Alert archive / Colorado / Special Weather Statements in 2023
Special Weather Statement, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this special weather statement at Jul 4, 2023, 2:21 PM MDT for Boulder County, Broomfield County, Gilpin 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
- Jul 4, 2023, 2:21 PM MDT (20:21 UTC)
- Expired
- Jul 4, 2023, 2:45 PM MDT
- In force
- 24 min
- Issued by
- NWS Denver/Boulder, CO
- Hail
- 0.50 in
- Wind
- 40
Counties Boulder County, CO, Broomfield County, CO, Gilpin County, CO
The radar
The Denver radar (KFTG), 75 km from the middle of the area, began a volume at 20:23 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, 8.4 hours before the alert went out and 310 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.
- Mixed-layer CAPE
- 7 J/kg
- Mixed-layer CIN
- -527 J/kg
- Mixed-layer LCL
- 2975 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 35 m²/s²
- 0-3 km storm-relative helicity
- 225 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>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 Jul 4, 10:22 AM MDT, 3 hours 59 minutes earlier.
Area forecast discussion, Jul 4, 10:22 AM MDT, 3 hours 59 minutes before
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</html>Hazardous weather outlook, Jul 4, 9:47 AM MDT, 4 hours 34 minutes before
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 947 AM MDT Tue Jul 4 2023 COZ030>051-051600- 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- 947 AM MDT Tue Jul 4 2023 ...Severe storms possible this afternoon and evening... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Numerous showers and thunderstorms are expected this afternoon and tonight over the foothills and plains. Some of the storms could be severe with large hail, damaging winds and heavy rain. Heavy rainfall could also cause flash flooding problems, most notably over the burn areas. There could be severe rounds of storms today, with the second round coinciding with fire work displays and picnics this evening. Holiday enthusiasts are urged to have adequate ways to take cover during their outside festivities. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Showers and thunderstorms are likely over the mountains on Wednesday with mainly scattered showers over the plains. There will be a threat of flash flooding over the alpine burnt areas. Scattered late day showers and thunderstorms are forecast for Thursday through Saturday with hail and heavy rainfall possible. Chances for thunderstorms decrease Sunday and into early next week. .SPOTTER INFORMATION STATEMENT... Spotter activation will be needed after 1 pm this afternoon. Reports of hail, heavy rain and flooding will be appreciated.
In the hours before
Special weather statement, Jul 4, 12:44 PM MDT, 1 hour 37 minutes before
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Special Weather Statement
National Weather Service Denver CO
143 PM MDT Tue Jul 4 2023
COZ032>036-042015-
South and Southeast Grand/West Central and Southwest
Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet CO-Grand and Summit Counties Below 9000 Feet CO-
Larimer and Boulder Counties Between 6000 and 9000 Feet CO-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet CO-
South and East Jackson/Larimer/North and Northeast Grand/Northwest
Boulder Counties Above 9000 Feet CO-
143 PM MDT Tue Jul 4 2023
...Strong thunderstorms will impact portions of south central
Larimer, Gilpin, eastern Grand, northwestern Clear Creek and western
Boulder Counties through 215 PM MDT...
At 142 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 4 miles northwest of Bear Lake to near Berthoud
Pass, or along a line extending from 36 miles west of Fort Collins to
42 miles west of Denver. Movement was east at 40 mph.
HAZARD...Wind gusts up to 50 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...
Estes Park, Nederland, Fraser, Bear Lake, Winter Park, Central City,
Grand Lake, Jamestown, Ward, Black Hawk, Raymond, Berthoud Pass,
Brainard Lake, Tolland, Gold Hill, Tabernash, Meeker Park, Rollins
Pass, Eldora and Rollinsville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle.
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4042 10537 3981 10542 3979 10586 4039 10584
TIME...MOT...LOC 1942Z 262DEG 36KT 4035 10571 3982 10575
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
RPKSpecial weather statement, Jul 4, 2:21 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Denver CO
221 PM MDT Tue Jul 4 2023
COZ033>036-038>040-043-042045-
South and Southeast Grand/West Central and Southwest
Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet CO-Central and South Weld County CO-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County
CO-Larimer and Boulder Counties Between 6000 and 9000 Feet CO-
North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe
Counties/East Broomfield County CO-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet CO-
Larimer County Below 6000 Feet/Northwest Weld County CO-
South and East Jackson/Larimer/North and Northeast Grand/Northwest
Boulder Counties Above 9000 Feet CO-
221 PM MDT Tue Jul 4 2023
...Strong thunderstorms will impact portions of southwestern Weld,
Broomfield, southeastern Larimer, Gilpin, northern Jefferson,
northwestern Adams and Boulder Counties through 245 PM MDT...
At 221 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 3 miles southeast of Buckhorn Mountain to near
Idledale, or along a line extending from 10 miles west of Fort
Collins to 16 miles west of Denver. Movement was east at 35 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...
Southern Fort Collins, Thornton, Arvada, Westminster, Boulder,
Longmont, Loveland, Broomfield, northwestern Commerce City,
Northglenn, Lafayette, Windsor, Louisville, Erie, Superior, Federal
Heights, Firestone, Johnstown, Frederick and Estes Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
central, north central and northeastern Colorado.
&&
LAT...LON 4054 10486 3981 10487 3981 10565 4055 10567
TIME...MOT...LOC 2021Z 257DEG 31KT 4059 10527 3969 10526
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 3, 7:00 PM MDT | Special Weather Statement | BOU | Weld | 45 min |
| Jul 4, 12:44 PM MDT | Special Weather Statement | BOU | Larimer | 31 min |
| Jul 4, 12:47 PM MDT | Special Weather Statement | BOU | Douglas | 28 min |
| Jul 4, 1:00 PM MDT | Severe Thunderstorm Warning | BOU | Grand | 30 min |
| Jul 4, 1:11 PM MDT | Special Weather Statement | BOU | Larimer | 34 min |
| Jul 4, 1:17 PM MDT | Severe Thunderstorm Warning | BOU | Grand | 28 min |
| Jul 4, 1:36 PM MDT | Special Weather Statement | BOU | Larimer | 24 min |
| Jul 4, 1:43 PM MDT | Special Weather Statement | BOU | Boulder, Gilpin | 32 min |
| Jul 4, 2:00 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 30 min |
| Jul 4, 2:13 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 47 min |
| Jul 4, 2:38 PM MDT | Areal Flood Advisory | BOU | Larimer | 3 hr |
| Jul 4, 2:42 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 33 min |
| Jul 4, 3:40 PM MDT | Special Weather Statement | BOU | Logan | 35 min |
| Jul 4, 4:05 PM MDT | Special Weather Statement | BOU | Grand | 25 min |
| Jul 4, 4:31 PM MDT | Special Weather Statement | BOU | Jackson | 29 min |
| Jul 4, 4:52 PM MDT | Severe Thunderstorm Warning | BOU | Jackson | 23 min |
| Jul 4, 5:14 PM MDT | Severe Thunderstorm Warning | BOU | Jackson, Larimer | 31 min |
| Jul 4, 5:19 PM MDT | Special Weather Statement | BOU | Boulder | 26 min |
| Jul 4, 5:36 PM MDT | Severe Thunderstorm Warning | BOU | Larimer | 24 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.