Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 50, NWS Salt Lake City, UT

August 19, 2012Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 19, 2012, 4:29 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
Aug 19, 2012, 4:29 PM MDT (22:29 UTC)
Expired
Aug 19, 2012, 7:30 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), 35 km from the middle of the area, began a volume at 22:30 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, 10.5 hours before the alert went out and 244 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°0°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.

978 
WGUS55 KSLC 192229
FFWSLC
UTC053-200130-
/O.NEW.KSLC.FF.W.0050.120819T2229Z-120820T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL WASHINGTON COUNTY IN UTAH INCLUDING NORTH CREEK AND 
  THE SUBWAY AREA WITHIN ZION NATIONAL PARK...

* UNTIL 730 PM MDT

* AT 422 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM A THUNDERSTORM ACROSS THE NORTH CREEK 
  DRAINAGE WITHIN ZION NATIONAL PARK. THIS INCLUDES THE SUBWAY AREA. 

* HEAVY RAINFALL IS EXPECTED ACROSS NORTH CREEK THROUGH 5 PM...WHICH 
  WILL LIKELY RESULT IN FLASH FLOODING WITH THE SUBWAY AREA OF ZION 
  NATIONAL 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 3734 11311 3737 11306 3737 11298 3725 11300
      3725 11314

$$

MPS
3 follow-up statements
684 
WGUS75 KSLC 192344
FFSSLC

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

UTC053-200130-
/O.CON.KSLC.FF.W.0050.000000T0000Z-120820T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
544 PM MDT SUN AUG 19 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MDT FOR EAST 
CENTRAL WASHINGTON COUNTY INCLUDING THE NORTH CREEK DRAINAGE AND 
SUBWAY AREA WITHIN ZION NATIONAL PARK...

AT 540 PM MDT...DOPPLER RADAR ESTIMATED 2 TO 3 INCHES OF RAIN HAD 
FALLEN ACROSS MUCH OF THE NORTH CREEK DRAINAGE AREA INCLUDING THE 
SUBWAY. THIS IS LIKELY PRODUCING A SIGNIFICANT FLASH FLOOD AT THIS 
TIME.

IF YOU ARE IN THE AREA NEAR NORTH CREEK MOVE TO HIGHER GROUND 
IMMEDIATELY! 

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 3734 11311 3737 11306 3737 11298 3725 11300
      3725 11314

$$

MPS
690 
WGUS75 KSLC 200044
FFSSLC

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

UTC053-200130-
/O.CON.KSLC.FF.W.0050.000000T0000Z-120820T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
644 PM MDT SUN AUG 19 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MDT FOR EAST 
CENTRAL WASHINGTON COUNTY INCLUDING THE NORTH CREEK DRAINAGE AND 
SUBWAY AREA WITHIN ZION NATIONAL PARK...

AT 620 ZION NATIONAL PARK RANGERS REPORTED SIGNIFICANT FLASH 
FLOODING ALONG NORTH CREEK INCLUDING THE SUBWAY. THIS FLASH FLOODING 
IS RESULTING FROM RAINFALL IN EXCESS OF 3 INCHES WHICH FELL ACROSS 
THE AREA EARLIER IN THE AFTERNOON. THIS EXCESS RUNOFF WILL CONTINUE 
ACROSS THE AREA THROUGH 730 PM. 

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 3734 11311 3737 11306 3737 11298 3725 11300
      3725 11314

$$

MPS
623 
WGUS75 KSLC 200129
FFSSLC

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

UTC053-200136-
/O.EXP.KSLC.FF.W.0050.000000T0000Z-120820T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
729 PM MDT SUN AUG 19 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 730 PM MDT FOR THE NORTH 
CREEK DRAINAGE AND SUBWAY AREA WITHIN ZION NATIONAL PARK...

RUNOFF IS DIMINISHING ALONG NORTH CREEK IN ZION NATIONAL PARK. 
THEREFORE...THE FLASH FLOOD WARNING WILL BE 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 3734 11311 3737 11306 3737 11298 3725 11300
      3725 11314

$$

MPS

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, 4:39 PM MDTFlash Flood WarningSLCGarfield3 hr
Aug 19, 4:59 PM MDTFlash Flood WarningSLCKane, Washington4 hr
Aug 19, 5:38 PM MDTFlash Flood WarningSLCWashington4 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.