[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 100557
SWODY1
SPC AC 100556

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT TUE OCT 10 2006

VALID 101200Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF CNTRL INTO ERN
TX INTO WRN LA...

...SYNOPSIS...

OPENING MID-LEVEL TROUGH ALONG THE AZ/NM BORDER IS FORECAST TO
DE-AMPLIFY THROUGH THE PERIOD AS IT RAPIDLY TRANSLATES NEWD INTO THE
MID MS VALLEY. AS THIS OCCURS...A STRONG SUBTROPICAL JET WILL
BECOME ESTABLISHED FROM THE SWRN DESERTS TO THE LOWER MS VALLEY.  IN
THE LOW-LEVELS...SURFACE LOW ATTENDANT TO WEAKENING UPPER SYSTEM
WILL DEVELOP NEWD FROM SWRN OR W-CNTRL TX INTO SRN MO BY LATE
TONIGHT WITH TRAILING COLD FRONT PUSHING EWD THROUGH CNTRL/ERN TX.

...CNTRL/ERN TX INTO WRN LA...

A COMPLEX FORECAST EXISTS OWING TO THE LIKELIHOOD OF AN ONGOING MCS
OVER CNTRL TX AT THE ONSET OF THE FORECAST PERIOD...AND ITS EFFECTS
ON AIR MASS DESTABILIZATION AND EVENTUAL FRONTAL MOVEMENT.  10/00Z
SOUNDINGS FROM THE TX COAST INDICATE THAT A MOIST LOW-LEVEL AIR MASS
HAS MOVED ONSHORE WITH LOWEST MEAN MIXING RATIOS OF AROUND 16 G/KG. 
CURRENT SURFACE OBSERVATIONS AND GOES GPS DATA SHOW THIS MOISTURE
ADVECTING NWD INTO CNTRL TX ALONG ERN EDGE OF LLJ BECOMING
ESTABLISHED OVER WRN TX.

AS MENTIONED ABOVE...STORM CLUSTERS OR AN MCS WILL LIKELY BE ONGOING
10/12Z OVER THE EDWARDS PLATEAU REGION...DRIVEN LARGELY BY LOW-LEVEL
WAA REGIME AHEAD OF WEAKENING MID-LEVEL TROUGH.  CONSIDERABLE CLOUDS
AND PRECIPITATION SHOULD LIMIT LAPSE RATES TO NEAR MOIST ADIABATIC
WITH INCREASING BOUNDARY-LAYER MOISTURE LARGELY CONTRIBUTING TO AIR
MASS DESTABILIZATION WITH MLCAPES OF 500-1000 J/KG EXPECTED.  AS
SUCH...SOME DIURNAL WEAKENING OF MCS MAY OCCUR DURING THE
MORNING...PRIOR TO STORMS INTENSIFYING BY AFTERNOON OVER CNTRL TX
SWD TOWARD THE MIDDLE TX COAST.

VERTICAL SHEAR PROFILES WILL BECOME INCREASINGLY SUPPORTIVE OF
SUPERCELLS/BOWING STRUCTURES CAPABLE OF MAINLY DAMAGING WINDS AND A
FEW TORNADOES OWING TO PERSISTENT LOW-LEVEL WAA PATTERN COUPLED WITH
INTENSIFYING SUBTROPICAL JET.  ACTIVITY SHOULD MOVE/DEVELOP EWD INTO
LA TONIGHT...WITH A CONTINUED THREAT OF ISOLATED DAMAGING WINDS AND
PERHAPS A TORNADO OR TWO NEAR AND E OF THE SABINE RIVER VALLEY.

FARTHER TO THE N OVER NERN TX INTO SERN OK AND SWRN AR...IT APPEARS
THAT INSTABILITY WILL REMAIN QUITE LIMITED SHOULD MCS PERSIST ACROSS
CNTRL/ERN TX AS IS BEING FORECAST.  SHEAR PROFILES WILL BE
SUPPORTIVE OF ORGANIZED...SEVERE STORMS...HOWEVER THE DEGREE OF
INSTABILITY REMAINS IN QUESTION ATTM.

..MEAD/GRAMS.. 10/10/2006