Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 271254
SWODY1
SPC AC 271253

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0653 AM CST FRI FEB 27 2015

VALID 271300Z - 281200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
SPORADIC WEAK THUNDERSTORMS ARE POSSIBLE TODAY FROM THE OREGON COAST
SOUTHEASTWARD ACROSS THE GREAT BASIN AND FOUR CORNERS REGIONS.

...SYNOPSIS...
BROADLY CYCLONIC FLOW WILL CHARACTERIZE UPPER-AIR PATTERN ACROSS
CONUS THIS PERIOD.  HOWEVER...WITHIN THAT CYCLONIC
PATTERN...MID/UPPER-LEVEL HEIGHTS SHOULD RISE FROM CENTRAL/SRN
ROCKIES EWD ACROSS SRN APPALACHIANS REGION....AS STG SHORTWAVE
TROUGH DIGS SWD ACROSS PAC NW AND NRN CA.  THAT PERTURBATION -- NOW
EVIDENT IN MOISTURE-CHANNEL IMAGERY OVER WA/ORE COAST AND ADJACENT
PAC WATERS -- WILL PHASE WITH TRAILING VORTICITY FIELD AS IT MOVES
SSEWD.

E OF ROCKIES...CENTER OF BIG/LOW-THETAE ANTICYCLONE WILL SHIFT EWD
ACROSS MIDWEST AND CENTRAL APPALACHIANS TO MID-ATLANTIC REGION.
ASSOCIATED LOW-LEVEL TRAJECTORIES WILL KEEP TSTM-SUPPORTING MOISTURE
SHUNTED AWAY FROM INLAND AREAS.

...ORE COAST SEWD OVER INTERIOR WRN CONUS...
LARGE-SCALE ASCENT/COOLING ALOFT RELATED TO POCKETS OF DCVA WILL
SPREAD ACROSS THIS REGION...JUXTAPOSED BY AFTN WITH AREAS OF
TEMPORALLY MAXIMIZED SFC TEMPS AWAY FROM PRECIP.  ASSOCIATED
STEEPENING OF LOW/MIDDLE-LEVEL LAPSE RATES AND MRGL MOISTURE WILL
SUPPORT WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS.  LEFT-EXIT
REGION OF 250-MB JET MAX ASSOCIATED WITH AFOREMENTIONED PROGRESSIVE
TROUGHING WILL SPREAD ACROSS MUCH OF GEN TSTM AREA THIS
AFTN...FURTHER CONTRIBUTING TO DESTABILIZATION ALOFT VIA
AGEOSTROPHICALLY DRIVEN ASCENT.  EVEN THEN...BUOYANCY WILL BE WEAK
WITH FCST SOUNDINGS SUGGESTING MLCAPE LESS THAN 200 J/KG IN MOST
AREAS.

..EDWARDS/GLEASON.. 02/27/2015




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