Alert archive / Wyoming / Red Flag Warnings in 2012

Red Flag Warning 7, NWS Riverton, WY

April 7, 2012Natrona County, Wyoming

NWS Riverton, WY issued this red flag warning at Apr 7, 2012, 2:20 AM MDT for Natrona County, Wyoming. It took effect at Apr 7, 2012, 12:00 PM MDT. It was in force for 7 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
Apr 7, 2012, 2:20 AM MDT (08:20 UTC)
In effect from
Apr 7, 2012, 12:00 PM MDT
Expired
Apr 7, 2012, 7:00 PM MDT
In force
7 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 08:20 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, 8.3 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 2012-04-07Temperature 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 2012-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 square meters per square second.1939587897Sfc1 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
3092 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
37 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.

707 
WWUS85 KRIW 070820
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
220 AM MDT SAT APR 7 2012

...VERY LOW HUMIDITY AND BREEZY CONDITIONS EXPECTED ACROSS NATRONA
COUNTY THIS AFTERNOON...

.VERY DRY AIR WILL MOVE INTO NATRONA COUNTY THIS MORNING BEHIND A
DEPARTING AREA OF LOW PRESSURE AND COLD FRONT. A COMBINATION OF VERY
LOW RELATIVE HUMIDITY AND GUSTY WEST TO SOUTHWESTERLY BREEZES WILL
RESULT IN CRITICAL FIRE WEATHER CONDITIONS.

WYZ280-300-080100-
/O.NEW.KRIW.FW.W.0007.120407T1800Z-120408T0100Z/
NATRONA COUNTY/CASPER BLM-CASPER MOUNTAIN-
220 AM MDT SAT APR 7 2012

...RED FLAG WARNING IN EFFECT FROM NOON TODAY TO 7 PM MDT THIS
EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
280 AND THE LOWER ELEVATIONS OF ZONE 300...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS ISSUED A RED FLAG
WARNING FOR WIND AND LOW RELATIVE HUMIDITY...WHICH IS IN EFFECT
FROM NOON TODAY TO 7 PM MDT THIS EVENING.

* AFFECTED AREA...FIRE WEATHER ZONES 280 AND THE LOWER ELEVATIONS OF
  ZONE 300.

* WINDS...WEST TO SOUTHWEST 15 TO 25 MPH WITH GUSTS UP TO 35 MPH.

* RELATIVE HUMIDITY...10 TO 15 PERCENT.

* IMPACTS...THE COMBINATION OF GUSTY WINDS AND LOW RELATIVE
  HUMIDITIES WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS
  DURING THE AFTERNOON UNTIL AROUND SUNSET.

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.

&&

$$

HTTP://WEATHER.GOV/RIVERTON
1 follow-up statement
466 
WWUS85 KRIW 080054
RFWRIW

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
654 PM MDT SAT APR 7 2012


WYZ280-300-080200-
/O.EXP.KRIW.FW.W.0007.000000T0000Z-120408T0100Z/
NATRONA COUNTY/CASPER BLM-CASPER MOUNTAIN-
654 PM MDT SAT APR 7 2012

...RED FLAG WARNING WILL EXPIRE AT 7 PM MDT THIS EVENING FOR WIND
AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 280 AND 300...

THE WIND WILL BE DECREASING AFTER 700 PM WITH RELATIVE HUMIDITY
RISING AS THE EVENING COOLS DOWN. THEREFORE...THE RED FLAG WARNING
WILL EXPIRE AT 700 PM MDT.

$$

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.