Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 69, NWS Flagstaff, AZ

September 11, 2002Coconino County, Navajo County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Sep 11, 2002, 12:28 PM MST for Coconino County, Navajo County, Arizona. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 11, 2002, 12:28 PM MST (19:28 UTC)
Expired
Sep 11, 2002, 1:00 PM MST
In force
32 min
Issued by
NWS Flagstaff, AZ
Area
Counties, with a storm outline in the text

Counties Coconino County, AZ, Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 117 km from the middle of the area, began a volume at 19:28 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 12:00Z, 7.5 hours before the alert went out and 81 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 12:00Z on 2002-09-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 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 12:00Z on 2002-09-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 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
46 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
795 m above ground
0-6 km bulk shear
0 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
0 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 Sep 11, 9:15 AM MST, 3 hours 13 minutes earlier.

Area forecast discussion, Sep 11, 9:15 AM MST, 3 hours 13 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
915 AM MST WED SEP 11 2002

.SYNOPSIS...TROPICAL MOISTURE WILL CONTINUE TO STREAM ACROSS
ARIZONA TODAY. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO
CONTINUE...SOME WITH LOCALLY HEAVY RAINFALL. SHOWERS SHOULD
DIMINISH IN COVERAGE LATER IN THE WEEK. EXPECT A DRYING TREND
WITH MOSTLY CLEAR SKIES BY THE WEEKEND. TEMPERATURES WILL
REMAIN BELOW NORMAL FOR THE NEXT FEW DAYS...THEN RISE TO
NORMAL BY THE WEEKEND.

.DISCUSSION...UPPER LOW CENTERED OVER EXTREME NW ARIZONA THIS
MORNING WITH A STRONG VORT LOBE EXTENDING SOUTHEASTWARD THROUGH NRN
AZ INTO THE WHITE MOUNTAINS. ENTRANCE REGION TO AN UPPER JET AXIS
AHEAD OF THIS SYSTEM IS MOVING THROUGH NE AZ WITH UPPER DIVERGENT
SIGNATURE. THIS WAS CAUSING A LARGE AREA OF RAIN AND THUNDERSTORMS OVER
THE SOUTHERN HALF OF APACHE COUNTY AT 900 AM. SOME DRYING NOTED
ALOFT ON THE WV LOOP MOVING INTO YAVAPAI COUNTY AND THIS IS EXPECTED
TO SPREAD NWD THROUGH THE SRN HALF OF THE CWA DURING THE DAY. THE
DRYING WILL BE 500MB AND ABOVE WITH THE LOW LEVELS REMAINING MOIST.
BEST DYNAMICS AND MOISTURE TODAY WILL BE OVER THE EASTERN ZONES AND
EXPECT THE HIGHEST POTENTIAL OF FLOODING TODAY OVER THAT AREA...
WHICH HAS ALREADY EXPERIENCED SIGNIFICANT FLOODING.  EVEN THOUGH THE
THREAT OF WIDESPREAD HEAVY RAIN OVER YAVAPAI CO IS LOW...WILL OPT TO
KEEP THE FLASH FLOOD WATCH FOR NOW DUE TO THE SATURATED GROUND AND
STREAMS ALREADY RUNNING. WILL MONITOR CONDITIONS OVER WRN CWA
THROUGH THE MORNING FOR POSSIBLE CANCELATION OF THE WATCH.  DRYING
TREND STILL ON TRACK FOR LATER IN THE WEEK...MORE ON THIS IN THE
AFTERNOON PACKAGE.  JOHNDROW

.FGZ...FFA ALL ZONES UNTIL MIDNIGHT.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES HI/LO           PROBABILITY OF PRECIP
                 TDY TON   THU     FRI        TDY TON   THU   FRI
FLAGSTAFF        067/045 069/043 068/041      070 040 040 030 020 000
WINSLOW          075/053 079/054 079/052      060 040 030 020 010 000
PRESCOTT         076/053 079/052 079/050      060 040 030 020 010 000
PAGE             077/060 079/061 080/059      060 040 040 020 010 000
WINDOW ROCK      068/045 073/045 071/043      080 060 050 040 030 020
CANYON DE CHELLY 074/052 079/052 077/050      080 060 050 040 030 020
COTTONWOOD       087/061 090/060 090/058      060 040 030 020 010 000
GRAND CANYON     068/046 070/044 069/042      070 040 040 030 020 000
GREER            064/044 066/042 065/040      080 060 050 040 030 010
HEBER            072/048 074/046 073/044      080 050 050 040 030 010
JACOB LAKE       064/045 066/043 065/041      060 040 030 020 010 000
NAVAJO N.M.      066/051 071/051 069/049      070 050 040 030 020 020
PAYSON           080/053 083/052 083/050      070 050 040 020 010 000
SEDONA           084/060 087/059 087/057      060 040 030 020 010 000
SELIGMAN         079/046 082/045 082/043      050 030 020 020 010 000
SHOW LOW         073/054 075/052 074/050      070 050 040 030 020 010
ST. JOHNS        071/049 075/050 075/048      060 040 030 020 010 000
WUPATKI N.M.     077/055 081/056 081/054      060 040 030 020 010 000

