Alert archive / Arizona / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 69, NWS Flagstaff, AZ

September 15, 1999Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Sep 15, 1999, 5:42 PM MST for Yavapai County, Arizona. It was in force for 33 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 15, 1999, 5:42 PM MST (00:42 UTC)
Expired: Sep 15, 1999, 6:15 PM MST
In force: 33 min
Issued by: NWS Flagstaff, AZ
Area: Whole counties

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 124 km from the middle of the area, began a volume at 00:46 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 00:00Z, 0.7 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-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: 419 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 1527 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 109 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 15, 2:50 PM MST, 2 hours 52 minutes earlier.

Area forecast discussion, Sep 15, 2:50 PM MST, 2 hours 52 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION...CORRECTION TO SYNOPSIS
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
250 PM MST WED SEP 15 1999

SYNOPSIS...A WEAK TROUGH WILL CONTINUE MOVING ACROSS NORTHERN
ARIZONA THROUGH TONIGHT. THUNDERSTORMS WILL BEGIN DISSIPATING LATER
THIS EVENING IN THE WEST...WHILE CONTINUING PAST MIDNIGHT NEAR THE
WHITE MOUNTAINS. LINGERING MOISTURE WILL ALLOW ISOLATED
THUNDERSTORMS TO DEVELOP WEST OF THE RIM...WITH SCATTERED STORMS
ALONG THE HIGHER TERRAIN OF THE RIM COUNTRY. A DRYING TREND WILL
BEGIN ON FRIDAY...BUT SOME MOISTURE ALONG WITH A CHANCE OF
THUNDERSTORMS WILL LINGER OVER EASTERN ARIZONA THROUGH MONDAY.

DISCUSSION...FORECAST FOCUS REMAINS ON THE EFFECTS OF THE MID LEVEL
SHORTWAVE THROUGH THE AREA. THUNDERSTORMS CONTINUE MOVING ALONG A
LINE IN THE SOUTHERN TO SOUTHEASTERN CWA. STORMS ARE MOVING EAST
WITH A SMALL GROUP COMPONENT TO THE NORTH. NONE OF THE STORMS HAVE
GOTTEN OUT OF HAND YET. THE ACTIVITY SHOULD CONTINUE MOVING EAST
THROUGH TONIGHT...WITH A DIURNAL TENDENCY TOWARD CLEARING. STORMS
WILL CONTINUE UNTIL PRETTY LATE TONIGHT. FOG IS A POSSIBILITY AGAIN
IN SOME OF THOSE AREAS THE REALLY CLEAR OUT.

MOISTURE WILL BE SLOW TO CLEAR OUT WITH THE RIDGE SETTING UP OVER
SOUTHERN NEW MEXICO THURSDAY. SCATTERED THUNDERSTORMS ARE LIKELY TO
DEVELOP OVER THE ERN AND SRN PORTIONS OF THE CWA. WITH MORE OF A
DIURNAL TENDENCY...WILL GO WITH SLIGHT CHANCE POPS THURDAY NIGHT
WHILE EXPECTING STORMS TO END LATE. BY FRIDAY...RH IS HIGH ENOUGH
OVER THE WHITE MTNS AND RIM COUNTRY FOR CHANCE POPS MENTIONED OVER
THE HIGHER TERRAIN.

IN THE EXTENDED...SATURDAY THROUGH MONDAY...MOISTURE APPEARS TO
LINGER IN THE FLG CWA THROUGH SATURDAY...WITH A CHANCE OF PRECIP.
SUNDAY AND MONDAY LOOK TO BE DRIER AS THE RIDGE AXIS PUSHES EAST.
WILL KEEP A CHANCE OF PRECIP IN THE EASTERN ZONES THROUGH DAY 5.

PEREZ

.FLG...NONE.

In the hours before

Local storm report, Sep 15, 5:08 PM MST, 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
508 PM MST WED SEP 15 1999

TIME(MST)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0455 PM    PRESCOTT VALLEY           AZ   2 INCH HAIL
09/15/99   YAVAPAI                        SKYLIGHT DAMAGE

JD

Local storm report, Sep 15, 5:08 PM MST, 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
508 PM MST WED SEP 15 1999

TIME(MST)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0455 PM    PRESCOTT VALLEY           AZ   2 INCH HAIL
09/15/99   YAVAPAI                        SKYLIGHT DAMAGE

JD

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 15, 5:12 PM MST	Tornado Warning	FGZ	Yavapai	33 min
Sep 16, 11:15 AM MST	Severe Thunderstorm Warning	FGZ	Coconino	30 min
Sep 16, 11:33 AM MST	Severe Thunderstorm Warning	FGZ	Coconino	47 min
Sep 16, 12:19 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	41 min
Sep 16, 12:35 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	45 min
Sep 16, 12:42 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	48 min
Sep 16, 1:17 PM MST	Tornado Warning	FGZ	Coconino	33 min
Sep 16, 1:59 PM MST	Tornado Warning	FGZ	Coconino	16 min
Sep 16, 2:24 PM MST	Tornado Warning	FGZ	Coconino	11 min
Sep 16, 2:30 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	50 min
Sep 16, 2:54 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	46 min
Sep 16, 4:16 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	49 min

Nearby

Severe Thunderstorm Warnings in Arizona, 1999 Every severe thunderstorm warning in 1999

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.