressure over the state brought another slow warming trend to the region. Fresno again reached 90 on May 15th, but Bakersfield still had not reached 90 by that point. Things changed abruptly the next day, as the ridge strengthened over the state and temperatures jumped as much as 10 degrees. Bakersfield went from a high of 88 on May 15th to 99 the next day, and topped out at a record-setting 105 degrees on May 17th. Fresno was even warmer, reaching 106, as did Naval Air Station, Lemoore. Castle Airport in Merced County reached 108 degrees, and Coalinga sizzled at 110 degrees.

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 Hanford, CA wrote its last area forecast discussion before the first event at May 12, 1:15 PM PST, 3 hours 32 minutes earlier.

Area forecast discussion, May 12, 1:15 PM PST, 3 hours 32 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
215 PM PDT TUE MAY 12 2009

.DISCUSSION...CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY TEMPERATURES
AT NOON /19Z/ WERE DOWN 4-8 DEGREES FROM 19Z MONDAY...AS A SERIES OF
WEAK UPPER-LEVEL SHORT-WAVE TROUGHS MOVES THROUGH CALIFORNIA...
BRINGING COOLER TEMPERATURES AND LOCALLY BREEZY CONDITIONS TO THE
REGION.

WINDS IN THE KERN COUNTY MOUNTAINS AND DESERTS SUBSIDED AROUND
DAYBREAK THIS MORNING...BUT HAVE INCREASED IN THE LAST COUPLE OF
HOURS. ALTHOUGH THE WINDS ARE BELOW ADVISORY CRITERIA AT THIS TIME...
EXPECT THESE CRITERIA TO BE MET AS THE SECOND SHORT-WAVE TROUGH
BRUSHES THE NORTHERN EDGE OF THE HANFORD WARNING/FORECAST AREA LATER
THIS AFTERNOON AND EVENING. HAVE LEFT THE WIND ADVISORY /SFONPWHNX OR
WWUS76 KHNX/ FOR THE KERN MOUNTAINS/DESERTS IN PLACE THROUGH 06Z
WEDNESDAY.

SATELLITE LOOPS SHOW THE SERIES OF UPSTREAM SHORT-WAVE TROUGHS RIDING
THE NEAR-ZONAL FLOW INTO CALIFORNIA. THIS WILL KEEP TEMPERATURES
ACROSS THE REGION NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THURSDAY...
WITH PERIODS OF GUSTY WINDS IN THE MOUNTAINS AND DESERTS. THE LAST
OF THESE TROUGHS IS FORECAST TO DEEPEN AS IT MOVES INTO THE ROCKIES.
THIS...IN TURN...WILL HELP STRENGTHEN AN EAST-PACIFIC UPPER-LEVEL
RIDGE BUILDING OFF THE COAST.

THE MODELS CONTINUE TO FORECAST THIS RIDGE TO BEGIN BUILDING INTO
CALIFORNIA FRIDAY...WITH THE RIDGE AXIS OVER THE CENTRAL CALIFORNIA
INTERIOR BY 00Z MONDAY. 500-MB HEIGHTS OVER THE REGION ARE FORECAST
TO REACH 5890 METERS SUNDAY AFTERNOON...WITH 1000-500-MB THICKNESSES
BETWEEN 5760 AND 5820 METERS. 850-MB TEMPERATURES ARE FORECAST TO BE
AROUND 24 C AT 00Z MONDAY. THE 12Z GFS WARMS 850-MB TEMPERATURES BY
1 C AT 00Z TUESDAY...WHILE THE 12Z ECMWF COOLS TEMPERATURES SLIGHTLY
/BY 0.5 C/. THE REGION REMAINS ON TRACK FOR THE FIRST TRIPLE-DIGIT
DAYS OF THE YEAR BEGINNING SUNDAY AT BOTH BAKERSFIELD AND FRESNO...
WITH TEMPERATURES APPROACHING RECORDS. /SEE BELOW./ THE LAST TIME
EITHER BAKERSFIELD OR FRESNO WAS SEPTEMBER 8TH 2008. SINCE 1952...
THE AVERAGE DATE FOR THE FIRST 100-DEGREE DAY AT BAKERSFIELD WAS MAY
27TH...AND AT FRESNO...JUNE 6TH. HAVE ISSUED A SPECIAL WEATHER
STATEMENT /SFOSPSHNX OR WWUS86 KHNX/ FOR THE COMING HOT WEATHER AND
SAFETY TIPS.

