Alert archive / Arizona / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 1, NWS Flagstaff, AZ

April 27, 2001Navajo County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Apr 27, 2001, 2:28 PM MDT for Navajo 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 outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Apr 27, 2001, 2:28 PM MDT (20:28 UTC)
Expired: Apr 27, 2001, 3:00 PM MDT
In force: 32 min
Issued by: NWS Flagstaff, AZ
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 98 km from the middle of the area, began a volume at 20:31 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, 8.5 hours before the alert went out and 161 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: 74 J/kg
Mixed-layer CIN: -108 J/kg
Mixed-layer LCL: 1684 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 32 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 272027
SVRFLG
AZC017-272100-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
128 PM MST FRI APR 27 2001

THE NATIONAL WEATHER SERVICE HAS ISSUED A

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

* UNTIL 200 PM MST

* AT 128 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 13 MILES SOUTHWEST OF WOODRUFF...OR ABOUT 29
  MILES NORTH OF SHOW LOW...MOVING NORTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT OR PASS CLOSE TO...      
  WOODRUFF AT 145 PM MST.

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

LAT...LON 3469 11030 3456 11015 3475 10990 3489 11008

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 Apr 27, 10:00 AM MDT, 4 hours 28 minutes earlier.

Area forecast discussion, Apr 27, 10:00 AM MDT, 4 hours 28 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
900 AM MST FRI APR 27 2001

SYNOPSIS...A WEATHER DISTURBANCE WILL MOVE ACROSS THE STATE
TODAY...BRINGING ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS TO MUCH OF THE REGION. THIS SYSTEM WILL MOVE EAST OF
THE STATE BY SATURDAY...WITH A DRY SOUTHWEST FLOW RETURNING FOR THE
WEEKEND AND INTO EARLY NEXT WEEK. EXPECT ABOVE NORMAL DAYTIME
TEMPERATURES TO CONTINUE INTO EARLY NEXT WEEK.

DISCUSSION...VERY ACTIVE DAY SETTING UP AS WATER VAPOR IMAGERY SHOWS
SHORTWAVE BEGINNING TO MOVE THROUGH WESTERN AZ THIS MORNING AND
FIRING CONVECTION IN YAVAPAI COUNTY ATTM.  12Z FGZ RAOB SHOWS
PLENTY OF RESIDUAL MOISTURE TO WORK WITH...LAPSE RATES ON THE ORDER
OF 8C/KM AND OVER 800 J/KG OF CAPE. PROGNOSTIC SOUNDINGS INCREASE
CAPE TO ABOUT 1000 J/KG LATER TODAY.  QUICK PEAK AT THE 12Z MESOETA
AND ETA SHOWS THIS WAVE TRAVERSING THE STATE TODAY AND EXITING
EARLY SAT MORNING. DEEP LAYER DIVQ FIELDS SUGGEST MAX FORCING AROUND
MIDDAY WITH SUBSIDENCE MOVING IN AFTER 03Z.  ANOTHER WEAK TROF
SKIRTS THE FORECAST AREA ON SUNDAY...BUT THE AIRMASS WILL BE TOO DRY
FOR ANY THREAT OF PRECIP. TW
A
.FGZ...NONE.

Nearby

Severe Thunderstorm Warnings in Arizona, 2001 Every severe thunderstorm warning in 2001

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.