DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 120104
SWODY1
SPC AC 120100

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0800 PM CDT SAT APR 11 2009

VALID 120100Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PART OF TX AND
SWRN OK...

...SYNOPSIS...
HIGH-AMPLITUDE UPPER TROUGH/LOW -- CENTERED INVOF THE FOUR CORNERS
ATTM -- WILL PROGRESS STEADILY EWD ACROSS THE SRN ROCKIES AND INTO
THE SRN PLAINS THE REMAINDER OF THE PERIOD.

AT THE SURFACE...A LOW INVOF MIDLAND TX ATTM WILL DEVELOP SLOWLY
NEWD ACROSS THE TX SOUTH PLAINS. WIDESPREAD LOW-LEVEL WARM
ADVECTION ACROSS THE SRN PLAINS AHEAD OF THIS LOW WILL SUPPORT
INCREASINGLY-WIDESPREAD ELEVATED CONVECTION THROUGH THE END OF THE
PERIOD.

...PARTS OF WRN AND NRN TX INTO SWRN OK...
WIDESPREAD THUNDERSTORMS ARE ONGOING ATTM ACROSS THE TX SOUTH PLAINS
REGION AND VICINITY...WITH MORE ISOLATED STORMS ACROSS A
LARGER/SURROUNDING AREA. SUPERCELLS ONGOING IN A NARROW N-S ZONE OF
SURFACE-BASED INSTABILITY -- NEAR AND NE OF MIDLAND TX -- HAVE
PRODUCED LARGE HAIL...TAKING ADVANTAGE OF MIXED-LAYER CAPE
APPROACHING 1000 J/KG AND 0-6 KM SHEAR NEAR 70 KT PER THE LATEST
JAYTON TX PROFILER. THIS CONVECTION WILL BECOME
INCREASINGLY-ELEVATED WITH TIME THIS EVENING...AS THE BOUNDARY LAYER
COOLS AND STORMS SHIFT ENEWD ATOP A COOLER/MORE STABLE AIRMASS IN
PLACE ACROSS THE REMAINDER OF THE SRN PLAINS.

INCREASING WARM ADVECTION AHEAD OF THE APPROACHING UPPER FEATURE
ATOP THE STABLE LOWER-LEVEL AIRMASS WILL CONTINUE TO SUPPORT
INCREASINGLY-WIDESPREAD CONVECTIVE DEVELOPMENT. WITH STEEP LAPSE
RATES -- PER EVENING RAOBS -- ABOVE THIS LOW-LEVEL
WARMING/MOISTENING...AMPLE ELEVATED INSTABILITY EXISTS TO SUPPORT A
THREAT FOR HAIL -- AND THUS CONTINUATION OF THE SLIGHT RISK
FORECAST. THE MAIN AREA OF CONVECTION WILL SPREAD EWD WITH
TIME...WITH STORMS -- AND SOME HAIL POTENTIAL -- EXTENDING AS FAR E
AS THE TX COAST/E TX/ERN OK BY THE END OF THE PERIOD.

..GOSS.. 04/12/2009

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