Alert archive / Utah / Flash Flood Warnings in 2017

Flash Flood Warning 6, NWS Salt Lake City, UT

July 17, 2017Iron County, Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 17, 2017, 8:12 PM MDT for Iron County, Kane County, Washington County, Utah. It was in force for 6 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 17, 2017, 8:12 PM MDT (02:12 UTC)
Expired
Jul 18, 2017, 2:15 AM MDT
In force
6 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

Counties Iron County, UT, Kane County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 32 km from the middle of the area, began a volume at 02:14 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, 2.2 hours before the alert went out and 251 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 2017-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 283 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 2017-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
283 J/kg
Mixed-layer CIN
-168 J/kg
Mixed-layer LCL
3130 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

290 
WGUS55 KSLC 180212
FFWSLC
UTC021-025-053-180815-
/O.NEW.KSLC.FF.W.0006.170718T0212Z-170718T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
812 PM MDT MON JUL 17 2017

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  East central Washington County in northern Utah...
  Western Kane County in southern Utah...
  Southeastern Iron County in southern Utah...

* Until 215 AM MDT Tuesday
    
* At 808 PM MDT, Doppler radar indicated a thunderstorm producing 
  heavy rain over the North Fork of the Virgin River north of Zion 
  National Park. This thunderstorm has produced heavy rainfall for 
  over 2 hours.  Radar rainfall estimates include more than 3" over 
  a wide area.  Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Zion National Park and Springdale. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3716 11302 3734 11297 3742 11305 3750 11305
      3749 11288 3734 11293 3726 11293 3719 11298

$$

McInerney/Verzella
2 follow-up statements
321 
WGUS75 KSLC 180514
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
1114 PM MDT MON JUL 17 2017

UTC021-025-053-180815-
/O.CON.KSLC.FF.W.0006.000000T0000Z-170718T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-Kane UT-Iron UT-
1114 PM MDT MON JUL 17 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 215 AM MDT FOR
EAST CENTRAL WASHINGTON...WESTERN KANE AND SOUTHEASTERN IRON
COUNTIES...

At 1111 PM MDT, rain has largely ended across Zion National Park, 
but flash flooding is still expected along the North Fork of the 
Virgin River. These flood waters will take several hours to move 
through the park, so anyone in this drainage should be prepared for 
flooding even though rain is no longer falling.

Some locations that will experience flooding include...
Zion National Park and Springdale. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3716 11302 3734 11297 3742 11305 3750 11305
      3749 11288 3734 11293 3726 11293 3719 11298

$$

Schoening
112 
WGUS75 KSLC 180810
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
210 AM MDT TUE JUL 18 2017

UTC021-025-053-180816-
/O.EXP.KSLC.FF.W.0006.000000T0000Z-170718T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-Kane UT-Iron UT-
210 AM MDT TUE JUL 18 2017

...THE FLASH FLOOD WARNING FOR EAST CENTRAL WASHINGTON...WESTERN KANE
AND SOUTHEASTERN IRON COUNTIES WILL EXPIRE AT 215 AM MDT...

Heavy rain has ended over the North Fork of the Virgin River. 
However, flows will remain high through late tonight as flooding 
from earlier heavy rain gradually recedes. Please continue to heed 
any remaining road and trail closures.

LAT...LON 3716 11302 3734 11297 3742 11305 3750 11305
      3749 11288 3734 11293 3726 11293 3719 11298

$$

LC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 6:05 PM MDTSevere Thunderstorm WarningSLCSalt Lake, Tooele40 min
Jul 17, 7:28 PM MDTSpecial Weather StatementSLCRich47 min
Jul 18, 11:38 AM MDTRed Flag WarningSLCBox Elder, Davis, Salt Lake, Tooele, Utah34 hr
Jul 18, 1:59 PM MDTFlash Flood WarningSLCIron3 hr
Jul 18, 3:09 PM MDTFlash Flood WatchSLC31 hr

Nearby

Flash Flood Warnings in Utah, 2017Every flash flood warning in 2017

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.