Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 18, NWS Tucson, AZ

July 17, 1998Graham County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Jul 17, 1998, 8:17 PM MST for Graham 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: Jul 17, 1998, 8:17 PM MST (03:17 UTC)
Expired: Jul 17, 1998, 9:05 PM MST
In force: 48 min
Issued by: NWS Tucson, AZ
Area: Whole counties

County Graham County, AZ

The radar

The Tucson radar (KEMX), 135 km from the middle of the area, began a volume at 03:19 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, 3.3 hours before the alert went out and 127 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: 979 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 3214 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

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

974 
WUUS1 KTUS 180318 RRA
SVRTUS
AZC009-180405-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
817 PM MST FRI JUL 17 1998

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL GRAHAM COUNTY IN SOUTHEASTERN ARIZONA

* UNTIL 905 PM MST

* AT 821 PM MST... DOPPLER RADAR INDICATED A LINE OF SEVERE
  THUNDERSTORMS APPROACHING THE GILA RIVER VALLEY INCLUDING SAFFORD
  AND THATCHER.  THESE STORMS ARE EXPECTED TO PRODUCE WIND GUSTS UP
  TO 65 MPH AS THEY MOVE OFF THE GILA MOUNTAINS INTO VALLEY
  LOCATIONS.

* THE SEVERE THUNDERSTORMS WILL BE NEAR...
     SAFFORD BY 845 PM MST

BRYANT

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 17, 2:30 PM MST, 5 hours 47 minutes earlier.

Area forecast discussion, Jul 17, 2:30 PM MST, 5 hours 47 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST FRI JUL 17 1998

SYNOPSIS...AN EASTERLY AIRFLOW AROUND AN UPPER HIGH CENTERED OVER
SOUTHERN NEVADA AND SOUTHWEST UTAH WILL CONTINUE TO INCREASE THE
MOISTURE OVER SOUTHEAST ARIZONA FOR AN UPSWING IN THUNDERSTORM
ACTIVITY THROUGH THE WEEKEND.

DISCUSSION...THE AIR MASS IS A LITTLE MORE MOIST TODAY THAN
YESTERDAY PER TUCSON SOUNDING THIS MORNING AND A LITTLE HIGHER
SURFACE DEW POINTS. THIS MOISTENING TREND WILL CONTINUE NEXT 24
HOURS AS HIGHER MOISTURE VALUES RESIDING TO OUR EAST IN NEW MEXICO
WILL BE ADVECTED INTO SOUTHEAST ARIZONA IN THE EASTERLY FLOW.
MODIFIED SOUNDING SHOWS CAPE AROUND 1100J/KG THIS AFTERNOON WHICH IS
A LITTLE HIGHER THAN YESTERDAY SO SHOULD SEE ANOTHER GOOD FIREWORKS
SHOW THIS EVENING ON THE LOWER DESERTS AS OUTFLOWS FROM THE RIM
COUNTRY PROPAGATE INTO THE LOWER DESERTS THIS EVENING AND INITIATE
THUNDERSTORMS. MAIN CONCERN AGAIN WILL BE STRONG DOWNBURST WINDS DUE
TO INVERTED V TYPE SOUNDING. ANOTHER THING THAT WILL HELP BEEF UP
THUNDERSTORM ACTIVITY LATE THIS AFTERNOON AND EVENING IS A CYCLONIC
CIRCULATION SEEN IN WATER VAPOR IMAGERY OVER WEST CENTRAL NEW MEXICO
WHICH WILL ADD DYNAMICAL SUPPORT TO THUNDERSTORM FORMATION AS IT
MOVES ACROSS SOUTHEAST ARIZONA THIS EVENING. SATURDAY AND SUNDAY
WILL CONTINUE TO BE ACTIVE AS THIS EASTERLY FLOW CONTINUES. THIS
SAME PATTERN CONTINUES THROUGH MIDWEEK.

TUS 5343. COLLINS

.TWC...NONE.

In the hours before

Local storm report, Jul 17, 6:10 PM MST, 2 hours 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON ARIZONA
610 PM MST FRI JUL 17 1998

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

605  PM    RYAN FIELD                AZ   WIND DAMAGE
07/17/98   PIMA                           94 MPH WIND GUST

600  PM    TUCSON                    AZ   WIND DAMAGE
07/17/98   PIMA                           MOBILE HOME ROOF DESTROYED

Local storm report, Jul 17, 7:00 PM MST, 1 hour 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON ARIZONA
610 PM MST FRI JUL 17 1998

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

605  ZPM    RYAN FIELD                AZ   WIND DAMAGE
07/17/98   PIMA                           94 MPH WIND GUST

600  PM    TUCSON                    AZ   WIND DAMAGE
07/17/98   PIMA                           MOBILE HOME ROOF DESTROYED

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 5:41 PM MST	Severe Thunderstorm Warning	TWC	Pima	49 min
Jul 17, 6:25 PM MST	Severe Thunderstorm Warning	TWC	Pima	60 min
Jul 17, 7:25 PM MST	Severe Thunderstorm Warning	TWC	Pima	45 min
Jul 17, 7:33 PM MST	Severe Thunderstorm Warning	TWC	Greenlee	47 min
Jul 17, 8:09 PM MST	Severe Thunderstorm Warning	TWC	Pima	61 min
Jul 17, 11:14 PM MST	Severe Thunderstorm Warning	TWC	Pinal	46 min
Jul 18, 12:15 AM MST	Severe Thunderstorm Warning	TWC	Pima	90 min
Jul 18, 1:44 AM MST	Severe Thunderstorm Warning	TWC	Pima	46 min
Jul 18, 1:37 PM MST	Severe Thunderstorm Warning	TWC	Santa Cruz	48 min
Jul 18, 2:08 PM MST	Severe Thunderstorm Warning	TWC	Pima, Santa Cruz	62 min
Jul 18, 2:44 PM MST	Severe Thunderstorm Warning	TWC	Pima	46 min
Jul 18, 3:25 PM MST	Severe Thunderstorm Warning	TWC	Pima	45 min

Nearby

Severe Thunderstorm Warnings in Arizona, 1998 Every 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.