Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 57, NWS Tucson, AZ

August 18, 2002Santa Cruz County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Aug 18, 2002, 3:16 PM MST for Santa Cruz County, Arizona. It was in force for 29 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 18, 2002, 3:16 PM MST (22:16 UTC)
Expired
Aug 18, 2002, 3:45 PM MST
In force
29 min
Issued by
NWS Tucson, AZ
Area
Counties, with a storm outline in the text

County Santa Cruz County, AZ

The radar

The Tucson radar (KEMX), 50 km from the middle of the area, began a volume at 22:20 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

Tuscon, AZ (KTUS), launched 12:00Z, 10.3 hours before the alert went out and 71 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 12:00Z on 2002-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1010 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tuscon, AZ at 12:00Z on 2002-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -62 square meters per square second.1939Sfc1 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
1010 J/kg
Mixed-layer CIN
-157 J/kg
Mixed-layer LCL
2013 m above ground
0-6 km bulk shear
1 kt
0-1 km storm-relative helicity
-62 m²/s²
0-3 km storm-relative helicity
-20 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.

337 
WUUS55 KTWC 182216
SVRTWC
AZC023-182245-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
315 PM MST SUN AUG 18 2002

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL SANTA CRUZ COUNTY IN ARIZONA
    THIS INCLUDES THE CITY OF NOGALES

* UNTIL 345 PM MST

* AT 305 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM 7 MILES NORTH OF NOGALES...OR NEAR RIO       
  RICO...MOVING WEST AT 10 MPH.

THIS WARNING REPLACES THE PREVIOUS SEVERE THUNDERSTORM WARNING FOR
THIS AREA.

LAT...LON 3163 11114 3136 11107 3136 11069 3170 11075

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 Aug 18, 2:10 PM MST, 1 hour 6 minutes earlier.

Area forecast discussion, Aug 18, 2:10 PM MST, 1 hour 6 minutes before
SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
210 PM MST SUN AUG 18 2002

.SYNOPSIS...HIGH PRESSURE OVER NORTHERN ARIZONA WILL MOVE EAST AS
LOW PRESSURE ALOFT DEVELOPS ALONG THE WEST COAST THE NEXT FEW DAYS.
THIS PATTERN WILL PROVIDE SOUTHERLY FLOW AND AN INCREASE IN MOISTURE
FOR SOUTHEAST ARIZONA. LOOK FOR AN INCREASE IN THUNDERSTORM ACTIVITY
THIS WEEK.

.DISCUSSION...CONVECTION HAS EVOLVED AS EXPECTED SO FAR THIS
AFTERNOON. INITIAL DEVELOPMENT HAS BEEN RAPID AND STRONG OVER THE
MOUNTAINS. A VERY WEAK SHEAR PROFILE ALONG WITH A NEARLY
NON-EXISTENT STEERING FLOW HAS SEEN THEM DIE IN PLACE WITH LITTLE
INCLINATION TO PUSH INTO VALLEY LOCATIONS THUS FAR. WE MAY BE ABLE
TO GET LUCKY WITH OUTFLOW IN SOME SPOTS...BUT NOT AS A WIDESPREAD
TREND. MOISTURE TRENDS ARE ON THE INCREASE ACROSS THE AREA WITH AN
EBB FROM THE SOUTH. GOES SOUNDER PW ESTIMATES IN THE 1.2 TO 1.3 INCH
RANGE...AND SURFACE DEWPTS HOLDING IN THE 55 TO 60 RANGE (ABOUT 5
DEGREES BETTER THAN YESTERDAY). SO...ITS NOT OVER YET FOR THIS
AFTERNOON AND EVENING.

NICE COMPLEX ORGANIZING IN NORTHWEST MEXICO UNDER THE INFLUENCE OF
WEAKNESS IN FLOW. MAKING A PUSH IN OUR DIRECTION...COULD INFLUENCE
STORM DEVELOPMENT FROM THE SOUTH IN THE EVENING HOURS. AS THE HIGH
REFORMS TO OUR EAST AND THE SOUTHERLY FLOW INCREASES...WELL GET THE
DEEPER MOISTURE AND A MUCH MORE FAVORABLE PROFILE FOR CONVECTION BY
LATE MONDAY AND TUESDAY OVER THE AREA WITH AN EASTERLY WAVE ROTATING
THROUGH AROUND THE HIGH. AFTER THAT...STANDARD SEASONAL THUNDERSTORM
FORECAST WITH DRY WESTERLY COMPONENT TRYING TO PUSH INTO FAR WESTERN
AND NORTHERN AREAS FROM A DEVELOPING WEST COAST TROUGH. MOST OF OUR
AREA SHOULD MAINTAIN A MOIST THUNDERSTORM FLOW. M

TWC...NONE.

