Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 60, NWS Phoenix, AZ

September 10, 2002Yuma County, Arizona; Imperial County, California

NWS Phoenix, AZ issued this severe thunderstorm warning at Sep 10, 2002, 1:51 PM MST for Yuma County, Arizona; Imperial County, California. It was in force for 54 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 10, 2002, 1:51 PM MST (20:51 UTC)
Expired
Sep 10, 2002, 2:45 PM MST
In force
54 min
Issued by
NWS Phoenix, AZ
Area
Counties, with a storm outline in the text

Counties Yuma County, AZ, Imperial County, CA

The radar

The Yuma radar (KYUX), 46 km from the middle of the area, began a volume at 20:52 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Yuma Intl Airpor, AZ (KYUM), launched 12:00Z, 8.9 hours before the alert went out and 28 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, Yuma Intl Airpor, AZ at 12:00Z on 2002-09-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 366 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Yuma Intl Airpor, AZ at 12:00Z on 2002-09-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 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
366 J/kg
Mixed-layer CIN
-206 J/kg
Mixed-layer LCL
1713 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Sep 10, 9:55 AM MST, 3 hours 56 minutes earlier.

Area forecast discussion, Sep 10, 9:55 AM MST, 3 hours 56 minutes before
AZZ020>028-CAZ030>033-102245-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
955 AM MST TUE SEP 10 2002

.SYNOPSIS...
A LOW PRESSURE SYSTEM MOVING NORTHEAST FROM NORTHERN BAJA CALIFORNIA
COMBINED WITH A MOIST UNSTABLE AIRMASS MEANS SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THIS EVENING. THE LOW PRESSURE SYSTEM IS
EXPECTED TO CONTINUE MOVING NORTHEAST AWAY FROM ARIZONA WEDNESDAY
WITH GRADUALLY DRIER AIR MOVING IN THE FROM THE WEST. EVEN DRIER AIR
FROM THE NORTH IS EXPECTED TO MOVE IN BY FRIDAY AND THIS WEEKEND.
WITH LESS CLOUD COVER...WARMER WEATHER IS FORECAST TODAY. EVEN WARMER
WEATHER IS FORECAST THROUGH THE END OF THE WEEK AND THIS WEEKEND AS
HIGH PRESSURE ALOFT WEST OF BAJA CALIFORNIA EXPANDS NORTHEAST.

.DISCUSSION...
PLENTY OF MOIST AND UNSTABLE AIR CONTINUES OVER SOUTHEAST CALIFORNIA
...SOUTHWEST AND SOUTH-CENTRAL ARIZONA. TO GO ALONG WITH THIS...A
WEAK LOW PRESSURE SYSTEM FROM NORTHERN BAJA CALIFORNIA IS MOVING
NORTH-NORTHEAST. DYNAMICS WITH THIS SYSTEM COMBINED WITH A MOIST AND
UNSTABLE AIRMASS IS EXPECTED TO RESULT IN THE DEVELOPMENT OF
SCATTERED SHOWERS AND THUNDERSTORMS OVER SOUTHEAST CALIFORNIA...
SOUTHWEST AND SOUTH-CENTRAL ARIZONA TODAY AND THIS EVENING. THERE IS
PLENTY OF THERMODYNAMIC ENERGY AVAILABLE WITH HEATING COMBINED WITH
MOMENTUM ALOFT FOR POSSIBILITY OF SEVERE THUNDERSTORMS. THE LOW
PRESSURE SYSTEM WILL CONTINUE MOVING NORTHEAST AND AWAY FROM ARIZONA
WEDNESDAY WITH GRADUALLY DRIER AIR MOVING IN FROM THE WEST. THIS
WILL RESULT IN A DECREASING CHANCE OF SHOWERS AND THUNDERSTORMS
ESPECIALLY FOR THE DESERT AREAS. EVEN DRIER AIR FROM THE NORTH IS
EXPECTED TO MOVE IN BY FRIDAY AND THIS WEEKEND. WITH LESS CLOUD
COVER...WARMER WEATHER IS FORECAST TODAY. EVEN WARMER WEATHER IS
FORECAST THROUGH THE END OF THE WEEK AND THIS WEEKEND AS HIGH
PRESSURE ALOFT WEST OF BAJA CALIFORNIA EXPANDS NORTHEAST.
TEMPERATURES ARE EXPECTED TO RISE TO NEAR THE AVERAGE FOR MID
SEPTEMBER BY THE LATTER PART OF THE WEEK AND ABOVE AVERAGE BY THIS
WEEKEND.

.PSR...NONE.

ELLIS

In the hours before

Special weather statement, Sep 10, 10:30 AM MST, 3 hours 21 minutes before
AZZ020>028-CAZ031>033-110100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1030 AM MST TUE SEP 10 2002

...HAZARDOUS WEATHER IS POSSIBLE THIS AFTERNOON AND EVENING AS
THUNDERSTORMS WITH GUSTY WINDS...HAIL...AND BRIEF HEAVY RAIN MAY
DEVELOP...

A LOW PRESSURE SYSTEM OVER THE NORTHERN BAJA PENINSULA IS EXPECTED
TO TRIGGER THUNDERSTORMS BY MIDDAY TODAY. THESE THUNDERSTORMS ARE
EXPECTED TO MOVE NORTH INTO SOUTHEAST CALIFORNIA AND FAR SOUTHWEST
ARIZONA BETWEEN NOON AND 3 PM. THE THUNDERSTORMS HAVE THE POTENTIAL
TO PRODUCE GUSTY WINDS GREATER THAN 30 MPH...HAIL...AND BRIEF BUT
HEAVY RAIN. THEY ARE EXPECTED TO MOVE NORTH...OUT OF THE REGION BY
8 PM TONIGHT.

A RISK OF VERY STRONG THUNDERSTORMS EXISTS FOR SOUTH CENTRAL ARIZONA
BETWEEN 3 PM AND 9 PM THIS EVENING. THE COMBINATION OF AFTERNOON
HEATING...ABUNDANT MOISTURE...HIGH SPEED WINDS ALOFT...AND THE
APPROACHING BAJA LOW PRESSURE SYSTEM MAY CAUSE VERY STRONG
THUNDERSTORMS TO HAVE GUSTY WINDS GREATER THAN 40 MPH...HAIL...AND
BRIEF BUT HEAVY RAIN...ESPECIALLY OVER MARICOPA...NORTHERN PINAL AND
SOUTHERN GILA COUNTIES. THIS AREA INCLUDES GILA BEND...THE PHOENIX
METRO AREA...CASA GRANDE...SUPERIOR AND THE GLOBE/MIAMI AREA.

STORM SPOTTER ACTIVATION MAY BE NECESSARY THIS AFTERNOON AND EVENING.

RUNYAN

The office that day

Everything else NWS Phoenix, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 10, 2:08 PM MSTSevere Thunderstorm WarningPSRPinal37 min
Sep 10, 2:17 PM MSTSevere Thunderstorm WarningPSRGila58 min
Sep 10, 3:30 PM MSTSevere Thunderstorm WarningPSRGila60 min
Sep 10, 3:19 PM MSTSevere Thunderstorm WarningPSRImperial56 min
Sep 10, 4:15 PM MSTSevere Thunderstorm WarningPSRImperial60 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2002Severe Thunderstorm Warnings in California, 2002Every severe thunderstorm warning in 2002

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.