Alert archive / Arizona / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 55, NWS Tucson, AZ

August 20, 2001Cochise County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Aug 20, 2001, 5:28 PM MST for Cochise County, Arizona. It was in force for 27 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Aug 20, 2001, 5:28 PM MST (00:28 UTC)
Expired
Aug 20, 2001, 5:55 PM MST
In force
27 min
Issued by
NWS Tucson, AZ
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Cochise County, AZ

The radar

The Tucson radar (KEMX), 70 km from the middle of the area, began a volume at 00:29 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, 0.5 hours before the alert went out and 110 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 00:00Z on 2001-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 679 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 00:00Z on 2001-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
679 J/kg
Mixed-layer CIN
-32 J/kg
Mixed-layer LCL
2997 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
9 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.

049 
WUUS55 KTWC 210031
SVRTUS
AZC003-210045-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
528 PM MST MON AUG 20 2001

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN COCHISE COUNTY IN ARIZONA

* UNTIL 555 PM MST

* AT 527 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM ABOUT 11 MILES WEST OF BISBEE...NEAR 
  PALOMINAS...MOVING NORTHEAST AT 5 TO 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  RURAL SOUTHWESTERN COCHISE COUNTY AT 540 PM MST

REMEMBER...A SEVERE THUNDERSTORM CAN PRODUCE LARGE HAIL...DAMAGING
WINDS IN EXCESS OF 60 MPH...DEADLY LIGHTNING...AND HEAVY RAIN.

LAT...LON 3138 11027 3128 11010 3149 10988 3163 11009

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 20, 2:25 PM MST, 3 hours 3 minutes earlier.

Area forecast discussion, Aug 20, 2:25 PM MST, 3 hours 3 minutes before
SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
225 PM MST MON AUG 20 2001

.SYNOPSIS...ENOUGH MOISTURE WILL OVER SOUTHERN ARIZONA TO SUPPORT
ISOLATED THUNDERSTORMS TONIGHT AND TUESDAY. OTHERWISE...A DRYING
TREND CAN BE EXPECTED WEDNESDAY INTO THE WEEKEND AS A MODERATE
WESTERLY FLOW DEVELOPS OVER THE STATE.

.DISCUSSION...THE TAIL END OF A SHORTWAVE TROUGH MOVING THROUGH
NORTHERN ARIZONA AND SOUTHERN UTAH WAS HELPING FOCUS THUNDERSTORMS
EAST OF TUCSON THIS AFTERNOON. SUBSIDENCE AND DRYING WERE TAKING
PLACE OUT WEST OVER CENTRAL AND WESTERN PIMA COUNTY WHICH SHOULD
INHIBIT STORMS THERE. OTHERWISE...THE TROUGH WILL MOVE EAST OF THE
REGION OVERNIGHT SO DO NOT EXPECT MUCH OF THE TSTM ACTIVITY THIS
EVENING TO LINGER PAST MIDNIGHT. ANOTHER SHORTWAVE TROUGH IS
FORECAST TO ENTER NEVADA TOMORROW WITH THE TAIL END OF IT PROVIDING
SOME WEAK LIFT OVER SOUTHEAST ARIZONA. HOWEVER...THE AFFECTS OF THIS
TROUGH WILL BE MINIMAL THIS FAR SOUTH. SO WILL JUST CALL FOR LOW
SCATTERED OR ISOLATED POPS EAST OF TUCSON AGAIN TOMORROW AFTERNOON
AND EARLY EVENING. MODELS WERE IN GENERAL AGREEMENT WITH SPREADING
DRIER AIR INTO THE AREA AS A MODERATE WESTERLY FLOW DEVELOPS OVER
MOST OF THE STATE. STILL NOT SURE HOW MUCH LOW LEVEL MOISTURE WILL
BE SCARED OUT BY THIS PROCESS...BUT LATEST MRF SUGGESTED THAT ENOUGH
MOISTURE WILL LINGER ALONG THE ARIZONA/NEW MEXICO STATE LINE THROUGH
MONDAY. THUS...WILL KEEP A MENTION OF A CHANCE AFTN/EVE TSTMS FOR
THE FAR EASTERN MOUNTAINS DURING THE EXTENDED PERIOD.
OTHERWISE...DRY ELSEWHERE.

.TWC...NONE.

In the hours before

Special weather statement, Aug 20, 12:05 PM MST, 5 hours 23 minutes before
AZZ019-029>035-210700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1205 PM MST MON AUG 20 2001

.SYNOPSIS...THE COMBINATION OF AMPLE SUNSHINE...A MOIST
ATMOSPHERE...AND SOME WEAK VERTICAL MOTION OVER THE AREA...WILL
LEAD TO AN INCREASE IN THUNDERSTORM ACTIVITY LATER THIS AFTERNOON
AND THIS EVENING.

.DISCUSSION...ONLY A THIN SCATTERED DECK OF CIRRUS THIS MORNING
ACROSS SOME PORTIONS OF SOUTHEAST ARIZONA...HOWEVER THIS WILL NOT
LIMIT HEATING.  TEMPERATURES ACROSS THE COUNTY WARNING AREA WERE
SIMILAR TO YESTERDAY AS OF 12 NOON. BEST AREAS OF MOISTURE SEEM TO
BE FROM TUCSON EAST WITH PRECIPITABLE WATER VALUES 1.50.  FROM
TUCSON WEST PWAT VALUES ARE ONE INCH OR LESS.

A SHORT WAVE LOCATED IN NORTHWEST ARIZONA MAY PROVIDE SOME WEAK
UPWARD MOTION WHICH WILL HELP THUNDERSTORM ACTIVITY.  CURRENTLY
THERE IS SOME TOWERING CUMULUS DEVELOPING MAINLY OVER THE
MOUNTAINOUS TERRAIN. THE CU FIELD SHOULD DEVELOP INTO THUNDERSTORMS
LATER IN THE AFTERNOON WITH FURTHER HEATING...AND MOVE OFF INTO THE
VALLEY IN THE EARLY EVENING.  THE THREAT FOR FLASH FLOOD IS NEAR OR
SLIGHTLY ABOVE THAN CLIMATOLOGY FROM TUCSON WEST...SINCE STORM
MOVEMENT SHOULD BE AROUND 15 MPH.  THE MAIN THREAT TODAY WOULD BE
SEVERE THUNDERSTORM ACTIVITY FROM TUCSON EAST...WITH THREATS
SLIGHTLY HIGHER THAN CLIMATOLOGY.  FROM TUCSON WEST SEVERE
THUNDERSTORM THREATS ARE BELOW CLIMATOLOGY...WITH FLASH FLOOD THREAT
EVEN LOWER.

STORM MOVEMENT WILL BE GENERALLY TO THE NORTHWEST AT 15 MPH.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 8:16 PM MSTFlash Flood WarningTWCGreenlee

Nearby

Severe Thunderstorm Warnings in Arizona, 2001Every severe thunderstorm warning in 2001

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.