SWODY1
SPC AC 040547
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1147 PM CST THU MAR 03 2011
VALID 041200Z - 051200Z
...THERE IS A SLGT RISK OF SVR TSTMS ERN OK...WRN/CNTRL AR...SWRN
MO...
...SYNOPSIS...
AN UPPER-LEVEL SHORTWAVE TROUGH INITIALLY LOCATED OVER THE ROCKY
MTNS WILL AMPLIFY SLIGHTLY AND SLOWLY TRANSLATE EWD INTO THE CNTRL
CONUS. AN ASSOCIATED COLD FRONT WILL PROGRESS INTO THE SRN GREAT
PLAINS AND MS RIVER VALLEY...WHILE MODEST LOW LEVEL GULF MOISTURE
RETURN OCCURS AHEAD OF THIS FEATURE. THUNDERSTORM ACTIVITY IS
EXPECTED TO INCREASE ALONG AND AHEAD OF THE COLD FRONT THIS
AFTERNOON ACROSS THE SERN GREAT PLAINS INTO SWRN MO AND WRN
AR...SPREADING INTO CNTRL/E TX AND THE LOWER MS RIVER VALLEY AFTER
DARK.
...ERN OK...WRN/CNTRL AR...SWRN MO...
A WEAKLY UNSTABLE ENVIRONMENT WILL DEVELOP THIS AFTERNOON ACROSS ERN
OK AND SWRN MO AS SFC DEW POINTS IN THE MID 50S-LOW 60S ADVECT
NWD...WHILE A PLUME OF STEEP MIDLEVEL LAPSE RATES /7-8 DEG C PER KM/
SPREADS INTO THE REGION. ALTHOUGH THE STRONGEST MIDLEVEL FORCING IS
EXPECTED TO REMAIN FOCUSED W OF THE AREA IN CLOSER PROXIMITY TO THE
UPPER TROUGH...LOW LEVEL CONVERGENCE ALONG THE SEWD SAGGING COLD
FRONT SHOULD BE SUFFICIENT TO INITIATE THUNDERSTORM ACTIVITY ACROSS
NERN OK AND SERN MO...WHERE LITTLE TO NO CINH WILL BE PRESENT. OVER
SERN OK...A MORE CONDITIONAL THREAT MAY EXIST DUE TO THE PRESENCE OF
A WEAK INVERSION LAYER /AROUND 700 MB PER POINT FORECAST
SOUNDINGS/...WITH ANY CONVECTION LIKELY DELAYED UNTIL AFTER
21Z...DESPITE THE PRESENCE OF STEEPER MIDLEVEL LAPSE RATES OVERHEAD.
THUNDERSTORM MODES SHOULD INITIALLY FAVOR QUASI-DISCRETE CELLS AND
SMALL LINE SEGMENTS...AND GIVEN DEEP-LAYER SHEAR AROUND 40 KTS...THE
POTENTIAL FOR ROTATING STORMS CAPABLE OF PRODUCING ISOLATED DMGG
WIND GUSTS AND SEVERE HAIL WILL EXIST. ADDITIONALLY...THUNDERSTORM
DEVELOPMENT MAY OCCUR WITHIN A WEAK PRE-FRONTAL LOW LEVEL WAA REGIME
ACROSS FAR ERN OK INTO THE WRN HALF OF AR...WHERE 0-1 KM SRH VALUES
EXCEEDING 300 M^2/S^2 SHOULD YIELD A LOW POTENTIAL FOR AN ISOLATED
TORNADO /DESPITE MARGINAL CONVECTIVE INSTABILITY/. THIS ACTIVITY
WILL SHIFT SEWD INTO WRN AND CNTRL AR AFTER 04Z...WITH THE THREAT
FOR SVR WINDS/HAIL DIMINISHING SOMEWHAT AS INSTABILITY WEAKENS WITH
THE LOSS OF DIURNAL HEATING.
...CNTRL/E TX...
THUNDERSTORM DEVELOPMENT IS FORECAST TO OCCUR LATE IN THE PERIOD AS
INCREASING MIDLEVEL DCVA BECOMES JUXTAPOSED WITH LOW-LEVEL FRONTAL
CONVERGENCE. NAM POINT FORECAST SOUNDINGS INDICATE ANY CONVECTION
WILL BE ELEVATED IN NATURE /WITH PARCELS ROOTED NEAR 850 MB/...BUT
STEEP MIDLEVEL LAPSE RATES WILL YIELD MUCAPE VALUES OF 1200-1500
J/KG...AND A SUBSEQUENT LOW POTENTIAL FOR LARGE HAIL.
..ROGERS/DARROW.. 03/04/2011
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