Alert archive / Arizona / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 12, NWS Flagstaff, AZ

July 20, 2003Apache County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 20, 2003, 5:12 PM MST for Apache County, Arizona. It was in force for 38 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
Jul 20, 2003, 5:12 PM MST (00:12 UTC)
Expired
Jul 20, 2003, 5:50 PM MST
In force
38 min
Issued by
NWS Flagstaff, AZ
Area
Counties, with a storm outline in the text

County Apache County, AZ

The radar

The Flagstaff radar (KFSX), 144 km from the middle of the area, began a volume at 00:13 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

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 0.2 hours before the alert went out and 224 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, Flgstf/Belemont, AZ at 00:00Z on 2003-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 219 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, Flgstf/Belemont, AZ at 00:00Z on 2003-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 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
219 J/kg
Mixed-layer CIN
-83 J/kg
Mixed-layer LCL
2507 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
19 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 KFGZ 210012
SVRFGZ
AZC001-210055-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
510 PM MST SUN JUL 20 2003

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTH CENTRAL APACHE COUNTY IN NORTHEAST ARIZONA

* UNTIL 550 PM MST

* AT 504 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 9 MILES EAST OF VERNON...OR ABOUT 17 MILES
  NORTHWEST OF SPRINGERVILLE...MOVING SOUTHWEST AT 15 MPH.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN FLAGSTAFF.

LAT...LON 3419 10987 3401 10968 3418 10945 3436 10962

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 Flagstaff, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 2:35 PM MST, 2 hours 37 minutes earlier.

Area forecast discussion, Jul 20, 2:35 PM MST, 2 hours 37 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
235 PM MST SUN JUL 20 2003

.SYNOPSIS...THE DAILY PATTERN OF SCATTERED SHOWERS AND THUNDERSTORMS
WILL CONTINUE INTO NEXT WEEK AS A MOIST PATTERN STAYS IN PLACE. HIGH
PRESSURE TO THE NORTH WILL KEEP SEASONABLY WARM AFTERNOON CONDITIONS
OVER MUCH OF THE STATE FOR THE NEXT SEVERAL DAYS.

.DISCUSSION...CONVECTION THIS AFTERNOON TRAPPED OVER HIGH TERRAIN
WITH MAINLY DRY OUTFLOWS PROPAGATING INTO THE LOWER ELEVATIONS.
STILL THINK SOME RAIN WILL MAKE IT INTO THE LOWER ELEVATIONS IN THE
NEXT FEW HOURS...ESPECIALLY IN GILA AND YAVAPAI COUNTIES. HAVE CUT
BACK ON THE CONVECTIVE CHANCES IN THESE AREAS...BUT STILL WELL INTO
THE SCATTERED CATEGORY. CONVECTION SHOULD END BY MIDNIGHT AND ALLOW
FOR ENOUGH CLEARING TO GET A SUNNY START MONDAY. MODELS STILL
ADVERTISING A DECENT WAVE MONDAY AFTERNOON/EVENING AND THE ZONES
HAVE CORRESPONDINGLY HIGHER POPS. FAIRLY HIGH MOISTURE VALUES AND
GENERALLY EASTERLY FLOW STAY IN PLACE AFTER MONDAY AND THROUGH THE
REMAINDER OF THE FORECAST PERIOD. THIS WILL MAKE FOR A MODERATE
GRADE MONSOON FORECAST THROUGH DAY SEVEN. PETERSON.

.FGZ...NONE.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES LO/HI           PROBABILITY OF PRECIP
                 TON MON   TUE     WED        TON MON   TUE     WED
FLAGSTAFF        058/083 057/082 055/082      030 050 040 040 030 040
WINSLOW          068/094 066/091 065/091      020 020 030 020 020 020
PRESCOTT         065/092 068/090 066/090      040 030 040 030 030 030
PAGE             078/096 075/094 075/092      020 020 030 020 020 020
WINDOW ROCK      060/086 058/084 056/085      030 050 040 040 030 040
CANYON DE CHELLY 070/092 068/090 066/091      020 030 030 020 020 020
COTTONWOOD       073/103 076/101 074/101      030 030 040 030 030 030
GRAND CANYON     057/085 056/084 054/084      030 040 030 030 030 030
GREER            054/079 053/078 051/078      030 050 040 040 030 040
HEBER            059/088 058/087 056/087      030 050 040 040 030 040
JACOB LAKE       058/081 057/080 055/080      030 040 030 030 030 030
NAVAJO N.M.      064/086 062/084 060/085      030 040 040 030 030 030
PAYSON           066/097 069/095 067/095      040 030 050 040 030 040
SEDONA           071/101 074/099 072/099      030 030 040 030 030 030
SELIGMAN         058/095 061/093 059/093      040 030 040 030 030 030
SHOW LOW         066/089 065/088 063/088      030 050 040 040 030 040
ST. JOHNS        063/088 061/085 060/085      030 040 040 030 030 030
WUPATKI N.M.     071/096 069/093 068/093      020 020 030 020 020 020
Hazardous weather outlook, Jul 20, 9:25 AM MST, 7 hours 47 minutes before
AZZ004>018-037>040-210200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
925 AM MST SUN JUL 20 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...NORTHERN
GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN ARIZONA.

.DAY ONE...TODAY

DEEP MOISTURE REMAINS OVER MUCH OF THE REGION TODAY. SCATTERED
THUNDERSTORMS ARE AGAIN EXPECTED ACROSS MOST OF THE AREA FROM LATE
MORNING THROUGH THE EVENING HOURS. THE FIRST CONVECTIVE ACTIVITY IS
EXPECTED OVER THE MOGOLLON RIM AND WHITE MOUNTAINS...LIKELY BEFORE
10 AM MST. SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP OVER THE
OTHER HIGHER TERRAIN OF NORTHERN ARIZONA BY LATE MORNING AND EARLY
AFTERNOON. BY THE MID-AFTERNOON HOURS...STORMS ARE EXPECTED TO MOVE
SOUTHWEST INTO PORTIONS OF NORTHERN GILA AND YAVAPAI COUNTIES WHERE
ACTIVITY WILL LINGER INTO THE EVENING.

THE BEST THREAT FOR STRONGER STORMS TODAY WILL BE ALONG THE SOUTHERN
EDGE OF THE MOGOLLON RIM/WHITE MOUNTAINS AS WELL AS NORTHERN GILA
COUNTY AND YAVAPAI COUNTY. THE MAIN THREAT FROM THE THUNDERSTORMS
ACTIVITY TODAY WILL BE BRIEF HEAVY DOWNPOURS...AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

MOISTURE WILL REMAIN OVER ARIZONA THROUGH THE PERIOD FOR A CONTINUED
THREAT OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

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

DEFINITION OF HAZARDOUS WEATHER...A WEATHER EVENT POSING A THREAT
TO LIFE AND PROPERTY.

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.