SWODY1
SPC AC 140600
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE SEP 14 2010
VALID 141200Z - 151200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHERN/CENTRAL
PLAINS...
...SYNOPSIS...
A LOW AMPLITUDE/NEARLY ZONAL LARGE SCALE PATTERN WILL REMAIN
PREVALENT OVER THE NORTHERN HALF OF THE CONUS THROUGH THE PERIOD.
WITHIN THIS REGIME...A LOW AMPLITUDE UPPER TROUGH/SPEED MAX...OVER
NORTHERN/CENTRAL CA EARLY IN THE OVERNIGHT...IS EXPECTED TO CONTINUE
A STEADY EAST-NORTHEASTWARD PROGRESSION OVER THE GREAT BASIN
TODAY...AND REACH THE NORTH-CENTRAL ROCKIES LATE TONIGHT. A SLOW
MOVING FRONTAL ZONE...EXTENDING FROM THE LOWER MO VALLEY
WEST-NORTHWESTWARD INTO THE CENTRAL/NORTHERN HIGH PLAINS...WILL BE A
FOCUS FOR STRONG/SEVERE TSTM POTENTIAL ESPECIALLY THIS
AFTERNOON/EVENING.
...NORTHERN/CENTRAL HIGH PLAINS TO LOWER MO VALLEY/SOUTHERN
PLAINS...
A COMPLEX OF TSTMS IS EXPECTED TO BE ONGOING THIS MORNING ACROSS
PORTIONS OF THE LOWER MO VALLEY. THESE STORMS SHOULD
AUGMENT/SOUTHWARD SHUNT THE EFFECTIVE FRONTAL ZONE ACROSS PORTIONS
OF KS AND THE LOWER MO VALLEY. IT IS NOT ENTIRELY CLEAR HOW THIS
ACTIVITY WILL IMPACT LATER DAY SEVERE POTENTIAL...ESPECIALLY GIVEN
WHAT MAY BE RELATIVELY MODEST MASS CONVERGENCE VIA SHORTWAVE RIDGING
ALOFT/WANING INFLUENCE OF UPPER JET ENTRANCE REGION.
NONETHELESS...SOME SEVERE THREAT MAY EXIST DURING THE DAY ON THE
WEST/SOUTHWEST FLANK OF THESE EARLY DAY STORMS AND/OR IN VICINITY OF
THE OUTFLOW AUGMENTED FRONTAL ZONE...WHERE A MOIST/POTENTIALLY
UNSTABLE AIRMASS WILL OTHERWISE EXIST ACROSS KS INTO NEB.
FARTHER SOUTH...ADDITIONAL SEVERE STORMS WILL AGAIN BE POSSIBLE THIS
AFTERNOON/EARLY EVENING ACROSS PORTIONS OF OK AND NORTH/NORTHWEST
TX. WITH MID LEVEL WESTERLIES STEADILY DECREASING WITH SOUTHWARD
EXTENT...OVERALL ORGANIZATION/INDIVIDUAL STORM SUSTENANCE SHOULD
REMAIN LIMITED...BUT THE STRONGEST STORMS WILL NONETHELESS BE
CAPABLE OF MAINLY DAMAGING WINDS GUSTS.
OTHERWISE...AIDED BY THE ONSET OF LARGE SCALE HEIGHT FALLS...THE
HIGHEST CONFIDENCE SCENARIO IS FOR POTENTIALLY STRONG/SEVERE TSTMS
TO INCREASE ACROSS THE HIGH PLAINS DURING THE LATE AFTERNOON AND
/ESPECIALLY THE/ EVENING HOURS. THIS INCLUDES WHAT MAY BE AN
EFFECTIVE TRIPLE POINT/SURFACE LOW VICINITY ACROSS WESTERN
KS...NORTHWESTWARD IN A CORRIDOR INTO THE NORTH-CENTRAL HIGH PLAINS
INCLUDING WESTERN PORTIONS OF NEB/SD AND PROBABLY EASTERN
WY/SOUTHEAST MT. STRENGTHENING FLOW ALOFT /WITH 40+ KT EFFECTIVE
SHEAR/ COUPLED WITH A HIGH PLAINS-RETREATING MOIST AXIS WILL SUPPORT
SUSTAINED/ORGANIZED SEVERE STORMS...INCLUDING SUPERCELLS CAPABLE OF
LARGE HAIL THROUGH THE EVENING /WHICH SHOULD BE THE DOMINANT
HAZARD/. AIDED BY A NOCTURNALLY STRENGTHENING LOW LEVEL JET...SOME
OF THESE STORMS MAY TEND TO GROW UPSCALE DURING THE EVENING/LATE
NIGHT HOURS WITH SOME THREAT FOR DAMAGING WINDS AS WELL...ALTHOUGH
INCREASING NEAR-SURFACE CINH MAY LIMIT SUCH POTENTIAL.
...NORTHERN GREAT DIVIDE...
AHEAD OF THE APPROACHING WESTERN STATES UPPER TROUGH...STEEP LAPSE
RATES ALOFT/MODEST BUOYANCY MAY YIELD ISOLATED/MARGINAL SEVERE TSTMS
CAPABLE OF HAIL/GUSTY WINDS THIS AFTERNOON/EARLY EVENING...MAINLY
ACROSS PORTIONS OF CENTRAL ID/SOUTHERN MT.
..GUYER/SMITH.. 09/14/2010
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