Alert archive / Arizona / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 36, NWS Phoenix, AZ
NWS Phoenix, AZ issued this severe thunderstorm warning at Aug 18, 2002, 9:29 PM MST for Pinal County, Arizona. It was in force for 61 min. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 18, 2002, 9:29 PM MST (04:29 UTC)
- Expired
- Aug 18, 2002, 10:30 PM MST
- In force
- 61 min
- Issued by
- NWS Phoenix, AZ
- Area
- Counties, with a storm outline in the text
County Pinal County, AZ
The radar
The Phoenix radar (KIWA), 32 km from the middle of the area, began a volume at 04:30 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 18, 9:55 PM MST | Thunderstorm Wind 50 M | Florence, AZ | Measured winds of 57 mph at the Magma Dam automatic station. |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
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
Phoenix, AZ (KPSR), launched 00:00Z, 4.5 hours before the alert went out and 60 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.
- Mixed-layer CAPE
- 50 J/kg
- Mixed-layer CIN
- -196 J/kg
- Mixed-layer LCL
- 3179 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 23 m²/s²
- 0-3 km storm-relative helicity
- 66 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
962
WUUS55 KPSR 190429
SVRPSR
AZC021-190530-
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
927 PM MST SUN AUG 18 2002
THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
CENTRAL PINAL COUNTY IN SOUTH CENTRAL ARIZONA
* UNTIL 1030 PM MST
* AT 923 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 7 MILES NORTHWEST OF FLORENCE...MOVING
SOUTHWEST AT 20 MPH.
THIS STORM WILL AFFECT FLORENCE...COOLIDGE...AND CASA GRANDE.
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 3303 11138 3318 11151 3313 11160 3307 11174
3306 11181 3279 11156 3290 11140What 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 Aug 18, 9:13 PM MST, 16 minutes earlier.
Area forecast discussion, Aug 18, 9:13 PM MST, 16 minutes before
AZZ020>028-CAZ030>033-191045- SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 913 PM MST SUN AUG 18 2002 .SYNOPSIS... HIGH PRESSURE OVER NORTHERN ARIZONA WILL SHIFT EAST AS LOW PRESSURE ALOFT BEGINS TO DEVELOP ALONG THE WEST COAST EARLY THIS WEEK. THIS WILL RESULT IN A MOIST SOUTHERLY FLOW OVER SOUTH-CENTRAL ARIZONA... WHILE FAR SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA WILL REMAIN IN A DRIER SOUTHWESTERLY FLOW. HENCE...WE CAN LOOK FOR A GREATER CHANCE FOR SHOWERS AND THUNDERSTORMS OVER SOUTH-CENTRAL ARIZONA BY TUESDAY. TEMPERATURES WILL GRADUALLY LOWER SOME THIS WEEK AS THE WEST COAST LOW PRESSURE SYSTEM DEVELOPS FURTHER. .DISCUSSION... MORE CONVECTION ON HIGHER TERRAIN TO THE E THIS AFTERNOON AND EARLY EVENING HAS LED TO MORE MAKING ITS WAY TO THE LOWER ELEVATIONS THIS EVENING ON NELY STEERING FLOW. TSTMS MOVING OFF THE HIGHER TERRAIN OF AZ ZONE 24 TOWARDS THE PHX METRO AREA HAVE BEEN HOLDING TOGETHER ...WITH OUTFLOW FROM STORMS TO THE S SEEN MOVING TOWARDS THE STORMS NEAR APACHE JUNCTION. NOWCASTS HAVE BEEN ISSUED ABOUT POSSIBLE GUSTY WIND AND BLOWING DUST DUE TO THESE FEATURES. WILL CLOSELY WATCH FOR THE INTERSECTION OF OUTFLOW COMING UP FROM THE S AND STORMS COMING IN FROM THE E. OVERALL...WIND REGIME IS NOT ONE TO SUPPORT SEVERE WEATHER...BUT STEERING WIND APPEARS TO HAVE INCREASED FROM EARLIER IN THE DAY. MODEL SOUNDINGS SUGGEST AN INCREASE IN MOISTURE THROUGH TUE...AS FLOW BECOMES SLY. THIS SHOULD LEAD TO AN UPRAMP IN TSTM ACTIVITY OVER MARICOPA COUNTY AND POINTS TO E FOR AT LEAST MON AND TUE AS VORTICITY IMPULSES WILL ADD FORCING TO THE EQUATION AS THEY ARE PULLED NEWD ACROSS A RATHER TIGHT MOISTURE GRADIENT. ETA AND AVN BOTH SHOW THE DEVELOPING ERN PAC TROF MOVING INLAND THIS WEEK WITH DRIER AIR MOVING IN BY MID-WEEK. ETA DRIES THINGS A BIT FASTER THAN DOES THE AVN. IF MODELS ARE ON THE RIGHT TRACK...WE WILL BE SOMEWHAT OVER-FORECAST ON THE EXTENT OF STORMS THIS WEEK. WILL LEAVE AS IS FOR NOW...BUT WE WILL HAVE TO WATCH THIS POSSIBLE DRYING TREND AS THE TROF MOVES IN. WILT .PSR...NONE.
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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.