DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121630
SWODY1
SPC AC 121628

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1128 AM CDT THU APR 12 2007

VALID 121630Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SOUTHERN HIGH
PLAINS...

..SOUTHERN HIGH PLAINS...
MORNING WATER VAPOR IMAGERY SHOWS LARGE UPPER TROUGH DEVELOPING OVER
THE WESTERN STATES TODAY...WITH LEAD SHORTWAVE TROUGH NOW EVIDENT
ACROSS CENTRAL AZ. THIS FEATURE IS FORECAST TO MOVE ACROSS NM TODAY
AND INTO WEST TX/OK OVERNIGHT. STRONG DAYTIME HEATING IS OCCURRING
OVER MUCH OF THE SOUTHERN HIGH PLAINS WITH STRENGTHENING SOUTHERLY
LOW LEVEL WINDS ACROSS THE REGION. BY LATE THIS AFTERNOON...A
DEVELOPING DRYLINE SHOULD EXTEND FROM THE NM/TX BORDER WEST OF
MAF...INTO NORTHEAST NM. DEWPOINTS EAST OF THE DRYLINE WILL ONLY BE
IN THE 40S. HOWEVER...TEMPERATURES WELL INTO THE 60S WILL RESULT IN
STEEP DEEP LAYER LAPSE RATES AND MUCAPE VALUES APPROACHING 1000
J/KG.

SCATTERED HIGH-BASED CONVECTION IS EXPECTED TO DEVELOP WEST OF THE
DRYLINE AND BUILD EASTWARD INTO THE UNSTABLE AIR DURING THE LATE
AFTERNOON. THIS WILL LIKELY RESULT IN ISOLATED THUNDERSTORMS BY 00Z
OVER NORTHEAST NM AND WEST TX. THESE STORMS WILL LIKELY BECOME
SUPERCELLS WITH A RISK OF LARGE HAIL AND DAMAGING WINDS. AXIS OF
SURFACE-BASED INSTABILITY WILL BE RATHER NARROW...WITH ACTIVITY
BECOMING ELEVATED AS IT DEVELOPS NORTHEASTWARD INTO PARTS OF
SOUTHWEST KS AND WESTERN OK. POTENTIAL FOR ELEVATED HAIL STORMS
WILL LIKELY PERSIST THROUGHOUT THE NIGHT IN THOSE AREAS.

..EASTERN AZ...
PRIMARY UPPER TROUGH IS NOW DIGGING SOUTHWARD ACROSS CA/NV. LARGE
SCALE FORCING IN ADVANCE OF THIS FEATURE WILL BEGIN AFFECTING PARTS
OF AZ BY THIS EVENING. FORECAST SOUNDINGS IN THIS AREA SHOW ONLY
MARGINAL INSTABILITY...BUT VERY STEEP LAPSE RATES AND A DEEP...MIXED
BOUNDARY LAYER. ISOLATED THUNDERSTORMS MAY DEVELOP IN THIS
REGIME...WITH STRONGEST CELLS CAPABLE OF GUSTY/DAMAGING WINDS.

.HART/GRAMS.. 04/12/2007

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