DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 121747
SWODY2
SPC AC 121746

DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1246 PM CDT MON AUG 12 2013

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF ERN N C INTO
THE MID ATLANTIC AREA...

CORRECTED FOR WORDING IN LAST PARAGRAPH

...SYNOPSIS...

UPPER PATTERN WILL REMAIN DOMINATED BY A SYNOPTIC TROUGH OVER THE
ERN STATES WITH AN UPSTREAM RIDGE OVER THE INTERMOUNTAIN WEST. THE
ERN U.S. TROUGH IS EXPECTED TO AMPLIFY AS A STRONG SHORTWAVE TROUGH
DROPS SEWD INTO THE INTO THE GREAT LAKES AND NERN STATES. THIS WILL
FORCE A COLD FRONT THROUGH REMAINDER OF THE NERN U.S. AND MIDDLE
ATLANTIC REGION TUESDAY. THE TRAILING PORTIONS OF THIS FRONT WILL
EXTEND SWWD THROUGH THE SERN STATES AND INTO NRN TX WHERE IT SHOULD
STALL OR DEVELOP SLOWLY SWD. A WARM FRONT WILL LIFT NWD INTO SRN NEW
ENGLAND AHEAD OF THE COLD FRONT.

...ERN NC...MID ATLANTIC INTO NERN STATES...

PRIMARY LIMITING FACTOR IN THIS REGION IS LIKELIHOOD OF WIDESPREAD
CLOUDS AND AREAS OF ONGOING SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH AN UPPER IMPULSE CURRENTLY OVER THE MID MS VALLEY. TIMING OF
THIS FEATURE SHOULD PLACE IT INTO THE MID-ATLANTIC AND SRN PORTION
OF THE NERN STATES BETWEEN 12-15Z TUESDAY. DEEP LAYER WINDS AND
35-40 KT 0-6 KM VERTICAL SHEAR WILL SUPPORT THE POTENTIAL FOR
ORGANIZED STORMS. HOWEVER...WARM SECTOR DESTABILIZATION POTENTIAL
SHOULD REMAIN LIMITED..ESPECIALLY FROM THE MID-ATLANTIC INTO THE
NERN STATES. WHERE POCKETS OF HEATING CAN DEVELOP...POTENTIAL WILL
EXIST FOR A FEW STORMS TO BECOME ORGANIZED WITH A THREAT OF MAINLY
ISOLATED DAMAGING WIND.

FARTHER SOUTH INTO NC...GREATER INSOLATION IS EXPECTED...HOWEVER THE
DEEP LAYER WINDS AND VERTICAL SHEAR WILL BE SOMEWHAT WEAKER.
NEVERTHELESS...AS THE BOUNDARY LAYER DESTABILIZES AND LOW-LEVEL
LAPSE RATES STEEPEN...A FEW MULTICELLS MAY DEVELOP AHEAD OF THE
FRONT AND PRODUCE ISOLATED STRONG TO DAMAGING WIND GUSTS THROUGH
EARLY EVENING.

GIVEN THE PREVIOUSLY MENTIONED LIMITING FACTORS...OVERALL SEVERE
RISK APPEARS SOMEWHAT MARGINAL.

...OK INTO NRN TX...

STORMS WILL LIKELY BE ONGOING WITHIN ZONE OF WEAK WARM ADVECTION AND
ISENTROPIC ASCENT NORTH OF THE E-W FRONT ACROSS A PORTION OF OK INTO
AR. DIABATIC WARMING IS EXPECTED IN THE MOIST WARM SECTOR SOUTH OF
THIS BOUNDARY WHERE THE ATMOSPHERE WILL LIKELY BECOME MODERATELY
UNSTABLE. A FEW STORMS WILL LIKELY INITIATE ALONG THIS DIFFERENTIAL
HEATING ZONE DURING THE AFTERNOON AND SUBSEQUENTLY DEVELOP SEWD.
STRONGER VERTICAL SHEAR AND WIND PROFILES SHOULD REMAIN NORTH OF THE
CONVECTIVELY REINFORCED FRONT OR OUTFLOW BOUNDARY. HOWEVER...A FEW
OF THE STORMS MAY BECOME CAPABLE OF PRODUCING ISOLATED DOWNBURST
WINDS AS LOW-LEVEL LAPSE RATES STEEPEN. DUE TO UNCERTAINTY REGARDING
LOCATION OF THE BOUNDARY AND EARLY CONVECTION AND LIKELIHOOD THAT
THE STRONGER SHEAR WILL REMAIN POST FRONTAL...WILL MAINTAIN 5%
SEVERE PROBABILITIES THIS UPDATE AND CONTINUE TO MONITOR FOR A
POSSIBLE SLIGHT RISK.

...NRN AND CNTRL HIGH PLAINS AND NRN ROCKIES...

STORMS WILL LIKELY DEVELOP OVER THE HIGHER TERRAIN OF THE CNTRL AND
NRN ROCKIES AS WELL AS OVER PORTION OF HIGH PLAINS ALONG LEE TROUGH
AXIS WITHIN AN ENVIRONMENT CHARACTERIZED BY MODEST
INSTABILITY...STEEP LAPSE RATES AND WEAK VERTICAL SHEAR. WHILE
ISOLATED DOWNBURST WINDS AND SOME HAIL WILL BE POSSIBLE WITH SOME OF
THIS ACTIVITY...PROSPECTS FOR AN ORGANIZED SEVERE EVENT APPEAR
LIMITED.

..DIAL.. 08/12/2013

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.