SPC AC 300527
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 AM CDT MON APR 30 2007
VALID 011200Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS TUESDAY AFTERNOON AND EVENING
ACROSS PARTS OF THE OH VALLEY....
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN TX AND RIO
GRANDE VALLEY....
...SYNOPSIS...
MID/UPPER LEVEL PATTERN WILL BEGIN TRANSITIONING DURING THE LATTER
HALF OF THE PERIOD. MID LEVEL RIDGING WILL EXTEND NWD THRU THE NRN
PLAINS PUSHING A MID/UPPER LEVEL SHORTWAVE TROUGH SEWD ACROSS THE
GREAT LAKES REGION INTO NEW ENGLAND. MEANWHILE...LARGE TROUGH OVER
THE NRN PACIFIC WILL BEGIN MOVING TOWARDS THE NWRN U.S. THIS WILL
FORCE MID LEVEL TROUGH WITHIN THE SOUTHERN STREAM NEWD ACROSS THE
FOUR CORNERS REGION IN THE SWRN U.S. AND GRADUALLY WEAKEN PERSISTENT
TROUGH OVER THE S CENTRAL U.S.
...PARTS OF THE OHIO VALLEY...
MODELS HAVE SAME GENERAL IDEA OF TAKING SURFACE LOW EWD ACROSS NRN
OHIO DURING THE AFTERNOON EWD THROUGH PA AND NRN NJ BY THE END OF
THE PERIOD. MODELS DIVERGE IN ESTIMATING AMOUNT OF MOISTURE WITH
THE NAM/GFS AND RSM ALL FORECASTING SFC DEW POINTS AROUND 60 ALONG
AND S OF THE FRONTAL BOUNDARY. THIS FRONT WILL PUSH SWD/SEWD
THROUGH THE OHIO VALLEY DURING THE AFTERNOON AND EVENING. EVEN
REFERRED BACK TO THE OLD NGM TO GET A HANDLE OF SFC DEW POINTS AND
FOUND THAT MODEL MAY BE BETTER WITH DEW POINTS IN THE MID/UPPER 50S.
THE EFFECT ON THIS WOULD BE LESS MLCAPE FOR CONVECTION WITH THE
NAM/GFS FORECASTING AREAS OF CENTRAL OH TO BE NEAR 2000 J/KG BY
EARLY AFTERNOON. WITH LOWER DEW POINTS...MLCAPE MAY BE MORE BETWEEN
1000-1500 J/KG.
BOTTOM LINE IS THAT THERE WILL BE ENOUGH THERMODYNAMICS FOR A LINE
OF STRONG/SEVERE STORMS ALONG THE FRONTAL BOUNDARY COMBINED WITH
DEEP LAYER SHEAR ESTIMATED TO BE 35-45 KTS ACROSS THE REGION. THIS
WILL BE SUFFICIENT FOR MULTICELLULAR STORMS AND WITH MID LEVEL LAPSE
RATES AROUND 7C/KM..THE MAIN THREATS WILL BE STRONG GUSTY WINDS AND
HAIL.
...AREAS OF S TX INTO THE RIO GRANDE VALLEY...
MOIST AND UNSTABLE AIR MASS WILL REMAIN ACROSS THIS REGION DURING
THE PERIOD AS MID/UPPER LEVEL TROUGH WEAKENS OVER THE S CENTRAL U.S.
REMNANT OF MCS ACTIVITY EXPECTED TO KEEP SUFFICIENT MOISTURE AND
WITH SOME HEATING THE AIR MASS WILL DESTABILIZE WITH MUCAPE AROUND
1500 J/KG. THUS...A FEW STRONG/SEVERE THUNDERSTORMS WILL STILL BE
POSSIBLE ACROSS THIS REGION BEFORE NEXT SHORTWAVE TROUGH MOVES IN
WEDNESDAY.
..MCCARTHY.. 04/30/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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