Alert archive / Colorado / Flash Flood Warnings in 2002

Flash Flood Warning 49, NWS Grand Junction, CO

September 12, 2002La Plata County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Sep 12, 2002, 8:22 AM MDT for La Plata County, Colorado. It was in force for 6 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: Sep 12, 2002, 8:22 AM MDT (14:22 UTC)
Expired: Sep 12, 2002, 2:15 PM MDT
In force: 6 hr
Issued by: NWS Grand Junction, CO
Area: Counties, with a storm outline in the text

County La Plata County, CO

The radar

The Grand Junction radar (KGJX), 183 km from the middle of the area, began a volume at 14:24 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

Grand Junction, CO (KGJT), launched 12:00Z, 2.4 hours before the alert went out and 197 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: 190 J/kg
Mixed-layer CIN: -54 J/kg
Mixed-layer LCL: 1032 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
WGUS55 KGJT 121422
FFWGJT
COC067-122015-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
820 AM MDT THU SEP 12 2002

THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN LA PLATA COUNTY IN SOUTHWEST COLORADO

* UNTIL 215 PM MDT

* AT 819 AM MDT...WEATHER SERVICE DOPPLER RADAR INDICATED AN AREA
  OF MODERATE TO HEAVY RAIN BETWEEN DURANGO AND VALLECITO. MOVEMENT
  WAS TO THE NORTHEAST AT 10 MPH.

* THE THUNDERSTORM WITH EXCESSIVE RAINFALL WILL BE...
  BETWEEN VALLECITO AND LEMON RESERVOIRS BY 830 AM MDT
  
HEAVY RAIN OVER THE MISSIONARY RIDGE BURN AREA WILL CAUSE ADDITIONAL
DEBRIS AND MUD FLOWS. MORE THUNDERSTORM ACTIVITY IS EXPECTED THIS 
AFTERNOON.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE. IF YOUR VEHICLE STALLS, ABANDON IT IMMEDIATELY AND SEEK
HIGHER GROUND.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT AGENCY
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
GRAND JUNCTION.

LAT...LON 3734 10808 3731 10749 3761 10749 3761 10795

1 follow-up statement

115 
RWUS32 KGJT 121851
FFSGJT
COC067-122000-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1248 PM MDT THU SEP 12 2002

...FLASH FLOOD WARNING FOR NORTHERN LA PLATA COUNTY CANCELLED...

...FLASH FLOOD WATCH CONTINUES SOUTHWEST COLORADO AND SOUTHEAST
   UTAH UNTIL 10:00 PM MDT TONIGHT...

HEAVY RAIN HAS ENDED ACROSS THE MISSIONARY RIDGE AREA, SO THE FLASH
FLOOD WARNING HAS BEEN CANCELLED. HOWEVER, THUNDERSTORMS ARE
EXPECTED TO MOVE BACK INTO THE AREA LATER THIS AFTERNOON AND
TONIGHT. RESIDENTS IN AND NEAR THE BURN AREA SHOULD MONITOR THE
WEATHER CLOSELY AND BE PREPARED FOR RENEWED WARNINGS LATER TODAY.

$$

BA

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 11, 9:54 PM MDT	Flash Flood Warning	GJT	La Plata	6 hr
Sep 12, 11:38 AM MDT	Flash Flood Warning	GJT	Garfield	6 hr
Sep 12, 2:53 PM MDT	Flash Flood Warning	GJT	Montezuma	3 hr
Sep 12, 3:29 PM MDT	Severe Thunderstorm Warning	GJT	Montezuma	46 min
Sep 12, 4:06 PM MDT	Severe Thunderstorm Warning	GJT	Mesa	39 min
Sep 12, 4:16 PM MDT	Flash Flood Warning	GJT	Mesa	119 min
Sep 12, 4:57 PM MDT	Severe Thunderstorm Warning	GJT	Delta, Montrose	48 min
Sep 12, 5:28 PM MDT	Flash Flood Warning	GJT	La Plata	6 hr

Nearby

Flash Flood Warnings in Colorado, 2002 Every flash flood warning in 2002

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.