SWODY1
SPC AC 100449
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1049 PM CST FRI NOV 09 2007
VALID 101200Z - 111200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
PROGRESSIVE FLOW PATTERN IS FORECAST TO CONTINUE AS ERN US TROUGH
MOVES INTO THE ATLANTIC...UPSTREAM RIDGE OVER THE PLAINS MOVES
TOWARD THE MS VALLEY...AND SERIES OF SHORT WAVE TROUGHS MOVING EWD
ACROSS THE PACIFIC NW RESULT IN A BROAD TROUGH OVER NWRN STATES.
UPPER LOW OVER CENTRAL CA IS EXPECTED TO MOVE SEWD TOWARD THE SRN
ROCKIES.
SURFACE HIGH OVER THE MIDDLE/UPPER MS VALLEY WILL MOVE INTO THE ERN
STATES...AS PRESSURES FALL OVER THE PLAINS IN RESPONSE TO THE
DEVELOPING UPPER TROUGH OVER THE NORTHWEST AND HEIGHT FALLS MOVING
ACROSS THE SRN PLATEAU/SRN ROCKIES. A COLD FRONT WILL MOVE INLAND
ACROSS THE PACIFIC NORTHWEST DURING THE DAY...REACHING A NRN HIGH
PLAINS/NRN WY/NRN NV/NRN CA LINE BY 11/12Z....WHILE A NW/SE ORIENTED
WARM FRONT IS EXPECTED TO DEVELOP ACROSS THE MIDDLE MO/MIDDLE MS
VALLEYS SATURDAY NIGHT.
..WRN WA/EXTREME NWRN OREGON...
LEADING EDGE OF COLD UPPER TROUGH IS EVIDENT IN SATELLITE IMAGERY
APPROACHING 136W ACCOMPANIED BY WELL-DEFINED CONVECTIVE CLOUDS AND
OCCASIONAL LIGHTNING STRIKES ACCORDING TO NLDN OCEANIC DATA. THIS
SYSTEM IS EXPECTED TO MOVE INLAND ACROSS WRN WA BY 18Z...AND IS
ASSOCIATED WITH 500 MB TEMPERATURES AROUND -30C CONTRIBUTING TO
MODERATELY STEEP LAPSE RATES IN POST-FRONTAL ENVIRONMENT. WIDELY
SCATTERED THUNDERSTORMS MAY SPREAD ACROSS PARTS OF WRN WA AND
POSSIBLY EXTREME NWRN OREGON BY 18-21Z...WITH POTENTIAL FOR ISOLATED
THUNDERSTORMS CONTINUING THROUGH THE NIGHT AS THE NEXT SHORT WAVE
TROUGH MOVES ONSHORE AFTER 11/06Z.
..ERN TX/WRN LA...
LOW LEVEL MOISTURE HAS INCREASED OVER ERN TX AND LA WITH 00Z
SOUNDINGS AND GPS DATA INDICATING GREATER THAN 1 INCH PW. DIURNAL
HEATING IS EXPECTED TO STEEPEN THE LOW LEVEL LAPSE RATES
SUFFICIENTLY FOR MLCAPE TO REACH 500-750 J/KG. LARGE SCALE
ENVIRONMENT WILL BE LESS UNFAVORABLE FOR CONVECTIVE DEVELOPMENT AS
HEIGHTS GRADUALLY FALL DURING THE DAY...SUGGESTING POSSIBILITY OF
ISOLATED THUNDERSTORMS FORMING MAINLY DURING THE AFTERNOON.
..MIDDLE MS VALLEY REGION...
LOW LEVEL JET IS FORECAST TO STRENGTHEN FROM THE CENTRAL PLAINS NEWD
TOWARD THE MIDDLE/UPPER MS VALLEY LATE THIS AFTERNOON AND TONIGHT
WITH STRONG ELEVATED MOISTURE TRANSPORT INTO PARTS OF MO/IA/IL
THROUGH THE OVERNIGHT HOURS. FORECAST SOUNDINGS EXHIBIT MODERATELY
STEEP LAPSE RATES ABOVE 850-800 MB RESULTING IN MUCAPE OF 500-1000
J/KG. PERSISTENT LOW LEVEL WARM ADVECTION LIFT WILL RESULT IN
ELEVATED CONVECTION DEVELOPING MAINLY AFTER 00-03Z OVER PARTS OF NRN
MO AND IA...WITH ACTIVITY SPREADING EWD INTO NRN/CNTRL IL AND
POSSIBLY SRN WI DURING THE OVERNIGHT HOURS.
.WEISS.. 11/10/2007
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