Severe Storm Outlook Narrative (AC)
Issued by NWS

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000 ACUS11 KWNS 170924 SWOMCD SPC MCD 170924 CAZ000-171130- MESOSCALE DISCUSSION 1980 NWS STORM PREDICTION CENTER NORMAN OK 0324 AM CST WED DEC 17 2014 AREAS AFFECTED...PORTIONS OF COASTAL SRN CA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 170924Z - 171130Z PROBABILITY OF WATCH ISSUANCE...5 PERCENT SUMMARY...LIMITED RISK FOR A MARGINALLY DAMAGING WIND GUST OR TWO -- OR POSSIBLY A BRIEF/WEAK TORNADO -- IS EVIDENT OVER COASTAL PORTIONS OF VENTURA/LOS ANGELES/ORANGE COUNTIES IN SRN CA EARLY THIS MORNING. WW ISSUANCE WILL NOT BE REQUIRED. DISCUSSION...LATEST RADAR AND LIGHTNING DATA DEPICT A SMALL CLUSTER OF THUNDERSTORMS CROSSING THE CHANNEL ISLANDS AREA AND ADJACENT COASTAL SRN CA ATTM...COINCIDENT WITH A MID-LEVEL CYCLONIC CIRCULATION CENTER MOVING ESEWD ACROSS THIS AREA PER WV LOOP. DESPITE SURFACE DEWPOINTS ONLY IN THE LOW 50S...RELATIVELY STEEP LAPSE RATES THROUGH THE LOWER AND MIDDLE TROPOSPHERE ARE CONTRIBUTING TO MARGINAL CAPE /A FEW HUNDRED J/KG PER OBJECTIVE ANALYSES/...THUS FUELING UPDRAFTS WHICH ARE EXTENDING THROUGH THE MIXED-PHASE /-20 C/ LAYER. WHILE AREA VWPS DEPICT RELATIVELY MODEST /20 TO 30 KT/ SWLYS THROUGH H5...BACKED/SELY LOW-LEVEL WINDS AHEAD OF THE STORMS SEEM TO BE AIDING IN OCCASIONAL WEAK/SHORT-LIVED LOW-LEVEL CIRCULATIONS IN STRONGER CELLS -- AS OBSERVED BY KVTX /VENTURA/ WSR-88D. GIVEN THE SUSTAINED/WEAKLY ROTATING STORMS...A VERY ISOLATED/LOW-END SEVERE RISK MAY SPREAD ONSHORE OVER THE NEXT COUPLE OF HOURS. WITH THAT SAID...ANY RISK FOR STRONG WINDS AND/OR A BRIEF/WEAK TORNADO SHOULD REMAIN WELL BELOW THRESHOLDS REQUIRED TO CONSIDER WW ISSUANCE. ..GOSS/THOMPSON.. 12/17/2014 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SGX...LOX... LAT...LON 33831966 34421979 34531953 34431907 34101833 33781773 33401780 33231830 33171948 33391973 33831966

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