Alert archive / Arizona / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 74, NWS Tucson, AZ
NWS Tucson, AZ issued this severe thunderstorm warning at Aug 27, 1999, 1:11 PM MST for Pima County, Arizona. It was in force for 44 min. 1 report came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Aug 27, 1999, 1:11 PM MST (20:11 UTC)
- Expired
- Aug 27, 1999, 1:55 PM MST
- In force
- 44 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 20:12 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 27, 1:30 PM MST | Thunderstorm Wind 52 | Tucson Intl Arpt, AZ | Moisture from Hurricane Bret helped ignite severe thunderstorms in the Tucson International Airport area. These storms produced heavy rain, pea size hail and high winds that knocked over two power poles. |
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.
The nearest sounding before it
Tuscon, AZ (KTUS), launched 12:00Z, 8.2 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.
- Mixed-layer CAPE
- 672 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 1305 m above ground
- 0-6 km bulk shear
- 7 kt
- 0-1 km storm-relative helicity
- 30 m²/s²
- 0-3 km storm-relative helicity
- 38 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 27, 9:15 AM MST, 3 hours 56 minutes earlier.
Area forecast discussion, Aug 27, 9:15 AM MST, 3 hours 56 minutes before
SOUTHEAST ARIZONA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 915 AM MST FRI AUG 27 1999 SYNOPSIS...EAST TO SOUTHEST WINDS ALOFT OVER SOUTHERN ARIZONA HAS BROUGHT PLENTY OF MOISTURE TO FEED THUNDERSTORMS. EARLY MORNING THUNDERSTORMS WEST OF TUCSON HAVE WEAKENED BY MID MORNING BUT WILL LIKELY DEVELOP AGAIN DURING THE AFTERNOON HOURS. LOW LEVEL WINDS WILL REMAIN LIGHT THROUGH THE WEEKEND FOR A CONTINUED THUNDERSTORM THREAT EACH AFTERNOON AND EVENING. DISCUSSION...COPIOUS MOISTURE IN SOUTHERN ARIZONA THIS MORNING. 1.8 INCH PRECIPITABLE WATER IN TUCSON WITH ABOUT THE SAME THROUGH THE LOW DESERT TO THE WEST. SPECIAL 18Z TUCSON SOUNDING TODAY SHOULD HELP TO SHOW HOW MUCH OF THIS MOISTURE REMAINS WITH THE MORNING THUNDERSTORM COMPLEX NOW WEST OF TUCSON. ALSO...MODELS SHOW SOME WARMING ALOFT ON OUR DOORSTEP TO OUR EAST. HOPEFULLY 18Z SOUNDING WILL SHOW IF THE AIRMASS IS WARMING ALOFT. AND FINALLY...MID LEVEL WINDS THIS MORNING WERE PUSHING THE STORMS WEST NORTHWEST AT A GOOD CLIP. MODELS INDICAT WINDS WILL WEAKEN THUS SLOWING THE STORM MOTION AND ALLOWING HEAVY RAIN FROM STORMS THAT DEVELOP. CLOUD COVER OVER SOUTHERN ARIZONA SLOWING THE WARMING THIS MORNING. REMAINS OF BRET EVIDENT IN THE COPIOUS MOISTURE AND ALSO IN THE INVERTED TROF NOW OVER SOUTHEAST ARIZONA. ALL THIS SHOULD CONTINUE ITS SLOW NORTHWEST MOVEMENT NEXT 24 HOURS. THINK BEST THREAT FOR REALLY ACTIVE WEATHER TODAY IS WESTERN SECTIONS. OF COURSE THIS THINKING MAY CHANGE WITH RECEIPT OF 18Z SOUNDING LATER THIS MORNING. PRF .TWC...NONE.
In the hours before
Special weather statement, Aug 27, 12:45 PM MST, 26 minutes before
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</html>Special weather statement, Aug 27, 12:45 PM MST, 26 minutes before
AZZ019-029>035-280500-
SPECIAL WEATHER STATEMENT...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1245 PM MST FRI AUG 27 1999...THIS PRODUCT IS NOT UPDATED
*CONDITIONAL* *CONDITIONAL*
COUNTY AREAL PROBABILITY RAIN GREATER THAN STORM
COVERAGE OF SEVERE 1.00 2.00 MOTION
COCHISE 55 10 65 30 W 10
GRAHAM 60 10 75 40 NW 10
GREENLEE 60 10 75 40 NW 10
TUCSON/ERN PIMA 60 20 80 40 W 10
TOHONO OODHAM 55 20 80 40 W 10
SOUTHEAST PINAL 55 20 80 40 W 10
WESTERN PIMA 40 20 80 40 W 10
SANTA CRUZ 60 20 80 40 W 10
SYNOPSIS...THE ATMOSPHERE IS EXTREMELY MOIST AND UNSTABLE THIS
AFTERNOON AND EVENING. HEAVY RAIN THE MAIN CONCERN WITH SEVERE
POSSIBLE. ACTIVITY WILL LINGER IN THE LOWER DESERTS WELL INTO
THE EVENING HOURS.
*****************************************************************
KEY...
AREAL COVERAGE - PERCENT OF COUNTY OR AREA THAT WILL EXPERIENCE
THUNDERSTORMS
PROB OF SEVERE - THE PROBABILITY THAT AN INDIVIDUAL STORM WILL
REACH SEVERE LEVELS (DAMAGING WIND AND/OR
LARGE HAIL)
RAIN GRTR THAN - THE PROBABILITY THAT AN INDIVIDUAL STORM 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://WWW.WRH.NOAA.GOV/TUCSON/SWO/SWO.SHTML
END/The office that day
Everything else NWS Tucson, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 5:14 PM MST | Severe Thunderstorm Warning | TWC | Pima | 31 min |
| Aug 26, 7:21 PM MST | Severe Thunderstorm Warning | TWC | Pima, Santa Cruz | 49 min |
| Aug 26, 8:08 PM MST | Severe Thunderstorm Warning | TWC | Santa Cruz | 32 min |
| Aug 26, 8:49 PM MST | Flash Flood Warning | TWC | Pima | 101 min |
| Aug 27, 12:40 PM MST | Flash Flood Warning | TWC | Pima | 100 min |
| Aug 27, 1:15 PM MST | Flash Flood Warning | TWC | Pima | 60 min |
| Aug 27, 1:55 PM MST | Severe Thunderstorm Warning | TWC | Pima | 65 min |
| Aug 27, 3:00 PM MST | Severe Thunderstorm Warning | TWC | Pima, Pinal | 45 min |
| Aug 27, 3:50 PM MST | Severe Thunderstorm Warning | TWC | Pinal | 45 min |
Nearby
Severe Thunderstorm Warnings in Arizona, 1999Every severe thunderstorm warning in 1999
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.