In the hours before

Special weather statement, Aug 18, 10:53 AM MST, 4 hours 23 minutes before
AZZ019-029>035-190700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1145 AM MST SUN AUG 18 2002

.SYNOPSIS...A TYPICAL DAY WITH SUFFICIENT MOISTURE AND INSTABILITY
FOR CONVECTION TO DEVELOP OVER HIGHER TERRAIN. SOME STORMS WILL MOVE
INTO VALLEY LOCATIONS...BUT A WEAK SHEAR PROFILE AND SLOW STORM
MOVEMENT MAY INHIBIT THIS PROCESS. EXPECT THE CHANCES OF SEVERE
STORMS AND 1 INCH OR GREATER RAINFALL TO BOTH BE SUPERIOR TO
SATURDAY AND NEAR CLIMATOLOGY.

.DISCUSSION...12Z KTUS SOUNDING MOISTURE PROFILE PROBABLY A LITTLE
HOKEY AS PER THE MORNING AFD. EVEN SO...THE MOISTURE TREND WILL
INDEED BE UP OVER THE NEXT 24 TO 48 HRS AS MOISTURE SEEPS IN FROM
THE SOUTH. SOME SURGE SIGNATURE CONTINUES AT YUMA...BUT NOT
GANGBUSTERS. DECENT STORMS WILL HAVE NO PROBLEM FORMING OVER THE
MOUNTAINS AS USUAL. A LESS-THAN-FAVORABLE SHEAR PROFILE AND STEERING
FLOW MAY SHORTEN THE LIFE OF STORMS WHILE ALSO KEEPING THEM CLOSER
TO HIGHER TERRAIN IN GENERAL...ESPECIALLY EARLY IN THE AFTERNOON.

INDIVIDUAL CELL MOVEMENT WILL BE TO THE WEST OR NORTHWEST AT 5 TO 8
MPH.
Special weather statement, Aug 18, 11:45 AM MST, 3 hours 31 minutes before
AZZ019-029>035-190700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1145 AM MST SUN AUG 18 2002

.SYNOPSIS...A TYPICAL DAY WITH SUFFICIENT MOISTURE AND INSTABILITY
FOR CONVECTION TO DEVELOP OVER HIGHER TERRAIN. SOME STORMS WILL MOVE
INTO VALLEY LOCATIONS...BUT A WEAK SHEAR PROFILE AND SLOW STORM
MOVEMENT MAY INHIBIT THIS PROCESS. EXPECT THE CHANCES OF SEVERE
STORMS AND 1 INCH OR GREATER RAINFALL TO BOTH BE SUPERIOR TO
SATURDAY AND NEAR CLIMATOLOGY.

.DISCUSSION...12Z KTUS SOUNDING MOISTURE PROFILE PROBABLY A LITTLE
HOKEY AS PER THE MORNING AFD. EVEN SO...THE MOISTURE TREND WILL
INDEED BE UP OVER THE NEXT 24 TO 48 HRS AS MOISTURE SEEPS IN FROM
THE SOUTH. SOME SURGE SIGNATURE CONTINUES AT YUMA...BUT NOT
GANGBUSTERS. DECENT STORMS WILL HAVE NO PROBLEM FORMING OVER THE
MOUNTAINS AS USUAL. A LESS-THAN-FAVORABLE SHEAR PROFILE AND STEERING
FLOW MAY SHORTEN THE LIFE OF STORMS WHILE ALSO KEEPING THEM CLOSER
TO HIGHER TERRAIN IN GENERAL...ESPECIALLY EARLY IN THE AFTERNOON.

INDIVIDUAL CELL MOVEMENT WILL BE TO THE WEST OR NORTHWEST AT 5 TO 8
MPH.
Local storm report, Aug 18, 2:51 PM MST, 25 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON ARIZONA
0251 PM MST SUN AUG 18 2002

TIME (MST) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0232 PM    NOGALES                   AZ   60 MPH TSTM GUST
08/18/02   SANTA CRUZ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 3:25 PM MSTFlash Flood WarningTWCSanta Cruz95 min
Aug 18, 3:25 PM MSTFlash Flood WarningTWCSanta Cruz35 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2002Every 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.