SPC AC 040600
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT SAT AUG 04 2012
VALID 051200Z - 061200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE NORTHEAST
STATES/WESTERN NEW ENGLAND TO OH/TN VALLEYS...
...MUCH OF THE NORTHEAST STATES/NEW ENGLAND TO OH/TN VALLEYS...
DEEP CONVECTIVE/SEVERE POTENTIAL ON SUNDAY WILL BE TIED TO THE
EAST-NORTHEASTWARD ADVANCEMENT OF A POTENT SUMMERTIME UPPER
TROUGH...FROM THE GREAT LAKES REGION/ONTARIO EARLY SUNDAY TO
QUEBEC/NORTHERN NEW ENGLAND BY LATE SUNDAY. BROAD CYCLONIC FLOW
ALOFT WITH A MODERATELY STRONG BELT OF WESTERLIES WILL OVERSPREAD
THE UPPER OH VALLEY/NORTHEAST STATES INTO NEW ENGLAND THROUGH SUNDAY
NIGHT...WITH CONSIDERABLY WEAKER WESTERLIES SOUTH-SOUTHWESTWARD INTO
THE TN VALLEY.
AHEAD OF AN EASTWARD-MOVING COLD FRONT...IT SEEMS LIKELY THAT
SCATTERED TSTMS/PERHAPS AN MCS WILL BE ONGOING EARLY SUNDAY MORNING
ACROSS THE OH VALLEY/LOWER GREAT LAKES VICINITIES. SOME QUESTIONS
LINGER REGARDING CLOUD COVER/PRECIPITATION FROM SATURDAY NIGHT/EARLY
SUNDAY...AND THE EXACT MAGNITUDE/SPATIAL LOCATION OF PRIMARY
PRE-FRONTAL DESTABILIZATION AHEAD OF THE COLD FRONT SUNDAY AFTERNOON
FOR AREAS SUCH AS THE UPPER OH VALLEY. IT IS CONCEIVABLE THAT EARLY
DAY TSTMS AND REMNANT OUTFLOWS/PERHAPS EVEN AN MCV COULD BE FACTORS
THAT INFLUENCE/FOCUS A REINVIGORATION OF TSTMS INTO A
MOIST/INCREASINGLY UNSTABLE PRE-FRONTAL WARM SECTOR. WELL EAST OF
THE ACTUAL COLD FRONT...OTHER TSTMS MAY MATURE SUNDAY AFTERNOON
ACROSS PORTIONS OF NY/PA INTO FAR WESTERN NEW ENGLAND IN VICINITY OF
HIGHER TERRAIN AND POSSIBLE CORRIDOR OF PRE-FRONTAL
CONFLUENCE/SURFACE TROUGH.
REGARDLESS OF THESE DETAILS...A GENERAL INCREASE/INTENSIFICATION OF
TSTMS IS LIKELY BY EARLY AFTERNOON ESPECIALLY ACROSS PORTIONS OF
NY/PA AND OTHER PARTS OF THE UPPER OH VALLEY...SOUTHWESTWARD INTO
THE TN VALLEY. RELATIVELY HIGH MOISTURE CONTENT...STEEPENING LOW
LEVEL LAPSE RATES...AND MODERATE BUOYANCY /1000-3000 J PER KG
SBCAPE/ WILL ACCOUNT FOR STRONG/SUSTAINED STORMS WITHIN A WEAK TO
MODERATE VERTICAL SHEAR ENVIRONMENT. MULTICELLS/LINE SEGMENTS ARE
LIKELY WITH DAMAGING WINDS AS THE PRIMARY OVERALL HAZARD...BUT SOME
SUPERCELLS/PERHAPS EVEN A TORNADO MAY BE POSSIBLE ESPECIALLY ACROSS
PORTIONS OF NY/PA INTO FAR WESTERN NEW ENGLAND WHERE DEEP LAYER
SHEAR/LOW-LEVEL SRH WILL BE A BIT STRONGER. SEVERAL ORGANIZED
QUASI-LINEAR CLUSTERS AND MCS/S MAY ULTIMATELY EVOLVE BY LATE
AFTERNOON/EARLY EVENING...WITH AT LEAST AN ISOLATED SEVERE THREAT
/MAINLY DAMAGING WINDS/ REACHING AS FAR EAST AS INTERIOR NEW
ENGLAND/NORTHEAST SEABOARD SUNDAY NIGHT.
...TN VALLEY/MID-SOUTH TO SOUTHEAST STATES...
FARTHER SOUTH/SOUTHWEST ALONG THE FRONT...A MORE UNSTABLE BUT WEAKER
VERTICAL SHEAR ENVIRONMENT MAY ACCOUNT FOR AT LEAST PERIODIC
DAMAGING WINDS ACROSS THE TN VALLEY/MID-SOUTH SUNDAY
AFTERNOON/EVENING. OTHER ISOLATED SEVERE STORMS /PRIMARILY DAMAGING
WIND/ MAY OCCUR ACROSS PARTS OF THE SOUTHEAST STATES/CAROLINAS IN
VICINITY OF THE SEA BREEZE AND/OR PERIPHERY OF A FL DISTURBANCE.
...PORTIONS OF ORE AND NORTHERN CA/NORTHERN NV...
TSTM POTENTIAL IS EXPECTED TO INCREASE ACROSS THE REGION ON
SUNDAY...AS MOISTURE/FORCING FOR ASCENT INCREASES IN TANDEM WITH A
NORTHEASTWARD MOVING UPPER TROUGH. AS ISOLATED/WIDELY SCATTERED
STORMS DEVELOP/INCREASE SUNDAY AFTERNOON/EARLY EVENING...A MODEST
INCREASE IN MOISTURE/VERTICAL SHEAR ALONG WITH STEEP LAPSE RATES MAY
ACCOUNT FOR SOME POTENTIALLY SEVERE TSTMS CAPABLE OF STRONG
DOWNDRAFTS/HAIL.
..GUYER.. 08/04/2012
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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