Dust Storm in Arizona, July 3, 2014

Name: Dust Storm in Arizona, July 3, 2014
Start: 2014-07-03T18:20
End: 2014-07-03T23:00
Location: Arizona

July 3, 2014 · NWS PSR · 6 events in 6 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 6

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 PSR wrote it up.

Strong thunderstorms developed across southern Pinal county during the afternoon hours on July 3rd, and they generated strong gusty outflow winds in excess of 50 mph. The winds spread to the northwest and picked up massive amounts of dust, leading a major dust storm across the central deserts, including the greater Phoenix metropolitan area. Visibilities dropped to near zero miles at times, and given the late afternoon and early evening time frame, severely disrupted the evening rush hour. Initially, Blowing Dust Advisories were issued, but were later upgraded to Dust Storm Warnings. No significant accidents or injuries were reported due to the dense blowing dust.

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 Phoenix, AZ wrote its last area forecast discussion before the first event at Jul 3, 2:29 PM MST, 3 hours 51 minutes earlier.

Area forecast discussion, Jul 3, 2:29 PM MST, 3 hours 51 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
229 PM MST THU JUL 3 2014

.UPDATE...UPDATED AVIATION DISCUSSION...

&&

.SYNOPSIS...
THE ARRIVAL OF MONSOON MOISTURE WILL BRING COOLER TEMPERATURES FOR
THE REST OF THE WEEK AND INTO THE WEEKEND...ALONG WITH MORE CLOUDS
AND INCREASING STORM CHANCES. STORM CHANCES PEAK FOR THE FOURTH OF
JULY HOLIDAY AND ON SATURDAY ACROSS SOUTH-CENTRAL ARIZONA...AND THE
POTENTIAL FOR STORMS COULD REACH AS FAR WEST AS THE LOWER COLORADO
RIVER VALLEY AND INTO SOUTHEAST CALIFORNIA BY FRIDAY AND THROUGH THE
WEEKEND. THE THREAT OF SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THROUGH NEXT WEEK.

&&

.DISCUSSION...
LATEST STREAMLINE ANALYSIS INDICATES THAT THE MID-TROPOSPHERIC
ANTICYCLONE HAS MIGRATED NORTHEASTWARD TOWARDS THE FOUR CORNERS.
THIS IS PRODUCING A FAVORABLE EASTERLY FLOW ACROSS CENTRAL AZ AND
AFTERNOON MDCRS FLIGHTS SUGGEST WINDS NEAR 15K FT HAVE INCREASED TO
15-20 KT. MID-LEVEL TEMPERATURES REMAIN RELATIVELY
COOL...CONSIDERING THAT THE HIGH CENTER IS CLOSE...RESULTING IN
STEEP 700-500 MB LAPSE RATES >7C/KM. TEMPERATURES AT 500 MB HAVE
BEEN MEASURED AS LOW AS -8/-9C THIS AFTERNOON. LATEST GPS-IPW AT
TEMPE ALSO INDICATES THAT TOTAL MOISTURE CONTINUES TO STEADILY
INCREASE TO AROUND 1.4 INCHES. EVEN AT THE SURFACE...DEWPOINTS
REMAIN ABOVE AVERAGE WITH MID 50S PREVALENT ACROSS THE LOWER DESERTS
AND EVEN UPPER 60S IN THE IMPERIAL VALLEY.

CONVECTIVE ALLOWING MODELS REMAIN IN GENERALLY GOOD AGREEMENT FOR
LATE THIS AFTERNOON AND THIS EVENING...INDICATING THAT THUNDERSTORMS
WILL BE FAVORED ACROSS SOUTHERN AZ...INCLUDING PINAL AND SOUTHERN
MARICOPA COUNTIES...THOUGH RECENT TRENDS IN THE U OF A WRFS AND HRRR
SUGGEST THAT PORTIONS OF THE PHOENIX AREA MAY BE ACTIVE AS WELL THIS
EVENING. SOME INHIBITION IS PRESENT DUE TO WARMING AROUND 450 MB.
HOWEVER...NEIGHBORHOOD PROBABILISTIC GUIDANCE ALSO SUGGESTS THAT
STRONGER WINDS ASSOCIATED WITH OUTFLOWS WILL PROMOTE LOW-LEVEL
CONVERGENCE IN THE LOWER DESERTS MAINLY FROM MARICOPA COUNTY
EASTWARD LATER THIS EVENING. POPS WERE RAISED TO AROUND 30 PERCENT
IN THESE AREAS...THOUGH THE GREATER LIKELIHOOD IS AGAIN FOR
WIND/DUST IMPACTS.

