Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 64, NWS Salt Lake City, UT

July 28, 2021Davis County, Morgan County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 28, 2021, 3:47 PM MDT for Davis County, Morgan 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 28, 2021, 3:47 PM MDT (21:47 UTC)
Expired
Jul 28, 2021, 6:45 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

Counties Davis County, UT, Morgan County, UT

The radar

The Salt Lake City radar (KMTX), 60 km from the middle of the area, began a volume at 21:52 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 12:00Z, 9.8 hours before the alert went out and 32 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 12:00Z on 2021-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 104 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 12:00Z on 2021-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
104 J/kg
Mixed-layer CIN
-191 J/kg
Mixed-layer LCL
2082 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

442 
WGUS55 KSLC 282147
FFWSLC
UTC011-029-290045-
/O.NEW.KSLC.FF.W.0064.210728T2147Z-210729T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
347 PM MDT Wed Jul 28 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Eastern Davis County in northern Utah...
  West Central Morgan County in northern Utah...

* Until 645 PM MDT.

* At 347 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the upper headwaters of Smith Creek and Dalton 
  Creek. Between 2 and 3 inches of rain have fallen within the last 
  hour. Flash flooding is ongoing or expected to begin shortly. 
  Additional heavy rainfall is expected over the Deep Creek drainage.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Morgan, particularly west of Weber River.

This includes the following highways...
	Interstate 84 between mile markers 96 and 100.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4101 11182 4102 11182 4107 11183 4111 11179
      4112 11178 4113 11177 4109 11173 4104 11170
      4097 11176 4100 11180

FLASH FLOOD...RADAR INDICATED

$$

SW
1 follow-up statement
108 
WGUS75 KSLC 290042
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
642 PM MDT Wed Jul 28 2021

UTC011-029-290052-
/O.EXP.KSLC.FF.W.0064.000000T0000Z-210729T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Davis UT-Morgan UT-
642 PM MDT Wed Jul 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 645 PM MDT THIS EVENING FOR 
WEST CENTRAL MORGAN COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Runoff from earlier heavy rainfall will continue to diminish 
through the evening hours. Please continue to heed any road closures.

LAT...LON 4101 11182 4102 11182 4107 11183 4111 11179
      4112 11178 4113 11177 4109 11173 4104 11170
      4097 11176 4100 11180

$$

SW

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 28, 11:57 AM MDTSpecial Weather StatementSLCCache48 min
Jul 28, 12:19 PM MDTFlash Flood WarningSLCCache3 hr
Jul 28, 1:55 PM MDTFlash Flood WarningSLCMorgan3 hr
Jul 28, 2:17 PM MDTFlash Flood Warning Considerable damage threatSLCEmery3 hr
Jul 28, 3:50 PM MDTSevere Thunderstorm WarningSLCBox Elder25 min

Nearby

Flash Flood Warnings in Utah, 2021Every flash flood warning 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.