[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 191617
SWODY1
SPC AC 191616

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1116 AM CDT WED APR 19 2006

VALID 191630Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A BROAD AREA EXTENDING
FROM WRN TX INTO THE LOWER MS/TN RIVER VALLEYS AND SOUTHEASTERN
U.S....

...LOWER MS/TN RIVER VALLEYS ACROSS THE SOUTHEAST...
WRN REMNANTS OF OVERNIGHT MCS CONTINUE TO INTENSIFY WITHIN FEED OF
VERY UNSTABLE AIR AND STEEP LAPSE RATES IN PLACE OVER THE GULF COAST
STATES.  BROAD WAA-INDUCED THUNDERSTORM AREA ACROSS SC WILL
REINFORCE SURFACE OUTFLOW BOUNDARY EXTENDING FROM THE SAV AREA NWWD
TO NEAR ATL AND THEN INTO MIDDLE TN.  A LOW CENTER IS EXPECTED TO
REMAIN NEAR THE TRIPLE POINT OF THIS FEATURE AND SURFACE COLD FRONT
SHIFTING SLOWLY SEWD ACROSS MIDDLE TN TODAY.  SW OF THE LOW...THE
COLD FRONT IS EXPECTED TO STALL AND BECOME STATIONARY ACROSS SRN AR
INTO THE BIG BEND REGION OF TX THROUGH THE DAY.  IN ADDITION...A
WEAK MID LEVEL IMPULSE SUSTAINING THE MCS NOW MOVING ACROSS THE SRN
APPALACHIANS WILL CONTINUE SEWD AND MOVE OFF THE SC/GA COAST BY THE
EARLY EVENING.

STRONG TO OCCASIONALLY SEVERE STORMS...PRIMARILY ELEVATED TO THE
NORTH/EAST OF SURFACE OUTFLOW BOUNDARY...EXPECTED TO MAINTAIN
MARGINALLY SEVERE HAIL AND PERHAPS ISOLATED DAMAGING WIND ACROSS THE
SAVANNA RIVER VALLEY AND MUCH OF SC THROUGH THE DAY.  MORE INTENSE
STORMS WILL STRADDLE THE OUTFLOW BOUNDARY WHERE NWLY MID LEVEL FLOW
AND FEED OF STRONGLY UNSTABLE AIR WILL INCREASE THE SEVERE THREAT
FROM NRN/ERN AL INTO CENTRAL/SRN GA THIS AFTERNOON.  DEEP LAYER
SHEAR WILL BE SUFFICIENT FOR ORGANIZED LINES/SUPERCELLS WITH THESE
STORMS...ENHANCING THE THREAT OF VERY LARGE HAIL AND DAMAGING WINDS.
 ISOLATED TORNADOES MAY ALSO ACCOMPANY STRONGER STORMS...ESPECIALLY
NEAR THE NW-SE ORIENTED SURFACE BOUNDARY.  THIS ACTIVITY MAY SPREAD
INTO NRN FL/SERN GA BEFORE DIMINISHING/MOVING OFFSHORE EARLY THIS
EVENING.

FARTHER WEST AND NORTHWEST...WEAK MID LEVEL SHORTWAVE TROUGH EVIDENT
ON WV IMAGERY MOVING ACROSS THE LOWER MS RIVER VALLEY MAY AGITATE
THE WARM SECTOR SUFFICIENTLY FOR INCREASING MOIST CONVECTION THROUGH
THE DAY INTO PORTIONS OF NRN MS/WRN AND MIDDLE TN INTO CENTRAL AL. 
SEVERE POTENTIAL IS A BIT MORE CONDITIONAL ACROSS THIS REGION. 
THOUGH SHEAR WILL REMAIN MARGINAL ACROSS THIS REGION...ESPECIALLY
BELOW 5-6 KM...ANY INTENSE CORES WITHIN VERY STEEP LAPSE RATES AND
STRONG INSTABILITY WILL SUSTAIN A THREAT OF LARGE HAIL AND DAMAGING
WINDS INTO THE EARLY EVENING.

...ARKLATEX INTO WRN/CENTRAL TX...
CONVERGENCE WILL REMAIN FOCUSED ALONG STALLED SURFACE FRONT TODAY
FROM THE BIG BEND REGION OF TX INTO THE LOWER MS RIVER VALLEY. 
THOUGH LARGE SCALE ASCENT WILL REMAIN WEAK/ABSENT...WARM SECTOR WILL
BECOME VERY UNSTABLE AND WEAKLY CAPPED DURING THE MID TO LATE
AFTERNOON.  THEREFORE...EXPECT AT LEAST A FEW CLUSTERS OF INTENSE
THUNDERSTORMS WILL FORM ALONG THE BOUNDARY AND PERSIST INTO THE MID
EVENING.  FORECAST SOUNDINGS MAINTAIN 35-40 KT OF EFFECTIVE
SHEAR...SUGGESTING ACTIVITY WILL ORGANIZE INTO MULTICELL
LINES/CLUSTERS AND SUPERCELLS. LARGE HAIL AND DAMAGING WINDS CAN BE
EXPECTED WITH ANY DEVELOPMENT ACROSS THIS REGION LATER TODAY AND
THIS EVENING.  MOST LIKELY AREA WILL BE INTO THE BIG BEND REGION
WHERE TERRAIN WILL AID IN INITIATION...POSSIBLY BY 21Z.  VERY LARGE
HAIL WILL BE COMMON ACROSS THIS REGION.  DEVELOPMENT HERE MAY SPREAD
NNEWD ALONG AND NORTH OF THE FRONT SPREADING THREATS OF LARGE HAIL
AND ISOLATED DAMAGING WIND INTO N-CENTRAL/NERN TX THROUGH THE
EVENING.

LATER TONIGHT...INCREASING LARGE SCALE ASCENT ATOP STABLE BOUNDARY
LAYER NORTH OF STALLED FRONT WILL OVERSPREAD THE PERMIAN BASIN
REGION.  SREF AND GFS GUIDANCE BOTH EXPECT ELEVATED THUNDERSTORM
DEVELOPMENT INTO THIS REGION WHERE FORECAST SOUNDINGS YIELD MODERATE
MUCAPE AND SUFFICIENT EFFECTIVE SHEAR FOR ROTATING UPDRAFTS. 
THUS...LARGE HAIL WOULD ACCOMPANY STORMS IN THIS REGION WITH
ACTIVITY POSSIBLY SPREADING TOWARD CENTRAL TX BY DAY BREAK THURSDAY
MORNING.

..EVANS\CROSBIE.. 04/19/2006