SWODY1
SPC AC 121252
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT SAT MAY 12 2007
VALID 121300Z - 131200Z
..THERE IS A SLGT RISK OF SVR TSTMS FROM INTERIOR PARTS OF THE PAC
NW INTO THE NRN HI PLNS...
..SYNOPSIS...
RCKYS RIDGE WILL EXPAND E INTO THE CNTRL/NRN PLNS THIS PERIOD AS
TROUGH AMPLIFIES OVER THE LWR GRT LKS/NERN STATES...AND WEAK TROUGH
FURTHER ELONGATES FROM CNTRL TX INTO THE NRN GULF. IN THE WEST...
SYSTEM NOW APPROACHING THE ORE CST SHOULD CONTINUE NE INTO THE LWR
COLUMBIA VLY TODAY...BEFORE TURNING MORE ENE INTO ERN WA TONIGHT/
EARLY SUNDAY.
AT THE SFC...COLD FRONT WILL SETTLE S ACROSS THE OH VLY AND MID
ATLANTIC REGION. WRN PART OF SAME BOUNDARY SHOULD EDGE NE ACROSS
ERN MT AND THE WRN DAKOTAS AS LEE LOW DEVELOPS DOWNSTREAM FROM
ORE/WA TROUGH. FARTHER W...PACIFIC COLD FRONT ASSOCIATED WITH
AFOREMENTIONED UPR IMPULSE SHOULD CLEAR ERN ORE/WA LATE TODAY...AND
CONTINUE E ACROSS ID TONIGHT.
..INTERIOR PAC NW/NRN RCKYS/NRN HI PLNS...
SHORTWAVE RIDGING AHEAD OF ORE/WA DISTURBANCE WILL PREVAIL OVER THE
NRN RCKYS THROUGH MUCH OF THE DAY TODAY...LIMITING LARGE SCALE
FORCING FOR ASCENT. BUT HEIGHT FALLS WILL SPREAD SLOWLY E ACROSS
ORE/WA TOWARD ID/WRN MT THIS AFTERNOON/EARLY EVENING. COUPLED WITH
MODERATE TO STRONG SFC HEATING AND OROGRAPHIC UPLIFT...SETUP
SHOULD SUPPORT DEVELOPMENT OF SCTD LATE AFTN/EVE STORMS ALONG AND
AHEAD OF PACIFIC COLD FRONT FROM NE ORE INTO CNTRL ID AND WRN MT.
DEEP 40+ KT UNIDIRECTIONAL SSWLY FLOW AHEAD OF UPR IMPULSE WILL
PROVIDE SUFFICIENT DEEP SHEAR FOR ORGANIZED/SUSTAINED ACTIVITY
..WHERE THERMODYNAMICS APPEAR FAVORABLE FOR LOCALLY DAMAGING WIND
AND SEVERE HAIL. ADDITIONAL STORMS...SOME POSSIBLY WITH
HAIL...COULD FORM IN POST-FRONTAL ENVIRONMENT TONIGHT/EARLY SUNDAY
OVER ERN WA/NRN ID AND NRN MT.
..ERN MT/WRN SD...
SFC HEATING WILL STEEPEN LOW LEVEL LAPSE RATES AND CONTRIBUTE TO
LARGE CAPE INVOF WARM FRONT FROM ERN MT INTO SD. BUT INCREASING CIN
ASSOCIATED WITH AMPLIFYING UPR RIDGE EXPECTED TO PRECLUDE SFC-BASED
STORM DEVELOPMENT. ALTHOUGH SCTD ELEVATED ACTIVITY LIKELY WILL
PERSIST NE OF FRONT OVER SD AND PARTS OF ND/MN THROUGH THE PERIOD...
RELATIVELY LIMITED MOISTURE SUPPLY AND...THEREFORE...CAPE...SUGGEST
THAT ANY SEVERE THREAT WILL BE MINIMAL.
..E TX THROUGH THE SERN STATES INTO THE MID ATLANTIC REGION...
SCTD DIURNAL TSTMS WILL FORM FROM THE APPALACHIANS SWD
INTO FL AND W INTO TX...WHERE POCKETS OF 500 TO 1500 J/KG
MLCAPE WILL DEVELOP ON FRINGES OF WEAK UPR TROUGH. THE GREATEST
DESTABILIZATION IS EXPECTED OVER THE CAROLINAS...THE LWR TN VLY AND
CNTRL FL. WEAK UPR FLOW IN THESE AREAS SHOULD PRECLUDE AN ORGANIZED
SEVERE THREAT...BUT PULSE STORMS COULD YIELD ISOLATED HAIL/WIND.
STORM COVERAGE IN FL MAY BE LIMITED BY LARGE SCALE SUBSIDENCE
BETWEEN GULF TROUGH AND HYBRID SYSTEM OFF THE FL E CST.
FURTHER N...MODERATE /30 KT/ WNW MID LEVEL FLOW WILL PREVAIL OVER
THE MD/VA AREA AHEAD OF AMPLIFYING UPR TROUGH...WHERE SFC HEATING
MAY BOOST SBCAPE TO NEAR 1000 J/KG. WHILE A CLUSTER OR TWO OF
STRONG DIURNAL STORMS MAY DEVELOP...SEVERE THREAT SHOULD REMAIN
LIMITED GIVEN WEAK LOW LEVEL FLOW/CONVERGENCE.
.CORFIDI/TAYLOR.. 05/12/2007
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