In the hours before

Special weather statement, Sep 11, 9:30 AM MST, 2 hours 58 minutes before
AZZ004>018-037>040-111930-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
930 AM MST WED SEP 11 2002

...FLASH FLOOD WATCH IN EFFECT FOR NORTHERN ARIZONA UNTIL MIDNIGHT
MST...

A WEATHER DISTURBANCE WILL MOVE ACROSS THE NORTHEASTERN PART OF THE
STATE TODAY...BRINGING THE THREAT OF WIDESPREAD HEAVY RAIN AND
FLOODING. MANY STREAMS AND WASHES OVER THE NORTHEASTERN PORTION OF
THE STATE ARE ALREADY RUNNING AT BANKFULL...SO ANY ADDITIONAL HEAVY
RAINFALL COULD QUICKLY CAUSE FLOODING PROBLEMS. OVER YAVAPAI AND
COCONINO COUNTIES...DRIER AIR WILL MOVE IN ALOFT DECREASING THE
THREAT OF WIDESPREAD HEAVY RAIN. HOWEVER...WITH AFTERNOON HEATING...
THERE WILL BE A THREAT OF LOCALIZED STRONG THUNDERSTORMS WITH HEAVY
RAIN AND SMALL HAIL.

BURNED AREA RAIN OUTLOOK...

RODEO-CHEDISKI BURN AREA...EXPECT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP AND MOVE NORTHEAST OVER THE BURN AREA.
RAINFALL AMOUNTS OF UP TO TWO INCHES ARE POSSIBLE IN THE HEAVIER
SHOWERS. FLOODING POTENTIAL OVER THE FIRE SITE IS MODERATE TODAY.

INDIAN BURN AREA...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO
DEVELOP AND MOVE NORTHEAST OVER THE BURN AREA LATER THIS AFTERNOON.
RAINFALL AMOUNTS OF UP TO ONE INCH ARE POSSIBLE IN THE HEAVIER SHOWERS.
FLOODING POTENTIAL IN THIS REGION IS LOW TO MODERATE TODAY.

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 10, 5:01 PM MSTTornado WarningFGZApache29 min
Sep 10, 5:01 PM MSTTornado WarningFGZApache29 min
Sep 10, 5:08 PM MSTSevere Thunderstorm WarningFGZCoconino, Gila37 min
Sep 10, 5:26 PM MSTSevere Thunderstorm WarningFGZCoconino, Yavapai34 min
Sep 10, 5:43 PM MSTFlash Flood WarningFGZCoconino, Yavapai2 hr
Sep 10, 5:44 PM MSTFlash Flood WarningFGZCoconino, Yavapai3 hr
Sep 10, 5:45 PM MSTFlash Flood WarningFGZApache, Navajo3 hr
Sep 10, 5:45 PM MSTFlash Flood WarningFGZApache, Navajo2 hr
Sep 10, 5:55 PM MSTFlash Flood WarningFGZCoconino2 hr
Sep 10, 5:58 PM MSTFlash Flood WarningFGZCoconino3 hr
Sep 10, 7:45 PM MSTFlash Flood WarningFGZApache105 min
Sep 10, 7:45 PM MSTFlash Flood WarningFGZApache45 min
Sep 10, 8:35 PM MSTSevere Thunderstorm WarningFGZYavapai25 min
Sep 10, 8:54 PM MSTSevere Thunderstorm WarningFGZYavapai36 min
Sep 10, 9:40 PM MSTFlash Flood WarningFGZApache65 min
Sep 10, 9:49 PM MSTFlash Flood WarningFGZApache116 min
Sep 11, 1:25 AM MSTFlash Flood WarningFGZCoconino3 hr
Sep 11, 1:25 AM MSTFlash Flood WarningFGZCoconino2 hr
Sep 11, 12:25 PM MSTFlash Flood WarningFGZCoconino3 hr
Sep 11, 12:25 PM MSTFlash Flood WarningFGZCoconino110 min
Sep 11, 2:00 PM MSTSevere Thunderstorm WarningFGZNavajo45 min
Sep 11, 3:05 PM MSTFlash Flood WarningFGZCoconino3 hr
Sep 11, 3:05 PM MSTFlash Flood WarningFGZCoconino2 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.