ACUS01 KWNS 010602
SWODY1
SPC AC 010600
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT WED SEP 01 2010
VALID 011200Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHERN/CENTRAL
PLAINS TO LOWER/MIDDLE MO VALLEY...
...CENTRAL/NORTHERN PLAINS AND MIDDLE/LOWER MO VALLEY...
A CONSIDERABLE SPEED MAX MOVING INLAND OVER THE PACIFIC
NORTHWEST/NORTHERN INTERMOUNTAIN REGION EARLY TODAY WILL STEADILY
ADVANCE EAST-SOUTHEASTWARD TOWARD THE NORTH-CENTRAL
ROCKIES/NORTH-CENTRAL PLAINS TODAY AS AN UPPER TROUGH
AMPLIFIES/DEEPENS OVER THE NORTHERN HIGH PLAINS ESPECIALLY THIS
AFTERNOON/TONIGHT. AS THIS OCCURS...MODEST SURFACE CYCLOGENESIS IS
EXPECTED ACROSS THE NORTH-CENTRAL HIGH PLAINS...AS THE CURRENT
CENTRAL PLAINS FRONTAL ZONE/ATTENDANT MOIST SECTOR RETREATS
NORTHWARD THIS AFTERNOON/EVENING.
IT SHOULD BE NOTED THAT THERE IS UNCERTAINTY REGARDING THE TIMING OF
A LEAD SHORTWAVE TROUGH CROSSING THE HIGH PLAINS...AS WELL AS
UNCERTAINTY REGARDING THE TIMING/EXTENT OF MOISTURE RETURN ACROSS
NEB INTO SD. HOWEVER...CURRENT THINKING IS THAT THERE WILL BE TWO
MAIN AREAS FOR STRONG/SEVERE SURFACE BASED TSTM DEVELOPMENT LATER
TODAY. THE FIRST WILL BE IN A GENERAL NORTH-SOUTH AXIS ACROSS
CENTRAL SD/WEST-CENTRAL NEB AND PERHAPS NORTHERN KS IN VICINITY OF
AN EASTWARD SHIFTING SURFACE TROUGH/FRONT AND/OR THE NORTHWARD
RETREATING PRIMARY FRONTAL ZONE. CONSIDERABLE COOLING/STRENGTHENING
FLOW ALOFT...WITH STEEPENING MID LEVEL LAPSE RATES/POTENTIAL FOR
MODERATE BUOYANCY AND 45-50 KT OF EFFECTIVE SHEAR...WILL SUPPORT
WELL-ORGANIZED STORMS INCLUDING SUPERCELLS/BOWS CAPABLE OF LARGE
HAIL...DAMAGING WINDS...AND PERHAPS A TORNADO.
ADDITIONAL STRONG/SEVERE STORMS MAY FORM ACROSS KS...WHERE STRONG
HEATING SHOULD ERODE CINH IN VICINITY OF SURFACE LOW/FRONTAL
ZONE/OUTFLOW. HERE...FORCING ON THE LARGE SCALE WILL NOT BE
PARTICULARLY STRONG COINCIDENT WITH PEAK HEATING...BUT SUFFICIENT
LOW LEVEL CONVERGENCE/WEAK CINH BENEATH CYCLONIC FLOW ALOFT MAY
SPARK A SURFACE BASED TSTM THREAT BY LATE AFTERNOON/EARLY EVENING.
...MIDWEST/MIDDLE MS VALLEY...
ONGOING SHOWERS/TSTMS SHOULD CONTINUE TO OUTRUN THE PRIMARY
EAST-SOUTHEAST ADVANCING SURFACE FRONTAL ZONE OVERNIGHT/EARLY TODAY.
WITH STORMS CONTINUING TO WEAKEN EARLY THIS MORNING...CONVECTIVE
OVERTURNING/RESIDUAL CLOUD COVER IS LIKELY TO LIMIT APPRECIABLE
DESTABILIZATION ACROSS MUCH OF THE PRE-COLD FRONTAL CORRIDOR ACROSS
THE MIDWEST/MIDDLE MS VALLEY. FURTHERMORE...WELL SOUTH OF THE
PRIMARY WESTERLIES/CYCLONIC FLOW ALOFT...VERTICAL SHEAR SHOULD
REMAIN WEAK COINCIDENT WITH RELATIVELY WARM THERMAL PROFILES ALOFT
/-6C AT 500 MB/. WHILE AN ORGANIZED/CONCENTRATED SEVERE THREAT IS
NOT ANTICIPATED...SUFFICIENT LOW LEVEL HEATING COULD YIELD ISOLATED
DOWNBURSTS CAPABLE OF WIND DAMAGE THIS AFTERNOON.
...SOUTHERN PLAINS...
SCATTERED TSTMS SHOULD ESPECIALLY DEVELOP/INCREASE THIS AFTERNOON
WITHIN A TROPICAL-LIKE AIRMASS ACROSS THE SOUTHERN PLAINS INCLUDING
PORTIONS OF OK/TX. WHILE VERTICAL SHEAR/ANTICIPATED ORGANIZATION
WILL BE LIMITED...SUFFICIENT HEATING/WATER LOADING IMPLY THAT THE
STRONGEST STORMS WILL AGAIN BE CAPABLE OF DAMAGING DOWNBURSTS MAINLY
DURING THE MID/LATE AFTERNOON HOURS.
...ND/MT...
OTHER LOWER TOPPED STORMS SHOULD DEVELOP THIS AFTERNOON ACROSS
EAST-CENTRAL ND...WITH THE STRONGEST STORMS POTENTIALLY CAPABLE OF
SEVERE HAIL. FARTHER WEST...OTHER LOW-TOPPED STORMS PERHAPS CAPABLE
OF GUSTY WINDS/SMALL HAIL WILL LIKELY DEVELOP THIS AFTERNOON ACROSS
EASTERN MT TO THE WESTERN DAKOTAS...BUT LIMITED MOISTURE/SCANT CAPE
ACROSS THIS REGION SHOULD GENERALLY PRECLUDE SEVERE POTENTIAL.
..GUYER/GRAMS.. 09/01/2010
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