Alert archive / Arizona / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 71, NWS Flagstaff, AZ

October 17, 2002Coconino County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Oct 17, 2002, 5:07 PM MST for Coconino County, Arizona. It was in force for 23 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: Oct 17, 2002, 5:07 PM MST (00:07 UTC)
Expired: Oct 17, 2002, 5:30 PM MST
In force: 23 min
Issued by: NWS Flagstaff, AZ
Area: Counties, with a storm outline in the text

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 92 km from the middle of the area, began a volume at 00:06 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, 0.1 hours before the alert went out and 26 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: 101 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 1758 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: -24 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.

310 
WUUS55 KFGZ 180011 RRA
SVRFGZ
AZC005-180030-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
504 PM MST THU OCT 17 2002

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR CENTRAL COCONINO COUNTY...

* UNTIL 530 PM MST

* AT 504 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED  
A   OVER CENTRAL COCONINO COUNTY...IN EAST FLAGSTAFF NEAR THE MALL. 
...MOVING NORTH AT 10 MPH.

THIS STORM IS PRODUCING HAIL THREE QUARTER OF AN INCH IN DIAMETER.

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

LAT...LON 3541 11163 3520 11157 3528 11144 3545 11153

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 Oct 17, 2:50 PM MST, 2 hours 17 minutes earlier.

Area forecast discussion, Oct 17, 2:50 PM MST, 2 hours 17 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
250 PM MST THU OCT 17 2002

.SYNOPSIS...A PACIFIC STORM SYSTEM MOVING ACROSS THE STATE WILL
BRING SHOWERS AND SCATTERED EVENING THUNDERSTORMS...MAINLY FROM THE
MOGOLLON RIM AND TO THE EAST TONIGHT. TEMPERATURES WILL BE COOL
AGAIN FRIDAY. THE UNSETTLED WEATHER WILL MOVE TO THE EAST ON FRIDAY
WITH SHOWERS DIMINISHING BY FRIDAY EVENING. HIGH PRESSURE WILL MOVE
IN BY THE WEEKEND...BRINGING PARTLY CLOUDY SKIES AND SEASONAL
TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK.

.DISCUSSION...MAIN FORECAST CHALLENGE TONIGHT WILL BE FORECASTING
THE DEVELOPMENT OF THE NEXT DEFORMATION BAND PRECIP. SHOWERS AND
THUNDERSTORM ARE BEGINNING TO INCREASE DOWN TO OUR SOUTH AND
EAST...LOOKING FOR THIS MOISTURE AND CONVECTION TO WRAP NORTH AND
WEST AROUND THE LOW TONIGHT. BOTH THE MESO-ETA AND THE AVN SUGGEST
THIS...SO WE WILL CONTINUE WITH LIKELY AND CATEGORICAL CHANCE OF
PRECIP FROM FLAGSTAFF ON TO THE SOUTH AND EAST. PERSISTENT AREA OF
DIVERGENCE IN THE UPPER LEVELS OF THE ATMOS WILL SET UP OVER THE
FOUR CORNERS AREA DOWN INTO THE WHITE MOUNTAINS TONIGHT...SO WE WILL
KEEP LIKELY TO CATEGORICAL POPS IN THIS REGION AS WELL. AS FOR THE
SNOW LEVEL...WE MAY SEE LEVELS DIP DOWN TO AROUND 7000 FEET
TONIGHT...HOWEVER APPRECIABLE ACCUMULATIONS WILL REMAIN ABOVE 8000
FEET. THE UPPER LOW BY FRIDAY MORNING WILL HAVE SHIFTED INTO SOUTH
CENTRAL ARIZONA. MODELS STILL INSISTENT ON KEEP DEF ZONE PRECIP
GOING ACROSS EASTERN SECTIONS OF THE FORECAST AREA FRIDAY MORNING.
SHOWERS WILL DECREASE WEST TO EAST DURING THE DAY. WE WILL KEEP
LINGER SHOWERS FROM HEBER EASTWARD IN THE EVENING. HIGH PRESSURE
BUILDS IN OVER THE AREA...SATURDAY AND SUNDAY. HOWEVER THE AVN
SUGGEST ON KEEPING A WEAK TROUGH TO THE NORTHWEST OF THE AREA FRIDAY
AND SATURDAY...THEN IT BRINGS IT ACROSS THE AREA ON SUNDAY. THE AVN
TRIES TO GENERATE LIFT FROM THIS TROUGH AS IT SWINGS ACROSS NORTHERN
ARIZONA ON SUNDAY...PRODUCING SOME CONVECTION OVER THE SOUTHEAST.
THIS TROUGH IS FAIRLY WEEK AND DEPENDING UPON THE AVAILABLE
MOISTURE...WE WILL JUST MENTION PARTLY CLOUDY CONDITIONS FOR SUNDAY.

