Alert archive / Colorado / Flash Flood Warnings in 2017

Flash Flood Warning 1, NWS Denver/Boulder, CO

May 8, 2017Weld County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at May 8, 2017, 5:00 PM MDT for Weld County, Colorado. It was in force for 3 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 8, 2017, 5:00 PM MDT (23:00 UTC)
Expired
May 8, 2017, 8:00 PM MDT
In force
3 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Weld County, CO

The radar

The Denver radar (KFTG), 72 km from the middle of the area, began a volume at 22:59 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, 11.0 hours before the alert went out and 137 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 2017-05-08Temperature 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 12:00Z on 2017-05-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2189 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

647 
WGUS55 KBOU 082300
FFWBOU
COC123-090200-
/O.NEW.KBOU.FF.W.0001.170508T2300Z-170509T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
500 PM MDT MON MAY 8 2017

The National Weather Service in Denver Colorado has issued a

* Flash Flood Warning for...
  West central Weld County in northeastern Colorado...

* Until 800 PM MDT

* There have been reports of flooding in Greeley. Flash flooding is 
  occurring with 2 to 3 feet of water reported at the intersection 
  of Highway 85 and 34. There were also reports of at least a foot 
  of water running over other roads in the Garden City/Evans area.

* Some locations that will experience flooding include...
  Greeley, Evans, La Salle, Galeton, Gill, Lucerne and Barnesville. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, highways and underpasses. Additionally, country
roads and farmlands along the banks of creeks, streams and other low
lying areas are subject to flooding.

&&

LAT...LON 4032 10476 4044 10482 4059 10456 4049 10439

$$

TH
3 follow-up statements
867 
WGUS75 KBOU 082351
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
551 PM MDT MON MAY 8 2017

COC123-090200-
/O.CON.KBOU.FF.W.0001.000000T0000Z-170509T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-
551 PM MDT MON MAY 8 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 800 PM MDT FOR
WEST CENTRAL WELD COUNTY...

At 520 PM MDT, local law enforcement reported various roads had 
flooded and houses and basements were flooding in Greeley and Evans. 
Small reservoirs and ponds had also overtopped but there was no 
danger to any dams.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

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

&&

LAT...LON 4032 10476 4044 10482 4059 10456 4049 10439

$$

TH
847 
WGUS75 KBOU 090044
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
644 PM MDT MON MAY 8 2017

COC123-090200-
/O.CON.KBOU.FF.W.0001.000000T0000Z-170509T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-
644 PM MDT MON MAY 8 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 800 PM MDT FOR
WEST CENTRAL WELD COUNTY...

At 640 PM MDT, law enforcement officials reported that flooding 
continues in the Greeley and Evans area, especially along the 
Highway 34 bypass. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4032 10476 4044 10482 4059 10456 4049 10439

$$

TH
393 
WGUS75 KBOU 090157
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
757 PM MDT MON MAY 8 2017

COC123-090202-
/O.EXP.KBOU.FF.W.0001.000000T0000Z-170509T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-
757 PM MDT MON MAY 8 2017

...THE FLASH FLOOD WARNING FOR WEST CENTRAL WELD COUNTY WILL EXPIRE
AT 800 PM MDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
significant threat. 

Some roads may remain underwater through the evening as the high 
water gradually recedes.  Flooding of basements may also continue 
from the heavy rain that fell earlier this evening.  Additional 
light rain is expected at times through this evening, but no heavy 
showers are expected.  Motorists should continue to heed any 
remaining road closures.  

LAT...LON 4032 10476 4044 10482 4059 10456 4049 10439

$$

DANKERS

The office that day

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

IssuedProductOfficeCountiesLasted
May 8, 2:25 PM MDTSevere Thunderstorm WarningBOUClear Creek, Jefferson21 min
May 8, 2:37 PM MDTSpecial Weather StatementBOUElbert38 min
May 8, 2:44 PM MDTSevere Thunderstorm WarningBOULarimer, Weld46 min
May 8, 2:45 PM MDTSevere Thunderstorm WarningBOUAdams, Boulder, Broomfield, Denver, Jefferson45 min
May 8, 2:50 PM MDTTornado WarningBOUArapahoe, Elbert28 min
May 8, 3:21 PM MDTSevere Thunderstorm WarningBOUAdams, Broomfield, Denver, Jefferson39 min
May 8, 3:25 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Elbert50 min
May 8, 3:33 PM MDTAreal Flood AdvisoryBOUAdams, Arapahoe, Denver, Jefferson57 min
May 8, 3:34 PM MDTSevere Thunderstorm WarningBOULincoln, Washington41 min
May 8, 3:51 PM MDTSevere Thunderstorm WarningBOUWeld39 min
May 8, 4:15 PM MDTAreal Flood AdvisoryBOUWeld90 min
May 8, 4:18 PM MDTSpecial Weather StatementBOUAdams42 min
May 8, 4:23 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln37 min
May 8, 4:28 PM MDTSevere Thunderstorm WarningBOUWeld47 min
May 8, 4:46 PM MDTAreal Flood AdvisoryBOUAdams89 min
May 8, 4:59 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln25 min
May 8, 5:20 PM MDTSevere Thunderstorm WarningBOULincoln, Washington40 min
May 8, 5:38 PM MDTAreal Flood AdvisoryBOUElbert, Lincoln, Washington112 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.