Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 51, NWS Salt Lake City, UT

September 14, 2011Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Sep 14, 2011, 2:23 PM MDT for Washington County, Utah. It was in force for 6 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Sep 14, 2011, 2:23 PM MDT (20:23 UTC)
Expired
Sep 14, 2011, 8:15 PM MDT
In force
6 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), 79 km from the middle of the area, began a volume at 20:24 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.

What was reported inside it

TimeReportWhereRemark
Sep 14, 4:15 PM MDTFLASH FLOOD8 Se St. George, UTFORT PEARCE WASH GAGE NEAR ST GEORGE - FPWU1

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 8.4 hours before the alert went out and 250 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 12:00Z on 2011-09-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 224 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 12:00Z on 2011-09-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.19395878Sfc1 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
224 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
729 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

590 
WGUS55 KSLC 142023
FFWSLC
UTC053-150215-
/O.NEW.KSLC.FF.W.0051.110914T2023Z-110915T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
223 PM MDT WED SEP 14 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL WASHINGTON COUNTY IN UTAH
  THIS INCLUDES THE FT PEARCE WASH

* UNTIL 815 PM MDT

* AT 500 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS CAPABLE OF PRODUCING VERY HEAVY RAIN OVER THE WARNED
  AREA.

* THE STORM PRODUCING FLASH FLOODING WILL OTHERWISE REMAIN OVER      
  MAINLY RURAL AREAS OF SOUTH CENTRAL WASHINGTON COUNTY ALONG THE    
  ARIZONA BORDER.

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 3711 11352 3704 11339 3706 11327 3702 11327
      3699 11329 3698 11341 3700 11353 3707 11358
      3708 11357

$$

ROGOWSKI
2 follow-up statements
867 
WGUS75 KSLC 142153
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
353 PM MDT WED SEP 14 2011

UTC053-150215-
/O.CON.KSLC.FF.W.0051.000000T0000Z-110915T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
353 PM MDT WED SEP 14 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM MDT FOR SOUTH
CENTRAL WASHINGTON COUNTY...

AT 348 PM MDT...HEAVY THUNDERSTORMS WHICH PROMPTED THE FLASH FLOOD 
WARNING FOR SOUTH CENTRAL WASHINGTON COUNTY INCLUDING THE FORT 
PEARCE WASH HAVE MOVED NORTH OF THE WARNED AREA. PERIODS OF RAINFALL 
AND THE FLASH FLOOD THREAT HOWEVER WILL CONTINUE INTO MID 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 3711 11352 3704 11339 3706 11327 3702 11327
      3699 11329 3698 11341 3700 11353 3707 11358
      3708 11357

$$

ROGOWSKI
659 
WGUS75 KSLC 150218
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
818 PM MDT WED SEP 14 2011

UTC053-150227-
/O.EXP.KSLC.FF.W.0051.000000T0000Z-110915T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
818 PM MDT WED SEP 14 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR SOUTH CENTRAL WASHINGTON
COUNTY...

WATER LEVELS HAVE DROPPED IN THE FORT PEARCE WASH AND ADDITIONAL 
FLASH FLOODING IS NOT EXPECTED. 

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 3711 11352 3704 11339 3706 11327 3702 11327
      3699 11329 3698 11341 3700 11353 3707 11358
      3708 11357

$$

PW

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 14, 2:40 PM MDTFlash Flood WarningSLCKane, Washington3 hr
Sep 14, 3:30 PM MDTFlash Flood WarningSLCKane4 hr
Sep 14, 3:32 PM MDTSpecial Weather StatementSLC43 min
Sep 14, 5:09 PM MDTFlash Flood WarningSLCKane3 hr

Nearby

Flash Flood Warnings in Utah, 2011Every flash flood warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.