&&

.PREVIOUS DISCUSSION...
THE LATEST MODEL RUNS CONTINUE TO INDICATE THAT THE SEASONAL
REVERSAL OF WINDS THAT DEFINES THE NORTH AMERICAN MONSOON WILL BE
OCCURRING OVER THE NEXT FEW DAYS...AS THE LIGHT WESTERLY FLOW ALOFT
THAT TYPICALLY DOMINATES OUR WEATHER THROUGH THE MONTH OF JUNE
BECOMES EASTERLY TO SOUTHEASTERLY...AS WE BEGIN TO WORK OUR WAY
DEEPER INTO THE 1ST WEEK OF JULY.

AS FAR AS THE FORECAST FOR FRIDAY AND SATURDAY IS CONCERNED...LATEST
MODEL OUTPUT CONTINUES TO RAISE PWAT'S INTO THE 1.50-1.80 INCH RANGE
AND MUCAPES INTO THE 700-1000 J/KG RANGE LATE TONIGHT INTO
FRIDAY...AND NOW HOLD THEM AT THESE LEVELS THROUGH SATURDAY. GIVEN
THE MORE FAVORABLE ENVIRONMENT FOR STORM DEVELOPMENT AND
SOUTHEASTERLY STEERING FLOW ALOFT EACH DAY...IT APPEARS THAT AT
LEAST SOME STORMS WILL LIKELY MOVE INTO SOUTH-CENTRAL AND SOUTHWEST
AZ...AND EVEN A FEW INTO SOUTHEAST CA...AND BRING OUR FIRST
MEASURABLE RAIN OF THE SUMMER SEASON TO SOME LOWER DESERT LOCATIONS.
AS FAR AS WHICH DAY WILL BE MOST ACTIVE...THAT DEPENDS ON HOW MUCH
DEBRIS CLOUDINESS SPREADS NORTHWARD LATE THURSDAY NIGHT AND EARLY
FRIDAY...WHICH WOULD INHIBIT ACTIVITY ON FRIDAY AFTERNOON AND
PERHAPS ALLOW SATURDAY TO BE THE BUSIER DAY. ANYWAYS...AT THIS
POINT...IT APPEARS THAT FRIDAY WILL HAVE THE MORE FAVORABLE SHEAR
PROFILE AND DEEPER MOISTURE COLUMN TO WORK WITH. HOWEVER...ON EITHER
DAY...ANY STORM THAT DEVELOPS WILL BE CAPABLE OF PRODUCING BRIEF
HEAVY DOWNPOURS...STRONG WINDS...AND DENSE BLOWING DUST.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...

THUNDERSTORMS ARE CURRENTLY DEVELOPING ACROSS FAR SOUTHEAST ARIZONA
AND ALONG THE MOGOLLON RIM. THE EXPECTATION IS FOR THE STORMS IN
EACH AREA TO PRODUCE OUTFLOW WINDS WHICH WILL LIKELY MOVE INTO THE
METRO PHOENIX AREA SOMETIME THIS EVENING WITH THE MOST LIKELY
TIMEFRAME BEING BETWEEN 03 AND 06Z. GUSTY WINDS...BLOWING DUST...AND
EVEN A SLIGHT CHANCE OF THUNDERSTORMS WILL BE POSSIBLE AT THE
PHOENIX TERMINALS...ESPECIALLY KIWA. CONFIDENCE IN HOW STRONG THE
WINDS WILL BE AND AS FAR AS HOW LOW VISIBILITIES COULD GO DOWN TO IS
STILL LOW...BUT THERE IS DEFINITELY A FAIR SHOT AT SOME GUSTY WINDS
GREATER THAN 35 KNOTS AND DENSE BLOWING DUST. AM CURRENTLY WAITING
FOR THE STORMS TO BECOME MORE ORGANIZED TO ADD ANY STRONG WINDS OR
BLOWING DUST TO THE TAFS.