THE 12Z MODELS ARE NOW HINTING AT SLIGHTLY COOLER 850-MB TEMPERATURES
AT 00Z WEDNESDAY...WITH THE GFS AT 23.5 C AND THE ECMWF AT 22.5 C.
HIGH TEMPERATURES WILL REMAIN AROUND 100 IN THE CENTRAL AND SOUTHERN
SAN JOAQUIN VALLEY DUE TO THE THERMAL INERTIA OF THE WARM AIRMASS.

THE MAXIMUM TEMPERATURE GRIDS LOOK ON TRACK AND NO CHANGES WERE MADE.
DID ADJUST THE MINIMUM TEMPERATURE GRIDS FOR THE EXTENDED FORECAST
PERIOD UP SLIGHTLY TO REFLECT THE RESIDUAL WARMTH OF THE AIRMASS
OVERNIGHT.

THE GFS CONTINUES TO BRING A PUSH OF MID-LEVEL MOISTURE INTO THE
HANFORD WARNING/FORECAST AREA FOR THE FIRST PART OF NEXT WEEK.
HOWEVER...THE NEW /12Z/ ECMWF IS FURTHER SOUTH WITH THE MOISTURE
FETCH AND BRINGS IT OVER KERN COUNTY...KEEPING IT SOUTH OF THE
SIERRA NEVADA. THE FORECAST FOLLOWS THE GFS AND THE EARLIER ECMWF
RUNS AND HAS ISOLATED AFTERNOON AND EVENING THUNDERSTORMS OVER THE
HIGH COUNTRY OF THE SOUTHERN SIERRA NEVADA MONDAY AND TUESDAY.

FORECASTED AND RECORD HIGHS...

                                FORECASTED   RECORD
DATE                 CITY          HIGH       HIGH

SUNDAY....MAY 17TH   BAKERSFIELD   103        103 IN 1970
                     FRESNO        103        102 IN 2008

MONDAY....MAY 18TH   BAKERSFIELD   104        102 IN 1973
                     FRESNO        105        103 IN 2008

TUESDAY...MAY 19TH   BAKERSFIELD   104        101 IN 1954
                     FRESNO        102        103 IN 2008

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL OVER THE CENTRAL CALIFORNIA
INTERIOR THROUGH 00Z THURSDAY.

&&

.AIR QUALITY ISSUES...
NONE.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 11 PM PDT THIS EVENING FOR THE KERN COUNTY
MOUNTAINS AND DESERTS /CAZ095-098-099/.

&&

PUBLIC...SANGER
AVN/FW...JEB

WEATHER.GOV/HANFORD

In the hours before

Special weather statement, May 12, 12:45 PM PST, 4 hours 2 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
145 PM PDT TUE MAY 12 2009

CAZ089>095-098-099-130900-
WEST CENTRAL SAN JOAQUIN VALLEY-EAST CENTRAL SAN JOAQUIN VALLEY-
SOUTHWESTERN SAN JOAQUIN VALLEY-SOUTHEASTERN SAN JOAQUIN VALLEY-
MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS-
TULARE COUNTY FOOTHILLS-KERN COUNTY MOUNTAINS-INDIAN WELLS VALLEY-
SOUTHEASTERN KERN COUNTY DESERT-
145 PM PDT TUE MAY 12 2009

...HOT WEATHER TO BRING POTENTIAL HAZARDS THIS THE WEEKEND...

STRONG HIGH PRESSURE WILL MOVE INTO CALIFORNIA THIS WEEKEND. THIS
WILL PUSH TEMPERATURES TO WELL ABOVE SEASONAL AVERAGE...WITH RECORD
HIGH TEMPERATURES POSSIBLE EARLY NEXT WEEK AT BOTH BAKERSFIELD AND
FRESNO. HIGH TEMPERATURES IN THE SAN JOAQUIN VALLEY...LOWER
FOOTHILLS OF THE SOUTHERN SIERRA NEVADA...AND THE DESERTS OF KERN
COUNTY COULD APPROACH 100 SATURDAY...AND REACH OR TOP THE 100 DEGREE
MARK BEGINNING SUNDAY AND CONTINUING THROUGH TUESDAY. MONDAY WILL BE
THE HOTTEST DAY OF THE PERIOD...WITH THE WARMEST LOCATIONS POSSIBLY
AT OR ABOVE 105 DEGREES.