EXTENDED...PARTLY CLOUDY CONDITIONS AS SUBTROPICAL JET CONTINUES TO
UNDER CUT THE HIGH PRESSURE RIDGE ALONG THE WEST COAST...THUS
ALLOWING SOME MID AND UPPER LEVEL MOISTURE TO CROSS THE SOUTHWEST
U.S. TEMPERATURES NEAR SEASONAL VALUES THROUGH THE EXTENDED.

TC

FGZ...NONE.

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES LO/HI           PROBABILITY OF PRECIP
                 TON FRI   SAT     SUN        TON FRI   SAT     SUN
FLAGSTAFF        033/060 028/062 027/063      060 050 000 000 000 000
WINSLOW          045/067 036/069 036/071      060 060 000 000 000 000
PRESCOTT         044/068 042/070 041/073      050 040 000 000 000 000
PAGE             050/072 048/072 047/074      040 020 000 000 000 000
WINDOW ROCK      034/055 030/063 028/065      070 060 020 000 000 000
CANYON DE CHELLY 037/059 033/067 032/069      070 050 000 000 000 000
COTTONWOOD       050/078 048/080 047/083      060 040 000 000 000 000
GRAND CANYON     034/063 029/065 028/066      040 020 000 000 000 000
GREER            033/056 028/060 027/061      080 060 020 000 000 000
HEBER            035/065 030/068 029/069      060 060 020 000 000 000
JACOB LAKE       034/055 029/057 028/058      040 020 000 000 000 000
NAVAJO N.M.      041/060 037/068 035/070      060 050 000 000 000 000
PAYSON           046/071 045/073 042/076      060 050 000 000 000 000
SEDONA           049/074 047/076 046/079      060 040 000 000 000 000
SELIGMAN         037/070 035/072 034/075      040 030 000 000 000 000
SHOW LOW         045/066 040/070 035/071      070 060 020 000 000 000
ST. JOHNS        046/065 042/068 041/071      070 060 020 000 000 000
WUPATKI N.M.     050/071 041/073 041/074      060 050 000 000 000 000

Hazardous weather outlook, Oct 17, 9:15 AM MST, 7 hours 52 minutes before

AZZ004>018-037>040-180200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
915 AM MST THU OCT 17 2002

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

.DAY ONE...TODAY

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHERN
NAVAJO...NORTHERN GILA AND YAVAPAI COUNTY BY EARLY AFTERNOON. A FEW
OF THE THUNDERSTORMS WILL BE STRONG...CAPABLE OF PRODUCING HAIL UP
TO ONE INCH AND STRONG GUSTY WINDS AROUND 45 MPH.

A PACIFIC STORM SYSTEM MOVING ACROSS ARIZONA WILL BRING RAIN SHOWERS
WITH SCATTERED THUNDERSTORMS MAINLY SOUTH OF THE MOGOLLON RIM. HIGH
ELEVATION SNOW IS EXPECTED ON THE MOUNTAIN PEAKS OF NORTHERN ARIZONA
TODAY AND TONIGHT. THE SNOW LEVEL WILL BE AROUND 8500 FEET. UP TO
FOUR INCHES OF SNOW ACCUMULATION ARE POSSIBLE...ESPECIALLY OVER THE
SAN FRANCISCO PEAKS AND THE WHITE MOUNTAINS.

.INSTRUCTIONS TO SPOTTERS...

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

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

THE AREA OF UNSETTLED WEATHER WILL MOVE EAST ON FRIDAY...WITH
SCATTERED SHOWERS MAINLY EAST OF FLAGSTAFF. PRECIPITATION WILL END
AROUND MIDNIGHT ON FRIDAY. SNOW LEVELS WILL LOWER TO AROUND 8000
FEET BY FRIDAY MORNING...BUT LITTLE OR NO ADDITIONAL ACCUMULATION IS
EXPECTED.

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

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 17, 5:11 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	19 min
Oct 17, 5:21 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	9 min
Oct 17, 5:30 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	30 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.