Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 59, NWS Phoenix, AZ

September 8, 2002La Paz County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Sep 8, 2002, 4:23 PM MST for La Paz County, Arizona. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 8, 2002, 4:23 PM MST (23:23 UTC)
Expired
Sep 8, 2002, 5:00 PM MST
In force
37 min
Issued by
NWS Phoenix, AZ
Area
Counties, with a storm outline in the text

County La Paz County, AZ

The radar

The Yuma radar (KYUX), 172 km from the middle of the area, began a volume at 23:26 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

Phoenix, AZ (KPSR), launched 12:00Z, 11.4 hours before the alert went out and 165 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, Phoenix, AZ at 12:00Z on 2002-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 643 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phoenix, AZ at 12:00Z on 2002-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 square meters per square second.19395878Sfc1 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
643 J/kg
Mixed-layer CIN
-86 J/kg
Mixed-layer LCL
1135 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

306 
WUUS55 KPSR 082323
SVRPSR
AZC012-090000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
420 PM MST SUN SEP 8 2002

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL LA PAZ COUNTY IN WEST CENTRAL ARIZONA

* UNTIL 500 PM MST

* AT 411 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED
  A SEVERE THUNDERSTORM OVER VICKSBURG JUNCTION...MOVING NORTHEAST
  TOWARD SALOME AND WENDEN AT 20 MPH.

THUNDERSTORMS ARE CAPABLE OF PRODUCING WIND GUSTS TO NEAR 60 MPH...
ALONG WITH HEAVY RAIN.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A STRONG
BUILDING. DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS. STAY INSIDE AWAY
FROM WINDOWS UNTIL THE STORM HAS PASSED.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN PHOENIX.

LAT...LON 3388 11399 3360 11374 3361 11335 3410 11337

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 8, 2:45 PM MST, 1 hour 38 minutes earlier.

Area forecast discussion, Sep 8, 2:45 PM MST, 1 hour 38 minutes before
AZZ020>028-CAZ030>033-090545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
245 PM MST SUN SEP 8 2002

.SYNOPSIS...
A TROUGH OF LOW PRESSURE ALONG THE WEST COAST...AND A RIDGE OF
HIGH PRESSURE OVER THE SOUTHERN PLAINS AND NEW MEXICO...WILL
CONTINUE A SOUTHWEST FLOW OF MOIST...AND UNSTABLE AIR OVER SOUTHEAST
CALIFORNIA...AND SOUTHWEST ARIZONA. SOMEWHAT DRIER AIR IS EXPECTED
TO MOVE INTO SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA BY THE
MIDDLE OF NEXT WEEK AS WESTERLY FLOW DEVELOPS.  IN THE
MEANTIME...EXPECT A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH
DAY...AND DAYTIME HIGH TEMPERATURES WILL BE NEAR...OR SLIGHTLY
BELOW SEASONAL NORMALS.

