Alert archive / Arizona / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 33, NWS Phoenix, AZ

August 13, 2003Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Aug 13, 2003, 7:50 PM MST for Maricopa County, Arizona. It was in force for 40 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: Aug 13, 2003, 7:50 PM MST (02:50 UTC)
Expired: Aug 13, 2003, 8:30 PM MST
In force: 40 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), 88 km from the middle of the area, began a volume at 02:52 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

Phoenix, AZ (KPSR), launched 00:00Z, 2.8 hours before the alert went out and 81 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: 346 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 3137 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -14 m²/s²
0-3 km storm-relative helicity: 26 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KPSR 140250
SVRPSR
AZC013-140330-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
746 PM MST WED AUG 13 2003

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

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

* UNTIL 830 PM MST

* AT 745 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM OVER INTERSTATE 8 JUST WEST OF THE           
  MARICOPA-PINAL COUNTY LINE. THE STORM WAS MOVING WEST AT 10 MPH.  

DAMAGING MICROBURST WINDS AND LARGE HAIL ARE LIKELY WITH THIS STORM. 
VERY HEAVY RAIN IS ALSO POSSIBLE. TAKE COVER IN A SUBSTANTIAL 
SHELTER UNTIL THE STORM PASSES. THE STORM WILL TRACK WEST ALONG OR 
JUST SOUTH OF INTERSTATE 8. MOTORISTS ON INTERSTATE 8 BETWEEN 
MILEPOST MARKERS 135 AND 145 ARE URGED TO EXERCISE EXTREME CAUTION.

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 3281 11258 3288 11257 3290 11244 3297 11220
          3272 11220 3270 11230 3263 11247

$$

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 Aug 13, 4:16 PM MST, 3 hours 34 minutes earlier.

Area forecast discussion, Aug 13, 4:16 PM MST, 3 hours 34 minutes before

AZZ020>028-CAZ030>033-140545-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
315 PM MST WED AUG 13 2003

.SYNOPSIS...
STRONG HIGH PRESSURE RESPONSIBLE FOR NEAR RECORD HEAT IS DEPARTING
TO THE NORTHEAST...AS A LARGE TEXAS LOW PRESSURE SYSTEM APPROACHES
FROM THE EAST. MOISTURE AHEAD OF THIS SYSTEM MEANS SCATTERED SHOWERS
AND THUNDERSTORMS IN SOUTH-CENTRAL ARIZONA TONIGHT WITH AN INCREASING
CHANCE OF SHOWERS AND THUNDERSTORMS SPREADING WEST LATE TONIGHT AND
THURSDAY...ALONG WITH COOLER WEATHER...LINGERING FRIDAY. SOME
THUNDERSTORMS WILL PRODUCE STRONG GUSTY DAMAGING WINDS AND LOCALLY
HEAVY RAIN. HIGH PRESSURE WILL BEGIN TO BUILD WITH A SLOW RECOVERY
OF TEMPERATURES AND LESS THUNDERSTORMS LATE SUNDAY AND EARLY NEXT
WEEK.

.DISCUSSION...
DESPITE LOWER LEVELS OF THE ATMOSPHERE BEING A FEW DEGREES COOLER
AND MORE MOIST EARLY THIS MORNING COMPARED WITH THE SAME TIME
YESTERDAY...MID AFTERNOON TEMPERATURES WERE GENERALLY 2 TO 4 DEGREES
WARMER TODAY COMPARED WITH YESTERDAY. THE LOW PRESSURE SYSTEM THAT
WAS MOVING SLOWLY WEST OVER TEXAS TODAY IS EXPECTED TO REACH
SOUTHWEST TEXAS BY EARLY THURSDAY AND ARIZONA FRIDAY. HOWEVER...THE
FLOW ALOFT OVER SOUTH-CENTRAL ARIZONA IS ALREADY OUT OF THE
NORTHEAST. THIS WILL ALLOW THUNDERSTORMS THAT DEVELOP OVER THE
HIGHER TERRAIN TO DEVELOP SOUTHWEST INTO THE SOUTH-CENTRAL DESERT
AREAS INCLUDING THE GREATER PHOENIX AREA TONIGHT. SOME OF THESE
THUNDERSTORMS WILL BE SEVERE WITH STRONG GUSTY DAMAGING WINDS...AND
LOCALLY HEAVY RAIN. AS THE LOW CONTINUES MOVING WEST...EXPECT THE
CHANCE OF SHOWERS AND THUNDERSTORMS TO SPREAD FURTHER WEST TO
SOUTHWEST ARIZONA LATE TONIGHT AND THURSDAY AND SOUTHEAST CALIFORNIA
THURSDAY AND THURSDAY NIGHT. WITH THE LOW PRESSURE CONTINUING TO
LINGER...THE CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO
CONTINUE THROUGH FRIDAY...AND TO A LESSER EXTENT SATURDAY. THE LOW
PRESSURE SYSTEM IS EXPECTED TO MOVE NORTH BY LATE SUNDAY AND EARLY
NEXT WEEK. AT THE SAME TIME...HIGH PRESSURE WILL BEGIN TO BUILD WITH
A SLOW RECOVERY OF TEMPERATURES AND LESS THUNDERSTORMS LATE SUNDAY
AND EARLY NEXT WEEK.

.PSR...NONE.

ELLIS

Hazardous weather outlook, Aug 13, 2:28 PM MST, 5 hours 22 minutes before

AZZ020>028-CAZ030>033-140100-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
915 AM MST WED AUG 13 2003

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

.DAY ONE...TODAY

THERE IS AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS IN
SOUTH-CENTRAL ARIZONA TONIGHT. STRONG GUSTY POSSIBLY DAMAGING WINDS
...DENSE BLOWING DUST WITH REDUCED VISIBILITY...AND LOCALLY HEAVY
RAIN ARE EXPECTED WITH SOME STORMS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPREAD WEST INTO SOUTHWEST
ARIZONA AND PORTIONS OF SOUTHEAST CALIFORNIA THURSDAY AFTERNOON AND
EVENING. THE GREATEST THREAT WITH THESE STORMS IS HEAVY RAIN.
HOWEVER...STRONG GUSTY POSSIBLY DAMAGING WINDS ARE ALSO POSSIBLE...
ALONG WITH DENSE BLOWING DUST AND SAND WITH REDUCED VISIBILITY. THE
CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE FRIDAY...THEN
DIMINISH THIS WEEKEND.

.INSTRUCTIONS TO SPOTTERS...
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

ELLIS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 13, 7:03 PM MST	Severe Thunderstorm Warning	PSR	Pinal	42 min
Aug 13, 8:37 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	38 min
Aug 13, 9:24 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	51 min
Aug 14, 4:19 PM MST	Severe Thunderstorm Warning	PSR	Pinal	56 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2003 Every severe thunderstorm warning in 2003

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.