Alert archive / California / Red Flag Warnings in 2017

Red Flag Warning 21, NWS Las Vegas, NV

December 7, 2017San Bernardino County, California; Mohave County, Arizona; Clark County, Nevada

NWS Las Vegas, NV issued this red flag warning at Dec 7, 2017, 3:24 AM PST for San Bernardino County, California; Mohave County, Arizona; Clark County, Nevada. It was in force for 12 hr. 2 reports 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
Dec 7, 2017, 3:24 AM PST (11:24 UTC)
Expired
Dec 7, 2017, 3:00 PM PST
In force
12 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 11:29 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
Dec 7, 8:53 AM PSTNON-TSTM WND GST 552 E Ontario, CAASOS STATION ONT, ONTARIO AIRPORT.
Dec 7, 11:15 AM PSTNON-TSTM WND GST 642 Nw Running Springs, CAMESONET STATION HHPC1, RUNNING SPRINGS (2 NW).

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 00:00Z, 11.4 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 00:00Z on 2017-12-07Temperature 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 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 00:00Z on 2017-12-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 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
3322 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
35 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.

085 
WWUS85 KVEF 071124
RFWVEF

URGENT - FIRE WEATHER MESSAGE
National Weather Service Las Vegas NV
324 AM PST Thu Dec 7 2017

AZZ101-CAZ229-NVZ466-072300-
/O.NEW.KVEF.FW.W.0021.171207T1124Z-171207T2300Z/
Lake Mead NRA/Colorado River-AZ side-Lower Colorado River Valley-
Lake Mead NRA/Colorado River-NV side-
324 AM PST Thu Dec 7 2017 /424 AM MST Thu Dec 7 2017/

...RED FLAG WARNING IN EFFECT UNTIL 3 PM PST /4 PM MST/ THIS
AFTERNOON FOR LOW RELATIVE HUMIDITY AND GUSTY NORTH WINDS...

The National Weather Service in Las Vegas has issued a Red Flag
Warning, which is in effect until 3 PM PST /4 PM MST/ this
afternoon. 

* AFFECTED AREA...In Arizona...Fire weather zone 101.In 
  California...Fire weather zone 229.In Nevada...Fire weather 
  zone 466. 

* TIMING...Strong wind gusts will persist from this morning
  through early afternoon before gradually decreasing.

* WIND...North gusts 35 to 45 mph from Lake Mohave to Lake Havasu.

* HUMIDITY...12 to 15 percent this morning lowering to 8 to 10 
  percent early this afternoon.

* IMPACTS...A combination of strong winds and low relative
  humidity can contribute to extreme fire behavior. Any fires that
  develop will likely spread rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Outdoor burning is not recommended.

&&

$$

weather.gov/lasvegas

Nearby

Red Flag Warnings in California, 2017Red Flag Warnings in Arizona, 2017Red Flag Warnings in Nevada, 2017Every red flag warning in 2017

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.