Mesoscale Discussion 2

January 6, 2016

The Storm Prediction Center issued this mesoscale discussion at Jan 6, 2016, 4:32 PM CST. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jan 6, 2016, 4:32 PM CST (22:32 UTC)
Expired: Jan 6, 2016, 6:00 PM CST
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

The radar

The San Diego radar (KNKX), 15 km from the middle of the area, began a volume at 22:34 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, 10.5 hours before the alert went out and 10 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: 17 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 791 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 150 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

848 
ACUS11 KWNS 062233
SWOMCD
SPC MCD 062232 
CAZ000-070000-

MESOSCALE DISCUSSION 0002
NWS STORM PREDICTION CENTER NORMAN OK
0432 PM CST WED JAN 06 2016

AREAS AFFECTED...A SMALL PART OF COASTAL SRN CA INCLUDING THE SAN
DIEGO AREA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 062232Z - 070000Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A SMALL BOWING QLCS SEGMENT IS APPROACHING THE SAN DIEGO
COUNTY COAST FROM THE COASTAL WATERS. AS THIS ACTIVITY MOVES ONSHORE
IN THE NEXT HOUR OR SO...AN ISOLATED SVR WIND GUST OR TWO MAY OCCUR.
HOWEVER...WW ISSUANCE IS NOT NEEDED.

DISCUSSION...WSR-88D LOOPS INDICATE A SMALL QLCS WITH AN EMBEDDED
BOWING COMPONENT OFF THE SAN DIEGO COUNTY COAST ADVANCING ESEWD
AROUND 25-30 KT...WITH A LEADING ROTATING CELL NEARING THE COAST.
THIS ACTIVITY IS FORECAST TO REACH THE COAST AND AFFECT AREAS NEAR
AND N OF SAN DIEGO IN THE NEXT HOUR OR TWO -- ESPECIALLY IN THE
2245-2330 UTC TIME FRAME. THE NKX VWP SAMPLES AMPLE
LOW-LEVEL/DEEP-LAYER VERTICAL SHEAR...WITH AROUND 55 KT OF 0-6-KM
BULK SHEAR AND 20 KT OF 0-1-KM BULK SHEAR ASSOCIATED WITH A
VERTICALLY VEERING WIND PROFILE. THE OVERALL DEARTH OF BUOYANCY WILL
MITIGATE ANY MORE THAN AN ISOLATED SVR RISK. HOWEVER...SFC
OBSERVATIONS INDICATE SUFFICIENT MOISTURE /SFC DEWPOINTS IN THE
LOWER 50S/...WHEN COUPLED WITH SCATTERED CG LIGHTNING...TO WARRANT
SOME CONCERN FOR AN ISOLATED SVR RISK TO AFFECT COASTAL SAN DIEGO
COUNTY AND AREAS JUST ONSHORE. A DMGG WIND GUST OR TWO...OR PERHAPS
A BRIEF TORNADO...CANNOT BE RULED OUT. AS ADDRESSED IN PREVIOUSLY
ISSUED MCD 0001...THE SVR RISK IS PEAKING PRESENTLY...AND SHOULD BE
DECEASING AFTER THE AFOREMENTIONED ACTIVITY HAS MOVED INLAND BY
ABOUT 20 MILES BECOMING REMOVED FROM MOISTER/MARITIME AIR.

..COHEN/MEAD.. 01/06/2016

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

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

LAT...LON   32501710 32881721 33141737 33181718 32961694 32661688
            32491695 32501710

Nearby

Every 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.