Alert archive / Colorado / Flash Flood Watches in 2013

Flash Flood Watch 4, NWS Denver/Boulder, CO

September 9, 2013Boulder County, Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood watch at Sep 9, 2013, 10:58 AM MDT for Boulder County, Larimer County, Colorado. It took effect at Sep 9, 2013, 2:00 PM MDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued
Sep 9, 2013, 10:58 AM MDT (16:58 UTC)
In effect from
Sep 9, 2013, 2:00 PM MDT
Expired
Sep 10, 2013, 12:00 AM MDT
In force
10 hr
Issued by
NWS Denver/Boulder, CO
Flood severity
None

Counties Boulder County, CO, Larimer County, CO

The radar

The Denver radar (KFTG), 99 km from the middle of the area, began a volume at 17:04 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, 5.0 hours before the alert went out and 298 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 2013-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 316 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 2013-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
316 J/kg
Mixed-layer CIN
-54 J/kg
Mixed-layer LCL
930 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
165 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.3

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 2:57 PM MDTSpecial Weather StatementBOUDenver48 min
Sep 9, 3:11 PM MDTAreal Flood AdvisoryBOUJefferson94 min
Sep 9, 3:53 PM MDTAreal Flood AdvisoryBOUAdams, Broomfield, Denver67 min
Sep 9, 4:49 PM MDTSpecial Weather StatementBOUArapahoe41 min

Nearby

Flash Flood Watches in Colorado, 2013Every flash flood watch in 2013

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.