Alert archive / Wyoming / Flash Flood Warnings in 2016

Flash Flood Warning 13, NWS Cheyenne, WY

August 7, 2016Goshen County, Platte County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at Aug 7, 2016, 11:01 PM MDT for Goshen County, Platte County, Wyoming. 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
Aug 7, 2016, 11:01 PM MDT (05:01 UTC)
Expired
Aug 8, 2016, 2:00 AM MDT
In force
3 hr
Issued by
NWS Cheyenne, WY
Area
Storm-based polygon
Flood severity
None

Counties Goshen County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 125 km from the middle of the area, began a volume at 05:00 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

TimeReportWhereRemark
Aug 7, 11:15 PM MDTFLASH FLOOD2 Se Fort Laramie, WYGOSHEN COUNTY EMA REPORTS EVIDENCE OF FLASH FLOODING FROM HEAVY RAIN LAST EVENING. DEBRIS ON HIGHWAY 2 MILES SOUTHEAST OF FORT LARAMIE. AT 7 AM...WATER STILL HIGH IN CREEK WITH DEBRIS IN THE FENCE LINE. RAILROAD APPROACH WEST OF FORT LARAMIE WAS NEARLY WASHED

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 00:00Z, 5.0 hours before the alert went out and 240 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, Rapid City, SD at 00:00Z on 2016-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 966 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, Rapid City, SD at 00:00Z on 2016-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 square meters per square second.19395878Sfc1 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
966 J/kg
Mixed-layer CIN
-124 J/kg
Mixed-layer LCL
1514 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.7

Open this sounding in Storm Lab

The text

As transmitted.

547 
WGUS55 KCYS 080501
FFWCYS
WYC015-031-080800-
/O.NEW.KCYS.FF.W.0013.160808T0501Z-160808T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
1101 PM MDT SUN AUG 7 2016

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN GOSHEN COUNTY IN SOUTHEASTERN WYOMING...
  EAST CENTRAL PLATTE COUNTY IN SOUTHEASTERN WYOMING...

* UNTIL 200 AM MDT

* AT 1100 PM MDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. UP TO TWO INCHES OF RAIN HAVE
  ALREADY FALLEN. FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  GUERNSEY...LINGLE...FORT LARAMIE...GRAYROCKS RESERVOIR...
  FORT LARAMIE NATIONAL HISTORIC SITE...
  HARTVILLE AND HWY 85 AT DRY RAWHIDE CREEK.

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

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

&&

LAT...LON 4237 10426 4196 10427 4211 10475 4241 10473

$$

HAMMER
1 follow-up statement
675 
WGUS75 KCYS 080801
FFSCYS

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
201 AM MDT MON AUG 8 2016

WYC015-031-080811-
/O.EXP.KCYS.FF.W.0013.000000T0000Z-160808T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GOSHEN WY-PLATTE WY-
201 AM MDT MON AUG 8 2016

...THE FLASH FLOOD WARNING FOR NORTHWESTERN GOSHEN AND EAST CENTRAL
PLATTE COUNTIES HAS EXPIRED...

THE HEAVY RAIN HAS ENDED. FLOODING IS NO LONGER EXPECTED TO POSE A
THREAT. PLEASE CONTINUE TO HEED ANY REMAINING ROAD CLOSURES.

LAT...LON 4237 10426 4196 10427 4211 10475 4241 10473

$$

HAMMER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 6:07 PM MDTSpecial Weather StatementCYSConverse38 min
Aug 7, 6:53 PM MDTSpecial Weather StatementCYSConverse37 min
Aug 7, 7:33 PM MDTSpecial Weather StatementCYSPlatte57 min
Aug 7, 8:28 PM MDTSpecial Weather StatementCYSPlatte62 min
Aug 7, 8:37 PM MDTSpecial Weather StatementCYSNiobrara38 min
Aug 7, 9:26 PM MDTSpecial Weather StatementCYSGoshen64 min
Aug 7, 10:26 PM MDTSpecial Weather StatementCYSGoshen64 min
Aug 7, 10:28 PM MDTSevere Thunderstorm WarningCYSGoshen, Platte62 min
Aug 8, 2:47 AM MDTFire Weather WatchCYS17 hr
Aug 8, 3:50 PM MDTSpecial Weather StatementCYSNiobrara40 min

Nearby

Flash Flood Warnings in Wyoming, 2016Every flash flood warning in 2016

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.