WILL CERTAINLY SEE A SUBSTANTIAL INCREASE IN MID/HI LEVEL DEBRIS
CLOUD DECKS OVERSPREAD THE GREATER PHOENIX AREA OVERNIGHT TONIGHT
WITH SOME BASES DOWN TO NEAR 10K FEET BY EARLY MORNING FRIDAY. A
BETTER CHANCE FOR THUNDERSTORMS IN THE GREATER PHOENIX AREA DURING
THE AFTERNOON AND EVENING HOURS FRIDAY.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

CLEAR SKIES SHOULD BE THE RULE THROUGH THIS EVENING...WITH SOME
MID/UPPER LEVEL DEBRIS CLOUDS POSSIBLY SPREADING IN FROM THE EAST
AFTER MIDNIGHT. PERSISTENT SOUTHEAST WINDS TO 12KT EXPECTED AT KIPL
NEXT 24 HOURS...AND LOCALLY BREEZY SOUTH WINDS WILL AFFECT THE LOWER
CO RIVER VALLEY...AND KBLH INTO TONIGHT.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
INCREASING MONSOON MOISTURE WILL LEAD TO A GRADUAL RAMP-UP OF
THUNDERSTORM ACTIVITY INTO THE UPCOMING WEEKEND...WITH THE BEST
CHANCES FOR WETTING RAINS TO BE OVER THE HIGHER TERRAIN OF
SOUTH-CENTRAL AZ LINGERING FOR SATURDAY BEFORE SLIGHTLY DIMINISHING
INTO EARLY NEXT WEEK. ALONG WITH THE THUNDERSTORM ACTIVITY...
RELATIVE HUMIDITIES WILL BE INCREASING THROUGH THE PERIOD AS WELL.
HIGHEST MINIMUM HUMIDITY VALUES LIKELY TO BE ON SATURDAY WITH
MOST DESERT AREAS IN EXCESS OF 20 PERCENT. SLIGHT DRYING EXPECTED
SUNDAY INTO EARLY NEXT WEEK WITH MIN RH VALUES DROPPING TO AROUND 15
PERCENT OVER THE SERN CA/SWRN AZ DESERTS. DUE TO HIGH HUMIDITY
VALUES AND CLOUD COVER...HIGH TEMPERATURES SATURDAY WILL LOWER TO
BELOW SEASONAL NORMALS...THEN CLIMB BACK TOWARDS NORMAL OR EVEN
SLIGHT ABOVE BY NEXT WEEK AS MOISTURE VALUES GRADUALLY DECREASE.
WINDS EACH DAY WILL BE MAINLY LIGHT...EXCEPT FOR AREAS NEAR
THUNDERSTORMS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...PERCHA
AVIATION....KUHLMAN
FIRE WEATHER...NOLTE/CB

Hazardous weather outlook, Jul 3, 3:44 AM MST, 14 hours 36 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
344 AM MST THU JUL 3 2014

AZZ022>024-027-028-041045-
NORTHWEST MARICOPA COUNTY-GREATER PHOENIX AREA-
SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS-
SOUTHWEST MARICOPA COUNTY-NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
344 AM MST THU JUL 3 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST-CENTRAL ARIZONA AND
SOUTH-CENTRAL ARIZONA.

.DAY ONE...TODAY AND TONIGHT.

