DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 252009
SWODY1
SPC AC 252007

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0307 PM CDT MON JUN 25 2012

VALID 252000Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER SRN NEW ENGLAND SWD INTO
NC...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE NRN
ROCKIES EWD TO THE WRN DAKS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER FL INTO SRN GA...

SLGT RISK OVER NRN ROCKIES HAS BEEN EXPANDED TO INCLUDE MUCH OF NRN
AND ERN MT EWD INTO WRN PORTIONS OF THE DAKS AND NERN WY. IMPRESSIVE
LOW-LEVEL MOISTURE SITUATED OVER ERN MT EWD INTO THE WRN DAKS WITH
EFFECTIVE BULK SHEAR OF 35-40 KTS SUGGESTS ORGANIZED/SUPERCELL
STORMS ARE POSSIBLE. THE AMOUNT OF CONVECTIVE INITIATION REMAINS
SOMEWHAT IN QUESTION...BUT LATEST HRRR CONTINUES TO DEPICT
STRONG/SVR TSTM DEVELOPMENT THIS AFTERNOON ACROSS THE SLGT RISK
AREA. LARGE HAIL AND DAMAGING WINDS WILL BE PRIMARY THREATS.

HAVE ALSO EXPANDED THE 5 PERCENT WIND PROBS OVER SRN MO/NRN AR WHERE
DIURNAL HEATING HAS CONTRIBUTED TO A VERY UNSTABLE AIR MASS WITH
MLCAPE VALUES IN EXCESS OF 2500 J.KG. FURTHER...NORTHERLY EFFECTIVE
BULK SHEAR VALUES OF 40KT EXISTS ACROSS THE AREA. LATEST VISIBLE
SATL IMAGERY AND SFC TEMPS NEAR OR SLIGHTLY ABOVE 100 DEGREES
SUGGEST ISOLATED SVR STORMS ARE POSSIBLE THROUGH AFTN/ERLY EVENING
HOURS. PRIMARY THREAT WILL BE DAMAGING WINDS...HOWEVER SVR HAIL IS
ALSO POSSIBLE WITH ANY PERSISTENT UPDRAFTS THAT DEVELOP.

TRIMMED RISK AREAS OVER PORTIONS OF MID-ATLANTIC STATES IN THE WAKE
OF ON-GOING SVR TSTMS OTHERWISE REMAINDER OF EARLIER OUTLOOK LOOKS
GOOD.

..BUNTING.. 06/25/2012

.PREV DISCUSSION... /ISSUED 1129 AM CDT MON JUN 25 2012/

...SRN NEW ENGLAND INTO SWD INTO NC...
INITIAL BAND OF STRONG/SEVERE STORMS HAS WEAKENED AS IT MOVED ACROSS
SRN NEW ENGLAND...WHILE SRN PART OF THE LINE HAS MOVED OFFSHORE FROM
NJ AND DEL. ALTHOUGH VISIBLE IMAGERY SHOWS WIDESPREAD CLOUDS OVER
MUCH OF NEW ENGLAND...CLOUDS ARE THINNING TO THE WEST AND NEW
CONVECTION IS DEVELOPING OVER EAST CENTRAL/SERN NY. THIS IS
CONSISTENT WITH CONVECTION-ALLOWING MODEL GUIDANCE WHICH PREDICTS
REDEVELOPMENT OF STORMS OVER THIS AREA SWD INTO THE DEL RIVER VALLEY
THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO SPREAD EWD THROUGH THE
AFTERNOON INTO THE EARLY EVENING...AND IF SUFFICIENT DESTABILIZATION
CAN OCCUR IN THE WAKE OF MORNING STORMS...A FEW SEVERE STORMS WILL
BE POSSIBLE.

