Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 281234
SWODY1
SPC AC 281233

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0633 AM CST FRI NOV 28 2014

VALID 281300Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED THUNDERSTORMS MAY OCCUR NEAR THE COAST OF OREGON AND
EXTREME NOTHWESTERN CALIFORNIA.

...SYNOPSIS...
UPPER-AIR PATTERN WILL DEAMPLIFY OVER CONUS THROUGH 12Z...AS TROUGH
WEAKENS AND MOVES FARTHER OFFSHORE ATLANTIC COAST...AND ANTICYCLONIC
FLOW INITIALLY OVER WRN CONUS BECOMES NEARLY ZONAL AMIDST
LARGE-SCALE HEIGHT FALLS.  STG SHORTWAVE TROUGH NOW OVER BC IS FCST
TO MOVE SEWD...REACHING EXTREME NWRN WA NEAR END OF PERIOD.
MEANWHILE...SMALLER/POSITIVELY TILTED PERTURBATION -- NOW EVIDENT IN
MOISTURE-CHANNEL IMAGERY W OF ORE COAST BETWEEN 130W-140W -- WILL
MOVE SEWD IN PIECEMEAL FASHION AND WEAKEN GREATLY AS IT NEARS
ORE/NRN CA COAST...AMIDST STRENGTHENING CONFLUENT FLOW RELATED TO
NRN-STREAM SHORTWAVE.  IN LOW LEVELS...THETAE WILL REMAIN TOO MEAGER
TO SUPPORT TSTMS OVER CONUS E OF ROCKIES...IN WAKE OF COLD FRONT NOW
LOCATED OVER N ATLC...CUBA AND NWRN CARIBBEAN.

...NEAR-COASTAL PAC NW...
IR IMAGERY INDICATES ELONGATED BAROCLINIC-LEAF SIGNATURE APCHG NWRN
CA/SWRN ORE COAST ATTM...FOLLOWED BY SMALL POCKET OF
LOW-TOPPED/GLACIATED CONVECTION IN COLD-CORE REGION ASSOCIATED WITH
OFFSHORE TROUGH.  WEAK/ELEVATED BUOYANCY IS POSSIBLE NEAR COAST IN
ASSOCIATION WITH LEADING FEATURE...AND SUGGESTED BY SLGT
MODIFICATION OF 12Z SLE/MFR RAOBS.  WHILE ISOLATED LTG CANNOT BE
RULED OUT ACCORDINGLY THIS MORNING...SOMEWHAT GREATER THUNDER
POTENTIAL SHOULD ARISE THIS AFTN INTO EVENING AS COLDER AIR ALOFT
OVERTAKES MARINE LAYER NEAR COAST...JUXTAPOSING MRGL BOUNDARY-LAYER
THETAE WITH STEEPENING LOW-MIDDLE-LEVEL LAPSE RATES.  MUCAPE UP TO
300 J/KG IS POSSIBLE...BASED ON TIME SERIES OF FCST SOUNDINGS FROM
SEVERAL LOCATIONS AND MODELS.

..EDWARDS/LEITMAN.. 11/28/2014




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