Alert archive / California / Mesoscale Discussions in 2016

Mesoscale Discussion 66

January 31, 2016Orange County, California

The Storm Prediction Center issued this mesoscale discussion at Jan 31, 2016, 12:40 PM PST for Orange County, California. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jan 31, 2016, 12:40 PM PST (20:40 UTC)
Expired
Jan 31, 2016, 3:15 PM PST
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%

County Orange County, CA

The radar

The Santa Ana Mts radar (KSOX), 36 km from the middle of the area, began a volume at 20:41 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, 8.7 hours before the alert went out and 132 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 12:00Z on 2016-01-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLEL10008507005003002001001 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 12:00Z on 2016-01-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.1939587897117136Sfc1 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
2 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
482 m above ground
0-6 km bulk shear
86 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

083 
ACUS11 KWNS 312040
SWOMCD
SPC MCD 312040 
CAZ000-312315-

MESOSCALE DISCUSSION 0066
NWS STORM PREDICTION CENTER NORMAN OK
0240 PM CST SUN JAN 31 2016

AREAS AFFECTED...SRN CA COASTAL AREAS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 312040Z - 312315Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...SOME THREAT FOR A FEW STRONG TO DAMAGING WIND GUSTS WILL
EXIST THROUGH 00Z ALONG THE SWRN CA COAST GENERALLY NEAR THE LOS
ANGELES METRO AREA AND POINTS SOUTH. OVERALL THREAT IS NOT EXPECTED
TO BECOME SUFFICIENT FOR A WW.

DISCUSSION...VISIBLE SATELLITE IMAGERY SHOWS A BAND OF LOW-TOPPED
CONVECTION DEVELOPING ALONG A COLD FRONT THAT EXTENDS FROM NEAR
OXNARD SSWWD INTO THE ERN PACIFIC. THE LINE IS MOVING EAST AT AROUND
40 KT AND WILL APPROACH THE LOS ANGELES METRO AREA BY 21Z. NO
LIGHTNING HAS BEEN REPORTED WITH THIS ACTIVITY...SUGGESTING IT
REMAINS VERY SHALLOW...AND WIDESPREAD PRE-FRONTAL CLOUDS CONTINUE TO
LIMIT INSTABILITY INLAND. HOWEVER...DEEPER FORCING WITHIN THE
FRONTAL ZONE AUGMENTED BY ATTENDANT ESEWD-ADVANCING SHORTWAVE TROUGH
WILL CONTINUE TO PROMOTE WEAK INSTABILITY AND AT LEAST LOW-TOPPED
CONVECTION AS THE FRONT MOVES INLAND. VWP DATA SHOWS A 40-50 KT SWLY
LLJ IN PLACE JUST OFF THE SFC...AND SOME OF THIS MOMENTUM WILL BE
TRANSPORTED TO THE SFC WITHIN THE HEAVIER CONVECTIVE SHOWERS.

..DIAL/GOSS.. 01/31/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...SGX...LOX...

LAT...LON   34111876 34311849 33821752 33391713 33191732 33531775
            33711810 33771838 34111876

Nearby

Mesoscale Discussions in California, 2016Every mesoscale discussion in 2016

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.