DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 241954
SWODY1
SPC AC 241952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SUN JUN 24 2012

VALID 242000Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE FL GULF COASTAL
REGION...

...SYNOPSIS...
SEVERAL CHANGES ARE BEING MADE TO THE PRIOR FORECAST THIS PACKAGE --
PRIMARILY DOWNGRADES OF THE ONGOING SEVERE WEATHER PROBABILITIES.
SLIGHT RISK WILL BE MAINTAINED THIS FORECAST ACROSS THE FL GULF
COASTAL AREAS AND PART OF CENTRAL FL...BUT HAVE TRIMMED THE SLIGHT
RISK WWD/AWAY FROM THE SERN FL ATLANTIC COAST WHERE WEAKER SHEAR IS
PROGGED THE REMAINDER OF THE PERIOD. OTHERWISE...EXPECT POTENTIAL
FOR ISOLATED/BRIEF TORNADOES TO CONTINUE WITHIN THE ERN AND NERN
QUADRANT OF T.S. DEBBY.

ELSEWHERE...SEVERE WEATHER PROBABILITY HAS BEEN REMOVED FROM THE NRN
INTERMOUNTAIN REGION AND INTO ND...AS EARLIER ND STORMS HAVE
DISSIPATED AND NEW CONVECTION IS NOT EXPECTED. A FEW STORMS MAY
DEVELOP OVER PARTS OF NWRN MT...BUT APPRECIABLE SEVERE THREAT IS NOT
ANTICIPATED. AN ISOLATED SEVERE STORM MAY OCCUR OVER PARTS OF THE
NRN HIGH PLAINS OF ERN WY/WRN SD/WRN NEB AND VICINITY...AND THUS
WILL MAINTAIN A CORRIDOR OF LOW /5%/ SEVERE PROBABILITY IN THIS
AREA.

THE SLIGHT RISK AREAS WILL ALSO BE REMOVED FROM THE IL AREA AND FROM
THE LOWER GREAT LAKES REGION ATTM. STORMS OVER IL HAVE
DISSIPATED...AND CONVECTION ONGOING INVOF THE LOWER LAKES AREA
REMAINS WEAK -- GIVEN ONLY MINIMAL DESTABILIZATION WHICH HAS
OCCURRED THIS AFTERNOON. WHILE AN ISOLATED STRONGER CELL MAY OCCUR
ACROSS THIS REGION INVOF THE ADVANCING COLD FRONT...ANY WIND/HAIL
POTENTIAL SHOULD REMAIN MARGINAL/ISOLATED.

FINALLY...SCATTERED STORMS HAVE DEVELOPED IN LEE OF THE APPALACHIANS
FROM NRN VA SWD/SWWD ACROSS THE CAROLINAS AND THEN WSWWD INTO THE
GULF COAST STATES. THOUGH MODERATE DESTABILIZATION HAS OCCURRED
ACROSS THIS REGION -- PARTICULARLY ACROSS THE CAROLINAS AND N
GA...WEAK FLOW SUGGESTS LITTLE POTENTIAL FOR APPRECIABLE UPDRAFT
ORGANIZATION/LONGEVITY...AND THEREFORE ONLY ISOLATED/PULSE-TYPE
SEVERE THREAT IS EVIDENT THROUGH EARLY EVENING.

..GOSS.. 06/24/2012

.PREV DISCUSSION... /ISSUED 1134 AM CDT SUN JUN 24 2012/

...WRN/SRN FL PENINSULA INTO THE NERN GULF COAST...
STRONG WINDS ON THE ERN PERIPHERY OF TS DEBBY ARE RESULTING IN LARGE
LOW LEVEL SHEAR/SRH ASSOCIATED WITH ENLARGED CLOCKWISE TURNING
HODOGRAPH. THIS IS SUPPORTING SMALL TRANSIENT SUPERCELLS EMBEDDED
WITHIN LARGER CONVECTIVE SHIELD/OUTER BANDS OVER PARTS OF WRN/SRN
FL. THREAT OF A FEW BRIEF TORNADOES AND STRONG WIND GUSTS IS
EXPECTED TO CONTINUE AS DEBBY MOVES SLOWLY NWD.

