Alert archive / Arizona / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 63, NWS Phoenix, AZ

September 3, 2004Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Sep 3, 2004, 5:43 PM MST for Maricopa County, Arizona. It was in force for 47 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 3, 2004, 5:43 PM MST (00:43 UTC)
Expired: Sep 3, 2004, 6:30 PM MST
In force: 47 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), 61 km from the middle of the area, began a volume at 00:46 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, 0.7 hours before the alert went out and 61 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1460 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KPSR 040045
SVRPSR
AZC013-040130-
/X.NEW.KPSR.SV.W.0002.040904T0043Z-040904T0130Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
545 PM MST FRI SEP 3 2004

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

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

* UNTIL 630 PM MST

* AT 545 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DIME SIZE HAIL...AND
  DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED NEAR
  RIO VERDE...OR ABOUT 6 MILES NORTHEAST OF FOUNTAIN HILLS...AND
  MOVING NORTHEAST AT 30 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
  SUNFLOWER. THE STORM WILL TRACK ALONG AND JUST NORTH OF THE
  BEELINE HIGHWAY...NEAR BARTLETT LAKE. 

DENSE BLOWING DUST IS POSSIBLE WITH THIS SEVERE STORM. VISIBILITIES 
MAY BE REDUCED AT TIMES TO NEAR ZERO...MAKING FOR VERY DANGEROUS 
DRIVING CONDITIONS. BE SURE TO SLOW DOWN IF DENSE BLOWING DUST IS 
ENCOUNTERED AND LEAVE PLENTY OF ROOM BETWEEN YOU AND THE CAR AHEAD OF
YOU. SEVERE STORMS IN ENVIRONMENTS SUCH AS THIS CAN AND SOMETIMES DO 
PRODUCE TORNADOES WITH LITTLE OR NO WARNING.

LAT...LON 3357 11161 3370 11176 3400 11163 3400 11148
      3397 11146 3393 11145 3391 11141 3384 11137
      3377 11138 3371 11133

$$

DG

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 3, 3:07 PM MST, 2 hours 36 minutes earlier.

Area forecast discussion, Sep 3, 3:07 PM MST, 2 hours 36 minutes before

AZZ020>028-CAZ030>033-040545-

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
307 PM MST FRI SEP 3 2004

SOUTHWEST AND SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA
FORECAST DISCUSSION

.SYNOPSIS...
AN UNSEASONABLY STRONG TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE
REGION TONIGHT AND THIS WEEKEND FOR A CHANGE IN WEATHER CONDITIONS.
MOISTURE IS EXPECTED TO MOVE NORTHWARD INTO THE AREA...AND COMBINED
WITH THE STRONG WEATHER SYSTEM...WILL LEAD TO A THREAT OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON THROUGH SUNDAY...ALONG WITH BREEZY
TO WINDY CONDITIONS AND COOLER TEMPERATURES. THE TROUGH OF LOW
PRESSURE WILL MOVE EAST OF ARIZONA BY LATE SUNDAY...FOR WARMER AND
DRIER CONDITIONS THE FIRST HALF OF NEXT WEEK.

