Tuesday, May 15, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 151258
SWODY1
SPC AC 151256

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0756 AM CDT TUE MAY 15 2007

VALID 151300Z - 161200Z

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE OZARKS/MID MS VLY E/NE
INTO CNTRL NEW ENGLAND...

..SYNOPSIS...
WRN RIDGE/GRT LKS TROUGH PATTERN WILL PREVAIL THIS PERIOD...WITH
SOME AMPLIFICATION EXPECTED OVER THE CNTRL AND ERN STATES. LEAD
IMPULSE WITH GRT LKS SYSTEM HAS BECOME ABSORBED IN CONFLUENT FLOW
OVER LK HURON/GEORGIAN BAY...BUT WILL SERVE TO STRENGTHEN DEEP WLY
FLOW ACROSS THE LWR GRT LKS/NEW ENGLAND. FARTHER W...SATELLITE AND
VWP DATA SHOW AN UPSTREAM IMPULSE NOW CROSSING SD/NEB...AND A
STRONGER FEATURE DROPPING SE INTO ACROSS MANITOBA. TOGETHER THESE
TWO DISTURBANCES WILL SLOW EWD PROGRESSION OF LARGER SCALE TROUGH
OVER THE LAKES...AND WILL DISPLACE STRONGEST MID-LEVEL COOLING/
ASCENT WWD AWAY FROM GREATEST LOW LEVEL DESTABILIZATION OVER THE UPR
OH VLY/NORTHEAST.

AT LOWER LEVELS...ELONGATED SFC WAVE EXPECTED TO RIPPLE E ALONG
STATIONARY FRONT INTO NRN NEW ENGLAND LATER TODAY...WHILE TRAILING
COLD FRONT SETTLES FARTHER SE INTO THE PLNS/MID MS VLY. A NEW SFC
WAVE SHOULD EVOLVE OVER SE LWR MI OR SW ONTARIO TONIGHT/EARLY
WEDNESDAY AS UPR TROUGH AMPLIFIES. THE LOW SHOULD REACH THE
BUIF/ROC AREA BY THE END OF THE PERIOD.

..OZARKS NE INTO THE LWR GRT LKS/NEW ENGLAND...
MODERATE DESTABILIZATION SHOULD OCCUR IN WARM SECTOR FROM THE OZARKS
NE INTO MI AND THE LWR GRT LKS. WHILE BOUNDARY LAYER MOISTURE WILL
REMAIN MODEST BY MAY STANDARDS...STRONG HEATING WITH DEWPOINTS IN
THE 50S TO LOW 60S SHOULD YIELD SBCAPE AOA 1000 J/KG FROM IL INTO
THE UPR OH VLY. MORE APPRECIABLE MOISTURE MAY YIELD GREATER
INSTABILITY IN THE OZARKS...WHERE SBCAPE COULD APPROACH 2000 J/KG.

SCTD AREAS OF ONGOING STORMS FROM OK/KS INTO IL ARE BEING DRIVEN
MAINLY BY COLD POOL/FRONTAL UPLIFT. THEY SHOULD PERSIST THROUGH
MIDDAY AND MAY POSE AN OCCASIONAL RISK FOR MARGINALLY SVR HAIL.

THESE STORMS...AND ADDITIONAL ACTIVITY LIKELY TO FORM ALONG/AHEAD OF
COLD FRONT...SHOULD STRENGTHEN WITH AFTERNOON HEATING. POSITIVE
TILT TO AMPLIFYING UPR SYSTEM WILL KEEP STRONGEST LIFT/DEEP SHEAR
DISPLACED LARGELY W OF GREATEST SFC HEATING. SUFFICIENT DEEP SHEAR
WILL NEVERTHELESS BE PRESENT IN IL/IND AND LWR MI TO SUPPORT
ORGANIZATION INTO LINES. DEEP...LARGELY UNIDIRECTIONAL WSW FLOW AND
RELATIVELY LARGE T/TD SPREADS IN THIS REGION MAY SUPPORT BOWING
SEGMENTS WITH LOCALLY DAMAGING WIND/MARGINALLY SVR HAIL. SOME OF
THIS ACTIVITY COULD REACH WRN/NRN OH BY LATE IN THE DAY AND PERSIST
INTO THE NIGHT S/E INTO THE OH VLY. FARTHER S... MORE SUBSTANTIAL
CAPE AND WEAKER SHEAR LIKELY WILL YIELD MULTICELL CLUSTERS WITH A
THREAT FOR BOTH WIND AND HAIL. ISOLATED PULSE STORMS MAY EXTEND S
INTO LA.

OTHER STORMS EXPECTED TO FORM THIS AFTERNOON AND TONIGHT ALONG W-E
STATIONARY FRONT FROM UPSTATE NY INTO CNTRL NEW ENGLAND. WHILE CAPE
WILL BE MORE LIMITED RELATIVE TO POINTS FARTHER SW...40-50 KT DEEP
WLY SHEAR PARALLEL TO BOUNDARY SUGGESTS POSSIBILITY FOR A FEW
SUSTAINED STORMS/POSSIBLE SUPERCELLS WITH WIND/HAIL AND POSSIBLY A
TORNADO.

..SRN RCKYS INTO FAR W TX...
LOW LEVEL MOISTURE WILL CONTINUE TO SPREAD WWD IN WAKE OF COLD FRONT
MOVING S ACROSS ERN NM. WHILE MID LEVEL LAPSE RATES WILL BE
MODEST...COMBINATION OF UPSLOPE FLOW WITH SFC HEATING SHOULD SUPPORT
DEVELOPMENT OF SCTD STRONG DIURNAL STORMS. WEAK /20 KT/ WNWLY
MID-LEVEL FLOW MAY PROVE SUFFICIENT FOR A FEW SUSTAINED/ POSSIBLY
WEAKLY-ROTATING CELLS WITH HAIL/LOCALLY DAMAGING WIND. THESE MAY
CONSOLIDATE INTO ONE OR TWO CLUSTERS THAT LINGER INTO EARLY
WEDNESDAY.

..S FL...
ENVIRONMENT APPEARS TO HAVE BECOME MORE DEEPLY MARITIME ACROSS S FL
TODAY...ALTHOUGH WV IMAGERY DEPICTS CONTINUING PRESENCE OF
ELONGATING UPR TROUGH/SHEAR AXIS. ELY LWR-TROPOSPHERIC
FLOW SHOULD ONCE AGAIN FOCUS STRONGEST CONVERGENCE ALONG W CST SEA
BREEZE FRONT...WHERE A FEW PULSE SVR STORMS APPEAR POSSIBLE.

.CORFIDI/CROSBIE.. 05/15/2007

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