Alert archive / Utah / Flash Flood Watches in 2021

Flash Flood Watch 7, NWS Salt Lake City, UT

July 24, 20217 counties in Utah

NWS Salt Lake City, UT issued this flash flood watch at Jul 24, 2021, 3:23 AM MDT for 7 counties in Utah. It took effect at Jul 24, 2021, 12:00 PM MDT. It was in force for 34 hr.

The area

The counties it named.

The facts

Issued
Jul 24, 2021, 3:23 AM MDT (09:23 UTC)
In effect from
Jul 24, 2021, 12:00 PM MDT
Expired
Jul 25, 2021, 9:52 PM MDT
In force
34 hr
Issued by
NWS Salt Lake City, UT
Flood severity
None

Counties Beaver County, UT, Garfield County, UT, Iron County, UT, Kane County, UT, Piute County, UT, Washington County, UT, Wayne County, UT

The radar

The Cedar City radar (KICX), 57 km from the middle of the area, began a volume at 09:23 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

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 9.4 hours before the alert went out and 301 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 00:00Z on 2021-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 111 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 00:00Z on 2021-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
111 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
613 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
185 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

070 
WGUS65 KSLC 240923
FFASLC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Salt Lake City UT
323 AM MDT Sat Jul 24 2021

UTZ123>125-242200-
/O.NEW.KSLC.FF.A.0007.210724T1800Z-210725T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lower Washington County-Zion National Park-Southern Mountains-
Including the cities of Alton, St George, Hurricane, Springdale, 
Brian Head, and Ivins
323 AM MDT Sat Jul 24 2021

...FLASH FLOOD WATCH IN EFFECT FROM NOON MDT TODAY THROUGH THIS 
EVENING...

The National Weather Service in Salt Lake City has issued a

* Flash Flood Watch for a portion of Utah, including the following 
  areas, Southern Mountains, Lower Washington County and Zion 
  National Park.

* From Noon MDT today through this evening.

* Thunderstorms capable of heavy rainfall are expected to develop 
  over the southern Utah mountains this afternoon and move southeast 
  through Zion National Park and into lower Washington County 
  through this evening.

* Heavy rainfall may result in flash flooding, especially near the 
  Brian Head burn scar, in Zion National Park, and sensitive 
  drainages in lower Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

LC
5 follow-up statements
934 
WGUS65 KSLC 241120
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
520 AM MDT Sat Jul 24 2021

UTZ123>125-242200-
/O.CON.KSLC.FF.A.0007.210724T1800Z-210725T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lower Washington County-Zion National Park-Southern Mountains-
Including the cities of Alton, St George, Hurricane, Springdale, 
Brian Head, and Ivins
520 AM MDT Sat Jul 24 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM NOON MDT TODAY THROUGH 
THIS EVENING...

The Flash Flood Watch continues for

* A portion of Utah, including the following areas, Southern 
  Mountains, Lower Washington County and Zion National Park.

* From Noon MDT today through this evening.

* Thunderstorms capable of heavy rainfall are expected to develop 
  over the southern Utah mountains this afternoon and move southwest 
  through Zion National Park and into lower Washington County 
  through this evening.

* Heavy rainfall may result in flash flooding, especially near the 
  Brian Head burn scar, in Zion National Park, and sensitive 
  drainages in lower Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

LC
725 
WGUS65 KSLC 242052
FFASLC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Salt Lake City UT
252 PM MDT Sat Jul 24 2021

UTZ123>125-251100-
/O.EXT.KSLC.FF.A.0007.000000T0000Z-210726T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lower Washington County-Zion National Park-Southern Mountains-
Including the cities of Alton, St George, Hurricane, Springdale, 
Brian Head, and Ivins
252 PM MDT Sat Jul 24 2021

...FLASH FLOOD WATCH NOW IN EFFECT THROUGH SUNDAY EVENING...

The Flash Flood Watch is now in effect for

* A portion of Utah, including the following areas, Southern 
  Mountains, Lower Washington County and Zion National Park.

* Through Sunday evening.

