Alert archive / Arizona / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 20, NWS Flagstaff, AZ

July 31, 2000Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 31, 2000, 4:07 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 outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Jul 31, 2000, 4:07 PM MST (23:07 UTC)
Expired
Jul 31, 2000, 4:40 PM MST
In force
33 min
Issued by
NWS Flagstaff, AZ
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 87 km from the middle of the area, began a volume at 23:09 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

Phoenix, AZ (KPSR), launched 12:00Z, 11.1 hours before the alert went out and 90 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, Phoenix, AZ at 12:00Z on 2000-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phoenix, AZ at 12:00Z on 2000-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
4 J/kg
Mixed-layer CIN
-541 J/kg
Mixed-layer LCL
2590 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
17 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.

000 
WUUS55 KFGZ 312309
SVRFLG
AZC025-312340-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
407 PM MST MON JUL 31 2000

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS EXTENDED THE 

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN YAVAPAI COUNTY IN ARIZONA

* UNTIL 440 PM MST

* AT 407 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 10 MILES EAST OF CORDES JUNCTION...OR ABOUT 21
  MILES SOUTH OF CAMP VERDE...MOVING WEST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL CROSS INTERSTATE 17 BETWEEN CORDES    
  JUNCTION AND BUMBLE BEE AT APPROXIMATELY 4:20 PM MST

STRONG AND DAMAGING EASTERLY WINDS IN EXCESS OF 60 MPH ARE LIKELY 
FROM THIS STORM. HAIL MAY ACCUMULATE TO A DEPTH OF SEVERAL INCHES AS 
THE STORM PASSES. TAKE COVER IN A STURDY STRUCTURE UNTIL THE STORM 
PASSES.

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

LAT...LON 3420 11186 3434 11189 3434 11236 3412 11232

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 Jul 31, 2:30 PM MST, 1 hour 37 minutes earlier.

Area forecast discussion, Jul 31, 2:30 PM MST, 1 hour 37 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 PM MST MON JUL 31 2000

SYNOPSIS...HIGH PRESSURE OVER THE GREAT BASIN WILL CONTINUE TO BRING AN
EASTERLY FLOW TO NORTHERN ARIZONA. EXPECT A CHANCE OF AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS OVER MOST OF THE REGION THROUGH THE END OF
THE WEEK. TEMPERATURES WILL BEGIN COOLING TODAY...AND WILL TREND
TOWARD SEASONAL NORMALS BY TUESDAY OR WEDNESDAY.

DISCUSSION...MODELS IN GOOD AGREEMENT SETTLING RIDGE OVER THE GREAT
BASIN AREA...WHERE IT WILL SIT THROUGH THE MIDDLE OF THIS WEEK WITH
A SLIGHT EASTWARD SHIFTING OF THE RIDGE AXIS BY WEDNESDAY. THIS SHOULD
KEEP US IN A GOOD NORTHEASTERLY FLOW THROUGH THEN...KEEPING MOISTURE
FAIRLY LIMITED. HOWEVER...THERE STILL WILL BE ENOUGH MOISTURE
PRESENT FOR SIGNIFICANT CONVECTION TO OCCUR...ESPECIALLY ALONG THE
MOGOLLON RIM AND SOUTHWARD. STILL NOT ENOUGH LOW LEVEL MOISTURE
OVERALL TO SUSTAIN HEAVY RAINFALL. HOWEVER SOME STORMS...ESPECIALLY
THOSE DROPPING SOUTHWESTWARD OFF THE RIM...COULD PRODUCE SOME STRONG
GUSTY WINDS WITH THE POTENTIAL FOR DRY MICROBURSTS. COLD AIR...MINUS
7C...AT THE 500MB LEVEL SHOULD ALSO HELP KEEP US UNSTABLE ENOUGH FOR
DECENT AFTERNOON AND EARLY EVENING CONVECTIVE ACTIVITY. NOT A VERY
GOOD POSSIBILITY OF A GULF SURGE REACHING THIS AREA IN THE NEAR
FUTURE. FOR NOW...LOOKS LIKE THE NORTHEASTERLY FLOW OVER THE CWA
WILL KEEP THIS MOISTURE TO OUR SOUTH.

IN THE EXTENDED...HIGH IS EXPECTED TO REMAIN OVER THE GREAT BASIN
AREA THROUGH THE WEEK AND INTO THE WEEKEND. NOT MUCH CHANGE IN AIR
MASS EXPECTED...WITH ANY MOISTURE INCREASE SLOW TO OCCUR. EXPECT
MORE OF THE SAME WITH ISOLATED TO SCATTERED POPS OVER MOST OF THE
CWA.

KREITNER

.FGZ...NONE.

In the hours before

Special weather statement, Jul 31, 10:08 AM MST, 5 hours 59 minutes before
AZZ004>018-037>040-302030-

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
930 AM MST MON JUL 31 2000

...SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON OVER MUCH OF
NORTHERN ARIZONA...WITH THE GREATEST ACTIVITY BEING ALONG AND SOUTH
OF THE MOGOLLON RIM...

SPOTTER REPORTS OF GUSTY WINDS REQUESTED.

NORTHEASTERLY FLOW OVER NORTHERN ARIZONA WILL LIMIT SIGNIFICANT
INTRUSIONS OF NEW MOISTURE...BUT MOISTURE WILL STILL BE SUFFICIENT
ENOUGH FOR SIGNIFICANT WIDESPREAD CONVECTION TODAY. COLD AIR...
MINUS 7C...AT THE 500MB LEVEL SHOULD HELP KEEP REGION UNSTABLE
ENOUGH FOR DECENT CONVECTIVE ACTIVITY. HOWEVER...DRY AIR AT THE LOWER
LEVELS WILL LIMIT THE THREAT FROM THUNDERSTORMS TODAY TO STRONG GUSTY
WINDS AND DRY LIGHTNING. EXPECT ACTIVITY TO START AROUND NOON ALONG THE
RIM AND MOVE SOUTHWESTWARD OVER THE LOWER LYING AREAS...WITH SCATTERED
CONVECTION POPPING UP EVERYWHERE ELSE LATER IN THE AFTERNOON. STORM
MOVEMENT WILL BE TOWARD THE SOUTHWEST AT AROUND 15 MPH.

THE HAZARDOUS WEATHER OUTLOOK GIVES PRELIMINARY INFORMATION FOR THE
POSSIBILITY OF WEATHER THAT COULD BECOME SEVERE...DAMAGING WINDS IN
EXCESS OF 57 MPH...HAIL 3/4 INCH IN DIAMETER OR LARGER...AND HEAVY
RAINFALL THAT COULD CAUSE FLOODING OR RUNNING WASHES. WHEN
HAZARDOUS WEATHER BEGINS...IMPORTANT LIFE SAVING INFORMATION WILL BE
PROVIDED IN SHORT TERM FORECASTS...SEVERE WEATHER AND FLOOD WARNINGS
..).AND FOLLOW-UP STATEMENTS.

KREITNER

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 3:05 PM MSTSevere Thunderstorm WarningFGZGila, Yavapai30 min
Jul 31, 3:26 PM MSTSevere Thunderstorm WarningFGZGila, Yavapai49 min
Jul 31, 4:31 PM MSTSevere Thunderstorm WarningFGZGila, Navajo59 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2000Every severe thunderstorm warning in 2000

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.