SWODY1
SPC AC 241208
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0708 AM CDT TUE APR 24 2007
VALID 241300Z - 251200Z
..THERE IS A MDT RISK OF SVR TSTMS FROM KS/WRN MO SWD THRU OK/WRN
AR TO CENTRAL TX...
..THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK
FROM THE CENTRAL AND SRN PLAINS EWD TO THE MID MS...LOWER OH
VALLEYS....
..SEVERE THUNDERSTORMS EXPECTED TO BECOME WIDESPREAD ACROSS
PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS BEGINNING THIS AFTERNOON
AND CONTINUING TONIGHT...
..SYNOPSIS...
VIGOROUS UPPER LOW SPINNING SLOWLY EWD VICINITY SRN CO/NM BORDER
TODAY...INTO OK PANHANDLE TONIGHT. THE ASSOCIATED SURFACE LOW SERN
CO MOVES TO NWRN OK BY 12Z WED. WARM FRONT EXTENDS FROM SURFACE LOW
NEWD TO SRN NEB BORDER THEN EWD TO NRN MO. DRY LINE/PACIFIC FRONT
CURRENTLY CROSSING TX PANHANDLE INTO WRN OK EXPECTED TO EXTEND N/S
JUST W OF I-35 CORRIDOR SRN KS TO N TX BY LATE AFTERNOON. MODELS
SUGGEST LITTLE OR JUST VERY SLOW FURTHER EWD MOVEMENT THIS EVENING.
ABUNDANT GULF MOISTURE/INSTABILITY NOW PREVAILS E AND S OF THESE
BOUNDARIES ACROSS THE PLAINS.
..CENTRAL/SRN PLAINS...
GIVEN THE STRENGTH OF THE WIND FIELDS ROTATING ACROSS THE WARM
SECTOR TODAY...COUPLED WITH THE AVAILABILITY OF
INSTABILITY...CONFIDENCE IS HIGH THAT TORNADIC SUPERCELLS WILL
OCCUR. HOWEVER THE UNCERTAINTY IS STILL WHERE THE GREATEST THREAT IS
LOCATED THUS ATTM WILL CONTINUE WITH A RATHER LARGE MDT RISK.
WATER VAPOR IMAGERY INDICATES A SPEED MAX CURRENTLY ROTATING NEWD
AROUND UPR LOW ACROSS NERN NM WHICH SHOULD ENHANCE BOTH VERTICAL
MOTION AND DEEP LAYER SHEAR BY EARLY AFTERNOON IN THE WARM SECTOR
ACROSS WRN KS. THUNDERSTORMS EXPECTED TO INTENSIFY BY EARLY
AFTERNOON IN THE LOW LEVEL CONVERGENCE BOTH VICINITY OF WARM FRONT
NRN KS AND THE NRN EXTENSION OF DRY LINE/COLD FRONT WRN KS. WITH
MLCAPES AOA 2000 J/KG AND ENHANCED LOW LEVEL SHEAR...PARTICULARLY
VICINITY OF BOUNDARIES...SUPERCELLS INCLUDING LARGE HAIL AND
TORNADOES WILL BECOME MORE WIDESPREAD AS THE STORMS WORK EWD ACROSS
KS THRU THE AFTERNOON. POTENTIAL FOR STRONG TORNADOES ALSO SHOULD
INCREASE THRU THE AFTERNOON.
COLD FRONT HAS SURGED EWD INTO TX PANHANDLE AND THERE IS STILL
UNCERTAINTY AS TO WHERE THE FRONT WILL BE PRIOR TO WHEN SURFACE
INITIATION OCCURS THIS AFTERNOON. BY MID AFTERNOON WITH MLCAPES
ABOVE 2000 J/KG AND 50-60KT OF DEEP LAYER SHEAR...SUPERCELLS
EXPECTED TO RAPIDLY DEVELOP FROM SRN KS SWD INTO NCENTRAL TX
VICINITY OF DRY LINE. CONFIDENCE IS LOW ON AMOUNT OF STORM
COVERAGE...BUT ANY STORM SHOULD QUICKLY BECOME SUPERCELLULAR ALONG
WITH TORNADO AND LARGE HAIL THREAT. STORMS COULD THEN MOVE AWAY
FROM DRY LINE ACROSS THE WARM SECTOR ERN OK/KS WHERE CONDITIONS WILL
FAVOR POTENTIAL FOR LONG LIVED TORNADIC SUPERCELLS.
MID/UPPER LEVEL JET STREAK NOTED ON WV IMAGERY TRACKING ENEWD FROM
MEX COULD AID CONVECTIVE RELEASE ACROSS N TX BY THIS AFTERNOON WELL
AHEAD OF THE DRY LINE. AIR MASS THIS AREA CHARACTERIZED BY DEEPER
MOISTURE AND POTENTIALLY MLCAPES AOA 2000 J/KG. LOW LEVEL SHEAR OF
30KT AND DEEP LAYER SHEAR OF 50-60KT SUGGESTS ANY STORM THAT
DEVELOPS WILL AGAIN QUICKLY BECOME A SUPERCELL WITH TORNADO AND
LARGE HAIL POTENTIAL. ENVIRONMENT WILL THEN SUPPORT LONG LIVED
STORMS AS THEY TRACK NEWD ACROSS TX INTO SRN AR GIVEN THE
MOIST/UNSTABLE WARM SECTOR. AGAIN STRONG TORNADOES WILL BE POSSIBLE.
ADDITIONAL STORMS SHOULD EVENTUALLY FORM SWD ALONG/AHEAD OF DRY LINE
BY LATE AFTERNOON SWD TO SCENTRAL TX WHERE AIRMASS WILL LIKELY BE
VERY UNSTABLE WITH MLCAPES TO 3000 J/KG. VERY LARGE HAIL ALONG WITH
TORNADO POTENTIAL WILL BE ASSOCIATED WITH ANY STORM.
OVERNIGHT ALL MODELS HAVE A STRONG...CONSISTENT SIGNAL FOR THE
DEVELOPMENT OF A LINER MCS ACROSS ERN TX WHICH IMPLIES ORGANIZED
WIND DAMAGE POTENTIAL ALONG WITH THE TORNADO THREAT. SEVERE
THUNDERSTORMS LIKELY MUCH OF NIGHT SPREADING EWD TOWARD LOWER/MID MS
VALLEY.
ATTM WILL NOT UPGRADE ANY ONE OF THE AREAS DISCUSSED DUE TO
CONFLICTING MODEL CONVECTIVE SIGNALS...BUT THE LARGE SCALE
PARAMETERS SUGGEST THAT IT WILL BE A VERY ACTIVE SEVERE DAY AND
LATER OUTLOOKS DURING THE DAY MAY BE ABLE TO BETTER IDENTIFY WHERE
AN UPGRADE COULD BE SUPPORTED.
.HALES/JEWELL.. 04/24/2007
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