Alert archive / Utah / Flash Flood Watches in 2021

Flash Flood Watch 4, NWS Salt Lake City, UT

July 19, 202118 counties in Utah

NWS Salt Lake City, UT issued this flash flood watch at Jul 19, 2021, 4:32 AM MDT for 18 counties in Utah. It took effect at Jul 19, 2021, 1:00 PM MDT. It was in force for 11 hr.

The area

The counties it named.

The facts

Issued
Jul 19, 2021, 4:32 AM MDT (10:32 UTC)
In effect from
Jul 19, 2021, 1:00 PM MDT
Expired
Jul 20, 2021, 12:00 AM MDT
In force
11 hr
Issued by
NWS Salt Lake City, UT
Flood severity
None

Counties Beaver County, UT, Carbon County, UT, Duchesne County, UT, Emery County, UT, Garfield County, UT, Iron County, UT, Juab County, UT, Kane County, UT, Millard County, UT, Piute County, UT, Salt Lake County, UT, Sanpete County, UT, Sevier County, UT, Summit County, UT, Utah County, UT, Wasatch County, UT, Washington County, UT, Wayne County, UT

The radar

The Cedar City radar (KICX), 186 km from the middle of the area, began a volume at 10:35 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

Salt Lake City I, UT (KSLC), launched 00:00Z, 10.5 hours before the alert went out and 191 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, Salt Lake City I, UT at 00:00Z on 2021-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 79 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, Salt Lake City I, UT at 00:00Z on 2021-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 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
79 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
4022 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

054 
WGUS65 KSLC 191032
FFASLC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Salt Lake City UT
432 AM MDT Mon Jul 19 2021

UTZ106-111-113-117-191845-
/O.NEW.KSLC.FF.A.0004.210719T1900Z-210720T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Utah Valley-Wasatch Mountains South of I-80-Wasatch Plateau/Book
Cliffs-Central Mountains-
Including the cities of Fish Lake, Indian Canyon, Lehi, Provo, Alta, 
Payson, Joes Valley, Scofield, Cove Fort, and Brighton
432 AM MDT Mon Jul 19 2021

...FLASH FLOOD WATCH IN EFFECT FROM 1 PM MDT THIS AFTERNOON 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, Central Mountains, Wasatch Plateau/Book Cliffs, Utah Valley 
  and Wasatch Mountains South of I-80.

* From 1 PM MDT this afternoon through this evening.

* The potential for heavy rainfall and flash flooding or debris 
  flows exists this afternoon and evening over burn scars as 
  thunderstorms develop and move from south to north over the watch 
  area.

* Heavy rainfall may result in flash flooding or debris flows over 
  area burn scars, including: Trail Mountain, Bear, Dollar Ridge, 
  Tank Hollow, Bald Mountain, Pole Creek, William, Ether Hollow and 
  Knolls.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecast and be prepared to take action should 
Flash Flood Warnings be issued.

&&

$$

Church
3 follow-up statements
786 
WGUS65 KSLC 191734
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
1134 AM MDT Mon Jul 19 2021

UTZ106-111-113-117-200600-
/O.CON.KSLC.FF.A.0004.210719T1900Z-210720T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Utah Valley-Wasatch Mountains South of I-80-Wasatch Plateau/Book
Cliffs-Central Mountains-
Including the cities of Fish Lake, Indian Canyon, Lehi, Provo, Alta, 
Payson, Joes Valley, Scofield, Cove Fort, and Brighton
1134 AM MDT Mon Jul 19 2021

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

The Flash Flood Watch continues for

* A portion of Utah, including the following areas, Central 
  Mountains, Wasatch Plateau/Book Cliffs, Utah Valley and Wasatch 
  Mountains South of I-80.

* Through this evening.

* The potential for heavy rainfall and flash flooding or debris 
  flows exists this afternoon and evening over burn scars as 
  thunderstorms develop and move from south to north over the watch 
  area.

* Heavy rainfall may result in flash flooding or debris flows over 
  area burn scars, including: Trail Mountain, Bear, Dollar Ridge, 
  Tank Hollow, Bald Mountain, Pole Creek, William, Ether Hollow and 
  Knolls.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecast and be prepared to take action should 
Flash Flood Warnings be issued.

