Alert archive / Colorado / Flash Flood Warnings in 2018

Flash Flood Warning 8, NWS Denver/Boulder, CO

July 5, 2018Douglas County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 5, 2018, 3:19 PM MDT for Douglas County, Jefferson County, Colorado. It was in force for 115 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 5, 2018, 3:19 PM MDT (21:19 UTC)
Expired
Jul 5, 2018, 5:14 PM MDT
In force
115 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

Counties Douglas County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 83 km from the middle of the area, began a volume at 21:22 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

Denver, CO (KDEN), launched 12:00Z, 9.3 hours before the alert went out and 185 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 12:00Z on 2018-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 13 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2018-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -107 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
13 J/kg
Mixed-layer CIN
-455 J/kg
Mixed-layer LCL
2192 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-107 m²/s²
0-3 km storm-relative helicity
-52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

416 
WGUS55 KBOU 052119
FFWBOU
COC035-059-060015-
/O.NEW.KBOU.FF.W.0008.180705T2119Z-180706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
319 PM MDT THU JUL 5 2018

The National Weather Service in Denver Colorado has issued a

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

* Until 615 PM MDT.

* At 314 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over southern Jefferson and southwestern Douglas 
  Counties. The storms producing the heavy rainfall are moving 
  slowly north at 5 mph. Flash flooding is expected to begin shortly.

* Doppler radar estimates have indicated that up to 1.5 inches of 
  rain has fallen since 2:20 PM MDT. Heavy rain is continuing. 

* Some locations that will experience flooding include...
  Cheesman Reservoir, Wellington Lake and Deckers. 

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.

&&

LAT...LON 3917 10508 3916 10525 3922 10537 3930 10539
      3937 10536 3938 10525 3933 10513

$$

RJK
2 follow-up statements
350 
WGUS75 KBOU 052209
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
409 PM MDT THU JUL 5 2018

COC035-059-060015-
/O.CON.KBOU.FF.W.0008.000000T0000Z-180706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas CO-Jefferson CO-
409 PM MDT THU JUL 5 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM MDT FOR
SOUTHWESTERN DOUGLAS AND SOUTHWESTERN JEFFERSON COUNTIES...

At 405 PM MDT, a thunderstorm producing heavy rain was located over 
Cheesman Reservoir, or 34 miles northwest of Colorado Springs, 
moving slowing southeast at 5 mph. Flash flooding is likely.

Doppler radar estimates have indicated that up to 2.5 inches of rain 
n has fallen since 2:20 PM MDT.  Heavy rainfall is expected 
continue.  

Some locations that will experience flooding include...
Cheesman Reservoir, Wellington Lake and Deckers. 

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.

&&

LAT...LON 3917 10508 3916 10525 3922 10537 3930 10539
      3937 10536 3938 10525 3933 10513

$$

RJK
254 
WGUS75 KBOU 052314
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
514 PM MDT THU JUL 5 2018

COC035-059-052316-
/O.CAN.KBOU.FF.W.0008.000000T0000Z-180706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Douglas CO-Jefferson CO-
514 PM MDT THU JUL 5 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN DOUGLAS AND SOUTHWESTERN
JEFFERSON COUNTIES IS CANCELLED...

The heavy rain has ended in the warning area. There is still some 
light rain falling over the warning area but flooding is no longer 
expected to pose a threat.  Doppler radar estimates indicated that 
much of the warning area had 1.5 to 3.5 inches of rainfall. The few 
gauges that are in the Hayman Burn area recorded approximately 1 to 
2 inches of rainfall.  There were no reports of flooding.  The dry 
soils likely soaked up the rainfall with little runoff. 

LAT...LON 3917 10508 3916 10525 3922 10537 3930 10539
      3937 10536 3938 10525 3933 10513

$$

RJK

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 4, 6:02 PM MDTFlash Flood WarningBOULarimer69 min
Jul 4, 6:11 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe49 min
Jul 4, 6:28 PM MDTSpecial Weather StatementBOUWeld47 min
Jul 4, 6:29 PM MDTSevere Thunderstorm WarningBOULarimer32 min
Jul 4, 7:15 PM MDTSpecial Weather StatementBOUMorgan45 min
Jul 4, 7:58 PM MDTSevere Thunderstorm WarningBOUWeld47 min
Jul 4, 8:09 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld51 min
Jul 4, 8:14 PM MDTSpecial Weather StatementBOUJefferson46 min
Jul 4, 8:41 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld49 min
Jul 4, 8:56 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld49 min
Jul 4, 9:26 PM MDTSevere Thunderstorm WarningBOUMorgan20 min
Jul 4, 10:34 PM MDTSevere Thunderstorm WarningBOUWashington41 min
Jul 5, 1:27 AM MDTSpecial Weather StatementBOUArapahoe63 min
Jul 5, 2:24 AM MDTSpecial Weather StatementBOUAdams51 min
Jul 5, 10:16 AM MDTFlash Flood WatchBOUBoulder, Clear Creek, Douglas, Gilpin, Jefferson, Larimer and 1 more9 hr
Jul 5, 1:33 PM MDTTornado Warning Tornado observedBOUPark27 min
Jul 5, 1:34 PM MDTFlash Flood WarningBOUPark66 min
Jul 5, 2:37 PM MDTAreal Flood AdvisoryBOUPark83 min
Jul 5, 5:15 PM MDTAreal Flood AdvisoryBOUAdams31 min

Nearby

Flash Flood Warnings in Colorado, 2018Every flash flood warning in 2018

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.