Alert archive / Utah / Flash Flood Warnings in 2018

Flash Flood Warning 13, NWS Salt Lake City, UT

July 12, 2018Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 12, 2018, 6:40 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 12, 2018, 6:40 PM MDT (00:40 UTC)
Expired
Jul 12, 2018, 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), 56 km from the middle of the area, began a volume at 00:42 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 217 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 2018-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 790 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 2018-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -35 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
790 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
1866 m above ground
0-6 km bulk shear
2 kt
0-1 km storm-relative helicity
-35 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.

729 
WGUS55 KSLC 130040
FFWSLC
UTC053-130330-
/O.NEW.KSLC.FF.W.0013.180713T0040Z-180713T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
640 PM MDT THU JUL 12 2018

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Central Washington County in southwestern Utah...

* Until 930 PM MDT
    
* At 635 PM MDT, Doppler radar indicated a thunderstorm producing 
  heavy rain over over the Santa Clara River, Brush Creek, Ash 
  Creek, and Leap Creek. 

* Current radar rainfall estimates indicate over 2.5 inches of rain 
  has fallen in some areas.

* If you are traveling through the area please take measures to 
  ensure your safety now.

* Some locations that will experience flooding include...
  La Verkin, Toquerville, Leeds, Pine Valley and Pintura. 

LAT...LON 3745 11322 3722 11327 3732 11350 3739 11376
      3746 11370

$$

McInerney/Bonnette
1 follow-up statement
880 
WGUS75 KSLC 130322
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
922 PM MDT THU JUL 12 2018

UTC053-130330-
/O.EXP.KSLC.FF.W.0013.000000T0000Z-180713T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
922 PM MDT THU JUL 12 2018

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

The heavy rain has ended across central Washington County, with 
light rain expected to gradually taper off late this evening. Flood 
waters will recede through the night. Please continue to heed any 
remaining road closures.

LAT...LON 3745 11322 3722 11327 3732 11350 3739 11376
      3746 11370

$$

LC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 12, 6:23 PM MDTFlash Flood WarningSLCWashington3 hr
Jul 13, 5:14 PM MDTFlash Flood WarningSLCIron3 hr
Jul 13, 5:41 PM MDTFlash Flood WarningSLCGarfield, Kane, San Juan5 hr

Nearby

Flash Flood Warnings in Utah, 2018Every flash flood warning in 2018

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.