Alert archive / Wyoming / Red Flag Warnings in 2012

Red Flag Warning 8, NWS Riverton, WY

May 21, 2012Natrona County, Wyoming

NWS Riverton, WY issued this red flag warning at May 21, 2012, 8:33 PM MDT for Natrona County, Wyoming. It took effect at May 22, 2012, 11:00 AM MDT. It was in force for 8 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 21, 2012, 8:33 PM MDT (02:33 UTC)
In effect from
May 22, 2012, 11:00 AM MDT
Expired
May 22, 2012, 7:00 PM MDT
In force
8 hr
Issued by
NWS Riverton, WY

County Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 137 km from the middle of the area, began a volume at 02:35 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

Riverton, WY (KRIW), launched 00:00Z, 2.6 hours before the alert went out and 131 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, Riverton, WY at 00:00Z on 2012-05-22Temperature 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, Riverton, WY at 00:00Z on 2012-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
3931 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
84 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.

126 
WWUS85 KRIW 220233
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
833 PM MDT MON MAY 21 2012

...LOW HUMIDITY AND STRONG WIND WILL BRING RED FLAG CONDITIONS TO NATRONA
COUNTY...

.DRY CONDITIONS AND STRONG WIND AHEAD OF AN APPROACHING COLD FRONT
WILL BRING RED FLAG CONDITIONS TO THE LOWER ELEVATIONS OF NATRONA
COUNTY DURING THE AFTERNOON HOURS TUESDAY.

WYZ280-221045-
/O.NEW.KRIW.FW.W.0008.120522T1700Z-120523T0200Z/
NATRONA COUNTY/CASPER BLM-
833 PM MDT MON MAY 21 2012

...RED FLAG WARNING IN EFFECT FROM 11 AM TO 8 PM MDT TUESDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONE 280...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS ISSUED A RED FLAG
WARNING FOR WIND AND LOW RELATIVE HUMIDITY...WHICH IS IN EFFECT
FROM 11 AM TO 8 PM MDT TUESDAY.

* AFFECTED AREA...FIRE WEATHER ZONE 280.

* WINDS...SOUTHWEST TO WEST AT 25 TO 35 MPH WITH GUSTS UP TO 50
  MPH.

* RELATIVE HUMIDITY...13 TO 16 PERCENT.

* IMPACTS...THE COMBINATION OF STRONG AND GUSTY WINDS AND LOW
  RELATIVE HUMIDITY AS WELL AS CRITICALLY DRY FUELS WILL RESULT IN
  ENHANCED FIRE BEHAVIOR DURING THE AFTERNOON TUESDAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS
ARE EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF
STRONG WINDS...LOW RELATIVE HUMIDITY...AND WARM TEMPERATURES WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

&&

BERC

$$

HTTP://WEATHER.GOV/RIVERTON
2 follow-up statements
450 
WWUS85 KRIW 220700
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
100 AM MDT TUE MAY 22 2012

...LOW HUMIDITY AND STRONG WIND WILL BRING RED FLAG CONDITIONS TO
NATRONA COUNTY...

.DRY CONDITIONS AND STRONG WIND AHEAD OF AN APPROACHING COLD
FRONT WILL BRING RED FLAG CONDITIONS TO THE LOWER ELEVATIONS OF
NATRONA COUNTY DURING THE AFTERNOON HOURS TODAY.

WYZ280-230200-
/O.CON.KRIW.FW.W.0008.120522T1700Z-120523T0200Z/
NATRONA COUNTY/CASPER BLM-
100 AM MDT TUE MAY 22 2012

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM THIS MORNING TO
8 PM MDT THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONE 280...

* AFFECTED AREA...FIRE WEATHER ZONE 280.

* WINDS...SOUTHWEST TO WEST AT 25 TO 35 MPH WITH GUSTS UP TO 50 
  MPH. 

* RELATIVE HUMIDITY...13 TO 16 PERCENT.

* IMPACTS...THE COMBINATION OF STRONG AND GUSTY WINDS AND LOW
  RELATIVE HUMIDITY AS WELL AS CRITICALLY DRY FUELS WILL RESULT IN
  ENHANCED FIRE BEHAVIOR DURING THE AFTERNOON TODAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS
ARE EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF
STRONG WINDS...LOW RELATIVE HUMIDITY...AND WARM TEMPERATURES WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

&&

BERC

$$

HTTP://WEATHER.GOV/RIVERTON
443 
WWUS85 KRIW 230100
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
700 PM MDT TUE MAY 22 2012


WYZ280-230200-
/O.CAN.KRIW.FW.W.0008.000000T0000Z-120523T0200Z/
NATRONA COUNTY/CASPER BLM-
700 PM MDT TUE MAY 22 2012

...RED FLAG WARNING IS CANCELLED FOR FIRE WEATHER ZONE 280...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS CANCELLED THE RED
FLAG WARNING.

RELATIVE HUMIDITY HAS RISEN AND THE COLD FRONT HAS PASSED. THE
WIND WILL CONTINUE TO DECREASE THIS EVENING WHILE TEMPERATURES
COOL DOWN INTO THE 50S...REDUCING THE FIRE BEHAVIOR THREAT. 

$$

HTTP://WEATHER.GOV/RIVERTON

Nearby

Red Flag Warnings in Wyoming, 2012Every red flag warning in 2012

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.