DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 040530
SWODY1
SPC AC 040528

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 AM CDT THU APR 04 2013

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS FL...

...FL...

SUBSTANTIAL MID-HIGH LEVEL FLOW WILL SPREAD ACROSS THE GULF BASIN
TOWARD THE NRN FL PENINSULA DURING THE DAY WHICH SHOULD ENCOURAGE
WEAK SFC CYCLOGENESIS OVER THE FL PANHANDLE WITH SUBSEQUENT MOVEMENT
EXPECTED EWD ALONG THE GA/FL BORDER DURING THE EVENING. DEEPER SFC
DEVELOPMENT IS EXPECTED DURING THE OVERNIGHT HOURS NEAR THE CAROLINA
COAST BUT BUOYANCY WILL BE VERY LIMITED INLAND.

IT/S NOT ENTIRELY CLEAR WHAT PARTICULAR CONVECTIVE SCENARIO WILL
PROVE MOST SIGNIFICANT OTHER THAN DIURNALLY ENHANCED CONVECTION WILL
LIKELY BE NOTED ACROSS THE PENINSULA DUE TO MODEST HEATING.
SIGNIFICANT THUNDERSTORM ACTIVITY IS CURRENTLY ONGOING ACROSS THE
CNTRL GULF BASIN WHERE AT LEAST TWO MCS-TYPE CLUSTERS ARE NOTED.
THIS ACTIVITY SHOULD NOT SPREAD INLAND BEFORE SUNRISE ALTHOUGH
INCREASING LOW LEVEL WARM ADVECTION IS EXPECTED TO GENERATE TSTMS
AHEAD OF AFOREMENTIONED SFC CYCLONE OVER THE FL PANHANDLE EARLY.
FORECAST SOUNDINGS SUGGEST LOW LEVEL SHEAR IS NOT EXPECTED TO BE
PARTICULARLY STRONG IN ASSOCIATION WITH THIS SFC LOW BUT SIGNIFICANT
DEEP LAYER SHEAR AND WEAK WARM ADVECTION FAVOR DEEP ROTATING
UPDRAFTS CAPABLE OF EXHIBITING SUPERCELL CHARACTERISTICS. BY MID
DAY SIGNIFICANT BOUNDARY LAYER HEATING SHOULD ENHANCE THE PROSPECT
FOR MORE DISCRETE SUPERCELLS ACROSS CNTRL FL...POSSIBLY AIDED BY
LOCAL SEA BREEZES. A GRADUAL SWD SHIFT IN DEEP CONVECTION IS
EXPECTED THROUGH THE PERIOD WITH POSSIBLY AN ENHANCED THREAT ALONG
THE ADVANCING COLD FRONT DURING THE OVERNIGHT HOURS. A MULTIFACETED
TSTM SCENARIO WILL LIKELY BE NOTED FRIDAY DUE TO THE WARM
ADVECTION...DIURNAL HEATING...AND FRONTAL FORCING EXPECTED.

LATEST FORECAST SOUNDINGS SUGGEST CONVECTION THAT DEVELOPS DURING
THE AFTERNOON HOURS WILL BE ROOTED IN SBCAPE ON THE ORDER OF 1700
J/KG WITH POTENTIALLY STEEP SFC-2KM LAPSE RATES. THIS ACTIVITY
COULD PRODUCE HAIL THE SIZE OF GOLF BALLS AND LOCALLY DAMAGING WINDS
GIVEN THE EXPECTED INSTABILITY. ISOLATED TORNADOES MAY ALSO BE
NOTED WITH ANY SUPERCELLS GIVEN THE MOISTURE/SHEAR PROFILES.

AT THIS TIME WILL NOT INTRODUCE HIGHER SEVERE PROBS DUE TO THE LACK
OF CLARITY IN HOW/WHERE CONVECTION WILL ULTIMATELY EVOLVE.


...PACIFIC NW...

FORCING WILL INCREASE ACROSS ORE INTO NRN CA DURING THE AFTERNOON
HOURS AHEAD OF PROGRESSIVE SHORT-WAVE TROUGH. WEAK INSTABILITY IS
EXPECTED TO SUPPORT ISOLATED THUNDERSTORMS AIDED IN LARGE PART BY
DIURNAL HEATING.

..DARROW/GARNER.. 04/04/2013

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