Alert archive / Colorado / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 124

May 2, 202116 counties in Colorado

The Storm Prediction Center issued this severe thunderstorm watch at May 2, 2021, 11:45 AM MDT for 16 counties in Colorado. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
May 2, 2021, 11:45 AM MDT (17:45 UTC)
Expired
May 2, 2021, 6:28 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt

Counties Adams County, CO, Arapahoe County, CO, Bent County, CO, Cheyenne County, CO, Crowley County, CO, Douglas County, CO, El Paso County, CO, Elbert County, CO, Kiowa County, CO, Kit Carson County, CO, Lincoln County, CO, Morgan County, CO, Otero County, CO, Prowers County, CO, Washington County, CO, Yuma County, CO

The radar

The Denver radar (KFTG), 122 km from the middle of the area, began a volume at 17:47 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
5%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 2, 1:17 PM MDTSevere Thunderstorm WarningBOUAdams, Logan, Morgan, Washington28 min
May 2, 1:20 PM MDTSevere Thunderstorm WarningPUBEl Paso25 min
May 2, 1:37 PM MDTSevere Thunderstorm WarningPUBEl Paso23 min
May 2, 2:01 PM MDTSevere Thunderstorm WarningPUBCrowley, El Paso, Pueblo44 min
May 2, 2:13 PM MDTSevere Thunderstorm WarningBOULincoln32 min
May 2, 2:18 PM MDTSevere Thunderstorm WarningPUBCrowley, Pueblo57 min
May 2, 2:39 PM MDTSevere Thunderstorm WarningPUBOtero, Pueblo51 min
May 2, 3:07 PM MDTSevere Thunderstorm WarningPUBBent, Crowley, Kiowa, Otero53 min
May 2, 3:28 PM MDTSevere Thunderstorm WarningPUBBent, Otero32 min
May 2, 3:53 PM MDTSevere Thunderstorm WarningPUBBent, Kiowa, Otero, Prowers52 min
May 2, 4:25 PM MDTTornado Warning Tornado observedPUBBent, Prowers35 min
May 2, 4:44 PM MDTSevere Thunderstorm WarningPUBBent, Kiowa, Prowers61 min
May 2, 5:00 PM MDTSevere Thunderstorm WarningPUBProwers45 min
May 2, 5:11 PM MDTSevere Thunderstorm WarningPUBProwers34 min
May 2, 5:24 PM MDTTornado WarningPUBProwers51 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 5.8 hours before the alert went out and 38 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, Denver, CO at 12:00Z on 2021-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2021-05-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -89 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1976 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
-89 m²/s²
0-3 km storm-relative helicity
10 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

677 
WWUS20 KWNS 021743
SEL4  
SPC WW 021743
COZ000-030100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 124
NWS Storm Prediction Center Norman OK
1245 PM CDT Sun May 2 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  eastern Colorado

* Effective this Sunday afternoon and evening from 1245 PM until
  800 PM CDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...Storms will pose a risk for mainly damaging wind as they
develop and move through eastern Colorado this afternoon.

The severe thunderstorm watch area is approximately along and 75
statute miles east and west of a line from 20 miles northwest of
Akron CO to 60 miles east of Pueblo CO. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU4).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 400. Mean storm motion vector
27035.

...Dial

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 2, 10:14 AM MDTMesoscale DiscussionSPCAdams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 7 more2 hr
May 2, 1:15 PM MDTMesoscale DiscussionSPCCheyenne, Elbert, El Paso, Kit Carson, Lincoln, Morgan and 3 more90 min
May 2, 2:45 PM MDTMesoscale DiscussionSPCCheyenne, Crowley, Kiowa, Kit Carson, Lincoln, Phillips and 2 more90 min
May 2, 4:12 PM MDTMesoscale DiscussionSPCBaca, Bent, Prowers93 min

Nearby

Severe Thunderstorm Watches in Colorado, 2021Every severe thunderstorm 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.