Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 150914
SWOMCD
SPC MCD 150914
VAZ000-NCZ000-MDZ000-WVZ000-151145-

MESOSCALE DISCUSSION 1898
NWS STORM PREDICTION CENTER NORMAN OK
0414 AM CDT WED OCT 15 2014

AREAS AFFECTED...PORTIONS N-CENTRAL/NERN NC...CENTRAL/ERN VA...NWRN
MD...ERN PANHANDLE OF WV.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 150914Z - 151145Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...BANDS OF CONVECTION WITH ISOLATED TO WIDELY SCATTERED
EMBEDDED TSTMS MAY POSE RISK OF DAMAGING GUSTS APCHG SVR LIMITS.  A
SMALL/SHORT-LIVED QLCS TORNADO ALSO CANNOT BE RULED OUT.

WW IS NOT ANTICIPATED IN NEXT COUPLE HOURS...BARRING DRAMATIC UPWARD
TREND IN TSTM INTENSITY/ORGANIZATION.  HOWEVER...SVR PROBABILITIES
MAY INCREASE LATER THIS MORNING IN WHATEVER REMAINS OF
UNMODIFIED/PRECONVECTIVE WARM SECTOR...ONCE AT LEAST SUBTLE POCKETS
AND CORRIDORS OF DIURNAL HEATING CONTRIBUTE TO LOW-LEVEL
DESTABILIZATION.

DISCUSSION...PLUME OF PRECIP AND EMBEDDED CONVECTION...FROM WRN PA
SWD ACROSS SC...HAS BEEN EXHIBITING GRADUAL WIDENING DURING PAST
COUPLE HOURS WITH EXPANSION/FILLING OF TRAILING PRECIP SHIELD.
NARROW BAND OF ENHANCED LOW-LEVEL LIFT...OCCASIONALLY CONTAINING
ENHANCED STRANDS OF LOW-TOPPED CONVECTION...DEMARCATE ERN EDGE OF
THAT PRECIP BAND AND IS OUTPACING TRAILING COLD FRONT IN MOVING NEWD
ACROSS THIS REGION.  MEANWHILE...PRECURSORY CONFLUENCE LINE IS
EVIDENT IN 09Z SFC STREAMLINE ANALYSIS BETWEEN GRANVILLE AND
COLUMBUS COUNTIES NC....SUPPORTING GRADUALLY STRENGTHENING
CONVECTIVE BAND WITH A FEW EMBEDDED TSTMS.

ALL THIS ACTIVITY WILL MOVE NNEWD TO NEWD INTO ENVIRONMENT
CHARACTERIZED BY VERY WEAK LAPSE RATES...RICH BOUNDARY-LAYER
MOISTURE...AND PLUME OF MIDLEVEL DRYING AHEAD OF MAIN PRECIP BAND.
DRY PLUME IS NOT WELL-EVIDENT IN MOISTURE-CHANNEL IMAGERY  GIVEN
OVERLYING CIRRUS AND UPPER-LEVEL MOISTURE...HOWEVER IT HAS BEEN
EVIDENT IN COMBINATION OF MODIFIED 00Z RAOBS AND MODEL FCST
SOUNDINGS.  RELATED ENTRAINMENT ALOFT...COMBINED WITH AMBIENT WEAK
LAPSE RATES AND SMALL BUOYANCY...SHOULD KEEP RATE OF CONVECTIVE
GROWTH GRADUAL.  STILL...MLCAPE 200-800 J/KG AND 40-50-KT
EFFECTIVE-SHEAR MAGNITUDES ARE EVIDENT IN WARM SECTOR...ALONG WITH
EFFECTIVE SRH INCREASING FROM 150-300 J/KG WITH EWD EXTENT ACROSS
VA...TOWARD CHESAPEAKE BAY.  THESE MAY REPRESENT EVENT-PEAK SRH
VALUES FOR THIS AREA...HOWEVER...GIVEN PROJECTED WEAKENING AND NWD
SHIFT OF LLJ THROUGH REMAINDER MORNING.

MIDDLE/UPPER-LEVEL WINDS ARE EXPECTED TO REMAIN LARGELY PARALLEL TO
CORRIDORS OF CONVECTIVE LIFT...SUPPORTING CONTINUED QUASI-LINEAR
MODE.  WEAK LOW-LEVEL FORCING AWAY FROM CONVECTIVE BANDS WILL
SUBSTANTIALLY LIMIT COVERAGE...NUMBER AND INTENSIFICATION RATE OF
ANY RELATIVELY DISCRETE CELLS AWAY FROM THOSE BANDS.  HOWEVER...ANY
SUSTAINED/DISCRETE CELLS MAY DEVELOP ROTATION GIVEN AFOREMENTIONED
FAVORABLE PARAMETER SPACE IN WARM SECTOR.  BRIEF/QLCS MESOVORTICES
ALSO MAY OCCUR.

..EDWARDS/DIAL.. 10/15/2014

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

ATTN...WFO...AKQ...MHX...LWX...RAH...RNK...

LAT...LON   35367847 37027853 39427888 39587745 38067711 36797676
            36037695 35367847



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