Alert archive / Colorado / Flash Flood Warnings in 2015

Flash Flood Warning 8, NWS Denver/Boulder, CO

May 23, 2015Logan County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at May 23, 2015, 10:20 PM MDT for Logan County, Colorado. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 23, 2015, 10:20 PM MDT (04:20 UTC)
Expired
May 24, 2015, 3:45 AM MDT
In force
5 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
Major

County Logan County, CO

The radar

The Cheyenne radar (KCYS), 146 km from the middle of the area, began a volume at 04:22 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 00:00Z, 4.3 hours before the alert went out and 90 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 2015-05-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 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 2015-05-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -24 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2134 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-24 m²/s²
0-3 km storm-relative helicity
-22 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

207 
WGUS55 KBOU 240420
FFWBOU
COC075-240945-
/O.NEW.KBOU.FF.W.0008.150524T0420Z-150524T0945Z/
/00000.3.DM.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
1020 PM MDT SAT MAY 23 2015

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  A LEVEE FAILURE IN...
  SOUTHWESTERN LOGAN COUNTY IN NORTHEASTERN COLORADO...

* UNTIL 345 AM MDT

* AT 949 PM MDT...LOGAN COUNTY EMERGENCY MANAGEMENT REPORTED THAT 
  WATER WAS OVERFLOWING SEVERAL DITCHES IN THE AREA JUST NORTH OF 
  STERLING...INCLUDING THE AREA AROUND COUNTY ROADS 39 AND 41 AND 
  COUNTY ROADS 34 AND 36. FLASH FLOODING WAS OCCURRING IN 
  IMMEDIATELY SURROUNDING AREAS AND EVACUATIONS ARE IN PROGRESS.

* LOCATIONS IMPACTED INCLUDE...
  NORTHERN STERLING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

&&

LAT...LON 4065 10317 4064 10324 4072 10324 4073 10314

$$

GIMMESTAD
2 follow-up statements
768 
WGUS75 KBOU 240626
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1226 AM MDT SUN MAY 24 2015

COC075-240945-
/O.CON.KBOU.FF.W.0008.000000T0000Z-150524T0945Z/
/00000.3.DM.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOGAN CO-
1226 AM MDT SUN MAY 24 2015

...A FLASH FLOOD WARNING FOR A LEVEE FAILURE REMAINS IN EFFECT UNTIL
345 AM MDT FOR SOUTHWESTERN LOGAN COUNTY...

AT 1215 AM MDT LOGAN COUNTY EMERGENCY MANAGEMENT REPORTED THAT MANY 
COUNTY ROADS REMAIN CLOSED JUST NORTH OF STERLING. WATER WAS 
OVERFLOWING SEVERAL DITCHES IN THE AREA JUST NORTH OF   
STERLING...INCLUDING THE AREA AROUND COUNTY ROADS 39 AND 41 AND   
COUNTY ROADS 34 AND 36. OFFICIALS ARE STILL TRYING TO DETERMINE 
EXACTLY WHICH DITCHES HAVE CAUSED THE FLOODING. PRE-EVACUATION 
NOTIFICATIONS HAVE BEEN MADE TO RESIDENTS IN THE AREA OF COUNTY 
ROADS 36 TO 32 BETWEEN COUNTY ROADS 37 AND 43.5. 

LOCATIONS IMPACTED INCLUDE...
NORTHERN STERLING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING.

&&

LAT...LON 4065 10317 4064 10324 4072 10324 4073 10314

$$

ENTREKIN
128 
WGUS75 KBOU 240816
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
216 AM MDT SUN MAY 24 2015

COC075-240823-
/O.CAN.KBOU.FF.W.0008.000000T0000Z-150524T0945Z/
/00000.3.DM.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOGAN CO-
216 AM MDT SUN MAY 24 2015

...THE FLASH FLOOD WARNING FOR A LEVEE FAILURE HAS BEEN CANCELLED FOR
SOUTHWESTERN LOGAN COUNTY...

A NEW AREAL FLOOD WARNING HAS NOW REPLACED THIS FLASH FLOOD WARNING 
ACROSS SOUTHWESTERN LOGAN COUNTY. FLOODING CONTINUES ACROSS PORTIONS 
OF NORTH STERLING AT THIS TIME. 

LAT...LON 4065 10317 4064 10324 4072 10324 4073 10314

$$

ENTREKIN

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 6:27 PM MDTRiver Flood WarningBOULogan, Morgan, Washington72 hr
May 23, 8:18 PM MDTAreal Flood AdvisoryBOULogan3 hr
May 24, 2:10 AM MDTAreal Flood WarningBOULogan18 hr
May 24, 4:44 AM MDTFlash Flood WatchBOUAdams, Arapahoe, Elbert, Lincoln, Logan, Morgan and 4 more14 hr
May 24, 11:22 AM MDTAreal Flood AdvisoryBOUElbert3 hr
May 24, 11:57 AM MDTFlash Flood WarningBOUArapahoe, Elbert3 hr
May 24, 12:08 PM MDTSpecial Weather StatementBOUArapahoe37 min
May 24, 12:15 PM MDTTornado WarningBOUArapahoe, Elbert15 min
May 24, 12:33 PM MDTTornado WarningBOUArapahoe, Elbert27 min
May 24, 1:00 PM MDTTornado WarningBOUArapahoe18 min
May 24, 1:23 PM MDTAreal Flood AdvisoryBOUAdams, Arapahoe3 hr
May 24, 1:25 PM MDTSpecial Weather StatementBOUAdams35 min
May 24, 2:17 PM MDTSpecial Weather StatementBOUWashington28 min
May 24, 2:43 PM MDTAreal Flood AdvisoryBOUAdams, Morgan, Washington3 hr
May 24, 3:15 PM MDTSpecial Weather StatementBOUWashington30 min

Nearby

Flash Flood Warnings in Colorado, 2015Every flash flood warning in 2015

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.