INCREASING MONSOON MOISTURE WILL ALLOW THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS OVER SOUTHEAST ARIZONA...AND OVER THE RIM COUNTY AND
WHITE MOUNTAINS...AND OVER SOUTHERN GILA COUNTY...WITH ISOLATED
THUNDERSTORMS ELSEWHERE. THE BIGGEST THREAT FOR TODAY WILL AREAS OF
DENSE BLOWING DUST GENERATED BY DISTANT THUNDERSTORMS...PARTICULARLY
OVER PINAL AND MARICOPA COUNTY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

INCREASING MONSOON MOISTURE WILL ALLOW THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS ACROSS THE ENTIRE REGION ON FRIDAY AND SATURDAY. THESE
STORMS WILL BE CAPABLE OF PRODUCING BRIEF HEAVY DOWNPOURS...STRONG
AND GUSTY WINDS...AND AREAS OF DENSE BLOWING DUST. THUNDERSTORM
ACTIVITY WILL BECOME MORE ISOLATED FROM SUNDAY ONWARD INTO THE MIDDLE
OF NEXT WEEK AS SOMEWHAT DRIER AIR MOVES BACK INTO THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED.

AZZ020-021-025-026-CAZ030>033-041045-
LOWER COLORADO RIVER VALLEY AZ-WEST CENTRAL DESERTS-
YUMA/MARTINEZ LAKE AND VICINITY-SOUTHWEST DESERTS-
JOSHUA TREE NATIONAL PARK-LOWER COLORADO RIVER VALLEY CA-
RIVERSIDE COUNTY/EASTERN DESERTS-IMPERIAL COUNTY-
344 AM MST THU JUL 3 2014 /344 AM PDT THU JUL 3 2014/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EXTREME SOUTHWEST
ARIZONA...EXTREME WEST-CENTRAL ARIZONA...SOUTHWEST ARIZONA...WEST-
CENTRAL ARIZONA...EXTREME SOUTHEAST CALIFORNIA AND SOUTHEAST
CALIFORNIA.

.DAY ONE...TODAY AND TONIGHT.

INCREASING MONSOON MOISTURE WILL ALLOW THE DEVELOPMENT OF ISOLATED
THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS SOUTHWEST ARIZONA
AND ALONG THE LOWER COLORADO RIVER VALLEY...WITH THE THREAT OF
LOCALIZED BLOWING DUST NEAR ANY PARENT THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A FURTHER INCREASE OF MONSOON MOISTURE ON FRIDAY WILL BRING CHANCES
OF THUNDERSTORMS AND MORE BLOWING DUST ACROSS THE ENTIRE
REGION...EXTENDING INTO SOUTHEAST CALIFORNIA...AND THIS ACTIVITY WILL
LIKELY LAST INTO SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED.

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

In the hours before

Special weather statement, Jul 3, 6:12 PM MST, 8 minutes before

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Event by event

6 dust storm. Local standard time, as filed.

Dust Storm, Central Deserts

When: July 3, 6:20 PM MST to 8:26 PM MST
Where: Central Deserts forecast zone
Reported by: Trained Spotter

Thunderstorms developed during the afternoon hours across southern Pinal county, and due to favorable environmental conditions, they generated strong outflow winds to around 50 mph. The outflow winds spread to the northwest and picked up massive amounts of dust, creating dust storm conditions. The dust storm moved into the central deserts during the late afternoon hours, and initially led to the issuance of a Blowing Dust Advisory. At 1820MST, the advisory was upgraded to a Dust Storm Warning, which remained in effect through 2026MST. Several trained weather spotters in favored dust prone areas such as Coolidge and Casa Grande reported dust storm conditions with visibilities dropping at or below one quarter of a mile.

Dust Storm, Southwest Maricopa County

When: July 3, 6:20 PM MST to 11:00 PM MST
Where: Southwest Maricopa County forecast zone
Reported by: Trained Spotter

Thunderstorms developed across southern Pinal county during the afternoon hours on July 3rd, and due to favorable atmospheric conditions, they were able to generate strong gusty outflow winds in excess of 50 mph. These gusty winds spread to the west and northwest and moved into southwest Maricopa county, generating dust storm conditions as they moved across the desert. Initially, a Blowing Dust Advisory was issued for southwest Maricopa county, however at 1820MST it was upgraded to a Dust Storm Warning. The warning ran was in effect through 2100MST. At 1841MST, a trained weather spotter located 2 miles southwest of Gila Bend reported a dust storm with visibilities dropping below one quarter of a mile. No accidents or injuries were reported in Gila Bend due to the dust storm.