&&

.DISCUSSION...
SAT IMAGERY THIS AFTERNOON SHOWS MOSTLY CLEAR SKIES OVER SOUTHEAST
CALIFORNIA...AND PARTLY SUNNY SKIES OVER SOUTHWEST AND SOUTH-CENTRAL
ARIZONA. MOISTURE FROM HURRICANE HOWARD WILL CONTINUE TO MOVE ACROSS
NORTHERN MEXICO AND INTO ARIZONA AND NEW MEXICO OVER THE NEW 24-36
HOURS. WERE ALREADY SEEING A SIGNIFICANT INCREASE IN LOW
LEVEL MOISTURE WITH DEW POINTS ACROSS THE DESERTS IN THE MID TO
UPPER 50S (UP ABOUT 8-10 DEG FROM THIS TIME YESTERDAY). PWATER ON
THE PSR 18Z SOUNDING WAS 1.21 INCHES...UP FROM 0.95 INCHES
YESTERDAY. MEANWHILE...AN UNSEASONABLY STRONG TROUGH OF LOW PRESSURE
IN THE WESTERLIES IS CONTINUING TO WORK ITS WAY INTO THE PICTURE.
THE DYNAMICS WITH THIS SYSTEM ARE QUITE IMPRESSIVE...WITH A MAJOR
VORT MAX EXPECTED TO ROTATE THROUGH ARIZONA SOME TIME TONIGHT INTO
SATURDAY. FURTHERMORE...A MODIFIED 18Z SOUNDING WITH MIXING RATIO OF
10.4 G/KG AND A SURFACE HIGH AROUND 100 YIELDS ABOUT 1200 J/KG OF
CAPE--PRETTY IMPRESSIVE SO...THERE REALLY ARE A LOT OF FACTORS
WORKING IN FAVOR OF SHOWERS AND T-STORMS IN THE VALLEY THIS EVENING
AND SAT. THE ONLY REAL NEGATIVE IS THE STEERING FLOW...WHICH IS OUT
OF THE SOUTHWEST. HOWEVER...STORMS THIS EVENING WILL BE SYNOPTICALLY
DRIVEN...AND WE DONT REALLY NEED THE OUTFLOW FROM HIGHER TERRAIN
STORMS TO THE NORTH AND EAST (LIKE WE TYPICALLY DO DURING THE SUMMER
CONVECTIVE SEASON) TO GET THINGS GOING. SO WHAT DOES ALL THIS MEAN?
BOTTOM LINE...CENTRAL ARIZONA IS SITTING BETWEEN MOIST SUBTROPICAL
AIR TO THE SOUTHEAST AND A STRONG WEATHER SYSTEM TO THE NORTHWEST.
DEPENDING ON HOW FAR NORTH AND JUST HOW MUCH MOISTURE WORKS ITS WAY
INTO THE VALLEY...WE COULD GET A PRETTY DECENT ROUND OF SHOWERS AND
THUNDERSTORMS... MAINLY AFTER MIDNIGHT AND LASTING THROUGH THE
MORNING HOURS. THAT SAID...HAVE BUMPED POPS ACROSS MARICOPA AND
PINAL COUNTIES EASTWARD TO CHANCE CATEGORY AFTER MIDNIGHT..AND
LASTING THROUGH 18Z SAT...WITH A SLIGHT CHANCE IN THE
AFTERNOON/EVENING. AS FOR SOUTHEAST CALIFORNIA AND FAR WESTERN
ARIZONA...STRONG GUSTY WINDS WITH AREAS OF BLOWING DUST AND SAND
WILL BE THE MAIN THREAT ...AS THE MOISTURE BOUNDARY STAYS TO THE
SOUTHEAST OF THAT AREA. HOWEVER...THE ENTIRE CWA WILL EXPERIENCE
COOLER TEMPS SAT/SUN...AND PHX WILL LIKELY STAY BELOW 100 DEG. BY
LATE SUNDAY...THE TROUGH IS OVER NEW MEXICO...WITH LINGERING
MOISTURE OVER THE SOUTH-CENTRAL DESERTS...AND ESPECIALLY OVER THE
HIGHER TERRAIN EAST OF PHX FOR A DAILY THREAD OF SHOWERS AND TSTORMS
THROUGH THE MID PART OF NEXT WEEK. TEMPS WILL SLOWLY RAISE BEGINNING
EARLY NEXT WEEK...AND SHOULD BACK OVER THE CENTURY MARK BY MONDAY.
&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.
CA...NONE.

&&

22

Hazardous weather outlook, Sep 3, 3:50 PM MST, 1 hour 53 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
350 PM MST FRI SEP 3 2004

AZZ022>024-027-028-041300-
GREATER PHOENIX AREA-NORTHWEST AND NORTH CENTRAL PINAL COUNTY-
NORTHWEST MARICOPA COUNTY-SOUTHERN GILA/TONTO NF FOOTHILLS-
SOUTHWEST MARICOPA COUNTY-
350 PM MST FRI SEP 3 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH-CENTRAL
ARIZONA...INCLUDING THE GREATER PHOENIX AREA.

.DAY ONE...TODAY
THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING...INCREASING AFTER MIDNIGHT. STRONG GUSTY WINDS AND CLOUD TO
GROUND LIGHTNING WILL BE THE PRIMARY WEATHER HAZARDS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE SATURDAY AND
SUNDAY...WITH STRONG GUSTY WINDS AND LOCALLY HEAVY RAIN POSSIBLE. NO
HAZARDOUS WEATHER IS EXPECTED MONDAY THROUGH THURSDAY.

AZZ020-021-025-026-CAZ030>033-041300-
IMPERIAL COUNTY-JOSHUA TREE NATIONAL PARK-
LOWER COLORADO RIVER VALLEY AZ-LOWER COLORADO RIVER VALLEY CA-
RIVERSIDE COUNTY/EASTERN DESERTS-SOUTHWEST DESERTS-
WEST CENTRAL DESERTS-YUMA/MARTINEZ LAKE AND VICINITY-
350 PM MST FRI SEP 3 2004

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

.DAY ONE...TODAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 3, 6:22 PM MST	Severe Thunderstorm Warning	PSR	Pinal	53 min
Sep 3, 6:40 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	50 min
Sep 3, 7:15 PM MST	Severe Thunderstorm Warning	PSR	Pinal	45 min
Sep 3, 7:42 PM MST	Severe Thunderstorm Warning	PSR	Gila, Maricopa	48 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2004 Every severe thunderstorm warning in 2004

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.