Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 81, NWS Tucson, AZ

September 5, 1998Pima County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Sep 5, 1998, 2:17 PM MST for Pima County, Arizona. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 5, 1998, 2:17 PM MST (21:17 UTC)
Expired
Sep 5, 1998, 3:05 PM MST
In force
48 min
Issued by
NWS Tucson, AZ
Area
Whole counties

County Pima County, AZ

The radar

The Tucson radar (KEMX), 112 km from the middle of the area, began a volume at 21:18 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 12:00Z, 9.3 hours before the alert went out and 84 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 1998-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 191 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 1998-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 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
191 J/kg
Mixed-layer CIN
-210 J/kg
Mixed-layer LCL
1289 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
162 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.

140 
WUUS1 KTUS 052119 RRA
SVRTUS
AZC019-052205-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
217 PM MST SAT SEP 5 1998

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN PIMA COUNTY IN SOUTHERN ARIZONA
  AVRA VALLEY AND RYAN FIELD

* UNTIL 305 PM MST

* AT 217 PM MST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  NEAR RYAN FIELD MOVING NORTH NORTHEAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  AVRA VALLEY BY 230 PM MST


JD

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 Sep 5, 9:20 AM MST, 4 hours 57 minutes earlier.

Area forecast discussion, Sep 5, 9:20 AM MST, 4 hours 57 minutes before
SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
920 AM MST SAT SEP 5 1998

SYNOPSIS...DRIER AIR AT MID LEVELS OF THE ATMOSPHERE WILL CONTINUE
TO MOVE INTO SOUTHEAST ARIZONA THIS WEEKEND FOR A GRADUAL DECREASE IN
THUNDERSTORM ACTIVITY. DEEPER MOISTURE IS EXPECTED TO RETURN TO THE
SOUTHEAST PORTION OF THE GRAND CANYON STATE EARLY NEXT WEEK.

DISCUSSION...ANOTHER ROUND EARLY MORNING SHOWERS EXTENDED RIGHT UP
THE SANTA CRUZ VALLEY FROM NOGALES TO TUCSON. HOWEVER...THIS TIME
THERE WAS A FEW THUNDERSTORMS EMBEDDED IN THE SHOWER ACTIVITY.
LATEST ETA MODEL PICKED UP ON A VORT MAX CENTERED OVER SOUTHWEST
ARIZONA AT 12Z WITH DECENT UPWARD VERTICAL VELOCITY VALUES OVER AN
AREA FROM NOGALES NORTH TO TUCSON AND GLOBE. THIS FITS FAIRLY WELL
WITH WHERE THE BAND OF CONVECTION WAS LOCATED THIS MORNING. ETA MODEL
LIFTS THIS FEATURE NORTHWARD TODAY WITH SOME SUBSIDENCE PROGGED IN
THE WAKE OF IT OVER THE SOUTHEAST. EXPECT MORNING SHOWERS CURRENTLY
AROUND TUCSON AND IN SOUTHEASTERN PINAL COUNTY TO DIMINISH IN THE
NEXT HOUR OR TWO. THIS CLEARING SHOULD BE EARLY ENOUGH FOR THESE
AREAS TO RECEIVE SUFFICIENT SURFACE HEATING TODAY TO SUPPORT THE
REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON. DO
NOT EXPECT THE SUBSIDENCE BEHIND THIS WEAK IMPULSE TO BE STRONG
ENOUGH TO LIMIT DEEP CONVECTION ACROSS THE SOUTHEAST. LOWER LEVELS
HAVE NOT EXPERIENCED AS MUCH DRYING AS THE MID LEVELS DURING THE PAST
24 HOURS. SO PLENTY OF MOISTURE TO WORK WITH THIS AFTERNOON. EXPECT
STORMS TO FORM OVER THE MOUNTAINS AND HIGHER TERRAIN INITIALLY WITH A
FEW MAKING THEIR WAY INTO THE LOWER VALLEYS. UPPER AIR DATA CONTINUED
TO SHOW PWATER VALUES OVER 1 INCH...SO SOME OF THE STRONGER STORMS
COULD PRODUCE LOCALLY HEAVY RAINFALL. TUS 331. DAVIS.

.TWC...NONE.

In the hours before

Special weather statement, Sep 5, 10:50 AM MST, 3 hours 27 minutes before
AZZ019-029>035-060700-
SPECIAL WEATHER STATEMENT...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1050 AM MST SAT SEP 5 1998...THIS PRODUCT IS NOT UPDATED

                        *CONDITIONAL*    *CONDITIONAL*
                AREAL    PROBABILITY   RAIN GREATER THAN   STORM
COUNTY        COVERAGE    OF SEVERE     1.00       2.00    MOTION

COCHISE          30          20          40          0     NW 15
GRAHAM           30          20          40          0     NW 15
GREENLEE         30          20          40          0     NW 15
TUCSON/ERN PIMA  30          20          40          0     NW 15
TOHONO OODHAM   30          40          60          0     NW 15
WESTERN PIMA     30          40          60          0     NW 15
SOUTHEAST PINAL  30          20          40          0     NW 15
SANTA CRUZ       30          20          40          0     NW 15