...NERN MT INTO CENTRAL ND...
SEVERAL STRONG/SEVERE STORMS ARE CONTINUING THIS LATE MORNING OVER
EXTREME NERN MT INTO WEST CENTRAL ND. THE CONVECTION IS LIKELY
ELEVATED ALONG THE NERN EDGE OF THE EML/CAPPING INVERSION AS SEEN IN
12Z UPPER AIR DATA...WITH VERY STEEP MID LEVEL LAPSE RATES PROMOTING
INTENSE UPDRAFTS. THERE HAS BEEN UNCERTAINTY IN THE LONGEVITY OF
THIS ACTIVITY GIVEN ITS PROXIMITY TO THE UPPER RIDGE...BUT FAVORABLE
THERMODYNAMIC ENVIRONMENT COUPLED WITH STRONG DEEP LAYER SHEAR MAY
PROVIDE SUFFICIENT SUPPORT FOR A SEVERE THREAT TO PERSIST INTO THE
AFTERNOON.

...NRN/CENTRAL IL REGION...
CURRENT THUNDERSTORM ACTIVITY HAS SHOWN SIGNS OF WEAKENING AS IT
MOVES SSEWD OVER NWRN/WEST CENTRAL IL. THE STORMS ARE ALONG THE ERN
EDGE OF THE LOW LEVEL MOISTURE GRADIENT...AND SHOULD CONTINUE WITH A
PRONOUNCED NLY COMPONENT OF MOTION ALONG THE ERN SIDE OF THE UPPER
RIDGE. THERE IS A POSSIBILITY THAT THIS CONVECTION MAY INTENSIFY
SOMEWHAT THIS AFTERNOON AS DIABATIC HEATING/DESTABILIZATION OCCURS
IN ADVANCE. IN ADDITION...NEW STORMS MAY DEVELOP LATER THIS
AFTERNOON IN THE WAKE OF THE MORNING CONVECTION AS AN UPSTREAM COLD
FRONT MOVES SEWD IN ASSOCIATION WITH A STRONG UPPER SHORT WAVE
TROUGH DIGGING SEWD ACROSS THE UPPER LAKES. STRONGER CELLS WILL BE
CAPABLE OF PRODUCING SEVERE WINDS AND POSSIBLE HAIL.

...LOWER GREAT LAKES...
AS THE AFOREMENTIONED COLD FRONT ADVANCES SEWD ACROSS THE LOWER
LAKES...STORMS ARE FORECAST TO FORM ALONG/AHEAD OF THE FRONT IN
RESPONSE TO LOW LEVEL CONVERGENCE AND LARGE SCALE ASCENT AHEAD OF
THE UPPER TROUGH. ALTHOUGH LOW LEVEL MOISTURE WILL REMAIN MARGINAL
WITH DEW POINTS IN THE 50S...THE DYNAMIC FORCING IS EXPECTED TO
COMPENSATE FOR LIMITED INSTABILITY WITH A THREAT FOR DAMAGING WINDS
DEVELOPING LATE THIS AFTERNOON AND EVENING.

...SRN APPALACHIANS PIEDMONT/CAROLINAS...
A PROGRESSIVE WEAK SHORT WAVE TROUGH IS MOVING ESEWD TOWARD THE
CNTRL APPALACHIANS PER LATEST WV IMAGERY. BACKGROUND ASCENT WITH
THIS IMPULSE IS COINCIDING WITH DIURNAL DESTABILIZATION ACROSS THE
CAROLINAS...WITH A FEW STORMS NOW DEVELOPING. A WEAK FRONTAL ZONE
NEAR THE NC/SC BORDER...IN ADDITION TO TERRAIN AND SEA BREEZE
INFLUENCES...WILL ALSO PROMOTE SCATTERED TSTM DEVELOPMENT AMIDST
SUFFICIENT SHEAR FOR SOME STORM ORGANIZATION AND PERSISTENCE. STORM
MERGERS AND INTERACTIONS WILL FURTHER INCREASE CHANCES FOR SEVERE
HAIL AND DAMAGING WIND EVENTS.

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