160

ACUS02 KWNS 211717

SWODY2

SPC AC 211716



DAY 2 CONVECTIVE OUTLOOK  

NWS STORM PREDICTION CENTER NORMAN OK

1116 AM CST SAT NOV 21 2009



VALID 221200Z - 231200Z



...NO SVR TSTM AREAS FORECAST...



...SYNOPSIS...

MODELS ARE IN AGREEMENT THROUGH THE DAY 2 PERIOD SHOWING A SHORT

WAVE TROUGH...CURRENTLY MOVING EWD THROUGH SRN TX/NWRN GULF OF

MEXICO PER WATER VAPOR IMAGERY...WILL DEAMPLIFY SUNDAY AS THIS

FEATURE TRACKS THROUGH THE TN/OH VALLEYS.  AN OCCLUDED SURFACE LOW

AND TRIPLE POINT LOCATED ALONG THE MS DELTA AND CENTRAL GULF

COAST... RESPECTIVELY...AT 12Z SUNDAY WILL WEAKEN THIS PERIOD.  AS

THIS PROCESS OCCURS...A NEW SURFACE LOW IS EXPECTED TO DEVELOP OFF

THE SRN ATLANTIC COAST /E OF GA/.  MEANWHILE...GRADUAL HEIGHT RISES

OVER THE SERN STATES WITH THE NEWD TRACK OF THE UPPER TROUGH SUGGEST

A SURFACE FRONT RESIDING FROM NWRN FL TO SERN GA SHOULD REMAIN

QUASI-STATIONARY THROUGH 12Z MONDAY.



...NRN FL PENINSULA/SERN GA...

CURRENT THINKING REMAINS SIMILAR TO THE INITIAL DAY 2 OUTLOOK FOR AN

ISOLATED THREAT FOR SEVERE STORMS...WITH THE PRIMARY THREAT BEING

FOR A NON-ZERO POTENTIAL FOR AN ISOLATED/BRIEF TORNADO.  DEEP LAYER

AND LOW LEVEL SHEAR VALUES WILL BE FAVORABLE FOR ORGANIZED STORMS/

ROTATING UPDRAFTS THROUGH EARLY-MID SUNDAY AFTERNOON BEFORE THESE

FAVORABLE KINEMATICS SHIFT NWD AWAY FROM THE WARM SECTOR. 

HOWEVER...BOUNDARY LAYER DESTABILIZATION REMAINS THE PRIMARY

LIMITING FACTOR GIVEN WEAK LAPSE RATES AND CLOUDINESS/PRECIPITATION

ACROSS THE AREA OF CONCERN PRECLUDING GREATER INSTABILITY

DEVELOPING.  WIDESPREAD SEVERE STORMS ARE NOT EXPECTED...BUT ANY

AREAS THAT HAVE SOME SURFACE HEATING/DESTABILIZATION MAY PROVE

SUFFICIENT FOR DEEP MOIST CONVECTION WITH A LOW SEVERE PROBABILITY

GIVEN THE FAVORABLE KINEMATICS.  THE 5 PERCENT SEVERE PROBABILITY

HAS BEEN SHIFTED A LITTLE WWD OVER THE FL PANHANDLE.  THIS IS

PRIMARILY ALONG THE COASTAL AREAS TO ACCOUNT FOR THE TRIPLE POINT

LOW REACHING THIS REGION SUNDAY AFTERNOON...AND SUBSEQUENTLY

ENHANCING LOW LEVEL SHEAR VALUES FOR AN ISOLATED/BRIEF TORNADO

AND/OR WATERSPOUT MOVING ONSHORE.



..PETERS.. 11/21/2009