SWODY1
SPC AC 141613
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1113 AM CDT SUN JUN 14 2009
VALID 141630Z - 151200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE HIGH PLAINS
EWD TO THE LOWER MS VALLEY AND GULF STATES...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF OH VALLEY...
...SYNOPSIS...
TROUGH IN W AND FLAT RIDGE IN PLACE ACROSS SRN STATES. IMPULSES
CONTINUE TO MOVE OUT OF TROUGH AND THROUGH THE PLAINS/MID MS VALLEY.
WEAK FRONTAL ZONE EXTENDS WWD FROM NC TO TN VALLEY WITH ANOTHER
FRONT DROPPING SWD THRU OH VALLEY AHEAD OF S/WV TROUGH SWINGING
ESEWD ACROSS GREAT LAKES.
RESERVOIR OF GULF MOISTURE REMAINS IN PLACE FROM SRN PLAINS EWD AND
WITH LEE TROUGHING SUFFICIENT MOISTURE/INSTABILITY RETURNS NWD THRU
HIGH PLAINS TO FUEL ANOTHER ROUND OF SEVERE THUNDERSTORMS TODAY.
...HIGH PLAINS FROM OK/TX NWD TO DAKOTAS/SERN MT...
WITH A MID LEVEL TROUGH CURRENTLY MOVING NEWD ACROSS AZ/SRN UT AND
COUPLED WITH THE INCREASED MOISTURE/INSTABILITY IN THE UPSLOPE
REGIONS OF HIGH PLAINS...SCATTERED SEVERE THUNDERSTORMS EXPECTED TO
DEVELOP BY MID AFTERNOON MUCH OF AREA E OF ROCKIES. AIR MASS BECOMES
MDTLY UNSTABLE WITH MLCAPES RANGING DOWNWARDS FROM AOA 2000 J/KG
SOUTHERN HIGH PLAINS TO 1000 J/KG NRN HIGH PLAINS. SUFFICIENT
SUPPORT FOR SUPERCELL DEVELOPMENT GIVEN THE VEERING PROFILES OF THE
UPSLOPE FLOW AND 50KT OF DEEP LAYER SHEAR AHEAD OF S/W TROUGHS.
IN ADDITION TO LARGE HAIL A FEW TORNADOES ARE ALSO POSSIBLE
ASSOCIATED WITH SUPERCELLS THAT MOVE OUT INTO THE CENTRAL HIGH
PLAINS.
WITH LOW LEVEL JET INCREASING TO 30-40KT THIS EVENING...ONE OR MORE
SEVERE MCS/S SHOULD DEVELOP AND RIDE EWD ALONG THE MID LEVEL THERMAL
GRADIENT ACROSS KS/NRN OK. WITH AN EML IN PLACE AND PLENTIFUL
MOISTURE/INSTABILITY ACROSS THE CENTRAL/SRN PLAINS...POTENTIAL
EXISTS FOR AN ORGANIZED DAMAGING WIND EVENT CONTINUING ALL NIGHT EWD
TOWARD LOWER MO VALLEY. VERY LARGE HAIL WILL BE A THREAT ASSOCIATED
WITH SUPERCELLS THROUGH THE EVENING GIVEN THE FAVORABLE SHEAR AND
THERMODYNAMIC ENVIRONMENT.
...SRN STATES...
REF MCD 1111
FORWARD PROPAGATING MCS NOW INTO AL...WILL CONTINUE TO BE A WIND
DAMAGE THREAT THROUGH THE AFTERNOON AS IT TURNS MORE SEWD INTO THE
AXIS OF GREATEST INSTABILITY. GIVEN THE PRONOUNCED REAR-INFLOW JET
OF 40KT...HAVE INCREASED DAMAGING WIND PROBABILITIES CENTRAL AL AND
EXTENDED SLIGHT RISK INTO WRN GA.
...OH VALLEY...
WEAK FRONTAL ZONE ACROSS CENTRAL IN/IL WILL MOVE A LITTLE FURTHER SE
THIS AFTERNOON. STRONG HEATING OF A MOIST LOW LEVEL AIR MASS SHOULD
LEAD TO MLCAPES OF 1500-2000 J/KG ERN KY AND ADJACENT PORTIONS OF
SRN OH/IN. WITH STRONGER MID LEVEL FLOW ROTATING ACROSS THIS
AREA...SHEAR BECOMES FAVORABLE FOR ORGANIZED THUNDERSTORMS
DEVELOPING ALONG AND AHEAD OF FRONT BY MID AFTERNOON. SUFFICIENT
SHEAR FOR ISOLATED SUPERCELLS WHICH WOULD ENHANCE THREAT OF
WIND/HAIL AND EVEN BRIEF TORNADOES. HOWEVER PRIMARY MODE SHOULD BE
MULTICELL EVOLVING INTO SHORT LINES/BOWS FOR A WIND DAMAGE THREAT.
...NY/VT/NH...
A COOL UPPER TROUGH IS TRACKING EASTWARD ACROSS THE GREAT LAKES
REGION. THIS WILL PROMOTE STEEPENING LAPSE RATES AND THE RISK OF
SCATTERED AFTERNOON THUNDERSTORMS. VERTICAL SHEAR PROFILES ARE VERY
WEAK...AND A WEAK SUBSIDENCE INVERSION AROUND 700 MB WILL TEND TO
LIMIT SEVERE THREAT. HOWEVER...POTENTIAL WILL EXIST FOR RATHER
DISORGANIZED MULTICELL STORMS CAPABLE OF HAIL.
..HALES/SMITH.. 06/14/2009
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