DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 091227
SWODY1
SPC AC 091225

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0725 AM CDT WED OCT 09 2013

VALID 091300Z - 101200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
IN MID-UPPER LEVELS...HIGHLY AMPLIFIED LARGE-SCALE PATTERN IS
PRESENT ACROSS CONUS--DOMINATED BY W-COAST TROUGHING. MID-UPPER
LEVEL CYCLONE IS EMBEDDED WITHIN LARGER-SCALE RIDGING OVER E
COAST...AND IS CENTERED OVER NC ATTM. THIS FEATURE HAS BEEN MOVING
NEWD. HOWEVER...IN ABSENCE OF SUBSTANTIAL AMBIENT FORCING FOR
HEIGHT CHANGES...LOW SHOULD DECELERATE TO BECOME QUASISTATIONARY
OVER ERN NC THROUGH REMAINDER PERIOD. MEANWHILE...MAIN VORTICITY
LOBE ACCOMPANYING DEEP SHORTWAVE TROUGH OVER CA IS EVOLVING INTO
CLOSED CYCLONE. RESULTING 500-MB LOW SHOULD MOVE SEWD ROUGHLY ALONG
GEOGRAPHIC AXIS OF CA THROUGH 06Z...REACHING SRN CA THEN TURNING
NEWD ACROSS SRN TIP OF NV BY 12Z.

AT SFC...RECENT COLD FROPA HAS RENDERED AIR MASS ACROSS MOST OF
CONUS...E OF ROCKIES...TOO DRY AND/OR STABLE FOR TSTMS THROUGH
PERIOD. EXCEPTIONS ARE PORTIONS FL AND NC/VA TIDEWATER AS DISCUSSED
BELOW...AND TSTM POTENTIAL TIED TO WRN TROUGHING.

...WRN INTERMOUNTAIN REGION...GREAT BASIN TO PORTIONS CA...
ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE...PRIMARILY THIS
AFTN BUT WITH SPORADIC ACTIVITY LINGERING THROUGH EVENING AND
PERHAPS OVERNIGHT HOURS. AS MID-UPPER LEVEL CYCLONE BUILDS SEWD AND
ENLARGES...RELATED FIELDS OF LARGE-SCALE ASCENT AND HEIGHT FALLS
ALOFT WILL OVERSPREAD MUCH OF WRN GREAT BASIN AND PARTS OF INLAND
CENTRAL/SRN CA. SUFFICIENTLY COLD MIDLEVEL TEMPS AND
DIABATIC/DIURNAL SFC HEATING...COMBINED WITH LOCALIZED OROGRAPHIC
LIFT AND MRGL MOISTURE...WILL YIELD FAVORABLE ENVIRONMENT FOR
CONVECTION THIS AFTN.

...TIDEWATER VA/NC...
SFC FRONTAL-WAVE LOW RELATED TO MID-UPPER LEVEL VORTEX...AS WELL AS
SFC WARM SECTOR...ARE FCST TO REMAIN OFFSHORE. HOWEVER...ELY-NELY
CONVEYOR OF ELEVATED LOW-LEVEL WAA AND MOISTURE TRANSPORT WILL WRAP
AROUND NRN SEMICIRCLE OF LOW-LEVEL CYCLONE...RESULTING IN SUSTAINED
FETCH OF PRECIP AND ISOLATED TO WIDELY SCATTERED EMBEDDED/EPISODIC
TSTMS. GREATEST THUNDER POTENTIAL WILL REMAIN OFFSHORE...BUT SOME
ACTIVITY MAY MOVE INLAND WITHIN THAT CONVEYOR. FCST SOUNDINGS
SUGGEST THETAE ABOVE BOUNDARY LAYER COULD INCREASE ENOUGH TO SUPPORT
MUCAPE 200-500 J/KG AROUND ECG -- NEAR AXIS OF WAA CONVEYOR -- BY
EARLY EVENING. BUOYANCY AND TSTM RISK EACH SHOULD DIMINISH
NWD...SWD AND WWD FROM NERN NC.

...S FL...
MRGL/CONDITIONAL TSTM POTENTIAL IS APPARENT. WIND SHIFT
ACCOMPANYING WEAK FRONT...AND TRAILING FROM SFC LOW OFFSHORE
CAROLINAS...SHOULD MOVE SWD ACROSS THIS REGION THROUGH AFTN.
ACCOMPANYING WEAK LIFT MAY SUPPORT ISOLATED TSTM DEVELOPMENT MAINLY
NEAR AFTN SFC THERMAL PEAK. LACK OF SUBSTANTIAL FLOW OR SHEAR...AND
WEAK LAPSE RATES ALOFT...WILL TEMPER CONVECTIVE INTENSITY AND
PRECLUDE UNCONDITIONAL SVR PROBABILITIES.

..EDWARDS/LEITMAN.. 10/09/2013

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.