Alert archive / Wyoming / Flash Flood Warnings in 2014

Flash Flood Warning 2, NWS Cheyenne, WY

May 21, 2014Platte County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at May 21, 2014, 5:38 PM MDT for Platte County, Wyoming. It was in force for 6 hr. 3 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: May 21, 2014, 5:38 PM MDT (23:38 UTC)
Expired: May 21, 2014, 11:30 PM MDT
In force: 6 hr
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

County Platte County, WY

The radar

The Cheyenne radar (KCYS), 115 km from the middle of the area, began a volume at 23:38 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
May 21, 8:31 PM MDT	FLASH FLOOD	Wheatland, WY	8 MI WEST OF GUERNSEY HWY 26 IS CLOSED DUE TO FLOODING. 40 FT OF THE ROAD IS UNDER WATER.
May 21, 8:41 PM MDT	FLASH FLOOD	13 N Wheatland, WY	I-25 AT MILE MARKER 94. ROAD FLOODED AT CONSTRUCTION DETOUR.
May 21, 10:55 PM MDT	FLASH FLOOD	12 N Wheatland, WY	HIGHWAY 320 CLOSED IN BOTH DIRECTIONS FROM WHEATLAND TO JUNCTION OF HIGHWAY 26 DUE TO FLASH FLOODING.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Rapid City, SD (KRAP), launched 12:00Z, 11.6 hours before the alert went out and 271 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 865 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 85 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.

206 
WGUS55 KCYS 212338
FFWCYS
WYC031-220530-
/O.NEW.KCYS.FF.W.0002.140521T2338Z-140522T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
538 PM MDT WED MAY 21 2014

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL PLATTE COUNTY IN SOUTHEAST WYOMING...

* UNTIL 1130 PM MDT

* AT 535 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SLOW MOVING THUNDERSTORM WITH VERY HEAVY RAINFALL ACROSS THE     
  WARNED AREA. RADAR ESTIMATES OF 1.5 TO 2 INCHES OF RAIN HAS        
  FALLEN WITH THIS THUNDERSTORM JUST NORTHWEST OF WHEATLAND.


* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  WHEATLAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF UP TO AN INCH ARE POSSIBLE IN THE 
WARNED AREA.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
CHEYENNE.

&&

LAT...LON 4227 10485 4206 10486 4200 10518 4228 10515

$$

CLAYCOMB

1 follow-up statement

298 
WGUS75 KCYS 220212
FFSCYS

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
812 PM MDT WED MAY 21 2014

WYC031-220530-
/O.CON.KCYS.FF.W.0002.000000T0000Z-140522T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PLATTE WY-
812 PM MDT WED MAY 21 2014

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CENTRAL PLATTE COUNTY
UNTIL 1130 PM MDT...

AT 809 PM MDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR. LAW ENFORCEMENT REPORTED PORTIONS OF INTERSTATE 25 HAD 
STANDING WATER AS THE THUNDERSTORM MOVED OVERHEAD. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REPORT FLOODING TO THE NEAREST LAW ENFORCEMENT AGENCY SO THAT THEY
MAY TAKE APPROPRIATE ACTION TO CLOSE FLOODED ROADWAYS. THEY WILL
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN CHEYENNE.

&&

LAT...LON 4227 10485 4217 10486 4213 10516 4228 10515

$$

TJT

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 7:50 PM MDT	Special Weather Statement	CYS	Goshen	40 min
May 21, 2:53 PM MDT	Special Weather Statement	CYS	Converse	67 min
May 21, 3:10 PM MDT	Severe Thunderstorm Warning	CYS	Converse	50 min
May 21, 5:19 PM MDT	Special Weather Statement	CYS	Platte	56 min

Nearby

Flash Flood Warnings in Wyoming, 2014 Every flash flood warning in 2014

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.