SPC AC 300059
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CDT WED APR 29 2009
VALID 300100Z - 301200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CNTRL/SRN PLNS...
....CNTRL/SRN HIGH PLNS...
00Z UPR AIR ANALYSIS SUGGESTS STRONGEST SUPPORT FOR SVR THREAT
THROUGH LATE EVE WILL EXIST ACROSS THE CNTRL/ERN TX PNHDL INTO NWRN
TX. HERE...LARGE SUPERCELL STORMS WILL LIKELY PERSIST FOR A FEW
MORE HOURS WITHIN STRONG INSTABILITY GRADIENT. STORMS OVER THE E
PART OF THE S PLNS AND NWRN TX WILL PROBABLY PROPAGATE SSEWD ALONG/S
OF THE OUTFLOW BOUNDARY NEAR/NE OF SNYDER AND ABILENE WHERE MLCAPES
OF 2500-3000 J/KG EXISTS. VERY LARGE HAIL AND DMGG WINDS WILL BE
LIKELY. THERE WILL BE A SHORT TERM THREAT FOR TORNADOES...UNTIL THE
ACTIVITY ATTAINS A STRONG COLD POOL.
OTHERWISE...LEADING EDGE OF THE BOWING MCS ACROSS THE ARKLATEX WAS
DIMINISHING EARLY THIS EVENING AND WILL CONTINUE TO DO SO AS THE
FORWARD FLANK APCHS A MORE STABLE LLVL ENVIRONMENT. IN ITS WAKE...A
FEW ELEVATED TSTMS MAY DEVELOP OVERNIGHT ACROSS SRN/CNTRL OK AND
NCNTRL TX ATOP A COLD POOL. 00Z OUN SOUNDING STILL SHOWS MUCAPES OF
2500 J/KG AND STORMS COULD CONTAIN HAIL.
TO THE S...A COUPLE OF SUPERCELLS IN THE BIG BEND REGION OF TX WILL
LIKELY PROPAGATE TO NEAR/W OF DEL RIO THROUGH MID-EVENING.
BUT...ACTIVITY SHOULD BEGIN TO DIMINISH WITH TIME AS IT APCHS
STRONGER CAP NOTED FARTHER TO THE S.
...CNTRL/NRN PLNS...
00Z LEE TROUGH/DRYLINE EXTENDED FROM NCNTRL NEB SWWD INTO NERN CO
AND WILL RETREAT AND MEET THE SEWD MOVING CDFNT AFTER 03Z. EVENING
LBF SHOWED MLCAPE NEAR 2500 J/KG...H5-H7 LAPSE RATES IN EXCESS OF
7.5 C/KM AND ABOUT 40 KTS OF VERTICAL SHEAR. THUS FAR...WEAK MASS
CONVERGENCE HAS PROBABLY KEPT STORM INITIATION AT BAY...BUT WILL
IMPROVE LATER THIS EVE. EXPECT TSTMS WILL DEVELOP FROM SRN SD SWD
INTO SWRN NEB AS THE H5 TROUGH UPSTREAM OVER THE ROCKIES GRAZES THE
REGION AFT ABOUT 03Z. THEREAFTER...A SMALL MCS IS LIKELY TO EVOLVE
ALONG THE NOSE OF SLY H85 JET AND PROPAGATE SSEWD WITHIN STRONGER
INSTABILITY AXIS ACROSS CNTRL/SRN NEB AND POSSIBLY NCNTRL KS BY 12Z.
LARGE HAIL AND GUSTY WINDS WILL BE THE PRIMARY SVR THREATS.
...ERN DKTS INTO WRN MN...
CONSIDERABLE LLVL WARM/MOIST ADVECTION WILL OCCUR DOWNSTREAM FROM AN
EJECTING MID-LVL WAVE MIGRATING OUT OF THE HIGH PLNS OVERNIGHT.
MOISTENING ALONG ERN FRINGE OF STEEP MID-LVL LAPSE RATES WILL LIKELY
YIELD ONE OR TWO STRONG STORMS CAPABLE OF LARGE HAIL.
..RACY.. 04/30/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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