SWODY1
SPC AC 111258
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 AM CDT MON AUG 11 2008
VALID 111300Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND NRN
PLNS...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF NJ...NY AND NEW
ENG...
...SYNOPSIS...
RIDGE WILL PERSIST OVER THE SWRN U.S. THIS PERIOD WHILE LARGELY
CYCLONIC FLOW PREVAILS FROM THE NRN RCKYS AND PLNS E/SE ACROSS THE
REMAINDER OF THE U.S. MORE SPECIFICALLY...AB UPR LOW EXPECTED TO
CONTINUE E INTO SRN SK...WHILE PA UPR LOW GRADUALLY OPENS AND MOVES
E/NE TO NEAR CAPE COD. BETWEEN THOSE TWO SYSTEMS...A SERIES OF
WEAKER DISTURBANCES WILL TRACK GENERALLY ESE IN DIFFLUENT FLOW OVER
THE PLNS AND MS VLY.
FEATURES WILL REMAIN FAIRLY WEAK AT THE SFC. LOW NOW ALONG THE NJ
CST SHOULD EDGE SLOWLY E/NE TODAY/TONIGHT...REACHING CAPE COD BY THE
END OF THE PERIOD. WEAK COLD FRONT TRAILING SW FROM THE LOW WILL
SETTLE FARTHER S ACROSS THE GULF CST STATES...AND EVENTUALLY MERGE
WITH WEAK BOUNDARY EXTENDING ESE FROM N TX SFC WAVE. FARTHER
N...COLD FRONT IN THE WRN DAKS WILL CONTINUE SLOWLY E/SE...FURTHER
OVERTAKING LEE TROUGH AND ASSOCIATED LOW IN WRN SD.
...NRN/CNTRL PLNS TO SRN HI PLNS...
ELEVATED STORMS WILL PERSIST THROUGH THE DAY IN WAA ZONE OVER THE
ERN DAKS AS WEAKENING UPR IMPULSE CONTINUES E INTO DIFFLUENT UPR
FLOW. AIR MASS RECOVERY IN WAKE OF THIS ACTIVITY...UPLIFT ALONG
COLD FRONT/LEE TROUGH...AND UVV ASSOCIATED WITH NEXT DISTURBANCE
ROUNDING BASE OF AB/SK TROUGH LIKELY TO RESULT IN SCTD TSTMS ALONG
THE FRONT AND LEE TROUGH FROM SD INTO NEB AND PERHAPS SE WY/NE CO/NW
KS BY MID TO LATE AFTN.
COMBINATION OF FAIRLY STEEP MID LVL LAPSE RATES WITH STRONG SFC
HEATING AND SFC DEWPOINTS IN THE UPR 50S TO MID 60S F SHOULD YIELD
SBCAPE OF 1000-2000 J/KG. COUPLED WITH 30-35 KT DEEP WNW SHEAR
ASSOCIATED WITH BAND OF SLIGHTLY ENHANCED FLOW ON NERN FRINGE OF
UPR RIDGE...SETUP SHOULD SUPPORT BOTH SUPERCELLS AND MULTICELLS WITH
SVR HAIL AND HIGH WIND THROUGH EARLY EVE.
SLY LLJ SHOULD VEER TO W OR WSWLY OVER THE CNTRL PLNS TONIGHT IN
RESPONSE TO BOTH THE DIURNAL CYCLE AND CONTINUED EWD ADVANCE OF LEAD
UPR IMPULSE. AS A RESULT...ENHANCED WAA LIKELY WILL FOSTER
OVERNIGHT STORM CLUSTERS EWD ACROSS ERN NEB INTO IA AND MN. MODEST
DEGREE OF ELEVATED INSTABILITY SHOULD LIMIT SVR THREAT WITH THESE
STORMS...ALTHOUGH ISOLD MARGINALLY SVR HAIL MAY OCCUR.
FARTHER S...OTHER...MAINLY DIURNAL STORMS EXPECTED INVOF HIGHER
TERRAIN AND ALONG LEE TROUGH FROM SE CO INTO ERN NM. MODERATE
INSTABILITY /SBCAPE TO 1500 J PER KG/ AND 25-30 KT DEEP NWLY SHEAR
COULD SUPPORT A FEW ORGANIZED STRONG/BRIEFLY SVR STORMS...BUT
OVERALL THREAT SHOULD REMAIN LIMITED IN SPACE/TIME.
...WRN/CNTRL/NRN TX TO ARKLATEX/LWR MS VLY...
NUMEROUS AFTN/EVE STORMS EXPECTED TO FORM IN WEAKLY-CAPPED
ENVIRONMENT OVER PARTS OF TX AND LA...S OF WEAK FRONT/OUTFLOW
BOUNDARY OVER THE RED RVR VLY. MID LVL LAPSE RATES WILL BE WEAK
/500 MB TEMPS AROUND MINUS 5 C/...AND MID LVL WNW FLOW WILL REMAIN
MODEST /AOB 25 KT/. BUT PW VALUES WILL BE HIGH...ESPECIALLY ACROSS
NRN/ERN TX AND LA...AND SIZABLE TEMP-DEW POINT SPREADS WILL EXIST IN
WRN/CNTRL TX. IN ADDITION...SOME DEGREE OF LARGE SCALE FORCING FOR
ASCENT WILL BE PRESENT FROM /1/ WEAK DISTURBANCES IN SRN STREAM FLOW
AND/OR /2/ FROM MCV LEFT BY OVERNIGHT CONVECTIVE SYSTEM IN W TX.
SUCH A SETUP APPEARS FAVORABLE FOR THE DEVELOPMENT OF SUSTAINED
CLUSTERS OF STORMS...SOME OF WHICH COULD YIELD ISOLD WET MICROBURSTS
OR OTHER FORMS OF LOCALLY DMGG WIND...IN ADDITION TO HEAVY RAIN.
GRADUAL AMPLIFICATION OF SRN STREAM FLOW AND ASSOCIATED SFC
WAVE/SWLY LLJ SUGGEST THAT STORMS CLUSTERS WILL REMAIN STRONG
THROUGH EARLY TUESDAY FROM E TX EWD INTO LA/MS.
...SERN NY INTO ERN PA/NJ AND SRN NEW ENG...
PRESENCE OF UNUSUALLY COOL UPR LOW AND RESIDUAL LOW LVL MOISTURE
WILL CREATE MODERATELY UNSTABLE CONDITIONS /SBCAPE TO 1500 J PER KG/
OVER PARTS OF THE MID ATLANTIC AND SRN NEW ENGLAND STATES THIS AFTN.
PATH OF UPR SYSTEM WILL KEEP STRONGEST MID LVL FLOW AWAY FROM
OVERLAND REGION OF LOW LVL DESTABILIZATION. ALTHOUGH SETUP MAY
YIELD A FEW SUSTAINED/WEAKLY ORGANIZED STORMS WITH HAIL...
ESPECIALLY FROM THE LWR HUDSON VLY OF NY INTO CT...OVERALL SVR
THREAT SHOULD BE LIMITED BY WEAK SHEAR AND LIKELIHOOD FOR
DESTRUCTIVE INTERFERENCE BETWEEN STORMS.
..CORFIDI/HURLBUT.. 08/11/2008
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