Alert archive / California / Frost Advisories in 2013

Frost Advisory 7, NWS Los Angeles, CA

January 13, 2013Los Angeles County, California

NWS Los Angeles, CA issued this frost advisory at Jan 13, 2013, 9:02 PM PST for Los Angeles County, California. It took effect at Jan 14, 2013, 1:00 AM PST. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Jan 13, 2013, 9:02 PM PST (05:02 UTC)
In effect from
Jan 14, 2013, 1:00 AM PST
Expired
Jan 14, 2013, 9:00 AM PST
In force
8 hr
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 05:08 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 00:00Z, 5.0 hours before the alert went out and 184 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, San Diego, CA at 00:00Z on 2013-01-14Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 00:00Z on 2013-01-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -25 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
2013 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
-25 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this frost advisory 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 frost advisory went out at Jan 13, 1:00 PM PST, 8 hours 2 minutes earlier.

Area forecast discussion, Jan 13, 1:00 PM PST, 8 hours 2 minutes before
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
100 PM PST SUN JAN 13 2013

.SYNOPSIS...
BLUSTERY OFFSHORE WINDS WILL PERSIST THROUGH TUESDAY. TEMPERATURES
WILL REMAIN BELOW NORMAL UNTIL TUESDAY AFTERNOON...WHEN A WARMING
TREND SHOULD START. THE WARMING TREND WILL BRING TEMPERATURES TO
ABOVE THE SEASONAL NORMALS BY MID WEEK UNDER OFFSHORE FLOW AND HIGH
PRESSURE. THE AFTERNOON TEMPERATURES SHOULD REACH A MAXIMUM BY
MIDWEEK...WITH A MINOR COOLING TREND OVER THE WEEKEND WITH
TEMPERATURES LINGERING AROUND NORMAL.

&&

.SHORT TERM (TONIGHT-WED)...WILL UPGRADE THE HIGH WIND WATCH TO A
WARNING OVER THE HIGHER TERRIAN BUT WILL CONTINUE WITH THE WATCH
OVER THE VALLEYS. MODERATE LOW LEVEL HEIGHT RISES WILL OCCUR OVER
THE GREAT BASIN OVERNIGHT WHICH WILL REINFORCE THE RIDGE OF HIGH
PRESSURE ALREADY IN PLACE. AND AS A RESULT NORTHEAST WINDS WILL
LIKELY INCREASE TO AND OVER THE WARNING THRESHOLD OVER AREAS OF THE
HIGHER TERRAIN BY EARLY MONDAY MORNING. A PERSISTENT LONG WAVE
TROUGH CENTERED JUST EAST OF THE AREA WILL SHIFT EAST AS A LONG WAVE
RIDGE OVER THE EASTERN PACIFIC BEGINS TO SHIFT INLAND MONDAY. AND
SIGNIFICANT MID/UPPER LEVEL HEIGHT RISES WILL BUILD OVER THE GREAT
BASIN WHICH WILL LIKELY REINFORCE AND STRENGTHEN THE NORTHEAST WINDS
OVER THE AREA MONDAY AFTERNOON. THE REINFORCED WINDS WILL LIKELY
DESCEND TO THE LOWER ELEVATIONS AND POSSIBLY EXCEED WARNING
THRESHOLDS MONDAY AFTERNOON THROUGH TUESDAY MORNING. OTHERWISE
LITTLE CHANGE IS EXPECTED BETWEEN THE LOW TEMPERATURES THIS MORNING
AND TEMPERATURES MONDAY MORNING WHERE FREEZE WARNINGS ARE IN EFFECT
FOR THE COASTAL SECTIONS OF SLO AND SBA COUNTIES AS WELL AS SANTA
YNEZ AND OJAI VALLEYS TONIGHT. AND A WATCH CONTINUES MONDAY NIGHT
THROUGH TUESDAY MORNING FOR THE AFOREMENTIONED AREAS.

.LONG TERM (THU-SUN)...THE AIR MASS WILL MODERATE AS HIGH PRESSURE
SETTLES OVER THE AREA AND PERSISTS THROUGH THE PERIOD. DRY
CONDITIONS WILL PREVAIL AND TEMPERATURES WILL WARM AND LIKELY BE 3
TO 5 DEGREES ABOVE NORMAL BY THURSDAY...AND LITTLE CHANGE IS
EXPECTED THEREAFTER.

&&

.AVIATION...13/1800Z.
VFR CONDITIONS WILL CONTINUE AT ALL TAF SITES THROUGH MONDAY. BY
MONDAY MORNING...MANY TAF SITES VULNERABLE TO SANTA ANA WINDS WILL
DEAL WITH THE POSSIBILITY OF LOW LEVEL WIND SHEAR AND TURBULENCE.

KLAX AND KBUR...HIGH CONFIDENCE IN VFR CONDITIONS THROUGH MONDAY.
LOW LEVEL WIND SHEAR AND TURBULENCE ARE POSSIBLE AFTER SUNRISE.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING (SEE LAXNPWLOX).
FREEZE WARNING (SEE LAXNPWLOX).
HIGH WIND WATCH (SEE LAXNPWLOX).
FREEZE WATCH (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

PUBLIC...30
AVIATION...SWEET
SYNOPSIS...SETO

WWW.WEATHER.GOV/LOSANGELES
Hazardous weather outlook, Jan 13, 2:00 PM PST, 7 hours 2 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jan 14, 4:11 AM PSTFreeze WarningLOX29 hr
Jan 14, 2:39 PM PSTFrost AdvisoryLOXLos Angeles18 hr

Nearby

Frost Advisories in California, 2013Every frost advisory in 2013

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.