Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 42, NWS Flagstaff, AZ

September 7, 2002Coconino County, Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Sep 7, 2002, 11:13 AM MST for Coconino County, Yavapai County, Arizona. It was in force for 32 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: Sep 7, 2002, 11:13 AM MST (18:13 UTC)
Expired: Sep 7, 2002, 11:45 AM MST
In force: 32 min
Issued by: NWS Flagstaff, AZ
Area: Counties, with a storm outline in the text

Counties Coconino County, AZ, Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 113 km from the middle of the area, began a volume at 18:15 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
Sep 7, 11:15 AM MST	Thunderstorm Wind 50 E	Leupp, AZ	Strong wind tore the awning off of a camper in Leupp. The wind was estimated at 50 to 60 MPH.

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.

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, 6.2 hours before the alert went out and 33 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 112 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 929 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 98 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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 7, 9:40 AM MST, 1 hour 33 minutes earlier.

Area forecast discussion, Sep 7, 9:40 AM MST, 1 hour 33 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
940 AM MST SAT SEP 07 2002

.SYNOPSIS...TROPICAL MOISTURE CONTINUES TO STREAM NORTHWARD OVER
ARIZONA IN ADVANCE OF A STRONG EASTERN PACIFIC TROUGH OF LOW
PRESSURE. EXPECT MOSTLY CLOUDY SKIES WITH PERIODS OF HEAVY SHOWERS
AND THUNDERSTORMS CONTINUING INTO TUESDAY.

.DISCUSSION...MOISTURE NOT A PROBLEM TODAY...AND EITHER IS DYNAMICS
AS NORTHERN ARIZONA WILL SIT IN THE RIGHT ENTRANCE REGION OF A 90
KNOT JET MOST OF THE DAY. LACK OF INSOLATION AND A RAIN-COOLED
BOUNDARY LAYER WILL NOT MATTER EITHER...AS CONVECTION ALREADY GOING
STRONG IN THE WEST AND CENTRAL ZONES. MODELS SHIFT UPPER DIV
ASSOCIATED WITH JET...AND THE NEXT JET SEEN OFFSHORE...OVER CENTRAL
ARIZONA THIS AFTERNOON AND KEEP IT THERE FOR AWHILE. THE BOTTOM LINE
IS RAIN...AND LOTS OF IT. STRONGER STORMS TODAY MAY PRODUCE STRONG
WINDS WITH 40 KNOTS IN THE MID-LEVELS...BUT RAIN AND SMALL HAIL WILL
BE THE BIGGEST PROBLEMS. FLASH FLOOD WATCH ALREADY OUT AND THE
TIMING AND LOCATIONS SEEM APPROPRIATE. CURRENT ZONES FEATURE STRONG
WORDING...AND EVERYTHING LOOKS GOOD FOR NOW. THIS PATTERN WILL
REMAIN INTACT AT LEAST THROUGH TUESDAY PER 12Z MODELS...SO STAY
TUNED. NO UPDATES NEEDED AT THIS TIME. PETERSON.

.FGZ...FFA NOON UNTIL MIDNIGHT FOR:
       AZZ004>009-012-015-016-018-037-038.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES HI/LO           PROBABILITY OF PRECIP
                 TDY TON   SUN     MON        TDY TON   SUN   MON
FLAGSTAFF        070/049 070/048 071/047      080 080 070 050 060 050
WINSLOW          081/060 080/058 081/057      070 080 060 040 050 050
PRESCOTT         079/058 079/057 080/056      080 080 060 040 050 050
PAGE             076/062 077/061 080/060      080 080 060 040 050 050
WINDOW ROCK      079/052 078/051 079/050      070 080 060 050 060 050
CANYON DE CHELLY 085/059 084/058 085/057      070 080 060 050 060 050
COTTONWOOD       090/066 090/065 091/064      080 080 060 040 050 050
GRAND CANYON     071/050 071/049 072/048      080 080 070 050 060 050
GREER            067/048 067/047 068/046      070 070 060 050 060 050
HEBER            075/052 075/051 076/050      080 080 060 050 060 050
JACOB LAKE       067/049 067/048 068/047      080 080 060 050 050 050
NAVAJO N.M.      077/058 076/057 077/056      070 080 060 050 060 050
PAYSON           083/058 083/057 084/056      080 080 050 060 050 050
SEDONA           087/065 087/064 088/063      080 080 060 040 050 050
SELIGMAN         082/051 082/050 083/049      060 060 050 030 040 040
SHOW LOW         076/058 076/057 077/056      070 070 060 050 060 050
ST. JOHNS        077/056 076/054 077/053      070 070 060 040 050 050
WUPATKI N.M.     083/062 082/060 083/059      080 080 060 050 060 050

In the hours before

Special weather statement, Sep 7, 9:30 AM MST, 1 hour 43 minutes before

AZZ004>018-037>040-071930-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
930 AM MST SAT SEP 07 2002

...FLASH FLOOD WATCH FOR MUCH OF NORTHERN AND CENTRAL ARIZONA FROM
NOON TODAY THROUGH MIDNIGHT TONIGHT...

...WIDESPREAD HEAVY SHOWERS AND THUNDERSTORMS EXPECTED OVER MUCH OF
THE FORECAST AREA TODAY...

DEEP TROPICAL MOISTURE IS STILL ENTRENCHED OVER ARIZONA TODAY WITH
SHOWERS AND THUNDERSTORMS ALREADY OCCURRING WEST OF FLAGSTAFF. MUCH
OF THE WESTERN AND NORTHERN PORTIONS OF THE AREA RECEIVED OVER AN
INCH OF RAIN OVERNIGHT...WITH SOME MINOR FLOODING REPORTED. STORMS
TODAY WILL BE CAPABLE OF PRODUCING VERY HEAVY RAIN...DESPITE MOVING
VERY QUICKLY TO THE NORTH-NORTHEAST. THE STRONGER STORMS TODAY WILL
ALSO PRODUCE STRONG WIND GUSTS...AND MAINLY SMALL HAIL. THE BEST
CHANCE FOR HEAVY RAIN TODAY WILL BE FROM THE MOGOLLON RIM WEST AND
NORTH...WITH MORE SCATTERED ACTIVITY OVER THE LITTLE COLORADO RIVER
VALLEY AND FAR EASTERN ARIZONA.

RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE WITH THE HEAVIER RAIN
TODAY OVER THE FLASH FLOOD WATCH AREAS...WITH ONE HALF AN INCH TO
NEAR AN INCH OVER THE REMAINDER OF THE REGION.

BURNED AREA RAIN OUTLOOK...

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

INDIAN BURN AREA...EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP AND MOVE NORTHEAST OVER THE BURN AREA. RAINFALL AMOUNTS OF
ONE TO TWO INCHES ARE POSSIBLE IN THE HEAVIER SHOWERS. FLOODING
POTENTIAL IN THIS REGION IS MODERATE TODAY.

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 6, 9:15 PM MST	Flash Flood Warning	FGZ	Coconino, Gila, Navajo, Yavapai	9 hr
Sep 7, 10:16 AM MST	Severe Thunderstorm Warning	FGZ	Yavapai	29 min
Sep 7, 11:42 AM MST	Severe Thunderstorm Warning	FGZ	Coconino, Yavapai	33 min
Sep 7, 12:13 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	47 min
Sep 7, 12:20 PM MST	Flash Flood Warning	FGZ	Coconino	115 min
Sep 7, 12:21 PM MST	Flash Flood Warning	FGZ	Coconino	3 hr
Sep 7, 12:41 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Sep 7, 3:35 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	35 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2002 Every 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.