Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 20, NWS Salt Lake City, UT

July 21, 2012Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 21, 2012, 6:41 PM MDT for Washington County, Utah. It was in force for 3 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
Jul 21, 2012, 6:41 PM MDT (00:41 UTC)
Expired
Jul 21, 2012, 9:30 PM MDT
In force
3 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), 58 km from the middle of the area, began a volume at 00:41 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 00:00Z, 0.7 hours before the alert went out and 216 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 00:00Z on 2012-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 48 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 00:00Z on 2012-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -28 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
48 J/kg
Mixed-layer CIN
-112 J/kg
Mixed-layer LCL
3945 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-28 m²/s²
0-3 km storm-relative helicity
-9 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.

542 
WGUS55 KSLC 220041
FFWSLC
UTC053-220330-
/O.NEW.KSLC.FF.W.0020.120722T0041Z-120722T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
641 PM MDT SAT JUL 21 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL WASHINGTON COUNTY IN UTAH

* UNTIL 930 PM MDT

* AT 632 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN FROM A THUNDERSTORM BETWEEN THE TOWNS OF WASHINGTON AND 
  PINTURA. OVER TWO INCHES OF RAINFALL HAS OCCURRED ON THE HILLSIDE  
  WEST OF LEEDS. FLOODING IS EXPECTED IN THE NORMALLY DRY WASHES     
  WHICH DRAIN INTO LEEDS AND UNDER INTERSTATE 15 TOWARD TOQUERVILLE.

* THE STORM PRODUCING MAY PRODUCE AN ADDITIONAL INCH OF RAINFALL.

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.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 3732 11328 3722 11324 3715 11337 3717 11352 3734 11357     
          3744 11345

$$

ROGOWSKI
2 follow-up statements
409 
WGUS75 KSLC 220139
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
739 PM MDT SAT JUL 21 2012

UTC053-220330-
/O.CON.KSLC.FF.W.0020.000000T0000Z-120722T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
739 PM MDT SAT JUL 21 2012

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

AT 735 PM MDT...THUNDERSTORMS HAVE DIMINISHED ACROSS CENTRAL 
WASHINGTON COUNTY...BUT THE THREAT OF FLASH FLOODING REMAINS. THE 
RUNOFF IS FROM THE TERRAIN WEST OF LEEDS INTO TWO NORMALLY DRY 
WASHES. THE FIRST WASH EXTENDS EAST FROM THE MOUNTAINS TO JUST WEST 
OF LEEDS...THEN DRAINS SOUTH INTO QUAIL CREEK RESERVOIR. THE SECOND 
WASH...A BIT FURTHER NORTH...DRAINS UNDER INTERSTATE 15 INTO THE 
TOWN OF TOQUERVILLE FROM THE NORTH.

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.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 3732 11328 3722 11324 3715 11337 3717 11352
      3744 11345

$$

ROGOWSKI
356 
WGUS75 KSLC 220321
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
921 PM MDT SAT JUL 21 2012

UTC053-220331-
/O.EXP.KSLC.FF.W.0020.000000T0000Z-120722T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
921 PM MDT SAT JUL 21 2012

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

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

LAT...LON 3732 11328 3722 11324 3715 11337 3717 11352
      3744 11345

$$

ROGOWSKI

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.