...SYNOPSIS... LARGE SCALE SPLIT FLOW REGIME IS CHARACTERIZED BY TROUGHING ACROSS THE U.S./CANADIAN BORDER AND SUB-TROPICAL RIDGE AXIS OVER TX AND THE ADJACENT GULF OF MEXICO. IN THE SRN STREAM...A LOW AMPLITUDE SHORT WAVE TROUGH AND 50-60KT MID LEVEL JET STREAK WILL SPREAD NEWD FROM AZ/NM THIS MORNING TO MO BY TONIGHT. DEEP-LAYER ASCENT WITH THIS DISTURBANCE WILL CONTRIBUTE TO SIGNIFICANT SEVERE TSTM DEVELOPMENT ALONG AND NORTH OF A WELL-DEFINED WARM FRONT FROM KS/OK EWD ACROSS MO TO THE MID MS VALLEY THROUGH EARLY WEDNESDAY. THE WARM FRONT ACROSS NRN OK/ERN KS AREA WILL SERVE AS A FOCUS FOR POTENTIALLY LONG-TRACK SUPERCELLS CAPABLE OF PRODUCING A STRONG TORNADO OR TWO LATER TODAY.
A NRN STREAM SHORT WAVE TROUGH AND ASSOCIATED SURFACE LOW WILL TRACK INTO QUEBEC CANADA TODAY. COLD FRONT TRAILING THIS LOW WILL PASS ACROSS PORTIONS OF NY/PA WITH RESIDUAL/WEAKENING STATIONARY PORTION OF THIS FRONT REMAINING ALONG THE OH VALLEY. MODEST HEIGHT FALLS ASSOCIATED WITH THE PASSAGE OF THE NRN STREAM TROUGH MAY INDUCE WEAK CYCLOGENESIS ACROSS DELMARVA REGION LATER TODAY.
...NRN OK/SRN-CNTRL KS AND INTO WRN MO... A WARM AND VERY MOIST AIRMASS RESIDES ACROSS THE SOUTHERN PLAINS THIS MORNING ALONG AND SOUTH OF WARM FRONT FROM SOUTHEAST CO TO THE OK/KS BORDER. TSTMS...ROOTED WELL ABOVE THE BOUNDARY LAYER...WERE INCREASING IN COVERAGE ACROSS KS THIS MORNING AS MASS TRANSPORT AND ISENTROPIC LIFT ARE MAXIMIZED ON THE NOSE OF THE LOW LEVEL JET AND ALONG THE EDGE OF STRONG CAPPING INVERSION. CLOUD COVER AND PRECIPITATION WITH THE ELEVATED STORMS SHOULD INHIBIT SIGNIFICANT NWD RETREAT OF THE WARM FRONT AS VERY UNSTABLE TO EXTREMELY UNSTABLE CONDITIONS DEVELOP FROM SRN/CNTRL KS SWD ACROSS OK. FORECAST SOUNDINGS DEPICT SIGNIFICANT CONVECTIVE INHIBITION/CAPPING ACROSS MUCH OF THE WARM SECTOR THROUGH THE DAY. HOWEVER...MAGNITUDE OF INSTABILITY FUELING ELEVATED STORMS FROM KS INTO MO...AND EFFECTIVE SHEAR THIS AREA...SHOULD BE MORE THAN ADEQUATE FOR LARGE HAIL PRODUCTION AS STORMS INCREASE THROUGH LATE MORNING AND INTO THE AFTERNOON.
SURFACE-BASED STORM DEVELOPMENT/INITIATION IS ANTICIPATED AS CAP IS BREACHED THROUGH A COMBINATION OF WEAK LARGE SCALE ASCENT AND PERSISTENT LOW LEVEL CONVERGENCE NEAR DRYLINE/TRIPLE-POINT LOW AND WARM FRONT...SOMEWHERE NEAR SRN KS/NRN OK BY LATE AFTERNOON. THIS AREA SHOULD ALSO LIE NEAR THE SWRN/SRN FLANK OF RAIN-COOLED AIRMASS FROM EARLIER CONVECTION...IN A REGION WHERE THERMAL GRADIENT ALONG THE WARM FRONT MAY BE STRENGTHENED AND LOW LEVEL SHEAR WILL BE MAXIMIZED.
GIVEN MAGNITUDE OF AVAILABLE INSTABILITY /MLCAPE AROUND 3000 J/KG/ AND ENLARGED HODOGRAPHS RESULTING IN 0-1KM HELICITY VALUES IN THE RANGE OF 200-400 M2/S2...AND RELATIVELY LOW LFC NEAR THE WARM FRONT...POTENTIAL WILL EXIST FOR LONGER-LIVED SUPERCELLS/MESOCYCLONES CAPABLE OF PRODUCING A STRONG TORNADO OR TWO. IT IS TOO EARLY TO PREDICT EXACTLY WHERE GREATEST TORNADO POTENTIAL WILL EVOLVE AS THIS IS DEPENDENT ON DISCRETE STORM INITIATION NEAR THE AFOREMENTIONED SURFACE FEATURES. AT THIS POINT...THE WARM FRONT AND TRIPLE-POINT LOW ARE MOST LIKELY TO BE LOCATED SOMEWHERE NEAR THE OK/KS BORDER...OR PERHAPS IN SRN/SERN KS AT THE TIME SURFACE-BASED STORM INITIATION BETWEEN THE HOURS OF 20-22 UTC.
UPSCALE EVOLUTION INTO A SEVERE MCS IS LIKELY INTO THE EVENING FROM NERN OK/ERN KS SPREADING ACROSS MUCH OF CNTRL/NRN MO THROUGH THE NIGHT. LARGE HAIL IS LIKELY WITH DEEP CONVECTION NORTH OF THE WARM FRONT WHILE DAMAGING WINDS AND A POSSIBLE TORNADO OR TWO WILL ACCOMPANY THE STORMS NEARER THE SURFACE BOUNDARY AND CONVECTIVELY ENHANCED FRONTAL WAVE EXPECTED TO TRACK FROM KS/OK INTO CNTRL MO.
full range of continually updated information, including the watches and warnings that will be coming out later today into tonight, available at/via http://www.spc.noaa.gov/