Alert archive / Colorado / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 435, NWS Denver/Boulder, CO

August 7, 2023Logan County, Morgan County, Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 7, 2023, 2:57 PM MDT for Logan County, Morgan County, Washington County, Colorado. It was in force for 26 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 7, 2023, 2:57 PM MDT (20:57 UTC)
Expired: Aug 7, 2023, 3:23 PM MDT
In force: 26 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.25 in
Wind: 50.0 mph

Counties Logan County, CO, Morgan County, CO, Washington County, CO

The radar

The Denver radar (KFTG), 116 km from the middle of the area, began a volume at 21:01 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 7, 2:03 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 9.0 hours before the alert went out and 250 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1020 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 7, 2:46 PM MDT, 11 minutes earlier.

Area forecast discussion, Aug 7, 2:46 PM MDT, 11 minutes before

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Hazardous weather outlook, Aug 7, 10:37 AM MDT, 4 hours 20 minutes before

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1037 AM MDT Mon Aug 7 2023

COZ030>051-081645-
Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Central and Southeast Park County-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
1037 AM MDT Mon Aug 7 2023

...SEVERE STORMS POSSIBLE TODAY AND THEN AGAIN TUESDAY...

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

A few severe thunderstorms are possible over the plains this
afternoon and evening. Large hail up to 2 inches in diameter
along with wind gusts to 65 mph will be the main threat from the
storms.

Otherwise, scattered showers and thunderstorms are expected this
afternoon and evening. Brief heavy rain, small hail along with
wind gusts to 50 mph are possible.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Another round of thunderstorms, some severe, can be expected
late Tuesday afternoon into late Tuesday evening. The greatest
severe risk will be east of I-25, with very large hail and
damaging winds possible.

Wednesday will be dry. Afternoon and evening thunderstorm chances
may return Thursday or Friday, and then gradually increase through
this weekend. The highest coverage is expected to remain over the
mountains.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required east of the I-25 Corridor this
afternoon.

In the hours before

Special weather statement, Aug 7, 1:22 PM MDT, 1 hour 35 minutes before

Special Weather Statement
National Weather Service Denver CO
122 PM MDT Mon Aug 7 2023

COZ038-042-072015-
Northeast Weld County CO-
Larimer County Below 6000 Feet/Northwest Weld County CO-
122 PM MDT Mon Aug 7 2023

...A strong thunderstorm will impact portions of north central Weld
County through 215 PM MDT...

At 122 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles north of Purcell, or 27 miles southeast of Cheyenne, moving
east at 30 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Grover.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4073 10461 4088 10464 4095 10418 4072 10415
TIME...MOT...LOC 1922Z 265DEG 24KT 4080 10453

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

MENSCH

Special weather statement, Aug 7, 1:50 PM MDT, 1 hour 7 minutes before

Special Weather Statement
National Weather Service Denver CO
150 PM MDT Mon Aug 7 2023

COZ042-072030-
Northeast Weld County CO-
150 PM MDT Mon Aug 7 2023

...A strong thunderstorm will impact portions of northeastern Weld
County through 230 PM MDT...

At 150 PM MDT, Doppler radar was tracking a strong thunderstorm 6
miles south of Panorama Point, or 29 miles southwest of Kimball,
moving east at 35 mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Pawnee Buttes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4087 10357 4079 10357 4067 10364 4088 10418
      4099 10410
TIME...MOT...LOC 1950Z 290DEG 31KT 4091 10404

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

MENSCH

Special weather statement, Aug 7, 1:55 PM MDT, 1 hour 2 minutes before

Special Weather Statement
National Weather Service Denver CO
155 PM MDT Mon Aug 7 2023

COZ038-072030-
Larimer County Below 6000 Feet/Northwest Weld County CO-
155 PM MDT Mon Aug 7 2023

...A strong thunderstorm will impact portions of northwestern Weld
County through 230 PM MDT...

At 155 PM MDT, Doppler radar was tracking a strong thunderstorm 6
miles north of Rockport, or 10 miles south of Cheyenne, moving
southeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Carr, Rockport and Natural Fort.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4095 10441 4075 10465 4094 10500 4100 10496
      4100 10454
TIME...MOT...LOC 1955Z 297DEG 33KT 4099 10480

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

MENSCH

Local storm report, Aug 7, 2:49 PM MDT, 8 minutes before

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The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 6, 6:02 PM MDT	Special Weather Statement	BOU	Boulder	28 min
Aug 6, 7:03 PM MDT	Special Weather Statement	BOU	Elbert	42 min
Aug 6, 7:14 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	31 min
Aug 6, 8:40 PM MDT	Special Weather Statement	BOU	Park	50 min
Aug 6, 9:35 PM MDT	Special Weather Statement	BOU	Douglas	40 min
Aug 6, 11:18 PM MDT	Special Weather Statement	BOU	Lincoln	27 min
Aug 6, 11:45 PM MDT	Special Weather Statement	BOU	Crowley	30 min
Aug 7, 1:22 PM MDT	Special Weather Statement	BOU	Weld	53 min
Aug 7, 1:33 PM MDT	Severe Thunderstorm Warning	BOU	Weld	42 min
Aug 7, 1:55 PM MDT	Special Weather Statement	BOU	Weld	35 min
Aug 7, 2:07 PM MDT	Severe Thunderstorm Warning	BOU	Morgan, Weld	38 min
Aug 7, 2:26 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Logan, Weld	49 min
Aug 7, 2:39 PM MDT	Severe Thunderstorm Warning	BOU	Jackson, Larimer	51 min
Aug 7, 3:35 PM MDT	Severe Thunderstorm Warning	BOU	Washington	40 min
Aug 7, 3:49 PM MDT	Areal Flood Advisory	BOU	Grand	40 min
Aug 7, 3:57 PM MDT	Severe Thunderstorm Warning	BOU	Washington	29 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2023 Every severe thunderstorm warning in 2023

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.