SWODY1
SPC AC 110536
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT WED APR 11 2012
VALID 111200Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND
CNTRL HIGH PLAINS...
...SRN AND CNTRL HIGH PLAINS...
AN UPPER-LEVEL RIDGE THAT HAS BEEN PERSISTENT ACROSS THE SRN ROCKIES
WILL FINALLY BEGIN TO MOVE EWD TODAY WITH THE RIDGE AXIS LOCATED
ACROSS THE GREAT PLAINS BY AFTERNOON. ON THE WRN SIDE OF THE
UPPER-LEVEL RIDGE...AN AXIS OF MODERATE INSTABILITY SHOULD DEVELOP
FROM FAR WEST TX EXTENDING NWD ONTO THE CAPROCK AND WWD INTO ERN NM.
AS SFC TEMPS WARM TODAY...SCATTERED THUNDERSTORMS SHOULD INITIATE
ALONG THE WRN EDGE OF THE INSTABILITY AXIS EARLY THIS AFTERNOON WITH
CONVECTION SPREADING ESEWD ACROSS THE SLIGHT RISK AREA LATE THIS
AFTERNOON INTO EARLY THIS EVENING.
FORECAST SOUNDINGS AT 00Z ALONG THE INSTABILITY AXIS AT
AMARILLO...LUBBOCK AND MIDLAND SHOW MLCAPE IN THE 1000 TO 1500 J/KG
RANGE WITH 40 KT OF DEEP LAYER SHEAR AND LAPSE RATES AROUND 8.0
C/KM. THIS ENVIRONMENT SHOULD SUPPORT ISOLATED SUPERCELL DEVELOPMENT
WITH A THREAT FOR LARGE HAIL. AN ISOLATED WIND DAMAGE THREAT WILL
ALSO BE POSSIBLE AS STORMS INCREASE IN COVERAGE DURING THE LATE
AFTERNOON. AT THIS POINT...THE AREA WITH THE GREATEST SEVERE THREAT
ACROSS THE SRN HIGH PLAINS IS HIGHLY UNCERTAIN DUE TO VARIATIONS IN
THE MODEL SOLUTIONS. WILL KEEP THE WIND DAMAGE AND HAIL
PROBABILITIES AT 15 PERCENT TO ACCOUNT FOR AN ISOLATED SEVERE THREAT
ACROSS A BROAD CORRIDOR..
FURTHER TO THE NORTH IN ECNTRL CO...MODEL FORECASTS THIS AFTERNOON
DEVELOP A NARROW CORRIDOR OF INSTABILITY TO THE EAST OF THE FRONT
RANGE AND SANGRE DE CRISTO MOUNTAINS. AS SFC TEMPS WARM DURING THE
DAY...THUNDERSTORMS SHOULD INITIATE IN THE FOOTHILLS AND MOVE SLOWLY
EWD INTO THE HIGH PLAINS. FORECAST SOUNDINGS IN THE DENVER AND
COLORADO SPRINGS AREA AT 00Z SHOW MLCAPE OF AROUND 1000 J/KG WITH 40
KT OF DEEP LAYER SHEAR. THIS COMBINED WITH STEEP MID-LEVEL LAPSE
RATES SHOULD SUPPORT A LARGE HAIL THREAT LATE THIS AFTERNOON. NEARLY
DRY ADIABATIC LAPSE RATES BELOW 700 MB MAY ALSO ENHANCE DOWNDRAFTS
FOR AN ISOLATED DAMAGING WIND THREAT.
...NRN ROCKIES...
AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE INTO THE INTERMOUNTAIN
WEST TODAY AS A PRONOUNCED 65 TO 80 KT MID-LEVEL JET MOVES NEWD INTO
THE FOUR CORNERS REGION. THE EXIT REGION OF THE MID-LEVEL JET SHOULD
OVERSPREAD THE NRN ROCKIES THIS AFTERNOON WHERE MODEL FORECASTS
DEVELOP SCATTERED THUNDERSTORMS ALONG AN AXIS OF INSTABILITY. STRONG
DEEP LAYER SHEAR AND STEEP LAPSE RATES EVIDENT ON FORECAST SOUNDINGS
MAY BE ENOUGH FOR A MARGINAL THREAT FOR HAIL AND GUSTY WINDS.
HOWEVER...MODEL FORECASTS DIFFER CONCERNING THE AMOUNT OF
INSTABILITY THAT DEVELOPS ACROSS WRN MT SUGGESTING THE THREAT IS
CONDITIONAL.
...NRN CA...
A SYNOPTIC-SCALE UPPER-LEVEL TROUGH WILL MOVE ONTO THE WEST COAST
THIS MORNING AND INTO THE INTERMOUNTAIN WEST THIS AFTERNOON.
THUNDERSTORMS SHOULD DEVELOP IN NRN AND CNTRL CA AS THE TROUGH AXIS
MOVES ACROSS DURING THE LATE MORNING. FORECAST SOUNDINGS AT 18Z IN
THE SACRAMENTO VALLEY SHOW SFC-BASED CAPE APPROACHING 500 J/KG WITH
MOST OF THE CAPE BELOW 700 MB. THIS COMBINED WITH 30 KT OF DEEP
LAYER SHEAR MAY SUPPORT LOW-TOPPED ROTATING STORMS CAPABLE OF
PRODUCING STRONG GUSTY WINDS AND HAIL.
..BROYLES/MOSIER.. 04/11/2012
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