Alert archive / Arizona / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 145, NWS Flagstaff, AZ

October 20, 2015Apache County, Gila County, Navajo County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Oct 20, 2015, 5:01 PM MST for Apache County, Gila County, Navajo County, Arizona. It was in force for 29 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: Oct 20, 2015, 5:01 PM MST (00:01 UTC)
Expired: Oct 20, 2015, 5:30 PM MST
In force: 29 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon

Counties Apache County, AZ, Gila County, AZ, Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 96 km from the middle of the area, began a volume at 00:02 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Oct 20, 10:23 AM MST	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Tuscon, AZ (KDMA), launched 00:00Z, 0.0 hours before the alert went out and 307 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: 309 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 2070 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: -11 m²/s²
0-3 km storm-relative helicity: 67 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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 Oct 20, 3:30 PM MST, 1 hour 31 minutes earlier.

Area forecast discussion, Oct 20, 3:30 PM MST, 1 hour 31 minutes before

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Hazardous weather outlook, Oct 20, 10:48 AM MST, 6 hours 13 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1048 AM MST TUE OCT 20 2015

AZZ004>018-037>040-210245-
KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY-
COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS-
NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY-
CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS-
NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS-
OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA-
NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-
1048 AM MST TUE OCT 20 2015

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

.DAY ONE...TODAY AND TONIGHT

A SEVERE THUNDERSTORMS WATCH IS IN EFFECT FOR ALL OF
NAVAJO...APACHE AND GILA COUNTIES THROUGH 7 PM MST. LARGE HAIL IS
THE PRIMARY THREAT. STRONG WIND GUSTS AND AN ISOLATED TORNADO ARE
ALSO POSSIBLE.

MINOR FLOODING TO CONTINUE ACROSS SOUTHWESTERN YAVAPAI COUNTY
THROUGH AT LEAST EARLY THIS AFTERNOON.

THESE WEATHER CONDITIONS ARE DUE TO WIND SHEAR AHEAD OF A LOW
PRESSURE TROUGH THAT WILL MOVE INTO ARIZONA TODAY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

WEDNESDAY THROUGH THURSDAY...SHOWERS AND THUNDERSTORM CHANCES
WILL CONTINUE WEDNESDAY THEN DECREASE ON THURSDAY AS THE UPPER
LOW MOVES AWAY FROM THE AREA. THUNDERSTORMS THAT DEVELOP BOTH DAYS
SHOULD REMAIN BELOW SEVERE LEVELS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THE NATIONAL WEATHER SERVICE FLAGSTAFF OFFICE AT
1-888-745-1637.

In the hours before

Local storm report, Oct 20, 12:07 PM MST, 4 hours 54 minutes before

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Special weather statement, Oct 20, 12:53 PM MST, 4 hours 8 minutes before

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Special weather statement, Oct 20, 1:46 PM MST, 3 hours 15 minutes before

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Special weather statement, Oct 20, 1:57 PM MST, 3 hours 4 minutes before

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Special weather statement, Oct 20, 3:07 PM MST, 1 hour 54 minutes before

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Special weather statement, Oct 20, 4:06 PM MST, 55 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 20, 5:27 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Gila, Navajo	33 min
Oct 20, 5:59 PM MST	Special Weather Statement	FGZ		31 min
Oct 20, 6:29 PM MST	Special Weather Statement	FGZ	Gila	31 min
Oct 20, 6:54 PM MST	Special Weather Statement	FGZ	Gila	36 min
Oct 21, 2:48 PM MST	Special Weather Statement	FGZ		27 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2015 Every severe thunderstorm warning in 2015

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.