SWODY1
SPC AC 241300
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0800 AM CDT SUN OCT 24 2010
VALID 241300Z - 251200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM CNTRL/E TX INTO PARTS OF
THE LWR AND MID MS AND TN VLYS...
...SYNOPSIS...
WITHIN BROAD...SLOWLY PROGRESSIVE LARGE SCALE TROUGH OVER THE CNTRL
U.S...SATELLITE DATA SHOWS A SHORTWAVE IMPULSE AMPLIFYING SE ACROSS
ERN NM/W TX ATTM. THIS FEATURE SHOULD CONTINUE ESE ACROSS CNTRL AND
E TX LATER TODAY...BEFORE TURNING E/NE ACROSS THE LWR MS/TN VLYS
TONIGHT/EARLY MON.
AT THE SFC...NW IA LOW SHOULD WEAKEN AS IT MOVES ENE INTO WI WITH
ITS ASSOCIATED UPR VORT. WEAK COLD FRONT/WIND SHIFT EXTENDING SSW
FROM THE LOW INTO THE SRN PLNS WILL ADVANCE E/SE ACROSS THE ERN
PORTIONS OF THE CNTRL/SRN PLNS AND THE MID MS VLY...PRECEDED BY A
N/S CONFLUENCE ZONE OVER E TX/LA.
...E TX INTO LWR MS/TN VLYS/GULF CST...
PERSISTENT LOW LVL SLY FLOW AHEAD OF AMPLIFYING SHORTWAVE IMPULSE
WILL MAINTAIN MOISTURE RETURN ALREADY IN PROGRESS ACROSS E TX AND
THE LWR MS VLY TODAY...WITH SFC DEWPOINTS IN THE MID TO UPR 60S F
EXPECTED OVER REGION BY LATE IN THE DAY.
LOW LVL CONVERGENCE SHOULD REMAIN WEAK...MOST LIKELY FOCUSED ALONG
AFOREMENTIONED WIND SHIFT LINE...ALONG E TX/LA AXIS OF
CONFLUENCE...AND/OR ALONG RESIDUAL OUTFLOW BOUNDARY FROM YESTERDAY'S
MCS. BUT COMBINATION OF SFC HEATING AND MID LVL COOLING/ASCENT WITH
UPR IMPULSE EXPECTED TO YIELD FAIRLY SUBSTANTIAL INSTABILITY /SBCAPE
AOA 2000 J PER KG/...SUPPORTING ISOLD TO SCTD SVR TSTM DEVELOPMENT
FROM E CNTRL TX NEWD INTO PARTS OF AR/LA BY LATE IN THE DAY. ISOLD
STORMS ALSO MAY FORM ALONG THE CNTRL GULF CST...NEAR SHALLOW WARM
FRONTAL SEGMENT/ MOISTURE GRADIENT. THE TSTMS SHOULD CONTINUE TO
DEVELOP AND SPREAD E/NE ACROSS THE GULF CST STATES AND LWR MS/TN
VLYS TONIGHT/EARLY MON AS UPR TROUGH CONTINUES NEWD AND LOW LVL FLOW
STRENGTHENS/VEERS ACROSS REGION.
STEEP MID LVL LAPSE RATES...INCREASINGLY RICH MOISTURE...AND LIKELY
SUPERCELLULAR STORM MODE GIVEN 40-50 KT DEEP SHEAR TOGETHER SUGGEST
GOOD CHANCE FOR LARGE HAIL...ESPECIALLY OVER E TX AND THE ARKLATEX.
TORNADOES AND SMALL BOWING SEGMENTS WITH HIGH WIND ALSO WILL BE
POSSIBLE. DESPITE LOW LVL STABILIZATION AFTER SUNSET...IT APPEARS
THAT A SVR THREAT WILL PERSIST THROUGH EARLY MONDAY...ESPECIALLY
OVER THE CNTRL GULF CST STATES/LWR TN VLY.
...MID MS VLY...
WEAKER LARGE SCALE ASCENT/INSTABILITY WILL EXIST ACROSS THE MID MS
VLY RELATIVE TO POINTS SOUTH. BUT AT LEAST ISOLD TO WDLY SCTD
STORMS APPEAR POSSIBLE BY LATE AFTN OVER PARTS OF ERN MO...
CNTRL/NRN IL...AND POSSIBLY NW INDIANA...WHERE MODERATE INSTABILITY
/SBCAPE AOA 500 J PER KG/ SHOULD DEVELOP BENEATH ERN FRINGE OF LARGE
SCALE UPR TROUGH. THESE COULD YIELD SVR HAIL...ISOLD DMGG WIND AND
A COUPLE TORNADOES THROUGH EARLY TONIGHT.
...PACIFIC NW...
POWERFUL /150+ KT/ WLY JET STREAK WILL SWEEP E ACROSS ORE TODAY AS
ASSOCIATED EXIT REGION OVERSPREADS NRN ORE/WA. COOLING ALOFT ON
POLEWARD SIDE OF JET...AND ASSOCIATED ASCENT/DEEP CYCLONIC UPSLOPE
FLOW SHOULD SUPPORT SCTD TSTMS NOT ONLY ALONG THE CST BUT E INTO THE
NRN GRT BASIN/NRN RCKYS. WITH SBCAPE APPROACHING 500 J/KG ALONG THE
ORE/WA CST AND THE LWR COLUMBIA RVR VLY...SETUP MAY YIELD BOWING
SEGMENTS WITH LOCALLY DMGG WIND AND POSSIBLY A BRIEF TORNADO OR TWO
LATER TODAY.
..CORFIDI/GRAMS.. 10/24/2010
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