SWODY1
SPC AC 231945
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0145 PM CST SAT JAN 23 2010
VALID 232000Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN OK/NERN TX EWD INTO
THE MS DELTA REGION...
...SERN OK/NERN TX EWD INTO THE MID MS VALLEY...
A POTENT UPPER TROUGH WILL CONTINUE TO EXIT THE ROCKIES/ENTER THE
CENTRAL CONUS...WITH A STRONG SMALLER SCALE DISTURBANCE/JET EXIT
REGION CROSSING THE TX SOUTH PLAINS ATTM WHICH WILL CONTINUE ENEWD
TOWARD THE MID MS VALLEY THROUGH THE END OF THE PERIOD.
SHOWERS AND A FEW THUNDERSTORMS HAVE DEVELOPED THIS AFTERNOON ACROSS
THE TX SOUTH PLAINS...WITHIN THE ZONE OF STEEP LAPSE RATES ALOFT IN
THE IMMEDIATE VICINITY OF THE JET EXIT REGION. AS THIS AREA OF
CONVECTION PROGRESSES EWD...MARGINAL HAIL AND PERHAPS A LOCAL WIND
GUST MAY OCCUR.
LATER THIS EVENING...AS THE PRE-FRONTAL BAND OF PRECIPITATION
EXTENDING FROM CENTRAL TX NEWD INTO MO SHIFTS E...STORMS CROSSING
THE RED RIVER VALLEY AREA MAY ORGANIZE INTO ONE OR MORE FORCED LINE
SEGMENTS. WHILE SURFACE-BASED CAPE SHOULD PROVE LIMITED TO
NON-EXISTENT...STRENGTH OF THE UPPER FORCING COMBINED WITH VERY
STRONG FLOW ALOFT COULD RESULT IN DOWNWARD TRANSPORT OF MOMENTUM --
PERHAPS LOCALLY REACHING THE SURFACE AS DAMAGING WIND GUSTS.
THUS...WILL MAINTAIN A LOW-PROBABILITY SLIGHT RISK FORECAST FROM
SERN OK/NERN TX EWD TO THE MID MS VALLEY.
..GOSS.. 01/23/2010
.PREV DISCUSSION... /ISSUED 1028 AM CST SAT JAN 23 2010/
A POWERFUL UPPER LEVEL JET /150+ KNOTS AT 300MB/ IS MOVING EASTWARD
ACROSS NORTHERN MEXICO THIS MORNING...AND WILL NOSE INTO THE
SOUTHERN PLAINS LATER TODAY. THIS WILL HELP TO SHARPEN AN UPPER
TROUGH OVER THE CENTRAL STATES...AND FORCE THE TROUGH
NEGATIVELY-TILTED BY LATE TONIGHT ACROSS THE MS VALLEY. AN
INCREASING BAND OF SHOWERS AND THUNDERSTORMS WILL RESULT FROM OK/TX
INTO THE MID MS VALLEY AND LOWER OH VALLEY.
BY LATE THIS AFTERNOON...A MID LEVEL DRY SLOT WILL DEVELOP OVER TX
AND ROTATE NORTHEASTWARD TOWARD THE ARKLATEX...BENEATH THE INTENSE
UPPER LEVEL JET CORE. STRONG LARGE SCALE ASCENT AND STEEP LAPSE
RATES IN THE LEFT EXIT REGION OF THIS JET MAY RESULT IN ISOLATED
THUNDERSTORMS OVER SOUTH-CENTRAL OK AND NORTHEAST TX DURING PEAK
HEATING. RUC FORECAST SOUNDINGS SUGGEST WEAK BUT SUFFICIENT CAPE
FOR MARGINALLY SEVERE HAIL IN THE MOST ROBUST UPDRAFTS. MULTIPLE
MESOSCALE MODEL RUNS ALSO INDICATE THAT A FEW LINES/CLUSTERS OF
LOW-TOPPED CONVECTION WILL TRACK RAPIDLY EAST-NORTHEASTWARD THIS
EVENING INTO AR AND EVENTUALLY PARTS OF MO/KY/TN/MS. WEAK
INSTABILITY SHOULD PRECLUDE SEVERE HAIL LATER TONIGHT.
HOWEVER...STRENGTH OF WIND FIELDS AND STRONG DYNAMIC FORCING MAY
RESULT IN A FEW BOW STRUCTURES CAPABLE OF GUSTY/DAMAGING WINDS.
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