[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 190557
SWODY2
SPC AC 190556

DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT WED APR 19 2006

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN TX EWD INTO THE SRN TN
VALLEY AND CNTRL GULF COAST STATES...

CORRECTED FOR INCORRECT DAY REFERENCE

...SYNOPSIS...

AMPLIFIED LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO
PERIOD.  MID AND UPPER-LEVEL LOW OVER THE UPPER MS VALLEY WILL
SLOWLY TRANSLATE EWD INTO THE WRN GREAT LAKES...WHILE A MORE
PROGRESSIVE SRN STREAM IS MAINTAINED ACROSS THE SRN TIER OF STATES. 
IN ADDITION TO VORTICITY MAXIMUM SHIFTING EWD FROM AZ/NM INTO
TX/OK...OTHER MORE SUBTLE PERTURBATIONS MAY EXIST WITH WSWLY FLOW
FROM THE ARKLATEX INTO THE TN VALLEY AND CNTRL GULF STATES.

IN THE LOW-LEVELS...WEAK LOW PRESSURE IS FORECAST TO DEVELOP NEWD
FROM THE LOWER MS VALLEY INTO THE UPPER OH VALLEY /LIKELY ASSOCIATED
WITH A LEAD UPPER DISTURBANCE/ WITH TRAILING FRONTAL BOUNDARY
STRETCHING SWWD THROUGH THE WRN TN VALLEY INTO WRN TX. THE WRN
EXTENSION OF THIS BOUNDARY MAY ATTEMPT TO RETREAT SLIGHTLY NWD WITH
APPROACH OF AZ/NM SHORT WAVE TROUGH...BEFORE PUSHING MORE SWD WITH
THE PASSAGE OF THIS WAVE LATE THURSDAY NIGHT.

...TX INTO SRN OK...

SLY LLJ...MAINTAINED BY DIRECT THERMAL CIRCULATION ASSOCIATED WITH
ENTRANCE REGION OF UPPER JET STREAK OVER THE LOWER MO VALLEY...WILL
LIKELY BE SUPPORTING CLUSTERS OF ELEVATED TSTMS THURSDAY MORNING
OVER PORTIONS OF WRN AND NRN TX.  THESE STORMS MAY PERSIST THROUGH
THE DAY N OF SURFACE FRONT WITH SOME THREAT OF HAIL.  MORE INTENSE
SURFACE-BASED DEVELOPMENT IS ANTICIPATED BY AFTERNOON FROM THE
CONCHO VALLEY AND PERMIAN BASIN INTO THE BIG COUNTRY WHERE DEWPOINTS
IN THE 50S...COUPLED WITH STEEPENING LAPSE RATES WILL CONTRIBUTE TO
MLCAPES OF 1000-1500 J/KG.

IT APPEARS THAT THE SYNOPTIC FRONT...SHARPENING DRY LINE OVER SWRN
TX AND RESIDUAL OUTFLOW BOUNDARIES WILL PROVIDE THE FOCUS FOR THIS
MORE VIGOROUS STORM DEVELOPMENT.  FORECAST SOUNDINGS INDICATE
STRONGLY VEERING WIND PROFILES WITH 40-45 KTS OF SWLY DEEP-LAYER
SHEAR WHICH SHOULD SUPPORT THE DEVELOPMENT OF A FEW SUPERCELLS
CAPABLE OF MAINLY LARGE HAIL /SOME IT POSSIBLY SIGNIFICANT/.  GIVEN
THE EXPECTED W-E OR WSW-ENE ORIENTATION OF THE SYNOPTIC
BOUNDARY...POTENTIAL WILL EXIST FOR A FEW TORNADOES WITH ANY MORE
DISCRETE STORMS THAT CAN PROPAGATE ALONG THIS FEATURE WHERE
LOW-LEVEL SHEAR WILL BE MAXIMIZED.

SURFACE-BASED STORMS WITH A THREAT OF MAINLY HAIL AND HIGH WINDS ARE
EXPECTED TO SPREAD INTO PORTIONS OF CNTRL AND NRN TX THURSDAY NIGHT.
 STRENGTHENING LLJ WILL ALSO SUPPORT A FEW SEVERE ELEVATED STORMS N
OF FRONT INTO SRN OK WHERE LARGE HAIL WILL BE POSSIBLE.

...AR/LA EWD INTO TN VALLEY AND CNTRL GULF STATES...

A MOIST LOW-LEVEL AIR MASS /DEWPOINTS IN THE 60S/ WILL LARGELY
CONTRIBUTE TO THE DEVELOPMENT OF MODERATE AFTERNOON INSTABILITY FROM
THE LOWER MS VALLEY EWD ACROSS THE GULF COAST INTO THE TN VALLEY /S
OF WEAK FRONT/ WITH MLCAPES OF 1000-1500 J/KG. WHILE THE MAIN FOCUS
FOR CONVECTIVE INITIATION IS SOMEWHAT UNCERTAIN...THERE IS SOME
SUGGESTION THAT A LEAD IMPULSE MAY EXIST NEAR THE ARKLATEX THURSDAY
MORNING...WHICH WILL MOVE NEWD INTO THE TN VALLEY BY AFTERNOON.

SHOULD THIS SCENARIO OCCUR...A THREAT OF DAMAGING WINDS AND LARGE
HAIL WILL EXIST WITH ANY ORGANIZED CLUSTER OR MCS THAT CAN DEVELOP
AHEAD OF THIS IMPULSE. FARTHER S ACROSS CNTRL MS INTO CNTRL
AL...THE ABSENCE OF ANY DISCERNABLE BOUNDARY MAKE THE INITIATION OF
DEEP MOIST CONVECTION EVEN MORE UNCERTAIN.  HOWEVER...FORECAST
SOUNDINGS INDICATE THAT WEAK CAP SHOULD ERODE SUFFICIENTLY BY
AFTERNOON SUCH THAT STORMS SHOULD DEVELOP ON ANY SMALL-SCALE
BOUNDARIES PRESENT IN BROADER WARM SECTOR.

GIVEN THE INITIATION AND MAINTENENCE OF STORMS...THE MODERATE
INSTABILITY IN CONJUNCTION WITH A BELT OF 40-50 KT WLY MID-LEVEL
FLOW DEVELOPING EWD ACROSS THE AREA WILL SUPPORT ORGANIZED/ROTATING
STORMS WITH A THREAT OF LARGE HAIL AND DAMAGING WINDS.

..MEAD.. 04/19/2006