Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 45, NWS Phoenix, AZ

September 6, 2002Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Sep 6, 2002, 4:16 PM MST for Maricopa County, Arizona. It was in force for 59 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 6, 2002, 4:16 PM MST (23:16 UTC)
Expired: Sep 6, 2002, 5:15 PM MST
In force: 59 min
Issued by: NWS Phoenix, AZ
Area: Counties, with a storm outline in the text

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 65 km from the middle of the area, began a volume at 23:16 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, 11.3 hours before the alert went out and 34 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 907 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 2318 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -26 m²/s²
0-3 km storm-relative helicity: 40 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

860 
WUUS55 KPSR 062316
SVRPSR
AZC013-070015-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
411 PM MST FRI SEP 6 2002

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL MARICOPA COUNTY IN SOUTH CENTRAL ARIZONA

* UNTIL 515 PM MST

* AT 401 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 7 MILES SOUTH OF AVONDALE...MOVING NORTHEAST AT
  15 MPH. SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER  
  OTHER PORTIONS OF THE GREATER PHOENIX AREA THROUGH 515 PM...
  INCLUDING AVONDALE...LAVEEN...GLENDALE...WEST PHOENIX...
  AND POSSIBLY THE EAST VALLEY.

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 3331 11258 3328 11226 3351 11197 3371 11217
          3373 11244

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 6, 3:25 PM MST, 51 minutes earlier.

Area forecast discussion, Sep 6, 3:25 PM MST, 51 minutes before

AZZ020>028-CAZ030>033-070545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
325 PM MST FRI SEP 6 2002

.SYNOPSIS...
A MOIST AIRMASS WILL STAY IN PLACE ACROSS ALL OF ARIZONA AND
SOUTHEAST CALIFORNIA THROUGH THE WEEKEND AND INTO EARLY NEXT AS LOW
PRESSURE ALOFT REMAINS JUST OFF THE WEST COAST. WEAK IMPULSES WILL
MOVE ACROSS THE FORECAST AREA FROM TIME TO TIME AND WILL SERVE TO
TRIGGER SHOWERS AND THUNDERSTORMS INTO MONDAY. DRIER AIR WILL MOVE
INTO SOUTHEAST CALIFORNIA EARLY NEXT WEEK...WITH A MOIST SOUTHERLY
FLOW EXPECTED TO CONTINUE OVER SOUTH-CENTRAL ARIZONA THROUGH ABOUT
MIDWEEK. TEMPERATURES WILL FALL OFF TO NEAR SEASONAL NORMALS THE
NEXT FEW DAYS.

.DISCUSSION...
CONVECTION FIRING NICELY TODAY...MAINLY OVER ERN THIRD OF CWFA. LOTS
OF BOUNDARY INTERACTIONS COMMENCING...AND THESE SHOULD KEEP STORMS
FIRING WELL INTO THE NIGHT. SW AZ AND SE CA RATHER QUIET AT THIS
TIME...BUT EXPECT STORMS TO BEGIN GINNING UP THESE AREAS AS WELL
WITH VERY MOIST/UNSTABLE AIR IN PLACE CWFA-WIDE. SYNOPTICALLY...
UPPER LOW OFF W COAST WILL LIFT OUT IN PIECES OVER THE WEEKEND WITH
A SIGNIFICANT HANG-BACK LOW EXPECTED TO BE LEFT BEHIND OFF SRN CA
COAST. POSITION OF TROUGH WILL PRODUCE A PROLONGED NE/SW ORIENTED
JET TO OUR NW LEAVING MOST OF FORECAST AREA IN FAVORABLE RIGHT
ENTRANCE REGION FROM LATE SAT NIGHT INTO EARLY MONDAY. SECONDARY LOW
FORMING OFF THE SRN CA COST WILL HELP TO KEEP MOISTURE IN PLACE OVER
AZ PORTION OF CWFA WELL INTO NEXT WEEK...SO WILL KEEP STORM CHANCES
GOING MAINLY CENTRAL/ERN PORTIONS THRU MIDWEEK...AND HIGHER TERRAIN
ZONE 24 RIGHT ON THRU FRIDAY. TEMPS EXPECTED TO SETTLE DOWN NEAR OR
SLIGHTLY BELOW SEASONAL NORMALS.   ESTLE

.PSR...NONE.

In the hours before

Special weather statement, Sep 6, 1:09 PM MST, 3 hours 7 minutes before

AZZ020>028-CAZ030>033-070700-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
109 PM MST FRI SEP 6 2002

...A RISK OF STRONG THUNDERSTORMS AND HAZARDOUS WEATHER OVER ALL
OF SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AS WELL AS SOUTHEAST
CALIFORNIA DESERTS THIS AFTERNOON AND EVENING...

THE OUTLOOK AREA CONSISTS OF THE FOLLOWING COUNTIES...
MARICOPA...NORTHERN PINAL...SOUTHERN GILA...LA PAZ AND YUMA IN
ARIZONA...AND IMPERIAL AND EASTERN RIVERSIDE COUNTIES IN SOUTHEAST
CALIFORNIA. CITIES AND TOWNS IN THE OUTLOOK AREA INCLUDE...THE
GREATER PHOENIX METROPOLITAN AREA...CASA GRANDE...FLORENCE...
COOLIDGE...GLOBE...MIAMI...SUPERIOR...GILA BEND...WENDEN...PARKER
...QUARTZSITE AND YUMA...AS WELL AS BLYTHE AND THE IMPERIAL VALLEY
TOWNS IN SOUTHEAST CALIFORNIA.

THE PRIMARY HAZARDOUS WEATHER RISKS OVER THIS OUTLOOK AREA INCLUDE
STRONG AND DAMAGING WIND IN EXCESS OF 45 MPH...AREAS OF BLOWING
DUST AND BRIEF HEAVY RAIN...ALONG WITH LIGHTNING.

STORM SPOTTER ACTIVATION MAY BE NECESSARY LATER THIS AFTERNOON.

ESTLE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 6, 2:12 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	63 min
Sep 6, 3:22 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	53 min
Sep 6, 3:26 PM MST	Severe Thunderstorm Warning	PSR	Pinal	64 min
Sep 6, 4:17 PM MST	Severe Thunderstorm Warning	PSR	Gila	58 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2002 Every 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.