DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 111222
SWODY1
SPC AC 111219

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0719 AM CDT SAT OCT 11 2008

VALID 111200Z - 121200Z

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

POWERFUL UPPER TROUGH OVER THE WESTERN STATES CONTINUES TO DEEPEN
THIS MORNING...WHILE PLUME OF TROPICAL MIDLEVEL MOISTURE ASSOCIATED
WITH HURRICANE NORBERT SPREADS NORTHEASTWARD INTO THE SOUTHERN
ROCKIES. THESE TWO FACTORS WILL COMBINE TO POSE A RISK OF SEVERE
THUNDERSTORMS TODAY OVER PARTS OF THE SOUTHERN HIGH PLAINS AND
SOUTHERN ROCKIES.

WATER VAPOR IMAGERY AND MODEL GUIDANCE SHOW WEAK IMPULSES AND
INCREASING FORCING FOR UPWARD VERTICAL MOTION EMBEDDED IN THE PLUME
OF MOISTURE EMANATING FROM HURRICANE NORBERT. THESE FEATURES WILL
TRACK NORTHEASTWARD ACROSS NORTHERN MEXICO AND INTO PARTS OF
NM/TX/SOUTHWEST KS THIS AFTERNOON AND TONIGHT. THIS WILL OCCUR AS
110+ KNOT MID LEVEL JET ROTATES THROUGH BASE OF WESTERN TROUGH AND
INTO THE FOUR CORNERS AREA. 500MB HEIGHT FALLS WILL COMMENCE BY
EVENING OVER CO/NM...FURTHER ENHANCING LARGE SCALE ASCENT AND
LEADING TO WIDESPREAD SHOWERS AND THUNDERSTORMS. RATHER LIMITED LOW
LEVEL MOISTURE AND AT LEAST SCATTERED CLOUD COVER WILL LIKELY LIMIT
UPDRAFT INTENSITY WITH STORMS OVER CENTRAL NM AND SOUTHERN CO.
NEVERTHELESS...STRONG WINDS ALOFT AND RATHER STEEP MID LEVEL LAPSE
RATES MAY RESULT IN GUSTY WINDS AND HAIL IN ANY STORMS.

THE WESTERN EDGE OF SURFACE DEWPOINTS IN THE 50S TO LOWER 60S WILL
REMAIN ESTABLISHED OVER EASTERN NM AND WEST TX THROUGH THE DAY.
POCKETS OF STRONG HEATING WILL HELP TO YIELD LATE AFTERNOON MLCAPE
VALUES OF 500-1000 J/KG ALONG THIS ZONE. FORECAST SOUNDINGS SUGGEST
DEEP LAYER AND LOW LEVEL VERTICAL SHEAR WILL BE FAVORABLE FOR
SUPERCELL STORM STRUCTURES CAPABLE OF LARGE HAIL AND DAMAGING WINDS.
NORTHWARD EXTENT OF SEVERE IS UNCERTAIN DUE TO MEAGER LOW LEVEL
MOISTURE. HOWEVER...STRONG KINEMATIC FIELDS EXTEND AS FAR NORTH AS
WESTERN NEB...SUGGESTING A RISK OF STRONG CELLS AND HAIL DURING THE
EVENING IF MARGINAL ELEVATED INSTABILITY CAN DEVELOP.

..HART/GRAMS.. 10/11/2008

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