Alert archive / Arizona / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 22, NWS Tucson, AZ

July 25, 2001Pima County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Jul 25, 2001, 5:09 PM MST for Pima County, Arizona. It was in force for 36 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, 5:09 PM MST (00:09 UTC)
Expired
Jul 25, 2001, 5:45 PM MST
In force
36 min
Issued by
NWS Tucson, AZ
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Pima County, AZ

The radar

The Tucson radar (KEMX), 37 km from the middle of the area, began a volume at 00:13 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

Tuscon, AZ (KTUS), launched 00:00Z, 0.2 hours before the alert went out and 5 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-pSkew-T log-p diagram, Tuscon, AZ at 00:00Z on 2001-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 498 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tuscon, AZ at 00:00Z on 2001-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -38 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
498 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
2527 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-38 m²/s²
0-3 km storm-relative helicity
-21 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.4

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KTWC 260010
SVRTUS

AZC019-260045-

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

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL PIMA COUNTY IN ARIZONA
  THIS INCLUDES TUCSON

* UNTIL 545 PM MST

* AT 503 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 6 MILES SOUTHEAST OF TUCSON...MOVING NORTH AT
  10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  TUCSON AT 520 PM MST

WIND GUSTS TO 60 MPH ARE LIKELY. MOVE INSIDE A STRONG BUILDING.

LAT...LON 3205 11094 3204 11071 3234 11072 3234 11095

PYTLAK

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 Tucson, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 25, 4:51 PM MST, 18 minutes earlier.

Area forecast discussion, Jul 25, 4:51 PM MST, 18 minutes before
SOUTHEAST ARIZONA FORECAST DISCUSSION...MESOSCALE UPDATE
NATIONAL WEATHER SERVICE TUCSON AZ
451 PM MST WED JUL 25 2001

SYNOPSIS...A LOW PRESSURE SYSTEM NEAR LAS VEGAS WILL MOVE NORTHEAST
INTO UTAH ON THURSDAY. SOUTHWEST FLOW BEHIND THIS SYSTEM WILL BRING
PROGRESSIVELY DRIER AIR INTO THE REGION FOR THE REST OF THE WEEK.
MOISTURE MAY ONCE AGAIN INCREASE EARLY NEXT WEEK AS HIGH PRESSURE
ORGANIZES OVER NEW MEXICO.

DISCUSSION...TAIL OF THE UPPER LEVEL LOW IGNITED SEVERAL STRONG
HEAVY RAINERS AS SOON AS IT MADE CONTACT WITH THE SHEAR AXIS
EXTENDING FROM SANTA CRUZ COUNTY INTO E PINAL/W GRAHAM COUNTY.
STORMS HAVE BEEN TRYING TO BACKBUILD SW, BUT THEY KEEP RUNNING INTO
THE UPPER LEVEL CAP WHICH IS STRENGTHENING OVER W PIMA COUNTY. THIS
IS CREATING A TEMPERATURE AND MOISTURE BOUNDARY FOR NEW CELLS TO
FIRE AND TRAIN, AND WILL WORK WITH 15KTS OF LOW LEVEL SW FLOW AS
WELL AS A LITTLE DIRECTIONAL SHEAR. ACCORDING TO THE LATEST VISIBLE
IMAGERY, THIS BOUNDARY LIES RIGHT ALONG I-19 FROM NOGALES TO TUCSON,
AND THEN N ACROSS THE CATALINAS TOWARD ORACLE AND WINKLEMAN. FLASH
FLOODING CONTINUES TO BE THE PRIMARY THREAT IN THIS RATHER NARROW
CORRIDOR. RAINFALL RATES UP TO 2 INCHES PER HOUR HAVE BEEN COMMON
ACCORDING TO 88D ESTIMATES, AND BASED ON THE REFLECTIVITY PROFILES
(MOST OF THE HIGH REFLECTIVITIES IN THE LOWER PARTS OF THE STORM),
HAIL CONTAMINATION IS PROBABLY MINIMAL. PYTLAK

.TWC...NONE.

In the hours before

Special weather statement, Jul 25, 12:27 PM MST, 4 hours 42 minutes before
AZZ019-029>035-250700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1145 MST TUE JUL 24 2001

.SYNOPSIS...THE LOW PRESSURE SYSTEM NEAR LAS VEGAS HAS PULLED
MONSOON MOISTURE INTO SOUTHEAST ARIZONA.  THUNDERSTORM ACTIVITY HAS
ALREADY DEVELOPED AND WILL CONTINUE INTO THE LATE AFTERNOON AND
EVENING HOURS.  THE SEVERE THUNDERSTORM AND FLASH FLOODING THREAT IS
ABOVE CLIMATOLOGY ACROSS THE ENTIRE COUNTY WARNING AREA.

.DISCUSSION...THE INFLUX OF MOISTURE FROM MEXICO IS EVIDENT FROM THE
INCREASE IN DEWPOINT TEMPERATURES ACROSS SOUTHEAST ARIZONA.  THIS
CAN ALSO BE SEEN IN INFRARED AND WATER VAPOR IMAGERY.  THUNDERSTORM
ACTIVITY IS ALREADY ERUPTING ALONG THE MID LEVEL DRY LINE...SEEN IN
WATER VAPOR IMAGERY.  THE 18Z TUS SOUNDING SHOWED WIND INCREASING 10
TO 15 KNOTS...2000 CAPE VALUE...AND A LIFTED INDEX OF MINUS 6.  THE
BEST CHANCE OF SEVERE THUNDERSTORMS WILL BE ALONG THIS MID LEVEL DRY
LINE...AN AREA FROM CENTRAL PIMA TO CENTRAL GRAHAM AND COCHISE
COUNTIES.  SO FOR THE LATE AFTERNOON AND EVENING ORGANIZED AND
STRONG CONVECTION IS POSSIBLE.

THE FLASH FLOOD THREAT WILL ALSO BE ABOVE CLIMATOLOGY ACROSS THE
COUNTY WARNING AREA...WITH THE BEST CHANCES EXTENDING FROM EASTERN
PIMA THROUGH THE EASTERN COUNTIES....THIS INCLUDES
COCHISE...GRAHAM...SANTA CRUZ...GREENLEE COUNTIES THROUGH THE LATER
EVENING HOURS. SOME CELL TRAINING COULD OCCUR AND SOME STORMS COULD
LINGER INTO THE OVERNIGHT.

STORM MOVEMENT WILL BE NORTHEAST 15 MPH.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 6:10 PM MSTFlash Flood WarningTWCPima50 min
Jul 26, 2:07 PM MSTFlash Flood WarningTWCSanta Cruz53 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2001Every 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.