[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 131731
SWODY2
SPC AC 131730

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SAT MAY 13 2006

VALID 141200Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MID-ATLANTIC AND
SOUTHEAST STATES...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SWRN LA WWD THROUGH
CENTRAL/SRN TX INTO SW TX/SERN NM...

...SYNOPSIS...
LARGE CLOSED UPPER LOW ENCOMPASSING MUCH OF THE ERN TWO-THIRDS OF
THE U.S. IS EXPECTED TO WEAKEN SOME ON SUNDAY AS THE CENTER TRACKS
SLOWLY SEWD THROUGH THE OH VALLEY.  STRONG BAND OF MID LEVEL WINDS
/60-80 KT/ WILL EXTEND ALONG THE SWRN/SRN TO ERN PERIPHERY OF THIS
LARGE UPPER CYCLONE...RESULTING IN A CONTINUATION OF STRONG DEEP
LAYER SHEAR ACROSS THESE REGIONS.  SERIES OF VORTICITY/JET MAXIMA
WILL CONTINUE TO ROTATE THROUGH THE UPPER LOW. ONE SUCH SPEED
MAX...NOW LOCATED NEAR MKC...IS EXPECTED TO TRANSLATE FROM THE TN
VALLEY NEWD ACROSS GA/CAROLINAS TO THE DELMARVA REGION DURING DAY 2
PERIOD.

AT THE SURFACE...LOW PRESSURE...ASSOCIATED WITH TN VALLEY SHORT WAVE
TROUGH/SPEED MAX...SHOULD BE LOCATED OVER THE SRN APPALACHIANS AT
12Z SUNDAY.  THIS LOW IS EXPECTED TO TRACK ENE REACHING CENTRAL/NERN
NC BY SUNDAY EVENING...BEFORE TRACKING MORE NNE TOWARD THE DELMARVA
REGION SUNDAY NIGHT.  COLD FRONT WILL MOVE EWD ACROSS THE
MID-ATLANTIC/SERN STATES.  THE WWD TRAILING PORTION OF THIS BOUNDARY
SHOULD MOVE SWD THROUGH CENTRAL GULF COAST STATES AND TX...REACHING
THE GULF COAST AND SRN TX BY 12Z MONDAY.

...MID-ATLANTIC AND SOUTHEAST STATES...
LOW-LEVEL MOISTURE /SURFACE DEWPOINTS UPPER 50S TO AROUND 60/ IS
EXPECTED TO ADVECT NEWD FROM THE GULF COAST STATES AND ALSO NWD FROM
THE ATLANTIC WATERS INTO GA TO VA IN ADVANCE OF THE APPROACHING
SURFACE LOW AND TRAILING COLD FRONT.  ALTHOUGH THUNDERSTORMS SHOULD
BE ONGOING AT 12Z SUNDAY ACROSS PARTS OF THIS REGION...STRONG
SURFACE HEATING IN THE WAKE OF INITIAL ACTIVITY COMBINED WITH
MOISTURE RETURN WILL LIKELY RESULT IN MODERATE INSTABILITY BY SUNDAY
AFTERNOON.  NEW THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG SURFACE
LOW/TRAILING COLD FRONT BY AFTERNOON AS TN VALLEY TROUGH MOVES
ACROSS REGION. STRONG DEEP LAYER SHEAR IS EXPECTED TO SUPPORT
MULTIPLE STORM MODES WITH BOTH SUPERCELLS AND LINEAR STRUCTURES
POSSIBLE.  SRN SEVERE THREAT ACROSS GA MAY MOVE INTO FAR NRN FL
INCLUDING ERN FL PANHANDLE BY SUNDAY EVENING.

...SRN LA/CENTRAL-SRN TX TO SW TX/SERN NM...
AT 12Z SUNDAY...ONGOING STRONG TO SEVERE THUNDERSTORM CLUSTER IS
EXPECTED TO BE LOCATED ACROSS PARTS OF NERN TX EWD INTO NRN LA/MS. 
AIR MASS SOUTH OF THIS EARLY ACTIVITY FROM SRN LA INTO CENTRAL/SRN
TX IS EXPECTED TO BECOME VERY UNSTABLE WITH SUNDAY AFTERNOON MLCAPE
VALUES RANGING FROM 2000 J/KG IN SWRN LA TO 2500-3000 J/KG WWD INTO
TX.

GFS/NAMP SUGGEST A SERIES OF WEAK SRN STREAM IMPULSES WILL TRACK
FROM THE FOUR CORNERS REGION SEWD ACROSS TX TO THE NWRN GULF... WITH
LATEST WATER VAPOR IMAGERY INDICATING THESE IMPULSES FROM THE ERN
PACIFIC TO THE FOUR CORNERS REGION.  LARGE SCALE ASCENT WITH THESE
FEATURES COMBINED WITH LOW LEVEL FORCING ALONG THE COLD FRONT IS
EXPECTED TO SUPPORT ADDITIONAL THUNDERSTORMS FROM THE CENTRAL GULF
COAST WWD INTO CENTRAL/SRN TX AS THE FRONT MOVES SWD.
THE COMBINATION OF STRONG INSTABILITY/VERY STEEP LAPSE RATES AND
STRONG DEEP LAYER SHEAR ARE EXPECTED TO SUPPORT ORGANIZED SEVERE
STORMS FROM SWRN LA WWD INTO CENTRAL/SRN TX.  THE SEVERE THREAT MAY
PERSIST INTO THE OVERNIGHT PERIOD ACROSS SRN TX WHERE
INSTABILITY/SHEAR VALUES WILL REMAIN SUFFICIENT.

FURTHER W...THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE HIGHER
TERRAIN OF THE CENTRAL/SRN ROCKIES INTO SWRN TX...WITH THE GREATEST
POTENTIAL FOR A SEVERE THREAT ACROSS SW TX INTO SERN NM WHERE LOW
LEVEL MOISTURE RETURN WILL BE STRONGEST.  ELY LOW LEVEL UPSLOPE FLOW
BENEATH MODERATE WLY MID LEVEL WINDS WILL RESULT IN SUFFICIENT DEEP
LAYER SHEAR FOR ORGANIZED STORMS WITH HAIL/STRONG WIND GUSTS THE
GREATEST THREATS GIVEN STEEP LAPSE RATES.

..PETERS.. 05/13/2006