Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 20, NWS Phoenix, AZ

July 12, 2002La Paz County, Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 12, 2002, 8:20 PM MST for La Paz County, Maricopa County, Arizona. It was in force for 25 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: Jul 12, 2002, 8:20 PM MST (03:20 UTC)
Expired: Jul 12, 2002, 8:45 PM MST
In force: 25 min
Issued by: NWS Phoenix, AZ
Area: Counties, with a storm outline in the text

Counties La Paz County, AZ, Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 137 km from the middle of the area, began a volume at 03:20 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 00:00Z, 3.3 hours before the alert went out and 107 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: 1014 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 3305 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 61 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

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

885 
WUUS55 KPSR 130320
SVRPSR
AZC012-013-130345-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
820 PM MST FRI JUL 12 2002

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS RE-ISSUED A

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

* UNTIL 845 PM MST.

LOCATIONS THAT WILL BE AFFECTED INCLUDES INTERSTATE 10 FROM 
TONOPAH...WESTWARD INTO EASTERN LA PAZ COUNTY.

* AT 815 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
A  SEVERE THUNDERSTORM 15 MILES WEST OF TONOPAH...MOVING SOUTHWEST 
AT 20 MPH.

DAMAGING MICROBURST WINDS ARE LIKELY WITH THIS STORM. VERY HEAVY RAIN
IS ALSO POSSIBLE. TAKE COVER IN A SUBSTANTIAL SHELTER UNTIL THE STORM
PASSES.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH YOU SHOULD PREPARE 
FOR DAMAGING WIND...LARGE HAIL...AND DEADLY LIGHTNING. 

LAT...LON 3335 11286 3370 11287 3383 11305 3371 11350
          3341 11355

AJ

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 Jul 12, 3:15 PM MST, 5 hours 5 minutes earlier.

Area forecast discussion, Jul 12, 3:15 PM MST, 5 hours 5 minutes before

AZZ020>028-CAZ030>033-130545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
315 PM MST FRI JUL 12 2002

.SYNOPSIS...
A LARGE HIGH PRESSURE CENTERED OVER NORTHERN UTAH WILL MOVE
SLOWLY SOUTHWARD THIS WEEKEND.  THE COMBINATION OF MOIST EASTERLY
WINDS...AND PLENTY OF HEATING WILL CONTINUE THE CHANCE FOR
AFTERNOON AND EVENING THUNDERSTORMS THROUGH THE WEEKEND AND NEXT
WEEK.

.DISCUSSION...
ITS OFFICIAL...FOR THREE CONSECUTIVE DAYS BEGINNING LAST TUESDAY
JULY 9TH...THE DAILY AVG DEWPOINT HAS EQUALED OR EXCEEDED 55 DEG F
HERE IN PHOENIX. SO...FOR S CENTRAL AND SW AZ THE MONSOON HAS BEGUN
AS OF LAST TUESDAY JULY 9TH.

MEANWHILE...BACK TO THE PRSNT...WDLY SCTD CNVCTN ALONG THE HIER TRRN
IN S CNTRL THIS AFTN. NE TO E FLO ALF MAY BRING A FEW TSTMS DOWN
INTO THE S CNTRL LWR DESERTS...BUT THESE SHD BE STARVING FOR AVBL
MID LVL MOISTURE. LTG AND MAYBE SOME GUSTY WNDS ARE THE ONLY THREAT
TONIGHT.  THE AXIS OF THE MID-UPR LVL WEAK SPEED MAX LIES E TO W
ACRS S CNTRL AZ...AS EVIDENT ON THE WV STLT PIXS THIS AFTN. THE
CNVCTN THAT DOES DVLP THIS EVE SHD BE SUPPRESSED SOME IN S CNTRL AND
SW AZ.

THE UT HI SINKS S THIS WEEKEND...MID TO UPR LVL FLO STAYS NE TO E.
WHILE THE LOW LVL FLOW IS WEAK UNTIL EARLY SUNDAY WHEN A SOUTHERLY
FETCH KICKS IN WHICH MAY HERALD A SEEP ALG AND E OF THE LWR COLORADO
RIVER.  SO WILL RAMP UP CNVCTV ACTVITY ON SUNDAY...AND KP CHCS IN
PLACE THROUGH THE RMDR OF THE FCST.

CONTINUING THE NEAR NRML TO ABV TEMPS THROUGHT THE WEEKEND...LWRG
THEM DOWN A DEG OR TWO NEXT WEEK...BUT STILL AT OR ABV GUIDNC.
RUNYAN.

.PSR...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 7:28 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Maricopa	47 min
Jul 13, 4:01 PM MST	Severe Thunderstorm Warning	PSR	Gila, Pinal	44 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.