* Thunderstorms capable of producing heavy rainfall will continue 
  over portions of southwest Utah through this evening, including 
  Zion National Park and lower Washington County. After a break this 
  evening and overnight, showers and thunderstorms capable of 
  producing heavy rainfall are expected to develop over these same 
  areas Sunday afternoon and evening.

* Heavy rainfall may result in flash flooding, especially near the 
  Brian Head burn scar, in Zion National Park, and sensitive 
  drainages in lower Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

MT
488 
WGUS65 KSLC 250949
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
349 AM MDT Sun Jul 25 2021

UTZ123>125-252200-
/O.CON.KSLC.FF.A.0007.000000T0000Z-210726T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lower Washington County-Zion National Park-Southern Mountains-
Including the cities of Alton, St George, Hurricane, Springdale, 
Brian Head, and Ivins
349 AM MDT Sun Jul 25 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING...

The Flash Flood Watch continues for

* A portion of Utah, including the following areas, Southern 
  Mountains, Lower Washington County and Zion National Park.

* Through this evening.

* Thunderstorms capable of producing heavy rainfall will develop 
  over portions of southwest Utah again today. The strongest storms 
  are expected over the southern mountains and move southwest 
  towards Zion National Park and lower Washington County this 
  afternoon and evening.

* Heavy rainfall may result in flash flooding, especially near the 
  Brian Head burn scar, in Zion National Park, and sensitive 
  drainages in lower Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

LC
388 
WGUS65 KSLC 252103
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
303 PM MDT Sun Jul 25 2021

UTZ123>125-260400-
/O.CON.KSLC.FF.A.0007.000000T0000Z-210726T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lower Washington County-Zion National Park-Southern Mountains-
Including the cities of Alton, St George, Hurricane, Springdale, 
Brian Head, and Ivins
303 PM MDT Sun Jul 25 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 10 PM MDT THIS 
EVENING...

The Flash Flood Watch continues for

* A portion of Utah, including the following areas, Southern 
  Mountains, Lower Washington County and Zion National Park.

* Until 10 PM MDT this evening.

* Thunderstorms capable of producing heavy rainfall will continue 
  through this evening over southwest Utah. The strongest storms are 
  expected over the southern mountains, moving southwest toward Zion 
  National Park and lower Washington county this evening.

* Heavy rainfall may result in flash flooding, especially near the 
  Brian Head burn scar, in Zion National Park, and sensitive 
  drainages in lower Washington County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

MT
285 
WGUS65 KSLC 260352
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
952 PM MDT Sun Jul 25 2021

UTZ123>125-260500-
/O.CAN.KSLC.FF.A.0007.000000T0000Z-210726T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lower Washington County-Zion National Park-Southern Mountains-
Including the cities of Alton, St George, Hurricane, Springdale, 
Brian Head, and Ivins
952 PM MDT Sun Jul 25 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch has been cancelled for a portion of Utah, 
including the following areas, Southern Mountains, Lower Washington 
County and Zion National Park.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a threat for the remainder of tonight.

$$

WFO SLC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 6:14 PM MDTAreal Flood AdvisorySLCWashington61 min
Jul 24, 12:56 PM MDTFlash Flood Warning Considerable damage threatSLCKane3 hr
Jul 24, 12:58 PM MDTSpecial Weather StatementSLCKane32 min
Jul 24, 1:34 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Kane4 hr
Jul 24, 2:13 PM MDTFlash Flood Warning Considerable damage threatSLCWashington3 hr
Jul 24, 2:24 PM MDTSevere Thunderstorm WarningSLCWashington21 min
Jul 24, 3:16 PM MDTSevere Thunderstorm WarningSLCWashington29 min
Jul 24, 3:40 PM MDTSevere Thunderstorm WarningSLCIron, Washington35 min
Jul 24, 4:04 PM MDTSevere Thunderstorm WarningSLCWashington26 min
Jul 24, 4:07 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington3 hr
Jul 24, 4:12 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr
Jul 24, 4:30 PM MDTSevere Thunderstorm WarningSLCWashington30 min
Jul 24, 5:24 PM MDTFlash Flood Warning Considerable damage threatSLCWashington3 hr

Nearby

Flash Flood Watches in Utah, 2021Every flash flood watch in 2021

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.