Alert archive / Arizona / Flash Flood Warnings in 1998

Flash Flood Warning 10, NWS Flagstaff, AZ

July 31, 1998Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 31, 1998, 6:29 PM MDT for Navajo County, Arizona. It was in force for 91 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
Jul 31, 1998, 6:29 PM MDT (00:29 UTC)
Expired
Jul 31, 1998, 8:00 PM MDT
In force
91 min
Issued by
NWS Flagstaff, AZ
Area
Whole counties

County Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 122 km from the middle of the area, began a volume at 00:31 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 00:00Z, 0.5 hours before the alert went out and 136 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 00:00Z on 1998-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 77 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 1998-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 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
77 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
1809 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
31 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 
TTAA00 KFLG 010032
FFWFLG
AZC017-010155-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
529 PM MST FRI JUL 31 1998

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL NAVAJO COUNTY IN NORTHEASTERN ARIZONA

* UNTIL 700 PM MST

* AT 525 PM MST...THE NAVAJO COUNTY SHERIFF'S OFFICE REPORTED
  FLOODING WAS CONTINUING IN AND NEAR JOSEPH CITY. HEAVY RUNOFF
  FROM THUNDERSTORMS WILL CONTINUE THROUGH 7 PM MST THIS EVENING.

DO NOT ATTEMPT TO CROSS FLOODED ROADS IN YOUR CAR. THE WATER DEPTH
MAY BE TOO GREAT TO GET THROUGH OR THE ROADBED MAY NOT BE INTACT.
MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Jul 31, 3:07 PM MDT, 3 hours 22 minutes earlier.

Area forecast discussion, Jul 31, 3:07 PM MDT, 3 hours 22 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
207 PM MST FRI JUL 31 1998

SYNOPSIS...SOME LOW LEVEL MOISTURE REMAINING OVER EASTERN ARIZONA
WILL CONTINUE TO CAUSE SOME AFTERNOON SHOWERS AND THUNDERSTORMS TO
DEVELOP THROUGH SATURDAY IN THE EAST CENTRAL MOUNTAINS. OVER THE
REMAINDER OF NORTHERN ARIZONA...SUNNY MORNINGS...WITH A FEW CLOUDS
DEVELOPING OVER THE HIGHER TERRAIN WILL BE THE RULE.

DISCUSSION...LOW TO MID LEVEL RH OVER THE EASTERN HALF OF CWA...WITH
A DECENT MOISTURE GRADIENT CUTTING N-S THROUGH THE AREA. SOME
EFFICIENT PRECIP PRODUCING STORMS HAVE DEVELOPED ALONG THE SOUTHERN
EDGE OF THIS BOUNDARY IN GILA COUNTY. FURTHER N...ATMOSPHERE A BIT
MORE STABLE...AND ALTHOUGH SOME CONVECTION HAS OCCURRED...IT HAS NOT
BEEN QUITE AS STRONG OVER THE NE. THIS COULD CHANGE A CAP ERODES THIS
AFTERNOON. 12Z ETA CONTINUING THE TREND OF DRYING CWA OUT...AND IS
MORE AGGRESSIVE WITH THIS THAN THE AVN-NGM. PREFER NGM THE BEST AS IT
KEEPS RH HANGING AROUND FOR A WHILE. AS TROUGH OVER S NV-UT LIFTS
OUT...WE SHOULD SEE HEIGHTS AND THICKNESS REBOUND SOME WHICH WILL
BRING A DEGREE OR TWO OF WARMING INTO THE AREA. OTHERWISE WILL KEEP
DRY CONDITIONS IN THE WEST...WITH ISOLD TO SCT POPS OVER THE EASTERN
PORTIONS OF THE CWA.

IN THE EXTENDED...WITH DECENT NORTHWESTERLY FLOW CONTINUING
MONDAY...IT SHOULD REMAIN DRY. THE 5H RIDGE BUILDS BACK IN...AND
SUSPECT THAT MONSOONAL FLOW WILL TAKE OVER ONCE AGAIN...ALLOWING FOR
THE DEVELOPMENT OF AFTERNOON SHOWERS AND THUNDERTORMS FOR DAY 4 AND
5 OF THE PERIOD.
MCGRATH
FLG 0000 INW 21--
FLG...NONE.

Nearby

Flash Flood Warnings in Arizona, 1998Every flash flood warning in 1998

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.