Alert archive / Colorado / Flash Flood Warnings in 2017

Flash Flood Warning 5, NWS Denver/Boulder, CO

July 27, 2017Logan County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 27, 2017, 11:51 PM MDT for Logan County, Colorado. It was in force for 3 hr. 1 report 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 27, 2017, 11:51 PM MDT (05:51 UTC)
Expired: Jul 28, 2017, 2:45 AM MDT
In force: 3 hr
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Flood severity: None

County Logan County, CO

The radar

The Denver radar (KFTG), 126 km from the middle of the area, began a volume at 05:53 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 28, 12:15 AM MDT	FLASH FLOOD	Merino, CO	NUMEROUS REPORTS OF LOW-LAND FLOODING IN MERINO AND VICINITY. WATER IN BASEMENTS AND BUSINESSES TO ONE INCH DEPTH. ONE INCH OF WATER IN POST OFFICE. DAMAGE TO RURAL COUNTY DIRT ROADS DUE TO EXCESS RUNOFF IN FIELDS.

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, 5.9 hours before the alert went out and 72 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: 405 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 2244 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

023 
WGUS55 KBOU 280551
FFWBOU
COC075-280845-
/O.NEW.KBOU.FF.W.0005.170728T0551Z-170728T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
1151 PM MDT THU JUL 27 2017

The National Weather Service in Denver Colorado has issued a

* Flash Flood Warning for...
  Southwestern Logan County in northeastern Colorado...

* Until 245 AM MDT

* At 1149 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to three inches of rain have 
  already fallen just north of Merino, and additional heavy rainfall 
  is expected until 1 AM. Flash flooding is expected to begin 
  shortly. This Flash Flood Warning replaces the Small Stream Flood 
  Advisory that was in effect for southwestern Logan county. 

* Some locations that will experience flooding include...
  Merino, Willard and Atwood. 

This includes the following streams and drainages...Sand Creek...
Pawnee Creek and Baymer Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

&&

LAT...LON 4044 10319 4044 10347 4052 10347 4052 10358
      4060 10358 4060 10332

$$

BARJENBRUCH

2 follow-up statements

578 
WGUS75 KBOU 280711
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
111 AM MDT FRI JUL 28 2017

COC075-280845-
/O.CON.KBOU.FF.W.0005.000000T0000Z-170728T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Logan CO-
111 AM MDT FRI JUL 28 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 AM MDT FOR
SOUTHWESTERN LOGAN COUNTY...

At 109 AM MDT, Doppler radar indicated that thunderstorms had moved 
out of the area. Rainfall estimates from radar indicated between 3 
and 4.5 of rain had fallen in a small area from Merino to the north 
and northwest toward Willard.  Flash flooding is expected to be 
ongoing. 

Some locations that will experience flooding include...
Merino, Willard and Atwood. 

This includes the following streams and drainages...Sand Creek...
Pawnee Creek and Baymer Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

&&

LAT...LON 4044 10319 4044 10347 4052 10347 4052 10358
      4060 10358 4060 10332

$$

BARJENBRUCH

137 
WGUS75 KBOU 280842
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
242 AM MDT FRI JUL 28 2017

COC075-280851-
/O.EXP.KBOU.FF.W.0005.000000T0000Z-170728T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Logan CO-
242 AM MDT FRI JUL 28 2017

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN LOGAN COUNTY WILL EXPIRE
AT 245 AM MDT...

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

LAT...LON 4044 10319 4044 10347 4052 10347 4052 10358
      4060 10358 4060 10332

$$

BARJENBRUCH

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 8:30 PM MDT	Severe Thunderstorm Warning	BOU	Logan	45 min
Jul 27, 11:02 PM MDT	Areal Flood Advisory	BOU	Logan, Morgan	3 hr
Jul 28, 2:39 PM MDT	Areal Flood Advisory	BOU	Douglas, Jefferson	3 hr
Jul 28, 3:08 PM MDT	Special Weather Statement	BOU	Douglas	52 min
Jul 28, 3:42 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln, Washington	48 min
Jul 28, 4:15 PM MDT	Areal Flood Advisory	BOU	Douglas	90 min
Jul 28, 4:21 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	24 min
Jul 28, 5:41 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	34 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.