Alert archive / Colorado / Flash Flood Watches in 2008

Flash Flood Watch 4, NWS Denver/Boulder, CO

August 9, 20087 counties in Colorado

NWS Denver/Boulder, CO issued this flash flood watch at Aug 9, 2008, 11:40 AM MDT for 7 counties in Colorado. It took effect at Aug 9, 2008, 12:00 PM MDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Aug 9, 2008, 11:40 AM MDT (17:40 UTC)
In effect from
Aug 9, 2008, 12:00 PM MDT
Expired
Aug 9, 2008, 7:59 PM MDT
In force
8 hr
Issued by
NWS Denver/Boulder, CO
Flood severity
None

Counties Boulder County, CO, Clear Creek County, CO, Douglas County, CO, Gilpin County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO

The radar

The Denver radar (KFTG), 74 km from the middle of the area, began a volume at 17:44 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 5.7 hours before the alert went out and 435 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, N. Platte/Lee Bi, NE at 12:00Z on 2008-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 315 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, N. Platte/Lee Bi, NE at 12:00Z on 2008-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.1939Sfc1 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
315 J/kg
Mixed-layer CIN
-94 J/kg
Mixed-layer LCL
668 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch 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 watch went out at Aug 9, 3:22 AM MDT, 8 hours 18 minutes earlier.

Area forecast discussion, Aug 9, 3:22 AM MDT, 8 hours 18 minutes before
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Hazardous weather outlook, Aug 9, 11:19 AM MDT, 21 minutes before
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 6:33 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld42 min
Aug 8, 7:15 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld45 min
Aug 8, 7:19 PM MDTAreal Flood AdvisoryBOUMorgan116 min
Aug 8, 7:29 PM MDTFlash Flood WarningBOUMorgan3 hr
Aug 8, 7:30 PM MDTAreal Flood AdvisoryBOUArapahoe, Denver, Jefferson90 min
Aug 8, 7:51 PM MDTFlash Flood WarningBOUArapahoe, Denver94 min
Aug 8, 7:59 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Weld39 min
Aug 8, 8:10 PM MDTAreal Flood AdvisoryBOUAdams95 min
Aug 8, 8:16 PM MDTAreal Flood AdvisoryBOUMorgan, Washington119 min
Aug 8, 8:49 PM MDTAreal Flood AdvisoryBOUArapahoe116 min
Aug 8, 9:03 PM MDTAreal Flood AdvisoryBOUWashington117 min
Aug 8, 9:19 PM MDTSevere Thunderstorm WarningBOUWashington41 min
Aug 8, 9:54 PM MDTAreal Flood AdvisoryBOUAdams96 min
Aug 8, 9:59 PM MDTAreal Flood AdvisoryBOUElbert, Lincoln2 hr
Aug 8, 10:23 PM MDTAreal Flood WarningBOUAdams, Arapahoe, Denver3 hr
Aug 8, 10:48 PM MDTAreal Flood AdvisoryBOUArapahoe117 min
Aug 8, 11:01 PM MDTAreal Flood AdvisoryBOUWashington89 min
Aug 9, 5:42 PM MDTAreal Flood AdvisoryBOUDouglas, Jefferson, Park3 hr

Nearby

Flash Flood Watches in Colorado, 2008Every flash flood watch in 2008

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.