Tornado Alley (PROG)

[F6]

re Vortex2 today -- the ante has been upped:

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Jun 9, 2009 1300 UTC Day 1 Convective Outlook

    ...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.

http://www.spc.noaa.gov/products/outlook/day1otlk.html

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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/

excellent link to keep up with the latest tornado, severe thunderstorm and flash flood warnings: http://weather.cod.edu/kamala/svr/

forecast discussion for today/tonight at Stormtrack: http://www.stormtrack.org/forum/showthread.php?t=21028
[Stormtrack home: http://www.stormtrack.org/ -- for current chaser reports from the field later today, look for a new thread there titled "6/09/09 Now" (or similar, key words being "6/09/09" and "Now")]

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