Alert archive / Colorado / Flash Flood Warnings in 2017

Flash Flood Warning 3, NWS Denver/Boulder, CO

July 26, 2017Douglas County, Elbert County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 26, 2017, 7:09 PM MDT for Douglas County, Elbert County, Jefferson County, Colorado. It was in force for 3 hr. 2 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, 7:09 PM MDT (01:09 UTC)
Expired
Jul 26, 2017, 10:15 PM MDT
In force
3 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

Counties Douglas County, CO, Elbert County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 59 km from the middle of the area, began a volume at 01:11 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

TimeReportWhereRemark
Jul 26, 7:20 PM MDTHEAVY RAIN 08 N Elizabeth, COHEAVY RAINFALL STILL OCCURRING WITH POOLING IN YARDS.
Jul 26, 8:15 PM MDTHEAVY RAIN 1.362 Ene The Pinery, CO

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, 1.2 hours before the alert went out and 158 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, Denver, CO at 00:00Z on 2017-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 479 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2017-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
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.

890 
WGUS55 KBOU 270109
FFWBOU
COC035-039-059-270415-
/O.NEW.KBOU.FF.W.0003.170727T0109Z-170727T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Denver Colorado has issued a

* Flash Flood Warning for...
  Douglas County in northeastern Colorado...
  Northwestern Elbert County in east central Colorado...
  Southeastern Jefferson County in central Colorado...

* Until 1015 PM MDT

* At 708 PM MDT, Doppler radar indicated heavy rain across the warned
  area. Up to two inches of rain have already fallen. Flash flooding
  is expected to begin shortly.

* Some locations that will experience flooding include...
  Southwestern Centennial, Highlands Ranch, Castle Rock, Parker, Lone
  Tree, Roxborough Park, Elizabeth, Larkspur, Perry Park, Surrey
  Ridge, The Pinery, Louviers, Devils Head, South Platte, Franktown,
  Beverly Hills, Westcreek, Ponderosa Park, Sedalia and Sprucewood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy Rainfall will cause flash flooding of small creeks, streams,
and ditches in the Hayman burn area. Some drainage basins affected by
excessive runoff include Fourmile Creek, Goose Creek, Sixmile Creek,
Trail Creek, Turkey Creek, West Creek, and other tributaries of the
South Platte River. Rock slides or debris flows can also be expected
across rural roads.

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 3940 10522 3957 10496 3957 10476 3947 10435
      3917 10470 3913 10514 3913 10523

$$

BOWEN
1 follow-up statement
914 
WGUS75 KBOU 270244
FFSBOU

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

COC035-039-059-270254-
/O.CAN.KBOU.FF.W.0003.000000T0000Z-170727T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas CO-Elbert CO-Jefferson CO-
844 PM MDT WED JUL 26 2017

...THE FLASH FLOOD WARNING FOR DOUGLAS...NORTHWESTERN ELBERT AND
SOUTHEASTERN JEFFERSON COUNTIES 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 3940 10522 3957 10496 3957 10476 3947 10435
      3917 10470 3913 10514 3913 10523

$$

BOWEN

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 6:26 PM MDTAreal Flood AdvisoryBOUDouglas2 hr
Jul 26, 6:34 PM MDTFlash Flood WarningBOUDouglas3 hr
Jul 26, 7:26 PM MDTAreal Flood AdvisoryBOUBoulder3 hr
Jul 26, 7:50 PM MDTAreal Flood AdvisoryBOUDouglas, Jefferson, Park115 min
Jul 26, 8:09 PM MDTFlash Flood WarningBOUPark3 hr
Jul 26, 9:13 PM MDTAreal Flood AdvisoryBOUArapahoe, Denver2 hr
Jul 26, 9:55 PM MDTAreal Flood AdvisoryBOULincoln2 hr
Jul 26, 11:22 PM MDTAreal Flood WarningBOUPark6 hr
Jul 26, 11:31 PM MDTAreal Flood AdvisoryBOUDouglas, Elbert3 hr
Jul 26, 11:48 PM MDTRiver Flood WarningBOUDouglas11 hr
Jul 27, 3:19 PM MDTAreal Flood AdvisoryBOUPark3 hr
Jul 27, 3:29 PM MDTSpecial Weather StatementBOUTeller31 min
Jul 27, 5:42 PM MDTSpecial Weather StatementBOUPark33 min

Nearby

Flash Flood Warnings in Colorado, 2017Every 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.