&&

$$

WFO SLC
721 
WGUS65 KSLC 192026
FFASLC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Salt Lake City UT
226 PM MDT Mon Jul 19 2021

UTZ115-116-122-124-125-200600-
/O.EXA.KSLC.FF.A.0004.000000T0000Z-210720T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Western Millard and Juab Counties-Eastern Juab/Millard Counties-
Southwest Utah-Zion National Park-Southern Mountains-
Including the cities of Milford, Fillmore, Alton, Springdale, Cedar 
City, Nephi, Little Sahara, Delta, Brian Head, Beaver, and Scipio
226 PM MDT Mon Jul 19 2021

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

The National Weather Service in Salt Lake City has expanded the

* Flash Flood Watch to include a portion of Utah, including the 
  following areas, Eastern Juab/Millard Counties, Western Millard 
  and Juab Counties, Southern Mountains, Southwest Utah and Zion 
  National Park.

* Until Midnight MDT tonight.

* The potential for heavy rainfall and flash flooding or debris 
  flows exists this afternoon and evening over burn scars, normally 
  dry washes and streams surrounded by steep slopes as thunderstorms 
  develop and move from south to north over the watch area.

* Heavy rainfall may result in flash flooding or debris flows over 
  the area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

$$

UTZ106-111-113-117-200600-
/O.CON.KSLC.FF.A.0004.000000T0000Z-210720T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Utah Valley-Wasatch Mountains South of I-80-Wasatch Plateau/Book
Cliffs-Central Mountains-
Including the cities of Fish Lake, Indian Canyon, Lehi, Provo, Alta, 
Payson, Joes Valley, Scofield, Cove Fort, and Brighton
226 PM MDT Mon Jul 19 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

The Flash Flood Watch continues for

* A portion of Utah, including the following areas, Central 
  Mountains, Wasatch Plateau/Book Cliffs, Utah Valley and Wasatch 
  Mountains South of I-80.

* Until Midnight MDT tonight.

* The potential for heavy rainfall and flash flooding or debris 
  flows exists this afternoon and evening over burn scars as 
  thunderstorms develop and move from south to north over the watch 
  area.

* Heavy rainfall may result in flash flooding or debris flows over 
  area burn scars, including: Trail Mountain, Bear, Dollar Ridge, 
  Tank Hollow, Bald Mountain, Pole Creek, William, Ether Hollow and 
  Knolls.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecast and be prepared to take action should 
Flash Flood Warnings be issued.

&&

$$

WFO SLC
617 
WGUS65 KSLC 200553
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
1153 PM MDT Mon Jul 19 2021

UTZ106-111-113-115>117-122-124-125-200700-
/O.EXP.KSLC.FF.A.0004.000000T0000Z-210720T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Utah Valley-Wasatch Mountains South of I-80-Wasatch Plateau/Book
Cliffs-Western Millard and Juab Counties-Eastern Juab/Millard
Counties-Central Mountains-Southwest Utah-Zion National Park-
Southern Mountains-
Including the cities of Cedar City, Milford, Fillmore, Fish Lake, 
Joes Valley, Springdale, Indian Canyon, Delta, Lehi, Provo, Alta, 
Payson, Nephi, Little Sahara, Alton, Scofield, Brian Head, Cove 
Fort, Scipio, Beaver, and Brighton
1153 PM MDT Mon Jul 19 2021

...FLASH FLOOD WATCH WILL EXPIRE AT MIDNIGHT MDT TONIGHT...

The Flash Flood Watch will expire at Midnight MDT tonight for a 
portion of Utah, including the following areas, Central Mountains, 
Eastern Juab/Millard Counties, Wasatch Plateau/Book Cliffs, Western 
Millard and Juab Counties, Utah Valley, Wasatch Mountains South of 
I-80, Southern Mountains, Southwest Utah and Zion National Park.

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

$$

Church

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 7:02 PM MDTSpecial Weather StatementSLCTooele43 min
Jul 18, 7:54 PM MDTSpecial Weather StatementSLCTooele51 min
Jul 19, 1:44 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 hr
Jul 19, 2:34 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr
Jul 19, 2:45 PM MDTAreal Flood AdvisorySLCIron3 hr
Jul 19, 2:53 PM MDTSpecial Weather StatementSLCIron52 min
Jul 19, 3:04 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Jul 19, 3:22 PM MDTSevere Thunderstorm WarningSLCIron38 min
Jul 19, 3:46 PM MDTSpecial Weather StatementSLCUtah44 min
Jul 19, 4:54 PM MDTSpecial Weather StatementSLCDavis, Salt Lake36 min
Jul 19, 5:57 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 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.