Alert archive / Arizona / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 20, NWS Flagstaff, AZ

September 12, 2009Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Sep 12, 2009, 2:10 PM MST for Yavapai 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 12, 2009, 2:10 PM MST (21:10 UTC)
Expired
Sep 12, 2009, 2:42 PM MST
In force
32 min
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 124 km from the middle of the area, began a volume at 21:13 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.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.2 hours before the alert went out and 98 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 2009-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 23 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 12:00Z on 2009-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -58 square meters per square second.193958Sfc1 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
23 J/kg
Mixed-layer CIN
-147 J/kg
Mixed-layer LCL
1862 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-58 m²/s²
0-3 km storm-relative helicity
-58 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 12, 10:45 AM MST, 3 hours 25 minutes earlier.

Area forecast discussion, Sep 12, 10:45 AM MST, 3 hours 25 minutes before
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Hazardous weather outlook, Sep 12, 10:10 AM MST, 4 hours before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1010 AM MST SAT SEP 12 2009

AZZ004>018-037>040-130700-
WESTERN MOGOLLON RIM-GRAND CANYON COUNTRY-YAVAPAI COUNTY MOUNTAINS-
YAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONS-
MARBLE AND GLEN CANYONS-KAIBAB PLATEAU-COCONINO PLATEAU-
NORTHEAST PLATEAU AND MESAS HWY 264 NORTHWARD-
NORTHEAST PLATEAU AND MESAS SOUTH OF HWY 264-
CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
BLACK MESA AREA-LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
EASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTY-
1010 AM MST SAT SEP 12 2009

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

.DAY ONE...TODAY

THE MAIN THUNDERSTORM THREAT AREA WILL BE OVER THE EASTERN MOGOLLON
RIM...WHITE MOUNTAINS...WITH STORMS SHIFTING SOUTH INTO PORTIONS OF
...SOUTHEAST YAVAPAI AND NORTHERN GILA COUNTY BY EARLY EVENING. THE
WEATHER HAZARD TODAY WILL BE HEAVY RAIN AND LOCALIZED FLOODING AND
HAIL FROM THE STRONGER THUNDERSTORMS...FROM THE EASTERN MOGOLLON RIM
AND WHITE MOUNTAINS SOUTH. THUNDERSTORMS WILL GET A LITTLE LATER
START TODAY OVER THE EASTERN RIM AND WHITE MOUNTAINS...POSSIBLY BY
NOON. FOR THE REMAINDER OF THE AREA THUNDERSTORMS WILL DEVELOP BY
EARLY TO LATE AFTERNOON...WITH A SLIGHT INCREASE DURING THE EVENING
HOURS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

MOISTURE WILL LINGER OVER THE REGION...AND INTERACT WITH A COUPLE OF
WEATHER SYSTEMS MOVING THROUGH THE AREA DURING THE FORECAST PERIOD.
SCATTERED TO POSSIBLY NUMEROUS THUNDERSTORMS WILL DEVELOP BY SUNDAY
AFTERNOON AND CONTINUE INTO MONDAY EVENING. A LOW PRESSURE SYSTEM IS
FORECAST TO MOVE INTO NEVADA LATE SUNDAY AND MOVE ACROSS UTAH LATE
MONDAY. THIS WEATHER SYSTEM WILL INCREASE OUR CHANCES FOR SHOWERS
AND THUNDERSTORMS...ESPECIALLY SUNDAY NIGHT INTO MONDAY. THE MAIN
WEATHER IMPACTS WILL BE ISOLATED HAIL AND LOCALIZED AREAS OF HEAVY
RAINFALL AND POSSIBLE FLASH FLOODING FROM THE STRONGER STORMS.

.SPOTTER INFORMATION STATEMENT...

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

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 12, 2:29 PM MSTAreal Flood AdvisoryFGZYavapai4 hr
Sep 12, 3:32 PM MSTAreal Flood AdvisoryFGZCoconino, Yavapai3 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 2009Every severe thunderstorm warning in 2009

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.