HERE ARE SOME TIPS TO HELP YOU COPE WITH THE HEAT.

AVOID PROLONGED EXPOSURE TO THE SUN. WHEN POSSIBLE...STAY IN THE
SHADE OR AN AIR CONDITIONED ROOM. WEAR LOOSE FITTING...LIGHT
COLORED CLOTHES. DRINK PLENTY OF NON ALCOHOLIC FLUIDS.

NEVER LEAVE CHILDREN OR PETS IN A VEHICLE...EVEN FOR SHORT PERIODS
OF TIME. TEMPERATURES INSIDE VEHICLES CAN CLIMB RAPIDLY TO LIFE
THREATENING LEVELS...EVEN WITH WINDOWS PARTIALLY OPEN.

PERIODICALLY CHECK ON CHILDREN AND THE ELDERLY. ALSO...REMEMBER
THAT ANIMALS WILL BE AFFECTED BY THE HEAT. MAKE SURE THAT PETS
AND FARM ANIMALS HAVE PLENTY OF WATER AND ACCESS TO SHADE.

IF YOU ARE PLANNING TO TRAVEL INTO THE SOUTHERN SIERRA NEVADA FOR
RELIEF FROM THE HEAT...REMEMBER THAT THE INCREASED FLOW IN MOUNTAIN
RIVERS...STREAMS AND CREEKS HAS ITS OWN HAZARDS. EVEN THOUGH A
STREAM OR RIVER LOOKS COOL AND INVITING...THE WATER IS ACTUALLY
VERY COLD AND MAY BE DANGEROUSLY FAST. OUTDOOR ENTHUSIASTS ARE
ADVISED TO USE EXTREME CAUTION NEAR STREAMS AND RIVERS. IF YOU ARE
PLANNING ON CAMPING...REMEMBER THAT THE HIGHEST WATER LEVELS OCCUR
AT NIGHT...USUALLY WITHIN AN HOUR OR TWO EITHER SIDE OF MIDNIGHT. A
CAMPGROUND MAY LOOK DRY AND SAFE IN THE LATE AFTERNOON...BUT CAN
TAKE ON WATER AT NIGHT.

IF YOU ARE RAFTING OR BOATING ON RIVERS OR STREAMS...ALWAYS WEAR
LIFE JACKETS OR VESTS...AND KEEP OTHER FLOTATION GEAR HANDY. BE
ALERT FOR THE DANGERS OF HYPOTHERMIA IF YOU OR OTHERS FALL INTO THE
WATER...GET TO SAFETY AS QUICKLY AS POSSIBLE.

LISTEN TO NOAA WEATHER RADIO...OR YOUR FAVORITE NEWS SOURCE...FOR
UPDATES ON THIS SITUATION.

SANGER

WEATHER.GOV/HANFORD

Event by event

4 heat, 1 high wind. Local standard time, as filed.

High Wind, Se Kern Cty Desert

When: May 12, 4:47 PM PST to 10:00 PM PST
Where: Se Kern Cty Desert forecast zone
Measured: 63 kt (72 mph) measured gust
Reported by: Mesonet

Heat, W Central S.J. Valley

When: May 15, 11:00 AM PST to May 16, 8:00 PM PST
Where: W Central S.J. Valley forecast zone
Reported by: Mesonet

Heat, E Central S.J. Valley

When: May 15, 11:00 AM PST to May 16, 8:00 PM PST
Where: E Central S.J. Valley forecast zone
Reported by: Mesonet

Heat, Sw S.J. Valley

When: May 15, 11:00 AM PST to May 16, 8:00 PM PST
Where: Sw S.J. Valley forecast zone
Reported by: Mesonet

Heat, Se S.J. Valley

When: May 15, 11:00 AM PST to May 16, 8:00 PM PST
Where: Se S.J. Valley forecast zone
Reported by: Mesonet

What these are

High Wind: Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

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

The same day elsewhere

Every storm in California in 2009 Every state in 2009 This day in weather history Warnings 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: 176478, 176473, 176475, 176476, 176477.