SWODY1
SPC AC 301253
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0753 AM CDT SUN AUG 30 2009
VALID 301300Z - 311200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
BROAD...ELONGATED TROUGH WILL MOVE SLOWLY E ACROSS THE CNTRL AND ERN
STATES THIS PERIOD AS RDG PERSISTS OVER THE SRN RCKYS AND SW U.S. A
SHORTWAVE IMPULSE NOW IN BASE OF LARGER SCALE TROUGH OVER LA SHOULD
WEAKEN AS IT CONTINUES E/NE INTO THE CAROLINAS LATER TODAY/EARLY
MON...WHILE COMPACT CLOSED LOW NOW OVER ERN ORE MOVES SLOWLY E INTO
SRN/ERN ID. THE LOW AND THE SHORTWAVE TROUGH SHOULD BE THE MAIN
FOCI FOR ANY STRONGER STORMS THAT OCCUR THIS PERIOD.
...ID/WRN MT/WRN WY...
COMBINATION OF SFC HEATING AND SUSTAINED ASCENT/COOL AIR ALOFT WITH
EWD-MOVING ORE UPR LOW LIKELY WILL RESULT IN NUMEROUS
DIURNALLY-ENHANCED STORMS OVER THE NRN INTERMOUNTAIN REGION
TODAY...ESPECIALLY OVER THE HIGHER TERRAIN. RELATIVELY HIGH
MOISTURE AVAILABILITY /PW UP TO 1 INCH/ AND COOL MID LVL
TEMPERATURES /AROUND -14C AT 500 MB/ WILL SUPPORT A FEW STORMS WITH
HAIL/LOCALLY HEAVY RAIN AND POSSIBLY DMGG WIND AS SBCAPE INCREASES
TO AOA 1000 J/KG. THE GREATEST RISK FOR SVR WX MAY FOCUS FROM
CNTRL/SRN ID NEWD INTO SW MT/NW WY...WHERE 30+ KT SWLY MID LVL FLOW
COULD SUPPORT A FEW SUSTAINED STORMS/POSSIBLE WEAK SUPERCELLS THAT
MOVE MORE OR LESS PARALLEL TO THE SNAKE RVR VLY. THE SVR THREAT
SHOULD DIMINISH EARLY TONIGHT.
...ERN CO/NE NM...
ANOTHER ROUND OF AFTN/EARLY EVE STORMS IS EXPECTED OVER THE CNTRL
RCKYS TODAY AS REGION REMAINS BENEATH AXIS OF MODERATE /25 KT/ NWLY
MID LVL FLOW ON NE FRINGE OF UPR RDG. AT LWR LVLS...ERN PLNS/MS VLY
SFC RDG WILL MAINTAIN RELATIVELY MOIST SELY LOW LVL FLOW INTO THE
FRONT RANGE. STORMS SHOULD INITIALLY FORM OVER THE HIGHER TERRAIN
THIS AFTN...WHERE STRONGLY VEERING WIND PROFILES...35 KT DEEP NWLY
SHEAR...AND RELATIVELY COOL MID LVL TEMPERATURES /-10C AT 500 MB/
MAY SUPPORT BOTH MULTICELLS AND A FEW SUPERCELLS CAPABLE OF SVR
HAIL. WEAKER INSTABILITY/INCREASED CIN OVER THE LWR PLNS...AND
EXPECTED SSELY STORM MOTIONS...SHOULD CONFINE SVR THREAT TO THE
CO/NM FRONT RANGE AND IMMEDIATELY ADJACENT HI PLNS. THE STORMS
LIKELY WILL WEAKEN EARLY TONIGHT.
...CNTRL/ERN GULF CST TO CAROLINAS...
SW-NE ORIENTED COLD FRONT ASSOCIATED WITH ERN TROUGH SHOULD PROVIDE
THE MAIN LOW LVL FOCUS FOR DIURNALLY-ENHANCED TSTMS IN WARM/HUMID
AIR LINGERING OVER THE SERN STATES. SOME DEGREE OF LARGE SCALE
FORCING FOR ASCENT WILL EXIST ACROSS THE CNTRL/ERN GULF CST STATES
IN ASSOCIATION WITH AFOREMENTIONED UPR IMPULSE...AND POSSIBLY IN THE
FORM OF UPR DIFFLUENCE IN EXIT REGION OF HI-LVL JET STREAK NOW OVER
E TX. WEAK MID LVL LAPSE RATES AND MODEST MEAN FLOW SHOULD LIMIT
POTENTIAL FOR APPRECIABLE SVR WX. BUT SETUP COULD YIELD SEVERAL
BANDS OF STORMS THAT EXHIBIT BOTH FORWARD PROPAGATING AND
BACK-BUILDING/REGENERATIVE SEGMENTS. EMBEDDED STORMS IN THESE
CONVECTIVE SYSTEMS COULD PRODUCE LOCALLY DMGG WINDS/WET MICROBURSTS
GIVEN PW VALUES AOA 1.75 INCHES.
..CORFIDI/SMITH.. 08/30/2009
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