[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 211954
SWOMCD
SPC MCD 211953 
NCZ000-212200-

MESOSCALE DISCUSSION 2229
NWS STORM PREDICTION CENTER NORMAN OK
0153 PM CST TUE NOV 21 2006

AREAS AFFECTED...SRN PORTIONS NC OUTER BANKS.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 211953Z - 212200Z

AIR MASS MAY DESTABILIZE SUFFICIENTLY INVOF SFC WARM FRONT TO PERMIT
OFFSHORE SVR POTENTIAL TO BRUSH OUTER BANKS FROM CAPE HATTERAS TO
CAPE LOOKOUT.  STRONG GUSTS AND WATERSPOUTS ARE POSSIBLE
OFFSHORE...WITH SMALL BUT NONZERO PROBABILITY THAT SUCH ACTIVITY MAY
MOVE ASHORE WHILE STILL SVR...DURING REMAINDER AFTERNOON.  AFFECTED
LAND AREA WOULD BE TOO SMALL...WITH POTENTIAL CONDITIONAL AND
SHORT-LIVED...FOR WW.

SFC MESOANALYSIS SHOWS MAIN CYCLONE BECOME MORE VERTICALLY STACKED
WITH MID/UPPER LEVEL LOW...AND LOCATED OFFSHORE MOUTH OF ST JOHNS
RIVER. OCCLUDED FRONT EXTENDS NEWD TO TRIPLE POINT LOCATED ROUGHLY
60 SE ILM...WITH WARM FRONT NEWD TO ABOUT 15 SE HSE.  WARM FRONT IS
DRIFTING NWWD AND HAS PASSED BUOY 41025 DURING LAST 1-2 HOURS...WITH
SFC THERMAL GRADIENT OF 18 DEG F BETWEEN THOSE STATIONS.  STRONGEST
PRESSURE FALLS ARE WITHIN COLD AIR INLAND...BENEATH ELEVATED LOW
LEVEL WAA REGIME...HOWEVER SECONDARY ISALLOBARIC AXIS EXISTS ALONG
FRONT. EXPECT OCCLUSION LOW TO MOVE NEWD ALONG WARM FRONT TOWARD
FALL MAX NEAR BUOY 41025...PERHAPS WITH PRIOR DRIFT OF WARM FRONT
OVER THIS SECTION OF OUTER BANKS.  MODIFIED RAOBS AND RUC SOUNDINGS
SUGGEST AIR MASS ALONG AND JUST E OF WARM FRONT IS CHARACTERIZED BY
SBCAPES 500-800 J/KG.  VERY STRONG LOW LEVEL SHEAR IS EVIDENT
BENEATH 50 KT ELY LLJ...LEADING TO 0-1 KM SRH 250-400 J/KG IN
SUPPORT OF SVR POTENTIAL FOR ANY TSTMS ALONG WARM FRONT. 
ACCORDINGLY...SOME SUPERCELL CHARACTERISTICS HAVE BEEN NOTED WITH
OFFSHORE TSTMS DURING PAST 2-3 HOURS.  WARM SECTOR IS NOT EXPECTED
TO PENETRATE INTO INLAND PORTIONS NC GIVEN ISALLOBARICALLY
REINFORCED NELYS AND RELATED REINFORCEMENT OF COLD WEDGE W OF FRONT.
 THEREFORE ANY SVR THREAT SHOULD BE LIMITED TO DISCUSSION AREA.

..EDWARDS.. 11/21/2006

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

ATTN...WFO...MHX...

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