[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 210539
SWODY1
SPC AC 210537

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1137 PM CST TUE FEB 20 2007

VALID 211200Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

LARGE SCALE PATTERN IS FORECAST TO UNDERGO AMPLIFICATION THIS PERIOD
AS SYSTEMS OVER THE ERN PACIFIC AND THE GREAT LAKES INTENSIFY IN
POLAR BRANCH OF WESTERLIES.  MEANWHILE...SRN STREAM IMPULSE /NOW
OVER THE LOWER MS VALLEY/ WILL SHIFT ESEWD THROUGH THE SERN STATES
TODAY...IN ADVANCE OF INTENSIFYING GREAT LAKES SYSTEM.

IN THE LOW-LEVELS...WEAK SURFACE LOW ATTENDANT TO THIS SRN STREAM
WAVE WILL DEVELOP EWD FROM WRN/MIDDLE TN TO CNTRL NC BY EARLY
EVENING WHILE TRAILING COOL FRONT PUSHES SEWD THROUGH THE SRN
APPALACHIANS.

...CAROLINAS INTO NRN GA...

INCREASING SWLY LOW-LEVEL FLOW OFF THE ERN GULF OF MEXICO SHOULD
CONTINUE TO SUPPORT THE RETURN OF A MODIFIED CP AIR MASS INTO THE
REGION TODAY WITH DEWPOINTS INCREASING INTO THE LOW/MID 50S AS FAR
NE AS THE MIDLANDS AND COASTAL SC INTO SERN NC.  HOWEVER...
CONSIDERABLE CLOUDS AND SHOWER ACTIVITY WILL LIMIT AIR MASS
DESTABILIZATION.  POTENTIAL FOR LOCALLY STRONG/BRIEFLY SEVERE STORMS
IS EXPECTED TO INCREASE THIS AFTERNOON IN THE WAKE OF INITIAL
MORNING ACTIVITY FROM VICINITY SURFACE LOW OVER WRN OR S-CNTRL NC
SWWD INTO NRN GA WHERE POCKETS OF WEAK INSTABILITY CAN DEVELOP.

SOME STEEPENING OF LOW LEVEL LAPSE RATES COUPLED WITH UNIDIRECTIONAL
WIND FIELDS WITH MODEST DEEP LAYER SPEED SHEAR SUGGEST A THREAT OF
LOCALLY STRONG WIND GUSTS SHOULD SURFACE BASED STORMS DEVELOP AND
BECOME SUSTAINED.  MARGINALLY SEVERE HAIL MAY ALSO ACCOMPANY THE
MORE INTENSE STORMS.  ANY STORMS THAT DEVELOP SHOULD WEAKEN OR MOVE
OFFSHORE BY THIS EVENING.

..MEAD.. 02/21/2007