[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 150559
SWODY2
SPC AC 150558

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1158 PM CST TUE MAR 14 2006

VALID 161200Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS THU AFTN/EVE ACROSS PARTS OF S
CNTRL/SE TEXAS AND WRN LA....

MODELS CONTINUE TO INDICATE THAT A BROAD UPPER TROUGH WILL BEGIN TO
EVOLVE ACROSS THE EASTERN PACIFIC LATER TODAY INTO 12Z THURSDAY...
BEFORE AMPLIFICATION OCCURS ALONG THE PACIFIC COAST THROUGH THE
REMAINDER OF THIS FORECAST PERIOD.  DIFLUENT DOWNSTREAM REGIME MAY
SPREAD TO THE IMMEDIATE LEE OF THE ROCKIES...BUT BROADLY CONFLUENT
UPPER FLOW WILL PERSIST EAST OF THE HIGH PLAINS INTO BROAD WESTERN
ATLANTIC TROUGH.  

WITHIN THIS PATTERN...A SIGNIFICANT IMPULSE IN BELT OF POLAR
WESTERLIES IS PROGGED TO ACCELERATE SOUTHEAST OF THE MID MISSOURI
VALLEY THROUGH MUCH OF THE LOWER OHIO VALLEY BY 12Z FRIDAY...AHEAD
OF ANOTHER SHORT WAVE DIGGING SOUTH OF THE CENTRAL CANADIAN
PROVINCES.  A SHEARING IMPULSE IN THE SUBTROPICAL STREAM MAY
ACCOMPANY LEAD SYSTEM...AND MODELS SUGGEST LARGE-SCALE FORCING WILL
CONTRIBUTE TO EROSION/RETREAT OF SOUTH CENTRAL/SOUTHEAST STATES
SURFACE RIDGE. THIS SHOULD ALLOW FOR A RETURN FLOW OFF THE GULF OF
MEXICO...THROUGH SOUTHEAST TEXAS AND THE LOWER MISSISSIPPI
VALLEY...AND IN A NARROW TONGUE TO THE VICINITY OF A WEAK SURFACE
CYCLONE ACCOMPANYING POLAR TROUGH THROUGH THE LOWER OHIO VALLEY. 

...SOUTH CENTRAL STATES...
AHEAD OF NEXT COLD INTRUSION THROUGH THE PLAINS AND MISSISSIPPI
VALLEY...MODELS SUGGEST AN ELEVATED MIXED LAYER WILL ADVECT EAST
NORTHEAST OF THE MEXICAN PLATEAU THROUGH MUCH OF SOUTHERN/EASTERN
TEXAS INTO WESTERN LOUISIANA.  THIS WILL CONTRIBUTE TO STEEP LAPSE
RATES ABOVE A DEEPENING MOIST BOUNDARY WITH SURFACE DEW POINTS
CLIMBING IN EXCESS OF 60F.  

BY THURSDAY AFTERNOON...MIXED LAYER CAPE SEEMS LIKELY TO EXCEED 1000
J/KG...WITH INHIBITION WEAKENING IN RESPONSE TO MID-LEVEL COOLING IN
WAKE OF SUBTROPICAL IMPULSE.  MODELS SUGGEST THIS MAY BE ENOUGH FOR
SCATTERED VIGOROUS CONVECTIVE DEVELOPMENT.  AIDED BY FAVORABLE DEEP
LAYER SHEAR BENEATH MODERATELY STRONG MID/UPPER FLOW...ISOLATED
SUPERCELLS ARE EXPECTED.  RATHER LIGHT LOW-LEVEL FLOW AND SMALL
LOW-LEVEL HODOGRAPHS SHOULD LIMIT TORNADO POTENTIAL...BUT LARGE HAIL
AND DAMAGING WIND GUSTS WILL BE POSSIBLE.  THIS SHOULD CONTINUE INTO
EARLY EVENING...BEFORE COLD SURFACE RIDGE NOSES INTO THE WESTERN
GULF COAST.

IN RESPONSE TO DEVELOPMENTS IN THE UPSTREAM UPPER FLOW...MODELS
SUGGEST LOW-LEVEL WARM ADVECTION WILL INCREASE ABOVE FRONTAL
INVERSION LATE THURSDAY NIGHT...FROM PARTS OF THE TEXAS HILL COUNTRY
INTO THE TEXAS SOUTH PLAINS.  ELEVATED MOISTURE RETURN AND
STEEPENING MID-LEVEL LAPSE RATES MAY CONTRIBUTE TO ENOUGH CAPE FOR 
AT LEAST MARGINAL SEVERE HAIL POTENTIAL TOWARD 12Z FRIDAY.

...LOWER OHIO VALLEY...
MODELS CONTINUE TO SUGGEST ENOUGH DESTABILIZATION WILL OCCUR WITH
POLAR TROUGH BY THURSDAY AFTERNOON FOR RISK OF WEAK THUNDERSTORM
ACTIVITY.  THIS SEEMS MOST LIKELY NEAR/JUST SOUTHEAST OF SURFACE
LOW...FROM PARTS OF SOUTHEASTERN INDIANA INTO SOUTHERN OHIO...NEAR
OR SHORTLY AFTER PEAK DAYTIME HEATING.

...PACIFIC NORTHWEST...
POTENTIAL FOR ISOLATED THUNDERSTORMS WILL EXIST THURSDAY AFTERNOON
AND EVENING AS COLD MID-LEVEL CIRCULATION...WITHIN DEVELOPING LARGER
SCALE TROUGH...PROGRESSES INTO WESTERN WASHINGTON.

..KERR.. 03/15/2006