Alert archive / Colorado / Flash Flood Warnings in 2017

Flash Flood Warning 2, NWS Denver/Boulder, CO

July 26, 2017Douglas County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 26, 2017, 6:34 PM MDT for Douglas County, Colorado. It was in force for 3 hr. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 26, 2017, 6:34 PM MDT (00:34 UTC)
Expired: Jul 26, 2017, 9:30 PM MDT
In force: 3 hr
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Flood severity: None

County Douglas County, CO

The radar

The Denver radar (KFTG), 51 km from the middle of the area, began a volume at 00:36 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.

What was reported inside it

Time	Report	Where	Remark
Jul 26, 6:48 PM MDT	FLOOD	2 E Franktown, CO	ESTAMATED SEVERAL INCHES ALREADY WITH MORE FALLING.
Jul 26, 6:48 PM MDT	HEAVY RAIN 2	2 E Franktown, CO	ESTAMATED SEVERAL INCHES ALREADY WITH MORE FALLING.
Jul 26, 7:04 PM MDT	HEAVY RAIN 2.48	2 Se Franktown, CO	GAUGES ARE INDICATING 2.48 INCHES OF RAIN HAVE FALLEN IN ABOUT 45 MINUTES.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 0.6 hours before the alert went out and 141 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 479 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1416 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

099 
WGUS55 KBOU 270034
FFWBOU
COC035-270330-
/O.NEW.KBOU.FF.W.0002.170727T0034Z-170727T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
634 PM MDT WED JUL 26 2017

The National Weather Service in Denver Colorado has issued a

* Flash Flood Warning for...
  East central Douglas County in northeastern Colorado...

* Until 930 PM MDT

* At 632 PM MDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area.  A rain 
  gauge just southeast of Franktown indicates two and half inches of 
  rain has fallen in the past 40 minutes. Flash flooding is expected 
  to begin shortly.

* Some locations that will experience flooding include...
  Franktown and Ponderosa Park. 

LAT...LON 3931 10477 3940 10475 3940 10466 3930 10466

$$

MEIER

1 follow-up statement

913 
WGUS75 KBOU 270244 RRA
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
844 PM MDT WED JUL 26 2017

COC035-270254-
/O.CAN.KBOU.FF.W.0002.000000T0000Z-170727T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas CO-
844 PM MDT WED JUL 26 2017

...THE FLASH FLOOD WARNING FOR EAST CENTRAL DOUGLAS COUNTY IS
CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3931 10477 3940 10475 3940 10466 3930 10466

$$

MEIER

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 26, 6:26 PM MDT	Areal Flood Advisory	BOU	Douglas	2 hr
Jul 26, 7:09 PM MDT	Flash Flood Warning	BOU	Douglas, Elbert, Jefferson	3 hr
Jul 26, 7:26 PM MDT	Areal Flood Advisory	BOU	Boulder	3 hr
Jul 26, 7:50 PM MDT	Areal Flood Advisory	BOU	Douglas, Jefferson, Park	115 min
Jul 26, 8:09 PM MDT	Flash Flood Warning	BOU	Park	3 hr
Jul 26, 9:13 PM MDT	Areal Flood Advisory	BOU	Arapahoe, Denver	2 hr
Jul 26, 9:55 PM MDT	Areal Flood Advisory	BOU	Lincoln	2 hr
Jul 26, 11:22 PM MDT	Areal Flood Warning	BOU	Park	6 hr
Jul 26, 11:31 PM MDT	Areal Flood Advisory	BOU	Douglas, Elbert	3 hr
Jul 26, 11:48 PM MDT	River Flood Warning	BOU	Douglas	11 hr
Jul 27, 3:19 PM MDT	Areal Flood Advisory	BOU	Park	3 hr
Jul 27, 3:29 PM MDT	Special Weather Statement	BOU	Teller	31 min
Jul 27, 5:42 PM MDT	Special Weather Statement	BOU	Park	33 min

Nearby

Flash Flood Warnings in Colorado, 2017 Every flash flood warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.