[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 041719
SWODY2
SPC AC 041718

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1118 AM CST SAT MAR 04 2006

VALID 051200Z - 061200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A PROMINENT SHORT WAVE TROUGH...NOW CENTERED OVER ID PER WATER VAPOR
IMAGERY...IS EXPECTED TO TRACK SLOWLY EWD ACROSS THE DAKOTAS/SRN
CANADA ON SUNDAY AS IT TOPS THE CENTRAL STATES RIDGE.  THIS TROUGH
IS THEN PROGGED TO TURN SEWD TOWARD THE WRN GREAT LAKES LATE DAY
2...AS THE RIDGE RE-AMPLIFIES IN ITS WAKE.  THE SRN EXTENT OF THIS
TROUGH COMBINED WITH WEAKER/LOW AMPLITUDE PACIFIC WAVES SHOULD
TRANSLATE EWD ACROSS THE CENTRAL/SRN PLAINS TOWARD THE OH/TN RIVER
VALLEYS AND DEEP SOUTH.  IN THE LOW-LEVELS...A FRONT ASSOCIATED WITH
THE NRN SYSTEM SHOULD MOVE QUICKLY EWD ACROSS THE MID MS AND OH/TN
RIVER VALLEYS...REACHING OH INTO ERN KY/TN TO NRN MS BY 12Z MONDAY. 
THE SRN EXTENT OF THIS BOUNDARY WILL LIKELY MOVE AT A SLOWER PACE
ACROSS OK/AR INTO NRN TX. 

MEANWHILE...A PACIFIC TROUGH /CURRENTLY LOCATED SEVERAL HUNDRED
MILES OFF THE CA/ORE COASTS NEAR 140W/ IS EXPECTED TO MOVE INLAND
OVER THE WRN STATES DURING THE SECOND HALF OF DAY 2.  OFFSHORE
THUNDERSTORM THREAT SHOULD INCREASE LATE SUNDAY AFTERNOON...AND THEN
ALONG THE COASTAL REGIONS OF NRN CA TO WA AS A STEEPER LAPSE RATE
ENVIRONMENT SPREADS INLAND WITH THE PACIFIC TROUGH.

...ERN OK/WRN AR/NERN TX/NWRN LA...
SLY LOW-LEVEL FLOW...THOUGH VEERING WITH TIME AND LIMITING
CONVERGENCE ALONG THE FRONT...IS EXPECTED TO MAINTAIN MOISTURE
RETURN ACROSS THE ARKLATEX INTO LOWER/MID MS RIVER VALLEY.  SURFACE
DEWPOINTS IN THE UPPER 50S/LOWER 60S COMBINED WITH MODEST LAPSE
RATES /6.5-7 C/KM/ AND SOME SURFACE HEATING SHOULD RESULT IN AN AXIS
OF MODERATE INSTABILITY FROM NERN TX INTO PARTS OF ERN OK/WRN AR BY
SUNDAY AFTERNOON.

LATE DAY 1 THUNDERSTORMS SHOULD BE ONGOING AT THE START OF DAY 2
ACROSS SERN NEB/ERN KS AND POTENTIALLY ERN OK IN ASSOCIATION WITH
WAA REGIME ALONG THE NOSE OF LLJ.  THESE ELEVATED STORMS MAY WEAKEN
SOME DURING THE MORNING AND/OR GRADUALLY INCREASE IN COVERAGE AGAIN
ALONG THE NRN EXTENT OF MOISTURE RETURN AND WAA WITH THE VEERING LLJ
ACROSS MO/PARTS OF AR INTO THE LOWER OH/TN RIVER VALLEYS.  WEAK
INSTABILITY IS PROGGED TO PRECLUDE A SEVERE THREAT WITH THIS
ACTIVITY.

DESPITE WEAKER LARGE SCALE FORCING FARTHER TO THE SW OVER THE
ARKLATEX REGION...STRONGER AFOREMENTIONED INSTABILITY ACROSS THIS
AREA AND STRONG DEEP LAYER SHEAR WOULD SUPPORT A POTENTIAL FOR
ORGANIZED STORMS/SEVERE THREAT.  MODELS SUGGEST SURFACE HEATING
ALONG THE WRN/SRN PERIPHERY OF CLOUD SHIELD ASSOCIATED WITH ELEVATED
CONVECTION MAY BECOME SUFFICIENT TO WEAKEN THE CAP FOR SURFACE BASED
STORMS LATE SUNDAY AFTERNOON ACROSS WRN AR/ERN OK INTO NERN TX. 
GIVEN THIS TREND FOR THE DEVELOPMENT OF STRONGER INSTABILITY AND
CONDITIONAL POTENTIAL FOR SURFACE BASED STORMS...LOW SEVERE
PROBABILITIES WILL BE INTRODUCED WITH THIS OUTLOOK.  HIGHER
PROBABILITIES AND CATEGORICAL RISK MAY BE REQUIRED IN LATER
OUTLOOKS...IF CONFIDENCE BECOMES GREATER FOR WIDESPREAD THREAT OF
ORGANIZED STORMS/SEVERE THREAT.

..PETERS.. 03/04/2006