Alert archive / California / Red Flag Warnings in 2012

Red Flag Warning 9, NWS Las Vegas, NV

May 6, 2012San Bernardino County, California; Clark County, Nevada; Mohave County, Arizona

NWS Las Vegas, NV issued this red flag warning at May 6, 2012, 2:33 PM PDT for San Bernardino County, California; Clark County, Nevada; Mohave County, Arizona. It took effect at May 7, 2012, 8:00 AM PDT. It was in force for 7 hr. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
May 6, 2012, 2:33 PM PDT (21:33 UTC)
In effect from
May 7, 2012, 8:00 AM PDT
Expired
May 7, 2012, 3:00 PM PDT
In force
7 hr
Issued by
NWS Las Vegas, NV

Counties Mohave County, AZ, San Bernardino County, CA, Clark County, NV

The radar

The Las Vegas radar (KESX), 15 km from the middle of the area, began a volume at 21:35 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.

What was reported inside it

TimeReportWhereRemark
May 7, 1:37 PM PDTNON-TSTM WND DMG5 Ene Las Vegas, NVA DUST DEVIL DEVELOPED IN A DIRT LOT NEAR NELLIS BOULEVARD AND LAKE MEAD BOULEVARD THEN TRACKED SOUTH ALONG NELLIS BOULEVARD PASSING OVER A BANK WHERE IT TOOK OFF ROOF SHINGLES. THE DUST DEVIL THEN MOVED SOUTH DAMAGING CARS IN A PARKING LOT AND ROOF SHINGLES O

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

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 9.6 hours before the alert went out and 101 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, Las Vegas, NV at 12:00Z on 2012-05-06Temperature 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 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Las Vegas, NV at 12:00Z on 2012-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -27 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
4758 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
-27 m²/s²
0-3 km storm-relative helicity
47 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.

927 
WWUS85 KVEF 062133
RFWVEF

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE LAS VEGAS NV
233 PM PDT SUN MAY 6 2012

AZZ101-CAZ229-NVZ466-071300-
/O.UPG.KVEF.FW.A.0005.120507T1800Z-120508T0300Z/
/O.NEW.KVEF.FW.W.0009.120507T1500Z-120507T2200Z/
LAKE MEAD NRA/COLORADO RIVER-AZ SIDE-LOWER COLORADO RIVER VALLEY-
LAKE MEAD NRA/COLORADO RIVER-NV SIDE-
233 PM PDT SUN MAY 6 2012 /233 PM MST SUN MAY 6 2012/

...RED FLAG WARNING IN EFFECT FROM 8 AM PDT /8 AM MST/ TO 3 PM
PDT /3 PM MST/ MONDAY FOR STRONG WINDS AND LOW RELATIVE HUMIDITY
FOR FIRE WEATHER ZONES 101...229 AND 466...

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A RED FLAG
WARNING FOR STRONG WINDS AND LOW RELATIVE HUMIDITY...WHICH IS IN
EFFECT FROM 8 AM TO 3 PM MONDAY. THIS REPLACES THE FIRE WEATHER
WATCH PREVIOUSLY IN EFFECT.

* AFFECTED AREA...IN ARIZONA...FIRE WEATHER ZONE 101 LAKE MEAD
  NRA/COLORADO RIVER-AZ SIDE. IN CALIFORNIA...FIRE WEATHER ZONE
  229 LOWER COLORADO RIVER VALLEY. IN NEVADA...FIRE WEATHER ZONE
  466 LAKE MEAD NRA/COLORADO RIVER-NV SIDE. THE STRONGEST WINDS
  ARE EXPECTED ALONG THE STRETCH FROM DAVIS DAM TO NEEDLES.

* TIMING...STRONG NORTH WINDS WILL DEVELOP EARLY IN THE MORNING
  THEN PERSIST THROUGH EARLY AFTERNOON BEFORE GUSTS DECREASE TO
  LESS THAN 35 MPH.

* WIND...NORTH WIND 20 TO 30 MPH WITH GUSTS UP TO 45 MPH.

* HUMIDITY...RELATIVE HUMIDITY VALUES ARE EXPECTED TO BE BETWEEN
  10 AND 15 PERCENT EARLY MONDAY MORNING AND MINIMUM VALUES WILL
  DROP TO AROUND 5 PERCENT BY EARLY AFTERNOON.

* IMPACTS...THE COMBINATION OF GUSTY WINDS...LOW RELATIVE HUMIDITY
  AND DRY FUELS WILL CREATE CONDITIONS THAT ARE FAVORABLE FOR
  EXTREME FIRE BEHAVIOR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE ADVISE THE APPROPRIATE FIRE WEATHER OFFICIALS IN THE FIELD
OF THIS RED FLAG WARNING.

