SWODY2
SPC AC 300536
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT FRI MAY 30 2008
VALID 311200Z - 011200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF WRN NEW
ENGLAND/NRN APPALACHIANS SWD INTO THE CAROLINAS AND WWD INTO PARTS
OF THE CNTRL/SRN PLAINS...
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE UPPER MS VALLEY...
...SYNOPSIS...
A PROGRESSIVE LARGE-SCALE PATTERN WILL EXIST OVER THE CONUS DURING
THE DAY TWO PERIOD. THE PRIMARY FEATURE OF INTEREST WILL BE SHORT
WAVE TROUGH AND ASSOCIATED 50-60 KT MIDLEVEL JET STREAK WHICH WILL
MOVE FROM THE UPPER GREAT LAKES AND OH VALLEY EWD THROUGH THE NERN
STATES. IN THE W...UPPER LOW OFF THE BRITISH COLUMBIA/WA COASTS
WILL REMAIN QUASI-STATIONARY THROUGH THE PERIOD...WHILE A SERIES OF
SHORT WAVE TROUGHS ROTATE NEWD THROUGH THE BASE OF THIS FEATURE
ACROSS THE GREAT BASIN AND INTO THE NRN INTERMOUNTAIN REGION.
IN THE LOW LEVELS...OCCLUDED SURFACE LOW WILL DEVELOP ENEWD FROM
SWRN ONTARIO ACROSS SRN QUEBEC WITH TRAILING COLD FRONT PUSHING EWD
FROM THE LOWER GREAT LAKES THROUGH NEW ENGLAND AND THE MID ATLANTIC
STATES. THE WRN EXTENSION OF THIS BOUNDARY WILL SAG MORE SWD/SEWD
THROUGH THE OH INTO TN VALLEYS AND OZARK PLATEAU. A LEE TROUGH WILL
BECOME BETTER DEFINED SATURDAY FROM INTERSECTION WITH FRONT OR
PRE-FRONTAL CONVECTIVE BAND SWD THROUGH CNTRL PORTIONS OF VA AND THE
CAROLINAS.
...WRN NEW ENGLAND/NRN APPALACHIANS SWD INTO THE CAROLINAS AND WWD
INTO ERN PARTS OF THE CNTRL/SRN PLAINS...
A PRE-FRONTAL BAND OF TSTMS IS EXPECTED TO BE ONGOING SATURDAY
MORNING FROM PORTIONS OF THE LOWER GREAT LAKES SWWD INTO THE LOWER
OH VALLEY. DAYTIME HEATING...COUPLED WITH A MOISTENING BOUNDARY
LAYER AHEAD OF THESE STORMS AND LEE TROUGH ARE EXPECTED TO
CONTRIBUTE TO AN AXIS OF MODERATE INSTABILITY FROM THE MID ATLANTIC
COAST SWD ALONG THE SERN ATLANTIC COASTAL PLAIN WITH MLCAPES
APPROACHING 1000-2000 J/KG.
THIS AIR MASS DESTABILIZATION IN CONJUNCTION WITH LEADING EDGE OF
STRONGER HEIGHT FALLS ATTENDANT TO TRANSITORY SHORT WAVE TROUGH
SHOULD SUPPORT AND INCREASE IN TSTM COVERAGE AND INTENSITY BY
AFTERNOON AS ACTIVITY PROGRESSES EWD TOWARD THE MID ATLANTIC COAST.
FORECAST HODOGRAPHS INDICATE LARGELY UNDIRECTIONAL DEEP-LAYER WIND
FIELDS WITH 40-50 KT OF EFFECTIVE BULK SHEAR...SUPPORTIVE OF
EMBEDDED BOWING AND SUPERCELL STRUCTURES CAPABLE OF DAMAGING
WINDS...SEVERE HAIL AND PERHAPS A COUPLE OF TORNADOES.
WHILE DEEP-LAYER VERTICAL SHEAR WILL DECREASE WITH SWD EXTENT ALONG
LEE TROUGH...THE MODERATE INSTABILITY WILL STILL SUPPORT
SCATTERED...STRONG/SEVERE STORMS CAPABLE OF MAINLY DAMAGING WINDS
AND HAIL SATURDAY AFTERNOON INTO EVENING.
ADDITIONAL TSTMS WILL BE POSSIBLE SATURDAY AFTERNOON/EVENING ALONG
TRAILING...SYNOPTIC FRONT...NAMELY FROM THE SRN OH/TN VALLEYS WWD
INTO THE OZARK PLATEAU AND PERHAPS PARTS OF KS/OK. WHILE THESE
REGIONS ARE EXPECTED TO BE ON THE SRN FRINGE OF STRONGER DEEP-LAYER
SHEAR...A MODERATELY UNSTABLE INFLOW AIR MASS WILL SUPPORT ORGANIZED
STORMS/CLUSTERS WITH A THREAT OF DAMAGING WINDS AND HAIL.
...UPPER MS VALLEY...
A WEAK SURFACE LOW IS FORECAST TO ACCOMPANY A SHORT WAVE TROUGH
SEWD ACROSS REGION SATURDAY. RESIDUAL BOUNDARY LAYER MOISTURE
/DEWPOINTS IN THE UPPER 40S TO LOWER 50S/ AHEAD OF SURFACE LOW AND
ATTENDANT BAROCLINIC ZONE IN CONCERT WITH A POCKET OF STEEP MIDLEVEL
LAPSE RATES ACCOMPANYING SHORT WAVE TROUGH ARE EXPECTED TO
CONTRIBUTE TO AN AXIS OF MODERATE INSTABILITY WITH MLCAPES AROUND
1000 J/KG. VERTICAL SHEAR IS NOT EXPECTED TO BE PARTICULARLY
STRONG...BUT THE COMBINATION OF STEEP LAPSE RATES AND COOL
THERMODYNAMIC PROFILES WILL SUPPORT SEVERE HAIL WITH THE MOST
INTENSE STORMS. LOCALLY STRONG WIND GUSTS ARE ALSO POSSIBLE.
..MEAD.. 05/30/2008
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