SWODY2
SPC AC 130531
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1231 AM CDT WED AUG 13 2008
VALID 141200Z - 151200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL AND
SRN PLAINS...
...SYNOPSIS...
A BROADLY CYCLONIC LARGE-SCALE PATTERN WILL EXIST OVER THE CNTRL/ERN
CONUS WITH AMPLIFIED RIDGING IN THE W. THE PRIMARY FEATURE OF
INTEREST DURING THE DAY TWO PERIOD WILL BE UPPER LOW WHICH WILL
TRANSLATE SWD FROM SRN SASKATCHEWAN THROUGH THE NRN HIGH PLAINS. IN
THE LOW LEVELS...A COLD FRONT ASSOCIATED WITH ABOVE-MENTIONED UPPER
LOW WILL PUSH RAPIDLY SWD THROUGH THE CNTRL AND SRN HIGH PLAINS WITH
THE NERN EXTENSION OF THIS BOUNDARY MOVING MORE SLOWLY SEWD THROUGH
THE MID MO VALLEY.
...CNTRL/SRN PLAINS...
WITH THE EXCEPTION OF LOCALLY HIGHER MOISTURE CONTENT INVOF SURFACE
BOUNDARIES OVER NEB INTO SRN IA/NRN MO...WARM SECTOR AIR MASS IS NOT
EXPECTED TO BE PARTICULARLY MOIST WITH DEWPOINTS LARGELY IN THE 50S
TO LOWER 60S. HOWEVER...THE ERN EDGE OF AN EML/STEEP LAPSE RATE
PLUME ORIGINATING OVER THE ROCKIES WILL COINCIDE WITH THE LOW-LEVEL
MOISTURE AXIS...CONTRIBUTING TO MLCAPES APPROACHING 1500-2500 J/KG.
A RELATIVELY STRONG ISALLOBARIC GRADIENT IS LIKELY TO DEVELOP OVER
THE HIGH PLAINS AS A PRONOUNCED SURFACE HIGH BUILDS SEWD ALONG THE
LEE OF THE NRN ROCKIES. THIS SHOULD FORCE THE COLD FRONT RAPIDLY
SWD THROUGH THE CNTRL INTO SRN HIGH PLAINS. MESOSCALE FORCING ALONG
THIS BOUNDARY WILL SERVE AS THE PRIMARY FOCUS FOR STRONG TO SEVERE
TSTM DEVELOPMENT THURSDAY AFTERNOON AND NIGHT. MIDLEVEL WIND FIELDS
WILL BACK AND GRADUALLY STRENGTHEN THROUGH THE DAY AHEAD OF
SWD-MOVING UPPER LOW WITH 30-40 KT OF DEEP-LAYER SHEAR DEVELOPING
ACROSS PRE-FRONTAL WARM SECTOR. WHILE INITIAL STORM DEVELOPMENT MAY
BE MORE DISCRETE AND CELLULAR...THE SURGING FRONT WILL LIKELY
ENCOURAGE A MORE LINEAR MODE WITH TIME WITH ACTIVITY MOVING SWD INTO
THE SRN HIGH PLAINS THURSDAY NIGHT. LARGE HAIL AND DAMAGING WINDS
APPEAR TO BE THE PRIMARY SEVERE WEATHER THREATS.
ELSEWHERE...SCATTERED...STRONG TO MARGINALLY SEVERE STORMS MAY
DEVELOP DURING THE AFTERNOON AND EVENING HOURS ALONG SLOWER-MOVING
NERN EXTENSION OF FRONT OVER THE MID MO VALLEY...PERHAPS NWD INTO
THE ERN DAKOTAS AND WRN MN. OTHER STRONG STORMS WILL BE POSSIBLE
ALONG A MORE W-E ORIENTED FRONTAL SEGMENT ACROSS SRN IA/NRN MO.
VERTICAL SHEAR IS FORECAST TO BE WEAKER ACROSS THESE AREAS THAN
POINTS TO THE W...WHICH SHOULD TEND TO LIMIT STORM
ORGANIZATION/LONGEVITY. NONETHELESS...THE MORE INTENSE STORMS WILL
STILL BE CAPABLE OF SOME HAIL AND/OR LOCALLY STRONG WIND GUSTS.
..MEAD.. 08/13/2008
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