DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 191623
SWODY1
SPC AC 191621

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1021 AM CST TUE FEB 19 2013

VALID 191630Z - 201200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A DEEPENING MID-LEVEL LOW WILL MOVE ACROSS THE UPPER GREAT LAKES AND
INTO SWRN ONTARIO WHILE AN ASSOCIATED COLD FRONT PROGRESSES ACROSS
THE MID-ATLANTIC AND SE STATES. PRECIPITATION WILL CONTINUE ALONG
AND AHEAD THE FRONTAL BOUNDARY BUT 12Z SOUNDINGS AND RECENT MODEL
GUIDANCE SHOW LITTLE TO NO INSTABILITY. AN ISOLATED STRIKE OR TWO
MAY OCCUR ACROSS THE FL PANHANDLE BUT THE COVERAGE/FREQUENCY DOES
NOT JUSTIFY 10 PERCENT PROBABILITIES AND THE THUNDER AREA ACROSS THE
SE STATES HAS BEEN REMOVED. AS THE COLD FRONT MOVES
OFFSHORE...THUNDERSTORM ACTIVITY WILL LIKELY INCREASE OVER THE GULF
STREAM BUT WITH LITTLE CHANCE OF AFFECTING LAND AREAS.

FARTHER W...UPPER TROUGH WILL CONTINUE TO DIG SSEWD ACROSS
CA...AIDED BY A STRONG JET STREAK TROUGH ITS WRN HALF. STRONG
FORCING AND ASSOCIATED MID-LEVEL COOLING WILL RESULT IN AT LEAST
WEAK INSTABILITY AND A FEW CONVECTIVE STORMS ACROSS COASTAL CA.
ADDITIONALLY...ISOLATED TSTMS ARE ALSO POSSIBLE ACROSS CNTRL NV AS
THE UPPER TROUGH MOVES THROUGH THE REGION THIS AFTERNOON. IN BOTH
CASES...WEAK INSTABILITY PRECLUDES ANY SEVERE THREAT.

...SW TX...
MID-LEVEL SWLY FLOW WILL INCREASE ACROSS NRN MEXICO AS THE CA UPPER
TROUGH APPROACHES. EMBEDDED SPEED MAX/WEAK SHORTWAVE TROUGH WITHIN
THIS INCREASING MID-LEVEL FLOW...CURRENTLY OVER THE BAJA PENINSULA
PER WV IMAGERY...WILL EJECT INTO TX LATE TONIGHT/EARLY TOMORROW
MORNING. INCREASING WAA AHEAD OF THIS FEATURE...IN CONJUNCTION WITH
ENHANCED SLY RETURN FLOW ASSOCIATED WITH HEIGHT FALLS ACROSS THE
PLAINS...WITH LIKELY RESULT IN SOME ELEVATED TSTM ACTIVITY LATE IN
THE PERIOD. MARGINAL MOISTURE AND A RELATIVELY WARM EML ARE EXPECTED
TO KEEP INSTABILITY RATHER LOW BUT SOME SMALL HAIL MAY BE POSSIBLE
IN THE STRONGER CONVECTIVE ELEMENTS.

..MOSIER/HART.. 02/19/2013

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