Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 280632
SWODY2
SPC AC 280631

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1231 AM CST SAT FEB 28 2015

VALID 011200Z - 021200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE ACROSS
COASTAL AREAS OF CENTRAL AND SOUTHERN CALIFORNIA ON SUNDAY...AND
FROM PARTS OF EAST TEXAS INTO NORTHERN LOUISIANA AND SOUTHERN
ARKANSAS.

...SYNOPSIS...
IN THE LARGE SCALE...A BLOCKING RIDGE WILL REMAIN IN PLACE GENERALLY
WEST OF THE PACIFIC COAST...WHILE SPLIT BELTS OF DOWNSTREAM
WESTERLIES CONTINUE TO BE BROADLY CONFLUENT ALONG AND EAST OF THE
ROCKIES.  MODELS CONTINUE TO SHOW A PROGRESSIVE NRN-STREAM SHORTWAVE
TROUGH WILL TRACK EWD FROM THE NRN PLAINS THROUGH THE GREAT LAKES
REGION ON SUNDAY.  MEANWHILE...HEIGHTS WILL RISE INTO THE FOUR
CORNERS REGION AND ACROSS THE CENTRAL/NRN PLAINS IN THE WAKE OF THE
NRN-STREAM TROUGH AND AS A CA/NV TROUGH DEVELOPS SWD THROUGH SRN CA
AND WEST OF NRN BAJA.

AT THE SURFACE...A COLD FRONT ATTENDANT TO THE NRN-STREAM TROUGH
WILL ADVANCE SWD THROUGH THE SRN PLAINS...AND E/SEWD THROUGH THE
GREAT LAKES AND OH/TN VALLEYS.  BY 12Z MONDAY...THIS BOUNDARY SHOULD
EXTEND FROM ERN NY THROUGH THE CENTRAL APPALACHIANS TO NRN AL...SRN
LA TO CENTRAL TX...WHILE ANOTHER LARGE SURFACE RIDGE WILL HAVE
DEVELOPED SWD INTO MUCH OF THE CENTRAL UNITED STATES.

...EAST TX TO SRN AR/NRN LA...
S/SWLY LOW-LEVEL FLOW FROM THE WRN GULF OF MEXICO WILL SUPPORT
MOISTURE RETURN INVOF AN INVERTED TROUGH EXTENDING FROM THE MIDDLE
TX COAST THROUGH EAST TX INTO NRN LA/SRN AR.  DESPITE WEAK FORCING
ALOFT AND WARM MIDLEVEL TEMPERATURES /PER FORECAST SOUNDINGS/
ATTENDANT TO MID-UPPER-LEVEL RIDGING...SUFFICIENT LOW-LEVEL
MOISTENING ATOP A COOLER/MORE STABLE BOUNDARY LAYER AND WAA SUGGEST
MAINLY ELEVATED TSTMS WILL BE POSSIBLE.  ISENTROPIC ASCENT AND WAA
WILL BE THE PRIMARY FORCING MECHANISMS.

...CENTRAL AND SRN CA COASTAL AREAS...
STEEP LAPSE RATES ATTENDANT TO THE COLD MIDLEVEL TROUGH ACROSS THIS
REGION SHOULD SUPPORT PRIMARILY A POTENTIAL FOR DIURNAL TSTM
DEVELOPMENT AS THE TROUGH SHIFTS SWD.

...EXTREME EASTERN NC SUNDAY NIGHT...
WEAK HEIGHT FALLS ARE EXPECTED ACROSS ERN NC LATE SUNDAY NIGHT INTO
EARLY MONDAY MORNING AS THE NRN-STREAM TROUGH APPROACHES THE
NORTHEASTERN STATES FROM THE GREAT LAKES REGION.  THIS COMBINED WITH
A NWD MOISTURE RETURN ALONG A COASTAL BOUNDARY COULD RESULT IN A
POTENTIAL FOR LOW-TOPPED CONVECTION SUNDAY EVENING.  FORECAST
SOUNDINGS SUGGEST AS CONVECTION BECOMES UNDERCUT BY A FRONT MOVING
EWD THROUGH THIS AREA SUNDAY NIGHT...THAT ELEVATED PARCELS COULD
REACH EQUILIBRIUM TEMPERATURES COLD ENOUGH FOR CHARGE SEPARATION.
GIVEN THE FORECAST FOR MEAGER ELEVATED BUOYANCY AND A RELATIVELY
SMALL TEMPORAL WINDOW FOR THIS TSTM THREAT...A GENERAL TSTM AREA
WILL NOT BE INTRODUCED AT THIS TIME.  GREATER TSTM POTENTIAL SHOULD
OCCUR JUST OFFSHORE.

..PETERS.. 02/28/2015




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