Alert archive / Arizona / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 44, NWS Phoenix, AZ

August 20, 2003Yuma County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Aug 20, 2003, 1:27 PM MST for Yuma County, Arizona. It was in force for 63 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 20, 2003, 1:27 PM MST (20:27 UTC)
Expired
Aug 20, 2003, 2:30 PM MST
In force
63 min
Issued by
NWS Phoenix, AZ
Area
Counties, with a storm outline in the text

County Yuma County, AZ

The radar

The Yuma radar (KYUX), 17 km from the middle of the area, began a volume at 20:27 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.

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

Yuma Prvg Ground, AZ (K1Y7), launched 12:00Z, 8.5 hours before the alert went out and 10 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, Yuma Prvg Ground, AZ at 12:00Z on 2003-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Yuma Prvg Ground, AZ at 12:00Z on 2003-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939Sfc1 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
4 J/kg
Mixed-layer CIN
-263 J/kg
Mixed-layer LCL
1937 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
33 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.

000 
WUUS55 KPSR 202027
SVRPSR
AZC027-202130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
125 PM MST WED AUG 20 2003

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWEST YUMA COUNTY IN SOUTHWEST ARIZONA

* UNTIL 230 PM MST

* AT 125 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM JUST SOUTHEAST OF YUMA...MOVING NORTHEAST AT 
  10 MPH. THE STORM WILL AFFECT THE AREA BETWEEN YUMA AND FORTUNA    
  FOOTHILLS. 

DAMAGING MICROBURST WINDS ARE LIKELY WITH THIS STORM. VERY HEAVY RAIN
IS ALSO POSSIBLE. TAKE COVER IN A SUBSTANTIAL SHELTER UNTIL THE STORM
PASSES.

HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS AS THEY
MAY BE WASHED OUT. WATER LEVELS OF WASHES...SMALL STREAMS AND RIVERS
MAY ALSO RISE...THEREFORE SEEK HIGHER GROUND IF FLOOD WATERS
THREATEN.

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 3248 11467 3239 11438 3263 11420 3278 11454

$$

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 Phoenix, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 10:30 AM MST, 2 hours 57 minutes earlier.

Area forecast discussion, Aug 20, 10:30 AM MST, 2 hours 57 minutes before
AZZ020>028-CAZ030>033-201745-

SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1030 AM MST WED AUG 20 2003

.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM WILL MOVE NORTH ACROSS SOUTHERN
CALIFORNIA AND SOUTHWEST ARIZONA THIS AFTERNOON AND THIS EVENING.
THIS MEANS A CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY OVER
SOUTHERN CALIFORNIA AND SOUTHWEST ARIZONA THIS AFTERNOON AND THIS
EVENING. HIGH PRESSURE ALOFT OVER NEW MEXICO WILL MOVE NORTH TO
COLORADO BY THURSDAY...AND STAY TO THE NORTH THROUGH MONDAY. THIS
MEANS A MOIST FLOW OF AIR FROM THE EAST WITH A CHANCE OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS THROUGH EARLY NEXT WEEK.

.DISCUSSION...
LATE MORNING TEMPERATURES WERE GENERALLY 9 TO 14 DEGREES WARMER IN
THE PHOENIX AREA AND NORTH PORTION OF THE WEST CENTRAL DESERT AREAS
COMPARED WITH THE SAME TIME YESTERDAY. THIS WAS DUE TO SUNNY SKIES
THIS MORNING WITH THE LACK OF CLOUD COVER THERE WAS YESTERDAY.
OTHERWISE...TEMPERATURES WERE GENERALLY 4 OR 4 DEGREES WARMER IN THE
SOUTH PORTION OF SOUTH-CENTRAL ARIZONA...AND 2 OR 3 DEGREES COOLER
IN FAR SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA. THE AIRMASS IS
STILL MOIST AND UNSTABLE. THUS...WITH A WEAK LOW PRESSURE SYSTEM
MOVING NORTH ACROSS THE AREA...MAINLY SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA...EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP
PARTICULARLY IN THOSE AREAS THIS AFTERNOON. HOWEVER...THERE IS A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS DEVELOPING IN THE
SOUTH-CENTRAL ARIZONA DESERT AREAS INCLUDING PHOENIX AS WELL AND
PLAN ON UPDATING FOR THIS. ISOLATED THUNDERSTORMS WERE ALREADY
DEVELOPING IN JOSHUA TREE NATIONAL PARK LATE THIS MORNING AND
CONSIDERING A FLASH FLOOD WATCH FOR THIS AREA FOR THIS AFTERNOON AND
EVENING. HIGH PRESSURE ALOFT CENTERED OVER NEW MEXICO WILL MOVE
NORTH TO COLORADO BY THURSDAY...AND STAY TO THE NORTH THROUGH
MONDAY. THIS MEANS A MOIST FLOW OF AIR FROM THE EAST WITH A CHANCE
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH EARLY
NEXT WEEK. WEAK LOW PRESSURE SYSTEMS IN THIS FLOW ARE EXPECTED TO
ENHANCE THE CHANCE OF SHOWERS AND THUNDERSTORMS AT TIMES WHICH IS
EXPECTED TO BE THE CASE THURSDAY NIGHT INTO FRIDAY MORNING.

ELLIS

.PSR...NONE.
Hazardous weather outlook, Aug 20, 12:40 PM MST, 47 minutes before
AZZ020>028-CAZ030>033-210100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
1240 PM MST WED AUG 20 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWEST AND
SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA.

.DAY ONE...TODAY

A FLASH FLOOD WATCH IS IN EFFECT FOR SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA UNTIL 9 PM THIS EVENING. PLEASE SEE THE FLASH FLOOD WATCH
PRODUCT PHXHWOPSR OR WMO HEADER WGUS65 KPSR FFAPSR.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.INSTRUCTIONS TO SPOTTERS...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

ELLIS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 2:10 PM MSTFlash Flood WarningPSRYuma50 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2003Every severe thunderstorm warning in 2003

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.