Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS03 KWNS 280826
SWODY3
SPC AC 280824

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0224 AM CST SAT FEB 28 2015

VALID 021200Z - 031200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE ON
MONDAY ACROSS THE ARK-LA-TEX AND EASTERN OKLAHOMA THROUGH ARKANSAS
TO SOUTHERN MISSOURI AND FAR WESTERN TENNESSEE.  ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS WILL ALSO BE POSSIBLE EARLY MONDAY ACROSS A
SMALL PART OF SOUTHERN CALIFORNIA AND INTO THE LOWER COLORADO RIVER
VALLEY AND WESTERN ARIZONA MONDAY AFTERNOON.

...SYNOPSIS...
A STRONG MID-UPPER-LEVEL RIDGE WILL REMAIN ANCHORED FROM THE GULF OF
MEXICO INTO THE WRN CARIBBEAN.  HEIGHTS ARE EXPECTED TO RISE ACROSS
MUCH OF THE ERN HALF OF THE U.S. IN THE WAKE OF A TROUGH MOVING
THROUGH THE NERN STATES AND DEPARTING THE NRN ATLANTIC COAST MONDAY
AFTERNOON.  MEANWHILE...A BLOCKING RIDGE WILL REMAIN LOCATED WEST OF
THE PACIFIC COAST.  A SHORTWAVE TROUGH MOVING EWD ACROSS ALASKA
DURING DAY 1 IS EXPECTED TO MOVE S/SEWD IN PIECEMEAL FASHION THROUGH
WRN CANADA ON SUNDAY.  THE MOST PROMINENT PORTION OF THIS TROUGH
SHOULD EMERGE EAST OF THE CANADIAN ROCKIES ON MONDAY...MOVING
THROUGH CENTRAL CANADA TOWARD THE NRN ROCKIES/PLAINS.  A WEAKER
PORTION OF THIS AK SYSTEM IS EXPECTED TO AMPLIFY SWD FROM WRN WA/ORE
THROUGH NRN CA AND REACH ALONG AND OFF THE SRN CA COAST BY 12Z
TUESDAY WITH A CLOSED CIRCULATION CENTER.  THIS EVOLUTION WILL
RESULT IN DISLODGING THE DAY 2 SRN CA TROUGH NEWD THROUGH THE SWRN
STATES TO CENTRAL HIGH PLAINS.

...ERN OK/ARKLATEX TO SRN MO/WRN TN...
SLY LOW-LEVEL FLOW IS EXPECTED TO STRENGTHEN FROM CENTRAL AND
EASTERN TX THROUGH ERN OK INTO THE OZARKS.  THIS WILL RESULT IN
SUBSTANTIAL LOWER-TROPOSPHERIC MOISTENING AND WARM-AIR ADVECTION
WITH THESE FACTORS BEING GREATER ABOVE THE SURFACE.  A LARGE SURFACE
HIGH-PRESSURE AREA WILL SHIFT EWD FROM THE CENTRAL UNITED
STATES...THOUGH SURFACE TRAJECTORIES ACROSS THE SOUTH-CENTRAL STATES
SHOULD NOT BECOME SLY UNTIL LATE IN THE FORECAST PERIOD. THIS FACTOR
WILL LIMIT THE POTENTIAL FOR PARCELS TO BECOME SURFACE-BASED WITH
STRONGER DESTABILIZATION /MUCAPE OF 100-200 J PER KG/ TO OCCUR ABOVE
THE SURFACE.  FORECAST SOUNDINGS SUGGEST MOST PARCELS SHOULD BE
ROOTED AROUND 850 MB WITH THE TSTM POTENTIAL TENDING TO SHIFT FROM
SOUTH TO NORTH ACROSS THIS GENERAL TSTM AREA DURING THE FORECAST
PERIOD.

...PART OF SRN CA AND LOWER CO VALLEY INTO WRN AZ...
A LINGERING POTENTIAL FOR MAINLY ISOLATED TSTMS WILL EXIST ACROSS
PRIMARILY THE COASTAL AREAS OF FAR SRN CA MONDAY MORNING INTO THE
EARLY AFTERNOON BEFORE A SHORTWAVE TROUGH EJECTS NEWD.  THE COLD
MIDLEVEL TEMPERATURES AND FORCING FOR ASCENT ATTENDANT TO THE TROUGH
MOVING ACROSS THE LOWER CO RIVER VALLEY AND AZ MONDAY AFTERNOON WILL
SUPPORT DIURNALLY DRIVEN TSTMS...AS LAPSE RATES STEEPEN.

..PETERS.. 02/28/2015



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