Alert archive / California / Special Weather Statements in 2017

Special Weather Statement, NWS Los Angeles, CA

August 3, 2017Los Angeles County, California

NWS Los Angeles, CA issued this special weather statement at Aug 3, 2017, 12:08 PM PDT for Los Angeles County, California. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 3, 2017, 12:08 PM PDT (19:08 UTC)
Expired: Aug 3, 2017, 12:45 PM PDT
In force: 37 min
Issued by: NWS Los Angeles, CA

County Los Angeles County, CA

The radar

The Santa Ana Mts radar (KSOX), 71 km from the middle of the area, began a volume at 19:11 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

San Diego, CA (KNKX), launched 12:00Z, 7.1 hours before the alert went out and 188 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: 527 J/kg
Mixed-layer CIN: -342 J/kg
Mixed-layer LCL: 1297 m above ground
0-6 km bulk shear: 3 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: 1 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Los Angeles, CA wrote its last area forecast discussion before this special weather statement went out at Aug 3, 10:32 AM PDT, 1 hour 36 minutes earlier.

Area forecast discussion, Aug 3, 10:32 AM PDT, 1 hour 36 minutes before

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</head>
<body>
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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In the hours before

Special weather statement, Aug 3, 12:08 PM PDT, 0 minutes before

Special Weather Statement
National Weather Service OXNARD CA
1208 PM PDT THU AUG 3 2017

CAZ054-548-031945-
Los Angeles County San Gabriel Valley CA-
Los Angeles County Mountains excluding the Santa Monica Range CA-
1208 PM PDT THU AUG 3 2017

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL LOS ANGELES COUNTY
UNTIL 1245 PM PDT...

At 1203 PM PDT, Doppler radar was tracking two strong thunderstorms
over Mount Wilson and the Angeles Crest Highway, as well as along
the east side of the Sand Burn area, moving southwest at 10 mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm along with very heavy rain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways. Minor debris flow activity is possible near the Sand Burn
area.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3445 11820 3430 11793 3422 11798 3416 11808
      3425 11821 3434 11824
TIME...MOT...LOC 1903Z 044DEG 14KT 3424 11808

EB

The office that day

Everything else NWS Los Angeles, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 3, 2:33 PM PDT	Special Weather Statement	LOX	Ventura	42 min
Aug 3, 2:58 PM PDT	Flash Flood Warning	LOX	Los Angeles, Ventura	3 hr
Aug 3, 3:41 PM PDT	Flash Flood Warning	LOX	Los Angeles	94 min
Aug 3, 4:23 PM PDT	Special Weather Statement	LOX	Los Angeles	37 min

Nearby

Special Weather Statements in California, 2017 Every special weather statement 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.