Alert archive / Colorado / Special Weather Statements in 2023

Special Weather Statement, NWS Denver/Boulder, CO

August 6, 2023Larimer County, Colorado

NWS Denver/Boulder, CO issued this special weather statement at Aug 6, 2023, 2:36 PM MDT for Larimer County, Colorado. It was in force for 24 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
Aug 6, 2023, 2:36 PM MDT (20:36 UTC)
Expired
Aug 6, 2023, 3:00 PM MDT
In force
24 min
Issued by
NWS Denver/Boulder, CO
Hail
0.75 in
Wind
30

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 64 km from the middle of the area, began a volume at 20:38 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

Grand Junction, CO (KGJT), launched 12:00Z, 8.6 hours before the alert went out and 323 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, Grand Junction, CO at 12:00Z on 2023-08-06Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 2023-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939587897117Sfc1 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
2777 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 6, 11:56 AM MDT, 2 hours 40 minutes earlier.

Area forecast discussion, Aug 6, 11:56 AM MDT, 2 hours 40 minutes before
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<body>
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      <div class="status" id="status">Temporary Notice</div>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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Hazardous weather outlook, Aug 6, 11:26 AM MDT, 3 hours 10 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1126 AM MDT Sun Aug 6 2023

COZ030>051-071730-
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-
1126 AM MDT Sun Aug 6 2023

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

.DAY ONE...Today and Tonight

Scattered showers and thunderstorms will occur over the mountains
and foothills this afternoon and over the Palmer Divide by mid
afternoon. A couple of the storms could produce large hail and
damaging wind gusts, especially over the Palmer Divide. The threat
of flash flooding will remain very limited and mainly over the
burn areas.

Over the plains, isolated to scattered showers and thunderstorms
are expected this evening. Strong wind gusts are possible with the
storms.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Scattered afternoon thunderstorms can be expected Monday and
Tuesday, and a few storms could be severe especially east of the
I-25 Corridor. Large hail and damaging winds would be the main
threats.

Drier conditions are expected Wednesday. Scattered showers and a
few storms could redevelop later in the week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

In the hours before

Special weather statement, Aug 6, 2:36 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Denver CO
236 PM MDT Sun Aug 6 2023

COZ035-038-062100-
Larimer and Boulder Counties Between 6000 and 9000 Feet CO-
Larimer County Below 6000 Feet/Northwest Weld County CO-
236 PM MDT Sun Aug 6 2023

...A strong thunderstorm will impact portions of east central Larimer
County through 300 PM MDT...

At 235 PM MDT, Doppler radar was tracking a strong thunderstorm 4
miles south of Red Feather Lakes, or 27 miles northwest of Fort
Collins, moving east at 35 mph.

HAZARD...Winds in excess of 30 mph and penny size hail, and brief
         heavy rain.

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...
Stove Prairie, Mishawaka, Livermore, Red Feather Lakes, Teds Place,
Rustic, Poudre Park and Buckhorn Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4082 10516 4055 10518 4065 10560 4083 10559
TIME...MOT...LOC 2035Z 277DEG 34KT 4075 10553

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...30 MPH

COOPER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 7:33 PM MDTSpecial Weather StatementBOUBroomfield42 min
Aug 5, 7:49 PM MDTSpecial Weather StatementBOULincoln41 min
Aug 5, 8:13 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln47 min
Aug 5, 8:55 PM MDTSevere Thunderstorm WarningBOULincoln35 min
Aug 6, 3:38 PM MDTSevere Thunderstorm WarningBOUAdams, Broomfield, Denver25 min
Aug 6, 3:55 PM MDTSevere Thunderstorm WarningBOUArapahoe, Douglas, Elbert24 min
Aug 6, 4:01 PM MDTSpecial Weather StatementBOUJackson29 min
Aug 6, 4:05 PM MDTSevere Thunderstorm WarningBOUDouglas, Elbert25 min
Aug 6, 4:12 PM MDTSevere Thunderstorm WarningBOUJackson, Larimer33 min
Aug 6, 4:35 PM MDTAreal Flood AdvisoryBOULarimer85 min
Aug 6, 4:39 PM MDTSevere Thunderstorm WarningBOULarimer36 min
Aug 6, 5:04 PM MDTAreal Flood AdvisoryBOULarimer86 min
Aug 6, 5:16 PM MDTAreal Flood AdvisoryBOUGrand119 min
Aug 6, 5:17 PM MDTSevere Thunderstorm WarningBOUDouglas, Elbert43 min

Nearby

Special Weather Statements in Colorado, 2023Every special weather statement 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.