SWODY1
SPC AC 180543
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1143 PM CST THU DEC 17 2009
VALID 181200Z - 191200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF FL AND CSTL
GA/SC...
...FL AND CSTL GA/SC...
SATL IMAGERY SUGGESTS THAT THE UPR TROUGH OVER THE WRN GULF
BASIN/LWR MS VLY IS BEGINNING TO PHASE WITH THE NRN STREAM. THIS
WILL RESULT IN THE STRONGEST HEIGHT FALLS TURNING NEWD TOWARD THE
SRN APLCNS WITH SRN FRINGES OF THE TROUGH MOVING ACROSS FL FRIDAY
AFTN/EVE. MEANWHILE...A LEAD SUBTROPICAL DISTURBANCE...CURRENTLY
AUGMENTING CONVECTION BETWEEN CUBA/YUCATAN NWD TO THE SCNTRL GULF AT
05Z...WILL TRAVEL NEWD ACROSS FL FRIDAY MORNING AND EARLY AFTN.
SFC LOW WILL CONTINUE TO DEEPEN THIS MORNING OVER THE CNTRL GULF AND
MOVE NEWD ACROSS THE FL BIG BEND AND INTO CSTL GA/SC BY FRIDAY
EVENING...THEN OFFSHORE NC BY 12Z SATURDAY. A WRMFNT WILL REDEVELOP
NWD INTO SERN GA DURING THE DAY...WITH RICHER LLVL THETA-E
ENVIRONMENT REMAINING ACROSS CNTRL/SRN FL.
00Z WRF-NMM4KM...NAM AND 12Z ECMWF SUGGEST THAT THE HIGHEST SVR
PROBABILITIES WILL EXIST DURING THE FIRST HALF OF THE PERIOD AND
PRIMARILY ASSOCD WITH THE AFOREMENTIONED LEAD IMPULSE. AS WARM/
MOIST ADVECTION PROFILES INCREASE EARLY FRIDAY MORNING...TSTMS WILL
EXPAND/EVOLVE FROM THE SERN GULF EWD ACROSS THE FL PENINSULA.
MODEST STRENGTHENING OF THE SELY WINDS BENEATH INCREASING WSWLY
MID/UPR-LVL FLOW WILL RESULT IN 0-1KM SRH IN EXCESS OF 300 M2/S2 AND
0-6KM SHEAR NEAR 40 KTS. A COUPLE OF TORNADOES AND/OR A FEW DMGG
WIND GUSTS WILL BE POSSIBLE... PRIMARILY WITHIN THE STRONGER
INSTABILITY AXIS EXPECTED OVER CNTRL/SRN FL. THIS ACTIVITY WILL
LIKELY BEGIN SHIFTING E AND SE INTO THE ATLC WATERS DURING THE AFTN
WITH TRAILING STORMS LINGERING ACROSS EXTREME SRN FL/KEYS AS THE
PRIMARY TROUGH SWINGS ACROSS FL. DEEP-LAYER WIND PROFILES VEER WITH
TIME AS THE FORMER DISTURBANCE QUICKLY EXITS WITH LLVL SHEAR
RELAXING. HOWEVER...STORM MODE COULD EVOLVE INTO SHORT BOWING LINE
SEGMENTS AS THEY PROGRESS THROUGH THE KEYS THROUGH THE EVENING WITH
DMGG WIND GUSTS.
FARTHER N...THERMAL BUOYANCY WILL BE COMPARATIVELY WEAKER... THOUGH
LOW/DEEP-LAYER SHEAR WILL BE STRONGER INVOF THE WRMFNT/SFC LOW
TRACK. EXPECT THAT ANY SEMBLANCE OF A SQLN THAT IS ASSOCD WITH THE
PRIMARY UPR TROUGH WILL PEAK IN INTENSITY OVER THE LOOP CURRENT
MID-LATE MORNING AND SUBSEQUENTLY WEAKEN OVER WRN FL.
HOWEVER...GIVEN SUCH STRONG SHEAR AND AT LEAST SOME
INSTABILITY...THE SVR THREAT /INCLUDING BRIEF TORNADOES-DMGG WINDS/
WILL BE NON-ZERO ALONG/S OF THE SFC LOW TRACK FARTHER N.
..RACY.. 12/18/2009
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