&&

$$

HTTP://WEATHER.GOV/LASVEGAS
2 follow-up statements
262 
WWUS85 KVEF 070916
RFWVEF

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE LAS VEGAS NV
216 AM PDT MON MAY 7 2012

AZZ101-CAZ229-NVZ466-072200-
/O.CON.KVEF.FW.W.0009.120507T1500Z-120507T2200Z/
LAKE MEAD NRA/COLORADO RIVER-AZ SIDE-LOWER COLORADO RIVER VALLEY-
LAKE MEAD NRA/COLORADO RIVER-NV SIDE-
216 AM PDT MON MAY 7 2012 /216 AM MST MON MAY 7 2012/

...RED FLAG WARNING REMAINS IN EFFECT FROM 8 AM PDT /8 AM MST/
THIS MORNING TO 3 PM PDT /3 PM MST/ THIS AFTERNOON FOR STRONG
WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 101 - 229
AND 466...

* AFFECTED AREA...IN ARIZONA...FIRE WEATHER ZONE 101 LAKE MEAD 
  NRA/COLORADO RIVER-AZ SIDE. IN CALIFORNIA...FIRE WEATHER ZONE 
  229 LOWER COLORADO RIVER VALLEY. IN NEVADA...FIRE WEATHER ZONE 
  466 LAKE MEAD NRA/COLORADO RIVER-NV SIDE.

* TIMING...STRONG NORTH WINDS WILL DEVELOP THIS MORNING THEN
  PERSIST THROUGH EARLY AFTERNOON BEFORE GUSTS DECREASE TO LESS
  THAN 35 MPH.

* WIND...NORTH WIND 20 TO 30 MPH WITH GUSTS UP TO 45 MPH.

* HUMIDITY...RELATIVE HUMIDITY VALUES OF 10 TO 15 PERCENT EARLY
  THIS MORNING WILL DROP TO AROUND 5 PERCENT BY EARLY AFTERNOON.

* IMPACTS...THE COMBINATION OF GUSTY WINDS...LOW RELATIVE 
  HUMIDITY AND DRY FUELS WILL CREATE CONDITIONS THAT ARE 
  FAVORABLE FOR EXTREME FIRE BEHAVIOR. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE ADVISE THE APPROPRIATE FIRE WEATHER OFFICIALS IN THE FIELD
OF THIS RED FLAG WARNING.

&&

$$

MORGAN

HTTP://WEATHER.GOV/LASVEGAS
572 
WWUS85 KVEF 072157
RFWVEF

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE LAS VEGAS NV
257 PM PDT MON MAY 7 2012

AZZ101-CAZ229-NVZ466-072300-
/O.EXP.KVEF.FW.W.0009.000000T0000Z-120507T2200Z/
LAKE MEAD NRA/COLORADO RIVER-AZ SIDE-LOWER COLORADO RIVER VALLEY-
LAKE MEAD NRA/COLORADO RIVER-NV SIDE-
257 PM PDT MON MAY 7 2012 /257 PM MST MON MAY 7 2012/

...RED FLAG WARNING WILL EXPIRE AT 3 PM PDT /3 PM MST/ THIS
AFTERNOON FOR STRONG WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 101...229 AND 466...

AUTOMATED SENSORS ALONG THE COLORADO RIVER VALLEY SHOWED WIND
GUSTS HAD GENERALLY DECREASED TO BETWEEN 25 AND 30 MPH WHILE
RELATIVE HUMIDITY VALUES REMAINED IN THE SINGLE DIGITS. GUSTS WILL
REMAIN BELOW 35 MPH THE REST OF THE DAY AND THE RED FLAG WARNING
WILL EXPIRE ON SCHEDULE. NORTH WINDS WITH LOCAL GUSTS UP TO 30
MPH CAN STILL BE EXPECTED THIS EVENING AND OVERNIGHT ALONG THE
COLORADO RIVER VALLEY AND RELATIVE HUMIDITY VALUES WILL GRADUALLY
RECOVER TO AROUND 25 PERCENT AFTER MIDNIGHT.

$$

HTTP://WEATHER.GOV/LASVEGAS

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 6, 2:37 AM PDTFire Weather WatchVEFSan Bernardino12 hr
May 6, 3:12 PM PDTWind AdvisoryVEF21 hr

Nearby

Red Flag Warnings in California, 2012Red Flag Warnings in Nevada, 2012Red Flag Warnings in Arizona, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.