Alert archive / Colorado / Flash Flood Warnings in 2024

Flash Flood Warning 26, NWS Denver/Boulder, CO

August 13, 2024Boulder County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 13, 2024, 3:03 PM MDT for Boulder County, Colorado. It was in force for 2 hr. 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 13, 2024, 3:03 PM MDT (21:03 UTC)
Expired
Aug 13, 2024, 5:17 PM MDT
In force
2 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Boulder County, CO

The radar

The Denver radar (KFTG), 77 km from the middle of the area, began a volume at 21:07 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, 9.1 hours before the alert went out and 290 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 2024-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 joules per kilogram.LCLLFCEL10008507005003002001001 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 2024-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 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
46 J/kg
Mixed-layer CIN
-185 J/kg
Mixed-layer LCL
1235 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
128 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 flash flood 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 flash flood warning went out at Aug 13, 10:48 AM MDT, 4 hours 15 minutes earlier.

Area forecast discussion, Aug 13, 10:48 AM MDT, 4 hours 15 minutes before
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Hazardous weather outlook, Aug 13, 10:37 AM MDT, 4 hours 26 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1037 AM MDT Tue Aug 13 2024

COZ030>051-141645-
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 Tue Aug 13 2024

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

.DAY ONE...Today and Tonight

Another round of thunderstorms is expected today. Heavy rain is
likely with some of the storms, and there is also a higher threat
of severe storms with large hail and damaging winds on the plains
today. A Flood Watch will continue until 11 PM MDT tonight.

Storms will develop over the mountains by early afternoon, with
locally heavy rain the main threat. There is an elevated threat of
flash flooding on the more sensitive burn areas with 1 to 2 inches
of rain in an hour possible from the stronger storms.

Storms will spread into the I-25 corridor in the mid to late
afternoon, then across the plains in the late afternoon and
evening. The threat of large hail and heavy rain will increase as
the storms move eastward. The main severe threat for the Front
Range cities will be from 3 PM to 7 PM, then across the plains
from 5 PM to 9 PM. Hail up to golf ball size is possible, along
with wind gusts to 60 mph and up to 3 inches of rain in under two
hours. The greatest severe threat should be in a zone from eastern
Weld and Logan counties south to around Limon in the late
afternoon and early evening.

While some showers and thunderstorms may linger after midnight,
the threat of severe weather and heavy rain should be ended by
then.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

A gradual warming and drying trend is expected to begin Wednesday
continuing into Saturday. Scattered afternoon showers and storms are
still possible Wednesday before the more significant drying begins
Thursday. Moisture will begin to increase from the west Saturday
afternoon and spread east Sunday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected today or tonight. However, any
reports of heavy rainfall, flooding, or severe weather will be
appreciated.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 6:03 PM MDTTornado WarningBOUWeld27 min
Aug 12, 6:07 PM MDTAreal Flood AdvisoryBOUMorgan30 min
Aug 12, 6:22 PM MDTSevere Thunderstorm WarningBOULincoln23 min
Aug 12, 6:25 PM MDTFlash Flood WarningBOUElbert, Lincoln3 hr
Aug 12, 6:30 PM MDTTornado WarningBOUWeld13 min
Aug 12, 6:37 PM MDTFlash Flood WarningBOUMorgan3 hr
Aug 12, 6:41 PM MDTSevere Thunderstorm WarningBOULincoln34 min
Aug 12, 6:43 PM MDTSevere Thunderstorm WarningBOULincoln32 min
Aug 12, 6:44 PM MDTAreal Flood AdvisoryBOUElbert, Lincoln5 min
Aug 12, 6:49 PM MDTFlash Flood WarningBOUElbert, Lincoln2 hr
Aug 12, 6:50 PM MDTSevere Thunderstorm WarningBOUWeld40 min
Aug 12, 6:58 PM MDTFlash Flood WarningBOUWeld3 hr
Aug 12, 7:09 PM MDTFlash Flood WarningBOUMorgan, Washington3 hr
Aug 12, 7:14 PM MDTTornado WarningBOULincoln16 min
Aug 12, 7:15 PM MDTSevere Thunderstorm Warning Considerable damage threatBOUMorgan45 min
Aug 12, 7:24 PM MDTTornado WarningBOUMorgan36 min
Aug 12, 7:28 PM MDTTornado WarningBOULincoln32 min
Aug 12, 7:32 PM MDTFlash Flood WarningBOUElbert, Lincoln3 hr
Aug 12, 7:58 PM MDTSpecial Weather StatementBOULarimer47 min
Aug 12, 7:59 PM MDTAreal Flood AdvisoryBOULarimer2 hr
Aug 12, 7:59 PM MDTSpecial Weather StatementBOUMorgan46 min
Aug 12, 8:02 PM MDTSpecial Weather StatementBOUMorgan43 min
Aug 12, 8:04 PM MDTSpecial Weather StatementBOUWeld41 min
Aug 12, 8:10 PM MDTSevere Thunderstorm WarningBOUWeld50 min
Aug 12, 8:24 PM MDTAreal Flood AdvisoryBOUMorgan, Weld3 hr
Aug 12, 8:56 PM MDTAreal Flood AdvisoryBOULincoln2 hr
Aug 12, 9:33 PM MDTAreal Flood AdvisoryBOUWeld3 hr
Aug 12, 10:06 PM MDTAreal Flood WarningBOUMorgan, Washington3 hr
Aug 12, 10:19 PM MDTAreal Flood WarningBOUElbert, Lincoln3 hr
Aug 12, 11:11 PM MDTFlash Flood WarningBOUWeld4 hr
Aug 13, 3:03 AM MDTAreal Flood WarningBOUWeld3 hr
Aug 13, 10:29 AM MDTFlood WatchBOUArapahoe, Boulder, Broomfield, Clear Creek, Douglas, Elbert and 9 more10 hr
Aug 13, 3:23 PM MDTSpecial Weather StatementBOULarimer52 min
Aug 13, 3:35 PM MDTSpecial Weather StatementBOUArapahoe25 min
Aug 13, 3:44 PM MDTAreal Flood AdvisoryBOULarimer101 min
Aug 13, 3:46 PM MDTSevere Thunderstorm WarningBOUDouglas, Elbert44 min
Aug 13, 3:50 PM MDTSevere Thunderstorm WarningBOUArapahoe40 min
Aug 13, 3:59 PM MDTSevere Thunderstorm WarningBOUWeld44 min
Aug 13, 4:13 PM MDTFlash Flood WarningBOUWeld3 hr
Aug 13, 4:25 PM MDTSevere Thunderstorm WarningBOUWeld37 min
Aug 13, 4:26 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert49 min
Aug 13, 4:30 PM MDTAreal Flood AdvisoryBOUElbert3 hr
Aug 13, 5:18 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Washington42 min
Aug 13, 5:25 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert, Lincoln, Washington50 min
Aug 13, 5:57 PM MDTSevere Thunderstorm WarningBOUMorgan, Washington48 min

Nearby

Flash Flood Warnings in Colorado, 2024Every flash flood warning in 2024

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.