Dust Storm, Greater Phoenix Area

When: July 3, 7:00 PM MST to 9:00 PM MST
Where: Greater Phoenix Area forecast zone
Reported by: Trained Spotter

Thunderstorms developed across southern Pinal county during the afternoon hours on July 3rd, and due to favorable atmospheric conditions, they were able to generate strong gusty outflow winds in excess of 50 mph. These gusty winds spread to the northwest, picking up massive amounts of dust and dirt and generating dust storm conditions which spread into the southeast portions of the greater Phoenix area by early evening. Numerous trained weather spotters across the greater Phoenix area reported dust storm conditions, and a Dust Storm Warning was issued, running from 1900MST to 2100MST. At 1952MST, a trained spotter in Tempe reported a dust storm with visibility down to one tenth of a mile at the intersection of Mill and Southern. Another trained spotter 3 miles northwest of the Arizona State Fairgrounds reported a dust storm with one quarter mile visibility, accompanied by wind gusts estimated to be nearly 50 mph.

Dust Storm, Northwest Maricopa County

When: July 3, 7:00 PM MST to 11:00 PM MST
Where: Northwest Maricopa County forecast zone
Reported by: Trained Spotter

Thunderstorms developed across southern Pinal county during the afternoon hours on July 3rd, and due to favorable atmospheric conditions, they generated strong gusty outflow winds in excess of 50 mph. These winds spread to the northwest, picking up massive amounts of dirt and dust and creating dust storm conditions. The dust storm spread across the greater Phoenix area during the evening hours, eventually moving through northwest portions of Maricopa county. A Dust Storm Warning was issued at 1900MST and it continued through 2300MST. Numerous trained spotters in the greater Phoenix area reported dust storm conditions with this event, with visibilities dropping at or below one quarter of a mile.

Dust Storm, West Central Deserts

When: July 3, 7:08 PM MST to 11:00 PM MST
Where: West Central Deserts forecast zone
Reported by: Trained Spotter

Thunderstorms developed during the afternoon hours across southern Pinal county, and due to favorable environmental conditions, they were able to generate strong gusty outflow winds in excess of 50 mph. The winds spread to the west, and in the process they picked up significant amounts of dust and dirt which led to dust storm conditions. The dust storm then spread across the west central deserts during the evening hours; a Dust Storm Warning was issued for the area from 1908MST until 2300MT. Despite a lack of trained spotter reports from the sparsely populated west central deserts, numerous spotters across the south central deserts, including the greater Phoenix area, reported dust storm conditions with this event.

Dust Storm, Southwest Deserts

When: July 3, 7:08 PM MST to 11:00 PM MST
Where: Southwest Deserts forecast zone
Reported by: Trained Spotter

Thunderstorms developed during the afternoon hours across southern Pinal county, and due to favorable environmental conditions, they were able to generate strong gusty outflow winds in excess of 50 mph. The winds spread to the west, and in the process they picked up significant amounts of dust and dirt which led to dust storm conditions. The dust storm then spread across the southwest deserts during the evening hours; a Dust Storm Warning was issued for the area from 1908MST until 2300MT. Despite a lack of trained spotter reports from the sparsely populated southwest deserts, numerous spotters across the south central deserts, including the greater Phoenix area, reported dust storm conditions with this event.

What these are

Dust Storm: Blowing dust that reduced visibility to a quarter mile or less.

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

The same day elsewhere

Every storm in Arizona in 2014 Every state in 2014 This day in weather history Warnings in Arizona, July 2014

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 2026-09-30. Each event’s entry at NCEI: 525599, 525751, 525750, 525752, 525753, 525754.