.DISCUSSION...
UPPER HIGH OVER NM WITH TROF OVER CA KEEPING A VERY MOIST SW FLOW
OVER REGION TONIGHT. THIS IS CONITNUING TO BRING IN MOISTURE FROM
FORMER HERNAN ALONG WITH MOISTURE FROM TROPICAL DEPRESSION 11-E OFF
THE SOUTHERN TIP OF BAJA. ENOUGH SHEAR ALOFT IS PRESENT ALONG WITH A
JET CORE AT 300 MB OVER WESTERN AZ PLACING MUCH OF SOUTH CENTRAL AZ
IN ITS RIGHT REAR QUADRENT. THIS ALL TO COMBINE INTO KEEPING SHOWERS
AND THUNDERSTORMS OVER ENTIRE AREA TONIGHT. HOWEVER...SOME DRIER AIR
SEEMS TO BE EDGING INTO THE JOSHUA TREE PARK AREA BUT SATELLITE
PHOTOS ALSO SHOW LOWER LEVEL MOISTURE FROM 11-E SLOWING TRYING TO
MOVE NORTHWARD THRU SE CA. THUS WILL KEEP A CHANCE OF THUNDERSTORMS
IN JOSHUA TREE PARK. MODELS LIFT OUT TROF TONIGHT BUT KEEP A BAGGY
TROF OFF THE COAST MON. THIS BRINGS UP MORE MOISTURE FROM TROPICAL
DEPRESSION 11-E...OF WHICH AVN SPREADS INTO SE CA AND SW AZ AS
PER PREVIOUS RUNS...BUT ETA NOW SHIFTS ITS A BIT MORE EAST INTO AZ.
LOWER LEVEL FLOW SHOWS MORE SOUTHERLY COMPONENT THUS WILL FAVOR AVN
SHOWING A BIT MORE THRUST OF THIS MOISTURE INTO SE CA / SW AZ MON.
SOUTH CENTRAL AZ TO REMAIN UNDER THE SW MOIST FLOW MON AS THE TAIL
END OF THE JET CORE REMAINS OVER SOUTH CENTRAL AZ PROVIDING DYNAMICS
FOR CONTINUED SHOWERS/THUNDERSTORMS. BAGGY TROF OVER CA AND UPPER
HIGH OVER NM REMAINS TUES FOR LITTLE CHANGE WITH MODELS SHOWING A
VORTMAX MOVING UP LOWER CO RIVER VALLEY TUES / TUES NIGHT FOR
CONTINUED DYNAMICS TO KEEP ACTIVITY GOING. IN THE WAKE OF THIS
VORTMAX UPPER FLOW TURNS WESTERLY AS AN UPPER HIGH BEGINS TO BUILD
OVER BAJA. THIS WILL BEGIN BRINGING IN DRIER AIR INTO SE CA / SW AZ
WED...WITH THIS FLOW AND DRIER AIR REACHING SOUTH CENTRAL AZ BY
THURS. HOWEVER... SOUTHERN GILA COUNTY AND ITS HIGHER TERRAIN WILL
BE SLOW TO DRY OUT FROM MID WEEK INTO THE WEEKEND WILL HAVE A CHANCE
OF AFTERNOON AND EVENING THUNDERSTORMS. DKS

.PSR...NONE.

In the hours before

Special weather statement, Sep 8, 11:51 AM MST, 4 hours 32 minutes before
AZZ022>024-027-028-090000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1151 AM MST SUN SEP 8 2002

...A RISK OF STRONG THUNDERSTORMS AND HAZARDOUS WEATHER OVER
PORTIONS OF SOUTHWEST AND SOUTH-CENTRAL ARIZONA THIS AFTERNOON AND
EVENING...

THE OUTLOOK AREA CONSISTS OF THE FOLLOWING COUNTIES IN ARIZONA...
MARICOPA...NORTHERN PINAL...SOUTHERN GILA...LA PAZ AND YUMA. CITIES
AND TOWNS IN THE OUTLOOK AREA INCLUDE...THE GREATER PHOENIX
METROPOLITAN AREA...CASA GRANDE...FLORENCE...COOLIDGE...GILA BEND...
WICKENBURG...WENDEN...AND DATELAND.

THE PRIMARY HAZARDOUS WEATHER RISK OVER THIS OUTLOOK AREA IS
LOCALLY HEAVY RAIN. IN ADDITION TO HEAVY RAIN...HAIL...STRONG
AND DAMAGING WINDS IN EXCESS OF 50 MPH...AND AREAS OF BLOWING DUST
THAT COULD LOWER VISIBILITY TO UNDER ONE HALF MILE WILL BE POSSIBLE
WITH AND NEAR THE STRONGEST STORMS.

STORM SPOTTER ACTIVATION MAY BE NECESSARY THIS AFTERNOON AND
EVENING.

DKS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 6:11 PM MSTSevere Thunderstorm WarningPSRMaricopa39 min

Nearby

Severe Thunderstorm Warnings in Arizona, 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.