Alert archive / Arizona / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 12, NWS Phoenix, AZ

July 25, 2001Maricopa County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 25, 2001, 9:47 PM MST for Maricopa County, Arizona. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Jul 25, 2001, 9:47 PM MST (04:47 UTC)
Expired: Jul 25, 2001, 10:30 PM MST
In force: 43 min
Issued by: NWS Phoenix, AZ
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 68 km from the middle of the area, began a volume at 04:47 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.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 4.8 hours before the alert went out and 196 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: 2 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 1022 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 97 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 260448
SVRPHX

AZC013-260530-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
947 PM MST WED JUL 25 2001

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL MARICOPA COUNTY IN WEST CENTRAL ARIZONA...INCLUDING
  THE COMMUNITIES OF AVONDALE...TOLLESON...WEST PHOENIX...GLENDALE

* UNTIL 1030 PM MST

* AT 937 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER TOLLESON...MOVING NORTHWEST AT 25 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.

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 3338 11235 3346 11215 3376 11230 3366 11255

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 25, 9:40 PM MST, 7 minutes earlier.

Area forecast discussion, Jul 25, 9:40 PM MST, 7 minutes before

AZZ020>028-CAZ030>033-261045-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
940 PM MST WED JUL 25 2001

.SYNOPSIS...
AN UPPER LOW PRESSURE SYSTEM OVER SOUTHERN NEVADA WILL MOVE SLOWLY
NORTHEAST TO SOUTHERN UTAH BY THURSDAY. AS THIS HAPPENS...ABUNDANT
MOISTURE CURRENTLY OVER SOUTH-CENTRAL AND EASTERN ARIZONA WILL
GRADUALLY BE PUSHED EASTWARD. AS THE LOW INTERACTS WITH THE
MOISTURE...SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR OVER
PORTIONS OF SOUTH CENTRAL ARIZONA TONIGHT...AND LOCALLY HEAVY RAIN
WILL BE POSSIBLE WITH THE STRONGEST STORMS. FROM THURSDAY AFTERNOON
THROUGH THE UPCOMING WEEKEND...THE AREA MOST LIKELY TO EXPERIENCE A
SHOWER OR STORM WILL BE THE HIGHER TERRAIN OF SOUTH CENTRAL ARIZONA.

.DISCUSSION...
ALWAYS HAVE TO BE ON ALERT WHEN DRY AIR IMPINGES ON MOIST AIR AND
DYNAMICS ARE PRESENT...WHICH IS THE CASE OVER SOUTH CENTRAL AZ
TONIGHT. UNSTABLE AIR RESIDES OVER SOUTH CENTRAL AZ THIS EVENING
...WITH 850-700 MB THETA-E RIDGE OVER THE EASTERN HALF OF AZ.
MOISTURE GRADIENT IS QUITE STEEP FROM SFC RIGHT ON UP TO AT LEAST
400 MB...PER PLOT DATA...SATELLITE DERIVED P-WATER IMAGES...AND WV
IMAGERY. SFC DEW POINTS QUITE HIGH IN PHX AREA...IN THE MID TO UPPER
60S...WHILE UPPER 40S DEW POINTS OBSERVED AT GILA BEND. IN THE SHORT
TERM...PERSISTENT LOW LEVEL CONVERGENCE OCCURRING OVER PHX METRO
...WITH SFC WINDS FROM THE NORTHEAST OVER NORTHERN PORTION OF THE
METRO ...SOUTHEAST OVER SOUTHERN PORTION OF METRO THANKS TO OUTFLOW
FROM CONVECTION THAT AFFECTED SOUTHEAST PINAL COUNTY EARLIER THIS
EVENING...LIGHT NORTHWEST AT LUKE AFB...WEST-SOUTHWEST AT GILA
BEND...AND SOUTHERLY OVER NORTHWEST PINAL COUNTY. THUNDERSTORMS
DEVELOPING ALONG A NNE-SSW ORIENTED BAND EXTENDING FROM THE SAND
TANK MOUNTAINS TO NEAR SUN LAKES ATTM...AND WITH INDIVIDUAL CELLS
MOVING TOWARD THE NORTH-NORTHEAST...LOCALLY HEAVY RAINFALL IS
POSSIBLE...ESPECIALLY OVER NORTHWEST PINAL COUNTY AND CENTRAL
/EASTERN MARICOPA COUNTY...AT LEAST THROUGH MIDNIGHT.  ALL IN
ALL...LOOKS LIKE A RELATIVELY ACTIVE NIGHT WEATHERWISE...AT LEAST
IN THE PHOENIX AREA.

AM A BIT CONCERNED ABOUT IMPACT ONGOING CONVECTION JUST SOUTH OF
INTERNATIONAL BORDER MAY HAVE ON US THURSDAY...INCLUDING DEGREE OF
CLOUD COVER...MAX TEMPS...DEGREE OF LOW LEVEL MOISTURE...ETCETC.
WILL LET MIDSHIFT DO BATTLE WITH THIS! DG

Nearby

Severe Thunderstorm Warnings in Arizona, 2001 Every severe thunderstorm warning in 2001

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.