Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 53, NWS Salt Lake City, UT

August 19, 2012Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 19, 2012, 5:38 PM MDT for Washington County, Utah. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 19, 2012, 5:38 PM MDT (23:38 UTC)
Expired
Aug 19, 2012, 9:30 PM MDT
In force
4 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

County Washington County, UT

The radar

The Cedar City radar (KICX), 71 km from the middle of the area, began a volume at 23:40 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

Las Vegas, NV (KVEF), launched 12:00Z, 11.6 hours before the alert went out and 203 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, Las Vegas, NV at 12:00Z on 2012-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 75 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Las Vegas, NV at 12:00Z on 2012-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
75 J/kg
Mixed-layer CIN
-233 J/kg
Mixed-layer LCL
2531 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
12 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.

123 
WGUS55 KSLC 192338
FFWSLC
UTC053-200330-
/O.NEW.KSLC.FF.W.0053.120819T2338Z-120820T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
538 PM MDT SUN AUG 19 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL WASHINGTON COUNTY IN UTAH...INCLUDING
  LEEDS...WASHINGTON...AND SNOW CANYON STATE PARK

* UNTIL 930 PM MDT

* AT 527 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  TORRENTIAL RAINFALL FROM THUNDERSTORMS MOVING ACROSS THE SOUTHERN 
  SLOPES OF THE PINE VALLEY MOUNTAINS. RADAR ESTIMATED 3 TO 4 INCHES 
  HAS FALLEN ACROSS THIS AREA. ADDITIONAL THUNDERSTORMS PRODUCING 
  TORRENTIAL RAINFALL WILL CONTINUE THROUGH AT LEAST 6 PM.  

* FLASH FLOODING IS EXPECTED IN AND AROUND LEEDS...QUAIL CREEK...AND 
  THE RED CLIFFS AREA...WITH ADDITIONAL THUNDERSTORMS EXPECTED TO 
  PRODUCE FLASH FLOODING IN AND AROUND THE SNOW CANYON AREA. RUNOFF 
  FROM THIS TORRENTIAL RAINFALL IS EXPECTED TO MAKE ITS WAY TOWARD 
  WASHINGTON BY EARLY EVENING.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 3721 11367 3730 11370 3733 11350 3732 11330
      3720 11334 3718 11338 3712 11349 3713 11362

$$

MPS
2 follow-up statements
546 
WGUS75 KSLC 200147
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
747 PM MDT SUN AUG 19 2012

UTC053-200330-
/O.CON.KSLC.FF.W.0053.000000T0000Z-120820T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
747 PM MDT SUN AUG 19 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM MDT FOR
CENTRAL WASHINGTON COUNTY...

AT 737 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
UPWARDS OF 5 INCHES OF RAIN HAD FALLEN ACROSS THE SOUTHERN SLOPES OF 
THE PINE VALLEY MOUNTAINS SINCE APPROXIMATELY 4 PM. ALTHOUGH 
RAINFALL HAS TAPERED OFF...THIS RUNOFF IS LIKELY PRODUCING FLASH 
FLOODING ALONG SMALL STREAMS AND CREEKS ALONG THE SOUTH SLOPES OF 
THE PINE VALLEYS...LEADING TOWARD LEEDS...WASHINGTON...AND SNOW 
CANYON STATE PARK. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 3721 11367 3730 11370 3733 11350 3732 11330
      3720 11334 3718 11338 3712 11349 3713 11362

$$

MPS
230 
WGUS75 KSLC 200323
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
923 PM MDT SUN AUG 19 2012

UTC053-200333-
/O.EXP.KSLC.FF.W.0053.000000T0000Z-120820T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
923 PM MDT SUN AUG 19 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 930 PM MDT FOR CENTRAL
WASHINGTON COUNTY...

RUNOFF FROM EARLIER PRECIPITATION HAS DIMINISHED GREATLY AND RIVER 
AND STREAM LEVELS HAVE DECREASED.  THEREFORE... THE FLASH FLOOD 
WARNING HAS BEEN ALLOWED TO EXPIRE. MONITOR NOAA WEATHER RADIO OR 
LOCAL TELEVISION OR RADIO FOR THE LATEST WEATHER INFORMATION.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

LAT...LON 3721 11367 3730 11370 3733 11350 3732 11330
      3720 11334 3718 11338 3712 11349 3713 11362

$$

DUNN

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 2:53 AM MDTFlash Flood WatchSLC19 hr
Aug 19, 2:41 PM MDTFlash Flood WarningSLCKane9 hr
Aug 19, 3:52 PM MDTFlash Flood WarningSLCKane4 hr
Aug 19, 4:29 PM MDTFlash Flood WarningSLCWashington3 hr
Aug 19, 4:39 PM MDTFlash Flood WarningSLCGarfield3 hr
Aug 19, 4:59 PM MDTFlash Flood WarningSLCKane, Washington4 hr

Nearby

Flash Flood Warnings in Utah, 2012Every flash flood warning in 2012

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.