SWODY1
SPC AC 111234
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0734 AM CDT SUN APR 11 2010
VALID 111300Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN HI
PLNS...
...SYNOPSIS...
STRONG E PACIFIC UPR LOW SHOULD CONTINUE GENERALLY E TO THE NRN CA
CST BY 12Z MON AS DOWNSTREAM RIDGE BUILDS N ACROSS THE PLNS.
FARTHER S...ZONAL SRN STREAM JET EXPECTED TO PERSIST FROM CNTRL/SRN
BAJA CA TO DEEP S TX.
AT LWR LVLS...ELONGATED HIGH PRESSURE WILL PERSIST FROM THE WRN
ATLANTIC AND THE SERN STATES INTO THE SRN PLNS. LEE TROUGH WILL
INTENSIFY OVER THE HI PLNS...S AND W OF STRENGTHENING FRONTAL ZONE
EXTENDING FROM THE DAKOTAS ESE INTO THE MID MS VLY.
...SRN HI PLNS...
S TO SELY LOW-LVL FLOW ASSOCIATED WITH AFOREMENTIONED LEE TROUGH/
SFC RIDGE WILL ALLOW MOISTURE TO GRADUALLY INCREASE OVER S TX AND
THE SRN HI PLNS THROUGH TONIGHT. EXTRAPOLATION OF CURRENT
SATELLITE/GPS DATA SUGGEST THAT PW SHOULD REACH 1 INCH OVER WRN
OK/NW TX BY LATE IN THE DAY...WITH VALUES ABOVE 1.5 INCHES OVER DEEP
S TX. COUPLED WITH RELATIVELY COOL MID-LVL TEMPERATURES/ BROAD
EML...SFC HEATING SHOULD BOOST AFTN SBCAPE TO NEAR 2000 J/KG OVER W
CNTRL TX...WITH SOMEWHAT LESSER VALUES EXTENDING NE INTO OK...AND S
TO THE RIO GRANDE.
CONVERGENCE AND SLIGHT UPSLOPE COMPONENT TO LOW-LVL FLOW SHOULD
SUPPORT SCTD STORM DEVELOPMENT BY MID TO LATE AFTN ALONG LEE
TROUGH/DRY LINE FROM W TX INTO WRN OK. THE MEAN FLOW WILL BE
WEAK...AS WILL LARGE SCALE FORCING FOR ASCENT. BUT GIVEN DEGREE OF
SFC-BASED INSTABILITY AND FOCI FOR LOW-LVL ASCENT...SOME STRONG
PULSE UPDRAFTS APPEAR LIKELY. THESE MAY YIELD SVR HAIL AND PERHAPS
AN ISOLD SVR WIND GUST OR TWO BEFORE THE STORMS MERGE INTO ONE OR
MORE SMALL SSE-MOVING CLUSTERS THIS EVE.
...S TX...
MODERATE /30-40 KT/ DEEP WLY SHEAR WILL EXIST OVER THE RIO GRANDE
VLY REGION THOUGH THE PERIOD...BENEATH NRN FRINGE OF SRN STREAM JET.
WV IMAGERY SUGGESTS THE POSSIBLE PRESENCE OF SEVERAL UPSTREAM
DISTURBANCES THAT COULD ENHANCE LARGE SCALE FORCING FOR ASCENT. BUT
CONFIDENCE IS NOT GREAT REGARDING THE STRENGTH/TIMING OF THESE
FEATURES. NEVERTHELESS...GIVEN AVAILABILITY OF COMPARATIVELY RICH
MOISTURE OVER THE REGION...AND MORE SUBSTANTIAL UPSLOPE FLOW
RELATIVE TO POINTS FARTHER N...IT SEEMS LIKELY THAT A FEW SUPERCELLS
WILL FORM THIS AFTN OVER THE MOUNTAINS OF NE MEXICO. THESE SHOULD
MOVE MAINLY SE AND REMAIN PRIMARILY SW OF THE INTERNATIONAL BORDER.
BUT A LOW PROBABILISTIC THREAT WILL EXIST FOR SOME STORMS TO CROSS
THE LWR RIO GRANDE AND AFFECT PARTS OF S TX LATE THIS AFTN INTO
TONIGHT...WITH THE MAIN THREAT BEING LARGE HAIL.
...NRN/CNTRL CA...
WIND PROFILES WILL BECOME INCREASINGLY FAVORABLE FOR SUSTAINED
STORMS/SUPERCELLS OVER NRN PARTS OF THE CNTRL VLY AND ALONG THE
NRN/CNTRL CA CST LATE TODAY/TONIGHT AS SHORTWAVE IMPULSE ROUNDS BASE
OF OFFSHORE LOW...AND SWEEPS INLAND WITH A SLIGHTLY NEGATIVE TILT.
ATTM...TIMING BASED ON CURRENT CONDITIONS/SATELLITE DATA SUGGESTS
THAT CLOUDS/RAIN ASSOCIATED WITH SYSTEM WARM CONVEYOR BELT WILL
LIMIT LOW LVL DESTABILIZATION/POTENTIAL FOR STORMS. SHOULD IT
APPEAR THAT GREATER BOUNDARY LAYER DESTABILIZATION WILL OCCUR THAN
IS NOW EXPECTED...LOW TORNADO PROBABILITIES MAY BE REQUIRED IN LATER
OUTLOOKS.
..CORFIDI/GRAMS/JIRAK.. 04/11/2010
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