[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 061737
SWODY2
SPC AC 061735

DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1235 PM CDT THU APR 06 2006

VALID 071200Z - 081200Z

...THERE IS A HIGH RISK OF SVR TSTMS ACROSS NE MS...NRN AL...SCNTRL
TN AND FAR NW GA...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF
MS...AL...TN...GA...LA...ERN AR...WRN NC AND FAR WRN SC...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS
VALLEY...OH VALLEY...SRN AND CNTRL APPALACHIANS AND IMMEDIATE GULF
COAST...

CORRECTED FOR WORDING LAST PARAGRAPH

A POTENT UPPER-LEVEL TROUGH OVER THE PLAINS STATES WILL SHIFT SEWD
INTO THE OZARKS FRIDAY AHEAD OF A MOIST AND VERY UNSTABLE WARM
SECTOR ACROSS THE TN VALLEY. THE SHEAR ENVIRONMENT WILL BE VERY
FAVORABLE FOR TORNADOES AND A SIGNIFICANT TORNADO OUTBREAK IS
EXPECTED FRIDAY AFTERNOON AND EVENING ACROSS NRN AL...NE MS...SCNTRL
TN AND FAR NW GA.

...TN VALLEY...
SEVERAL MESOSCALE CONVECTIVE SYSTEMS ONGOING AT THE BEGINNING OF THE
PERIOD IN THE MID-MS VALLEY WILL DRIFT QUICKLY NEWD AS A 90-100 KT
MID-LEVEL JET EJECTS NEWD OUT OF THE CNTRL PLAINS TROUGH. THIS WILL
INCREASE MOISTURE ADVECTION STRENGTHENING A 40-50 KT LOW-LEVEL JET
TRANSPORTING MID TO UPPER 60S F SFC DEWPOINTS NNEWD ACROSS THE TN
VALLEY. THE MODELS ARE IN GOOD AGREEMENT SHUNTING MORNING CONVECTION
AWAY FROM THE HIGH RISK AREA DURING THE MORNING LEAVING THE AIRMASS
UNDISTURBED MIDDAY FRIDAY ACROSS MS...AL...TN AND NRN GA. AS STORMS
INITIATE FRIDAY AFTERNOON...SUPERCELLS WILL BE LIKELY DUE TO THE
STRONG VERTICAL SHEAR ASSOCIATED WITH THE MID-LEVEL JET. NAMKF
FORECAST SOUNDINGS FOR TUPELO MS...FLORENCE ALABAMA AND HUNTSVILLE
ALABAMA FRIDAY AFTERNOON SEEM REASONABLE WITH MODERATE TO STRONG
INSTABILITY (MLCAPE VALUES 2500-3000 J/KG)...0-6 KM SHEAR VALUES
AT/ABV 60 KT AND IMPRESSIVE LOW-LEVEL SHEAR PROFILES (0-3 KM SRH
AT/ABV 350 M2/S2). IN THIS ENVIRONMENT...STORMS SHOULD REMAIN
DISCRETE FOR THE LATE AFTERNOON AND EARLY EVENING HOURS. IN
ADDITION...LCL HEIGHTS ARE FORECAST TO REMAIN LOW WHICH COMBINED
WITH THE INSTABILITY AND STRONG LOW-LEVEL SHEAR WILL BE VERY
FAVORABLE FOR TORNADOES. LONG-TRACK STRONG OR EVEN VIOLENT TORNADOES
WILL BE POSSIBLE ESPECIALLY WITH SUPERCELLS THAT TRACK ALONG ANY
PRE-EXISTING BOUNDARIES OR CONVERGENCE ZONES. THE
INSTABILITY...SHEAR AND STEEP MID-LEVEL LAPSE RATES NEAR 8.0 C/KM
SHOWN ON THE FORECAST SOUNDINGS WILL ALSO BE FAVORABLE FOR LARGE
HAIL AND WIND DAMAGE WITH THE SUPERCELLS. VERY LARGE HAIL WILL ALSO
BE POSSIBLE WITH THE STRONGER SUPERCELLS.

STORM COVERAGE WILL LIKELY EXPAND DURING THE EVENING AS THE
UPPER-TROUGH APPROACHES FROM THE NORTHWEST. ALTHOUGH CONVECTION MAY
GRADUALLY ORGANIZE INTO A LINEAR ORIENTATION BY LATE EVENING...THE
WIND SHEAR ENVIRONMENT SHOULD REMAIN SUPPORTIVE OF DISCRETE
SUPERCELLS AS THE LOW-LEVEL JET INCREASES AND EXPANDS NWD ACROSS THE
HIGH RISK AREA. THE WIND DAMAGE POTENTIAL WILL LIKELY BE ENHANCED
WITH SUPERCELLS AND/OR BOW ECHOES THAT DEVELOP DURING THE LATE
EVENING. THE SEVERE THREAT ACROSS THE TN VALLEY SHOULD BEGIN TO DROP
OFF AFTER MIDNIGHT AS INSTABILITY DECREASES AND A COLD FRONT
ADVANCES EWD ACROSS THE REGION.

...OH VALLEY...
VERY STRONG LARGE-SCALE ASCENT WILL SPREAD EWD ACROSS THE OH VALLEY
FRIDAY MORNING AS A LARGE AREA OF CONVECTION SPREADS NEWD ACROSS THE
REGION. THIS WILL LIKELY DELAY DESTABILIZATION ACROSS MUCH OF THE OH
VALLEY AND UNCERTAINTY REMAINS CONCERNING THE DEVELOPMENT OF
INSTABILITY IN THE AFTERNOON HOURS. THE NAM AND GFS INITIATE
POST-FRONTAL CONVECTION EARLY IN THE AFTERNOON NORTH OF A FRONTAL
BOUNDARY EXTENDING WSWD TO ENEWD ACROSS THE OH VALLEY. FORECAST
SOUNDINGS FOR THIS AREA FRIDAY AFTERNOON SHOW SUFFICIENT
INSTABILITY/SHEAR PROFILES AND STEEP LAPSE RATES THAT SHOULD BE
FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. FURTHER SOUTH ACROSS
KY...SFC DEWPOINTS IN THE UPPER 50S TO NEAR 60 F SHOULD ALLOW
MODERATE INSTABILITY TO DEVELOP. ALTHOUGH CONVECTIVE INITIATION MAY
HOLD OFF UNTIL LATER IN THE AFTERNOON...SFC-BASED STORMS APPEAR
LIKELY TO DEVELOP ALONG AND SOUTH OF THE BOUNDARY DURING THE LATE
AFTERNOON AND EVENING HOURS. STEEP LOW-LEVEL LAPSE RATES...GREATER
MOISTURE AND STRONG LOW-LEVEL SHEAR WILL FAVOR LARGE HAIL...WIND
DAMAGE AND A FEW TORNADOES WITH SUPERCELLS THAT TRACK ENEWD ACROSS
THE REGION. THE SEVERE THREAT SHOULD CONTINUE INTO THE EVENING HOURS
WITH THE THREAT GRADUALLY BECOMING MARGINAL TOWARD MIDNIGHT AS
INSTABILITY DECREASES.

..BROYLES.. 04/06/2006