FARTHER TO THE SOUTH...WEAK CONVECTION EXTENDS WSWWD NEAR THE COLD
FRONT ACROSS NRN VA. VISIBLE IMAGERY INDICATES FEW CLOUDS SOUTH OF
THE FRONT OVER ERN/SRN VA INTO NC WHERE STRONG DIABATIC HEATING AND
DESTABILIZATION IS OCCURRING WITHIN AN AIR MASS CHARACTERIZED BY
SURFACE TEMPERATURES IN THE 80S AND DEW POINTS NEAR 70. THIS WILL
RESULT IN MLCAPE REACHING 2000-2500 J/KG THIS AFTERNOON. AS THE CAP
GRADUALLY WEAKENS AND DYNAMIC FORCING FOR LARGE SCALE ASCENT
ASSOCIATED WITH A SHORT WAVE TROUGH MOVING SEWD ACROSS THE MID
ATLANTIC REGION...STORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND
MOVE SEWD FROM THE DELMARVA AND SRN/ERN VA INTO PARTS OF CENTRAL/ERN
NC BY EVENING. NWLY MID LEVEL WINDS OF 25-35 KT WILL CONTRIBUTE TO
SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZED MULTICELL STORMS AND SHORT
LINE SEGMENTS...WITH POTENTIAL FOR DAMAGING WIND GUSTS AND HAIL TO
OCCUR THROUGH THE EVENING.

...FL INTO SRN GA...
SEVERAL CONVECTIVE BANDS EXTEND FROM THE ERN GULF OF MEXICO NNEWD
INTO FL TO THE EAST OF TS DEBBY. WDSS-II MOSAIC DATA CONTINUE TO
SHOW ROTATIONAL TRACKS SOUTH OF TPA AND MOVING INTO EAST CENTRAL FL
ATTM...AND THESE SMALL SUPERCELLS WILL HAVE POTENTIAL TO PRODUCE
BRIEF TORNADOES. ADDITIONAL BANDS OVER THE ERN GULF IMMEDIATELY
EAST OF THE TS CENTER ARE EXPECTED TO MOVE INLAND FROM WEST CENTRAL
INTO NRN FL/SRN GA THIS AFTERNOON AND EVENING...WITH NEW CELLS ALSO
FORMING OVER NRN FL WHERE BREAKS IN CLOUDS/STRONGER HEATING IS
OCCURRING. PERSISTENT STRONG LOW LEVEL SHEAR/SRH TO THE EAST AND
NORTHEAST OF THE TS WILL PROMOTE FORMATION OF OCCASIONAL
MESOCYCLONES AND CONTINUED POTENTIAL FOR A FEW TORNADOES.

...NWRN MT INTO FAR NRN ID...
AN ENVIRONMENT CHARACTERIZED BY STEEP MID LEVEL LAPSE RATES AND
AMPLE LOW LEVEL MOISTURE EXTENDS WWD ACROSS MT TO WEST OF THE
DIVIDE. SOME THUNDERSTORMS ARE CURRENTLY OVER FAR NWRN MT/NRN ID
PANHANDLE...AND ADDITIONAL STORMS ARE EXPECTED TO DEVELOP LATER THIS
AFTERNOON AND EVENING. INITIAL ACTIVITY IS LIKELY TO FORM OVER
FAVORED HIGH TERRAIN...POSSIBLY ENHANCED BY ASCENT ASSOCIATED WITH A
WEAK SHORT WAVE TROUGH LIFTING NNEWD ACROSS OREGON ATTM. STRONG
DEEP LAYER SHEAR /40-50 KT IN THE LOWEST 6 KM/ WILL ENHANCE
CONVECTIVE ORGANIZATION WITH THE POSSIBILITY OF ISOLATED SUPERCELLS.
STRONGER STORMS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND STRONG
WIND GUSTS MAINLY FROM LATE AFTERNOON THROUGH THE EVENING.

...ERN MT SWD INTO ERN WY AND WRN DAKOTAS...
CONSIDERABLE INSTABILITY EXISTS FROM ERN MT SWD OVER THE HIGH PLAINS
INTO ERN WY AND ADJACENT PARTS OF THE DAKOTAS...AS 12Z SOUNDINGS
SHOW VERY STEEP LAPSE RATES AND MOIST LOW LEVEL CONDITIONS. A
STRONG CAPPING INVERSION IS ALSO PRESENT WHICH WILL LIKELY INHIBIT
SURFACE-BASED STORM DEVELOPMENT. HOWEVER...THE FAVORABLE CAPE/SHEAR
ENVIRONMENT WILL SUPPORT A CONDITIONAL THREAT OF SEVERE STORMS FOR
ANY PERSISTENT UPDRAFT THAT CAN DEVELOP. A LOW PROBABILITY OF
SEVERE STORMS WILL BE MAINTAINED AND THE AREA WILL NEED TO BE
MONITORED FOR SIGNS OF CONVECTIVE INITIATION LATER THIS AFTERNOON
AND EVENING.

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