Alert archive / Utah / Flash Flood Warnings in 1998

Flash Flood Warning 40, NWS Salt Lake City, UT

August 21, 1998San Juan County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 21, 1998, 9:48 PM MDT for San Juan County, Utah. It was in force for 57 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
Aug 21, 1998, 9:48 PM MDT (03:48 UTC)
Expired
Aug 21, 1998, 10:45 PM MDT
In force
57 min
Issued by
NWS Salt Lake City, UT
Area
Whole counties

County San Juan County, UT

The radar

The Grand Junction radar (KGJX), 212 km from the middle of the area, began a volume at 03:49 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, 3.8 hours before the alert went out and 321 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 1998-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 53 joules per kilogram.LCLLFCEL10008507005003002001001 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 1998-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 square meters per square second.1939Sfc1 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
53 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
1607 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
106 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 KSLC 220355
FFWSLC
UTC037-220445-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
948 PM MDT FRI AUG 21 1998

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

   * FLASH FLOOD WARNING FOR...
     NORTH CENTRAL SAN JUAN COUNTY IN UTAH

   * UNTIL 1045 PM MDT

   * AT 940 PM MDT WEATHER SERVICE DOPPLER RADAR INDICATED VERY HEAVY
     RAIN OVER NORTH CENTRAL SAN JUAN COUNTY...IN THE CANYON RIMS    
     RECREATION AREA...OR ABOUT 21 MILES NORTHWEST                   
     OF MONTICELLO...MOVING EAST SOUTHEAST AT 20 MILES PER HOUR.

   * THUNDERSTORM WITH EXCESSIVE RAINFALL WILL BE NEAR THE JUNCTION  
     OF ROUTE 211 AND 191 BY 1005 PM...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF CREEKS 
AND NORMALLY DRY WASHES.   CAMPERS IN THE WARNING AREA SHOULD SEEK 
HIGHER GROUND IMMEDIATELY.

TO REPORT FLASH FLOODING HAVE THE NEAREST LAW ENFORCEMENT AGENCY
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY.
STAY TUNED TO LOCAL TELEVISION...RADIO...CABLE TV...OR NOAA WEATHER
RADIO FOR UPDATES.

LAT...LON 3818 10967 3800 10959 3791 10934 3821 10946

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 21, 6:12 PM MDTFlash Flood WarningSLCEmery78 min
Aug 21, 8:39 PM MDTFlash Flood WarningSLCSan Juan66 min
Aug 22, 1:23 PM MDTSevere Thunderstorm WarningSLCDuchesne37 min
Aug 22, 1:30 PM MDTFlash Flood WarningSLCDuchesne60 min

Nearby

Flash Flood Warnings in Utah, 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.