SYNOPSIS...A WEAK DISTURBANCE ROTATING AROUND A LOW PRESSURE
SYSTEM OVER SOUTHERN CALIFORNIA WILL INTERACT WITH RESIDUAL LOW
LEVEL MOISTURE ACROSS THE REGION TO PRODUCE AFTERNOON AND EVENING
THUNDERSTORMS. A COMBINATION OF SUFFICIENT DAYTIME HEATING...DEEPER
MOISTURE...AND LARGE SCALE LIFT WILL FOCUS STRONGER STORMS OVER
CENTRAL AND WESTERN PIMA COUNTY TODAY. OTHER THUNDERSTORMS WILL
INITIALLY FORM OVER THE MOUNTAINS AND HIGHER TERRAIN OF THE
SOUTHEAST...WITH A FEW MAKING THEIR WAY INTO THE LOWER DESERT
VALLEYS LATE THIS AFTERNOON AND EVENING.
*****************************************************************
KEY...AREAL COVERAGE - PERCENT OF COUNTY OR AREA THAT WILL EXPERIENCE
                  THUNDERSTORMS PROB OF SEVERE - THE PROBABILITY THAT
ANY ONE OF THE STORMS WILL                   REACH SEVERE LEVELS
(DAMAGING WIND AND/OR                   LARGE HAIL) RAIN GRTR THAN
-THE PROBABILITY THAT ANY ONE OF THE STORMS WILL PRODUCE RAIN
EXCEEDING 1 INCH OR 2 INCHES IN                   ANY LOCATION STORM
MOTION   - GENERAL DIRECTION TO WHICH THE STORMS WILL   LIKELY MOVE
AND SPEED IN MPH

NOTE...
VALID TIME IS FROM 12:45 PM TO 12 MIDNIGHT OF THE DAY OF ISSUANCE.
THIS PRODUCT IS NOT TO BE USED IN PLACE OF SEVERE THUNDERSTORM OR
FLASH FLOOD WARNINGS OR WATCHES. THIS PRODUCT IS ONLY USED FOR
OUTLOOK PURPOSES. CORRESPONDING GRAPHICS MAY BE FOUND ON THE NWS
TUCSON INTERNET PAGE AT
HTTP://NIMBO.WRH.NOAA.GOV/TUCSON/SWO/SWO.SHTML

END/JTD
Special weather statement, Sep 5, 10:50 AM MST, 3 hours 27 minutes before
AZZ019-029>035-060700-
SPECIAL WEATHER STATEMENT...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1050 AM MST SAT SEP 5 1998...THIS PRODUCT IS NOT UPDATED

                        *CONDITIONAL*    *CONDITIONAL*
                AREAL    PROBABILITY   RAIN GREATER THAN   STORM
COUNTY        COVERAGE    OF SEVERE     1.00       2.00    MOTION

COCHISE          30          20          40          0     NW 15
GRAHAM           30          20          40          0     NW 15
GREENLEE         30          20          40          0     NW 15
TUCSON/ERN PIMA  30          20          40          0     NW 15
TOHONO OODHAM   30          40          60          0     NW 15
WESTERN PIMA     30          40          60          0     NW 15
SOUTHEAST PINAL  30          20          40          0     NW 15
SANTA CRUZ       30          20          40          0     NW 15

SYNOPSIS...A WEAK DISTURBANCE ROTATING AROUND A LOW PRESSURE
SYSTEM OVER SOUTHERN CALIFORNIA WILL INTERACT WITH RESIDUAL LOW
LEVEL MOISTURE ACROSS THE REGION TO PRODUCE AFTERNOON AND EVENING
THUNDERSTORMS. A COMBINATION OF SUFFICIENT DAYTIME HEATING...DEEPER
MOISTURE...AND LARGE SCALE LIFT WILL FOCUS STRONGER STORMS OVER
CENTRAL AND WESTERN PIMA COUNTY TODAY. OTHER THUNDERSTORMS WILL
INITIALLY FORM OVER THE MOUNTAINS AND HIGHER TERRAIN OF THE
SOUTHEAST...WITH A FEW MAKING THEIR WAY INTO THE LOWER DESERT
VALLEYS LATE THIS AFTERNOON AND EVENING.
*****************************************************************
KEY...AREAL COVERAGE - PERCENT OF COUNTY OR AREA THAT WILL EXPERIENCE
                  THUNDERSTORMS PROB OF SEVERE - THE PROBABILITY THAT
ANY ONE OF THE STORMS WILL                   REACH SEVERE LEVELS
(DAMAGING WIND AND/OR                   LARGE HAIL) RAIN GRTR THAN
-THE PROBABILITY THAT ANY ONE OF THE STORMS WILL PRODUCE RAIN
EXCEEDING 1 INCH OR 2 INCHES IN                   ANY LOCATION STORM
MOTION   - GENERAL DIRECTION TO WHICH THE STORMS WILL   LIKELY MOVE
AND SPEED IN MPH

NOTE...
VALID TIME IS FROM 12:45 PM TO 12 MIDNIGHT OF THE DAY OF ISSUANCE.
THIS PRODUCT IS NOT TO BE USED IN PLACE OF SEVERE THUNDERSTORM OR
FLASH FLOOD WARNINGS OR WATCHES. THIS PRODUCT IS ONLY USED FOR
OUTLOOK PURPOSES. CORRESPONDING GRAPHICS MAY BE FOUND ON THE NWS
TUCSON INTERNET PAGE AT
HTTP://NIMBO.WRH.NOAA.GOV/TUCSON/SWO/SWO.SHTML

END/JTD

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 5, 3:03 PM MSTSevere Thunderstorm WarningTWCPima62 min
Sep 5, 3:53 PM MSTSevere Thunderstorm WarningTWCPinal62 min

Nearby

Severe Thunderstorm Warnings in Arizona, 1998Every severe thunderstorm warning in 1998

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.