Severe Storm Outlook Narrative (AC)
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000
ACUS03 KWNS 260807
SWODY3
SPC AC 260806

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0206 AM CST THU FEB 26 2015

VALID 281200Z - 011200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED TO WIDELY SCATTERED WEAK THUNDERSTORMS APPEAR POSSIBLE
SATURDAY ACROSS PARTS OF THE WEST...MAINLY ACROSS THE GREAT
BASIN...AND NEAR CENTRAL INTO SOUTHERN CALIFORNIA COASTAL AREAS.

...SYNOPSIS...
MODEL OUTPUT SUGGESTS THAT AT LEAST SOME SEMBLANCE OF OMEGA-TYPE
BLOCKING WILL PERSIST WITHIN THE LARGE-SCALE MID/UPPER FLOW ACROSS
THE EASTERN PACIFIC INTO WESTERN U.S. DURING THIS PERIOD.
ASSOCIATED WITH THIS REGIME...AN AMPLIFIED UPPER TROUGH APPEARS
LIKELY TO CONTINUE DIGGING ACROSS CALIFORNIA...WITH PERHAPS A CLOSED
CYCLONIC MID-LEVEL CIRCULATION EVOLVING NEAR CENTRAL INTO SOUTHERN
CALIFORNIA COASTAL AREAS.  COLD AIR ALOFT ASSOCIATED WITH THESE
FEATURES IS EXPECTED TO MAINTAIN STEEP LOWER/MID TROPOSPHERIC LAPSE
RATES ACROSS MUCH OF CALIFORNIA INTO THE GREAT BASIN SATURDAY INTO
SATURDAY NIGHT.  THIS MAY PROMOTE ISOLATED TO WIDELY SCATTERED WEAK
THUNDERSTORM ACTIVITY...MAINLY BENEATH A LINGERING ZONE OF UPPER
DIVERGENCE ACROSS THE GREAT BASIN DURING THE DAY...AND IN THE
VICINITY OF THE DEVELOPING MID-LEVEL CIRCULATION...NEAR/WEST OF THE
CALIFORNIA COAST.

DOWNSTREAM...SPLIT BELTS OF WESTERLIES SHOULD REMAIN CONFLUENT EAST
OF THE ROCKIES THROUGH THE ATLANTIC SEABOARD.  BUT UPPER RIDGING
APPEARS LIKELY TO AMPLIFY IN THE SOUTHERN STREAM...ACROSS MUCH OF
THE SOUTHERN TIER OF THE U.S...WHILE SUBTROPICAL RIDGING BUILDS
WESTWARD FROM THE BAHAMAS AND CARIBBEAN INTO THE GULF OF MEXICO.  AN
INCREASINGLY SUBSTANTIVE RETURN FLOW OF MOISTURE PROBABLY WILL
COMMENCE ACROSS WESTERN AND CENTRAL GULF COASTAL AREAS.  THIS MAY
BEGIN TO CONTRIBUTE TO WEAK DESTABILIZATION ABOVE A RESIDUALLY
COOL/STABLE LAYER NEAR THE SURFACE...AS FAR NORTH AS THE SOUTH
CENTRAL PLAINS AND OZARK PLATEAU.  HOWEVER...IT APPEARS THAT THIS
POTENTIAL INSTABILITY WILL BE CAPPED BY WARMING LAYERS ALOFT...WHICH
MAY TEND TO INHIBIT THE RISK FOR THUNDERSTORM ACTIVITY...AS
LARGE-SCALE FORCING FOR ASCENT REMAINS WEAK TO NEGLIGIBLE.

..KERR.. 02/26/2015



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