DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 090549
SWODY1
SPC AC 090547

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1247 AM CDT WED OCT 09 2013

VALID 091200Z - 101200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
LARGE SCALE PATTERN WITH A TROUGH IN THE WEST AND A RIDGE IN THE
EAST WILL BE MAINTAINED THIS FORECAST PERIOD. A COMPACT SHORTWAVE
TROUGH WILL CONTINUE TO DIG SWD FROM NRN CA TO ALONG THE SRN CA
COAST THROUGH LATE THIS AFTERNOON AS STRONG MID AND UPPER LEVEL NLY
WINDS SPREAD SWD ALONG THE WEST COAST. AFTER 10/00Z...THIS SYSTEM
AND THE PARENT WRN U.S. LONGWAVE TROUGH WILL BEGIN TO SHIFT EAST
TOWARD THE FOUR CORNERS REGION AS THE STRONG WINDS ALOFT TRANSLATE
THROUGH THE BASE OF THE TROUGH. THE PRESENCE OF THE RIDGE IN THE
EAST WILL RESULT IN VERY SLOW NWD MOVEMENT OF THE CAROLINAS CLOSED
LOW WITH THE CENTER OF THIS FEATURE REACHING SRN/SERN VA BY 10/12Z.

...PARTS OF CENTRAL/SRN CA EWD TO FOUR CORNERS/CENTRAL ROCKIES...
ASCENT ATTENDANT TO STRONG HEIGHT FALLS WITH THE DIGGING SHORTWAVE
TROUGH ACROSS CENTRAL/SRN CA INTO THE AFTERNOON...AND COOLING
MIDLEVEL TEMPERATURES ATOP SURFACE HEATING...WILL RESULT IN SOME
TSTM DEVELOPMENT ACROSS THE CA PORTION OF THE GENERAL TSTM AREA.
FORECAST SOUNDINGS SHOW BUOYANCY...THOUGH WEAK...IN A STEEPENING
LAPSE RATE ENVIRONMENT WILL PROVE FAVORABLE FOR EQUILIBRIUM
TEMPERATURES TO BECOME COLD ENOUGH FOR CHARGE SEPARATION/LIGHTNING
PRODUCTION. DESPITE BOUNDARY LAYER COOLING...AN INCREASE IN FORCING
FOR ASCENT AND MIDLEVEL COOLING/WEAK DESTABILIZATION WITHIN THE EXIT
OF THE STRONG JET ROUNDING THE BASE OF THE WRN TROUGH SHOULD SUPPORT
TSTM DEVELOPMENT INTO THE FOUR CORNERS REGION WEDNESDAY NIGHT. WEAK
INSTABILITY THROUGHOUT THIS FORECAST PERIOD WILL PRECLUDE A SEVERE
WEATHER THREAT.

...COASTAL NC/FAR SERN VA...
AN AREA OF LOW PRESSURE WILL REMAIN OFFSHORE THE SRN ATLANTIC STATES
WHILE MOVING SLOWLY NWD. THE NWD TRACK OF THE MIDLEVEL CLOSED LOW
WILL SUPPORT THE TRAILING BAROCLINIC ZONE FROM THE SURFACE LOW TO
MOVE FARTHER EWD AWAY FROM THE COAST...WITH THE PRIMARY CORRIDOR OF
DEEP CONVECTION FORECAST INVOF THE GULF STREAM. LOW LEVEL WAA NORTH
OF THE SURFACE LOW INTO COASTAL NC TO SERN VA AND SOME INSTABILITY
SHOULD PROVE FAVORABLE IN SUPPORTING ELEVATED CONVECTION.

...S FL...
A FEW TSTMS WILL BE POSSIBLE THIS AFTERNOON ACROSS S FL AS A SURFACE
WIND SHIFT ADVANCES SWD THROUGH A MODERATELY UNSTABLE AIR MASS.
RELATIVELY WEAK FORCING ALOFT AND WEAK SHEAR SHOULD LIMIT THE
OVERALL TSTM COVERAGE AND POTENTIAL FOR SEVERE WEATHER.

..PETERS/SMITH.. 10/09/2013

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