DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 020602
SWODY1
SPC AC 020600

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT WED OCT 02 2013

VALID 021200Z - 031200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
LARGE SCALE PATTERN AMPLIFICATION WILL OCCUR DURING THE
PERIOD...HIGHLIGHTED BY A SOUTHEASTWARD-ADVANCING UPPER TROUGH/JET
STREAK OVER THE PACIFIC NORTHWEST/GREAT BASIN. A WARM FRONT WILL
ADVANCE NORTH-NORTHEASTWARD ACROSS THE UPPER MIDWEST TODAY...WHILE A
COLD FRONT SPREADS SOUTHEASTWARD ACROSS THE NORTH-CENTRAL HIGH
PLAINS...WITH LEE-SIDE TROUGH DEVELOPMENT AND A SHARPENING DRYLINE
WITHIN A NORTH-SOUTH CORRIDOR OF THE SOUTH-CENTRAL HIGH PLAINS.
MEANWHILE...A PERSISTENT UPPER LOW ACROSS THE LOWER MS VALLEY WILL
ALSO CONTRIBUTE TO TSTM POTENTIAL ACROSS THAT REGION.

...CENTRAL PLAINS/MIDDLE MO RIVER VALLEY...
LOW-LEVEL MOISTURE CHARACTERIZED BY UPPER 50S/NEAR 60F SURFACE
DEWPOINTS WILL SPREAD NORTH-NORTHEASTWARD AND BECOME INCREASINGLY
ESTABLISHED WITHIN THE WARM SECTOR IN THE WAKE OF THE AFOREMENTIONED
WARM FRONT/AHEAD OF THE COLD FRONT. IN THE PRESENCE OF
BROAD/SOMEWHAT NEBULOUS SOUTHWESTERLY FLOW ALOFT...SUFFICIENT
HEATING/MASS CONVERGENCE NEAR ONE OR MORE WEAK SURFACE LOWS AND MORE
SO THE SLOWLY ADVANCING COLD FRONT SHOULD BE SUFFICIENT FOR SURFACE
BASED TSTM DEVELOPMENT BY LATE AFTERNOON/EARLY EVENING...WITH STORMS
BACKBUILDING/EXPANDING IN COVERAGE AS A LOW-LEVEL JET NOCTURNALLY
INCREASES. SUCH INITIAL DEVELOPMENT SHOULD OCCUR WITHIN A GENERAL
NORTHEAST-SOUTHWEST ORIENTED CORRIDOR INCLUDING SOUTHEAST
SD/NORTHWEST IA TO SOUTHWEST NEB.

ALTHOUGH RELATIVELY WEAK VERTICAL SHEAR /GENERALLY 20 KT DEEP LAYER/
WILL TEND TO BE A LIMITING FACTOR FOR A MORE ORGANIZED/SUSTAINED
SEVERE RISK...ISOLATED STRONG/SEVERE TSTMS CAN BE EXPECTED GIVEN
THAT THE COLD FRONT-PRECEDING AIRMASS WILL BE MODERATELY UNSTABLE.
AFOREMENTIONED SURFACE DEWPOINTS BENEATH A PLUME OF STEEP LAPSE
RATES ALOFT OVER THE CENTRAL PLAINS SHOULD CONTRIBUTE TO AS MUCH AS
1500-2250 J/KG OF MLCAPE. BOUTS OF LARGE HAIL AND POSSIBLY LOCALLY
DAMAGING WINDS WILL BE THE PRIMARY CONCERNS.

..GUYER/LEITMAN.. 10/02/2013

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