Alert archive / Utah / Special Weather Statements in 2021

Special Weather Statement, NWS Salt Lake City, UT

July 20, 2021Iron County, Utah

NWS Salt Lake City, UT issued this special weather statement at Jul 20, 2021, 2:21 PM MDT for Iron County, Utah. It was in force for 39 min. 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 20, 2021, 2:21 PM MDT (20:21 UTC)
Expired
Jul 20, 2021, 3:00 PM MDT
In force
39 min
Issued by
NWS Salt Lake City, UT

County Iron County, UT

The radar

The Cedar City radar (KICX), 38 km from the middle of the area, began a volume at 20:24 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 12:00Z, 8.4 hours before the alert went out and 238 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 12:00Z on 2021-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 33 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 12:00Z on 2021-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 square meters per square second.193958Sfc1 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
33 J/kg
Mixed-layer CIN
-208 J/kg
Mixed-layer LCL
2439 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
-8 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

656 
WWUS85 KSLC 202021
SPSSLC

Special Weather Statement
National Weather Service Salt Lake City UT
221 PM MDT Tue Jul 20 2021
 
UTZ122-125-202100-
Southwest Utah UT-Southern Mountains UT-
221 PM MDT Tue Jul 20 2021

...STRONG THUNDERSTORM MAY PRODUCE HEAVY RAINFALL AND HAIL OVER THE 
CITY OF NEW HARMONY AND ADDITIONAL PORTIONS OF NORTH CENTRAL 
WASHINGTON AND SOUTH CENTRAL IRON COUNTIES UNTIL 300 PM MDT...

At 218 PM MDT, National Weather Service Doppler radar indicated a
strong thunderstorm over New Harmony, or 18 miles southwest of Cedar
City...moving northeast at 10 mph.

Half inch hail will be possible.

Locations impacted include...
New Harmony and Kanarraville. 

This includes the following highways...
 Interstate 15 between mile markers 44 and 51.
 Utah Route 56 between mile markers 44 and 52.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall is also occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3744 11331 3753 11343 3771 11327 3757 11311
TIME...MOT...LOC 2018Z 228DEG 8KT 3751 11333 

$$

ND

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 6:01 PM MDTSpecial Weather StatementSLCTooele59 min
Jul 19, 6:10 PM MDTSpecial Weather StatementSLCJuab65 min
Jul 19, 6:13 PM MDTSpecial Weather StatementSLCWashington47 min
Jul 19, 8:19 PM MDTFlash Flood Warning Considerable damage threatSLCKane86 min
Jul 20, 12:11 PM MDTFlash Flood Warning Considerable damage threatSLCWayne3 hr
Jul 20, 1:18 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington4 hr
Jul 20, 3:26 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Kane6 hr
Jul 20, 3:41 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Kane3 hr
Jul 20, 4:03 PM MDTSpecial Weather StatementSLCSevier27 min
Jul 20, 4:58 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield3 hr

Nearby

Special Weather Statements in Utah, 2021Every special weather statement 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.