714

ACUS01 KWNS 161630

SWODY1

SPC AC 161629



DAY 1 CONVECTIVE OUTLOOK  

NWS STORM PREDICTION CENTER NORMAN OK

1129 AM CDT FRI MAY 16 2008



VALID 161630Z - 171200Z



...THERE IS A SLGT RISK OF SVR TSTMS FROM NRN FL ACROSS THE

CENTRAL/ERN CAROLINAS INTO SERN VA...



...NRN FL INTO PARTS OF SRN/EAST CENTRAL GA...

CONVECTIVE MESOSYSTEM IS MOVING EWD AT 30-40 KT ACROSS THE NERN GULF

COAST REGION...WITH RADAR INDICATING A BOW ECHO STRUCTURE ADVANCING

ALONG THE NWRN FL COAST.  SURFACE WIND GUSTS FROM METAR OBSERVATIONS

ASSOCIATED WITH THE PASSAGE OF THE BOW ECHO DURING THE LAST HOUR

HAVE BEEN LIMITED TO 20-25 KT...SUGGESTING THAT WEAK LOW LEVEL LAPSE

RATES AND NEAR SATURATED LOW LEVEL ENVIRONMENT SHOWN ON TLH SOUNDING

MAY BE CURRENTLY LIMITING DOWNDRAFT ENHANCEMENT. 

HOWEVER...INCREASINGLY STRONG WLY FLOW ALOFT/DEEP LAYER SHEAR

SPREADING ACROSS THE REGION MAY SUPPORT CONTINUED EWD MOVEMENT OF

THE CONVECTIVE BAND FROM THE NWRN FL COAST SWD INTO THE ADJACENT

GULF...WITH POTENTIAL TO PRODUCE A FEW DAMAGING WIND GUSTS THROUGH

THE AFTERNOON/EARLY EVENING HOURS.



DOWNSTREAM FROM THE BOW ECHO...AN EXTENSIVE BAND OF SCATTERED

THUNDERSTORMS HAVE DEVELOPED ACROSS PARTS OF NRN FL INTO SRN GA. 

DIURNAL HEATING WITHIN THE CONVECTIVE BAND IS LIKELY TO BE

DIMINISHED AND THIS MAY HELP TO ESTABLISH DIFFERENTIAL HEATING

BOUNDARIES ALONG THE NRN AND SRN EDGES OF THE CONVECTIVE BAND. 

MESOSCALE CIRCULATIONS ALONG THESE THERMAL BOUNDARIES MAY RESULT IN

NEW CONVECTIVE DEVELOPMENT ACROSS PARTS OF NRN FL AND CENTRAL GA. 

DESPITE MODEST DEEP LAYER LAPSE RATES ACROSS THESE REGIONS AND

GENERALLY WESTERLY UNIDIRECTIONAL WINDS IMMEDIATELY ABOVE THE

GROUND...STRONG HEATING AND DEW POINTS NEAR 70F WILL PROMOTE

DEVELOPMENT OF A FEW STRONG THUNDERSTORMS.  INCREASING DEEP LAYER

SHEAR WILL ENHANCE STORM ORGANIZATION...AND STEEPENING LOW LEVEL

LAPSE RATES INDICATE POTENTIAL FOR A FEW DOWNBURSTS TO DEVELOP WITH

STRONGEST STORMS.



...CENTRAL/ERN CAROLINAS INTO SERN VA...

WATER VAPOR IMAGERY SHOWS INITIAL SHORT WAVE TROUGH HAS MOVED OFF

THE MID ATLANTIC COAST WITH SUBSIDENCE IN THE WAKE OF THE SYSTEM. 

UPSTREAM TROUGH MOVING ACROSS THE MID MS VALLEY IS FORECAST TO

CONTINUE EWD TOWARD THE APPALACHIANS THIS EVENING.  CURRENT SURFACE

LOW OVER THE DELMARVA REGION IS EXPECTED TO MOVE EWD OFF THE COAST

THIS EVENING...WITH SWWD TRAILING COLD FRONT PROGRESSING ACROSS VA

AND THE ERN CAROLINAS DURING THE AFTERNOON AND EVENING.  LARGE SCALE

DYNAMIC FORCING FOR ASCENT AND COOLING ALOFT ASSOCIATED WITH THE MS

VALLEY TROUGH IS LIKELY TO REMAIN WEST OF THE SURFACE COLD

FRONT...SUGGESTING THAT FRONTAL CONVERGENCE WILL PROVIDE THE PRIMARY

MESOSCALE FOCUS FOR POSSIBLE THUNDERSTORM DEVELOPMENT.  THERE IS

SOME QUESTION CONCERNING THE DEPTH OF LOW LEVEL CONVERGENCE LAYER AS

WINDS ALOFT BECOME WLY ABOVE THE SURFACE AND THE EFFECTIVENESS OF

THE FRONT TO INITIATE CONVECTION WITHIN A MARGINALLY UNSTABLE

ENVIRONMENT.  HOWEVER...MOST MODELS DEVELOP STORMS ALONG THE FRONT

THIS AFTERNOON...AND GIVEN THE STRONG DEEP LAYER VERTICAL SHEAR

ACROSS THE REGION COUPLED WITH STRONG HEATING/STEEPENING LOW LEVEL

LAPSE RATES EXPECTED...THREAT FOR DAMAGING WIND GUSTS WILL EXIST

FROM EARLY AFTERNOON INTO THE EVENING HOURS.



..WEISS/GRAMS.. 05/16/2008