Tornado Alley (PROG)

[F6]

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CDT SAT APR 14 2012

...A SIGNIFICANT OUTBREAK OF STRONG TO VIOLENT TORNADOES IS EXPECTED
OVER PARTS OF THE CENTRAL AND SOUTHERN PLAINS THIS AFTERNOON AND
TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF SEVERAL STRONG TO VIOLENT...LONG-TRACK TORNADOES OVER
PARTS OF THE CENTRAL AND SOUTHERN PLAINS THIS AFTERNOON AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

CENTRAL AND EASTERN KANSAS
CENTRAL AND EASTERN NEBRASKA
CENTRAL AND NORTH CENTRAL OKLAHOMA

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM...NORTH TEXAS TO
IOWA AND SOUTHEAST SOUTH DAKOTA/SOUTHERN MINNESOTA.

A WARM AND HUMID AIR MASS WILL EXPAND NORTHWARD FROM OKLAHOMA TO
KANSAS AND NEBRASKA TODAY IN ADVANCE OF A POTENT STORM SYSTEM.
MULTIPLE ROUNDS OF DANGEROUS SEVERE THUNDERSTORMS ARE EXPECTED TO
IMPACT THE CENTRAL AND SOUTHERN PLAINS THIS AFTERNOON INTO TONIGHT.
THUNDERSTORMS...OVER PARTS OF WESTERN KANSAS INTO NEBRASKA LATE THIS
MORNING...ARE EXPECTED TO INTENSIFY THROUGH THIS AFTERNOON AS THEY
MOVE NORTHEASTWARD/EASTWARD. ADDITIONAL INTENSE STORMS ARE EXPECTED
TO DEVELOP NEAR A SURFACE LOW IN CENTRAL NEBRASKA THIS
AFTERNOON...AND SOUTHWARD ALONG THE WEST EDGE OF THE HUMID AIR MASS
INTO CENTRAL KANSAS AND WESTERN/CENTRAL OKLAHOMA. STRONG WINDS
THROUGHOUT THE ATMOSPHERE WILL BE VERY FAVORABLE FOR POWERFUL
SUPERCELL THUNDERSTORMS CAPABLE OF PRODUCING STRONG TO VIOLENT
TORNADOES...AS WELL AS VERY LARGE HAIL OVER LONG PATHS FROM THIS
AFTERNOON UNTIL AT LEAST MIDNIGHT. FAST-MOVING TORNADOES CONTINUING
AFTER DARK WILL HEIGHTEN THE RISK TO LIFE AND PROPERTY. SOME OF THE
LARGER CITIES THAT MAY BE AFFECTED INCLUDE OMAHA AND LINCOLN
NEBRASKA...TOPEKA AND WICHITA KANSAS...AS WELL AS OKLAHOMA CITY AND
TULSA OKLAHOMA.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS POTENTIALLY
VERY DANGEROUS SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO
REVIEW SEVERE WEATHER SAFETY RULES AND TO LISTEN TO
RADIO...TELEVISION...AND NOAA WEATHER RADIO FOR POSSIBLE
WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

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


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Apr 14, 2012 1630 UTC Day 1 Convective Outlook




Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.

Forecast Discussion

    SPC AC 141620 
     
    DAY 1 CONVECTIVE OUTLOOK   
    NWS STORM PREDICTION CENTER NORMAN OK 
    1120 AM CDT SAT APR 14 2012 
     
    VALID 141630Z - 151200Z 
     
    ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PORTIONS OF 
    NEBRASKA...KANSAS...AND OKLAHOMA... 
     
    ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF NEBRASKA...WESTERN 
    IOWA...KANSAS...WESTERN MISSOURI...AND OKLAHOMA... 
     
    ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE 
    CENTRAL/SOUTHERN PLAINS... 
     
    ...A SIGNIFICANT TORNADO OUTBREAK IS EXPECTED LATER TODAY AND 
    TONIGHT ACROSS PORTIONS OF NEBRASKA...KANSAS...AND OKLAHOMA... 
     
    A LARGE UPPER TROUGH REMAINS PLACED OVER THE WESTERN UNITED STATES 
    TODAY...WITH A STRONG MID/UPPER LEVEL JET EXTENDING FROM THE 
    SOUTHWEST STATES INTO THE CENTRAL PLAINS.  WATER VAPOR IMAGERY AND 
    MORNING MODEL SOLUTIONS SUGGEST SEVERAL SUBTLE SHORTWAVE TROUGHS 
    EMBEDDED IN THE FASTER FLOW.  THIS WILL RESULT IN THE POTENTIAL FOR 
    MULTIPLE ROUNDS OF SEVERE WEATHER OVER THE CENTRAL PLAINS TODAY. 
     
    THE FIRST CLUSTER OF SEVERE STORMS HAS NOW FORMED OVER SOUTHWEST KS 
    AND WILL LIKELY SPREAD NORTHEASTWARD INTO NEB THIS AFTERNOON AND 
    EVENING.  THESE STORMS WILL BE IN AN INCREASINGLY VOLATILE AIR MASS 
    AS DAYTIME HEATING AND LOW LEVEL MOISTURE ADVECTION DESTABILIZE THE 
    REGION.  LARGE HAIL AND DAMAGING WINDS ARE THE EARLY THREATS...BUT 
    AN INCREASING RISK OF SURFACE-BASED SUPERCELLS WILL POSE A THREAT OF 
    TORNADOES BY EARLY AFTERNOON.  AS THE ACTIVITY MOVES INTO SOUTHERN 
    NEB...EVEN STRONGER LOW LEVEL SHEAR SUGGESTS THAT THE POTENTIAL FOR 
    STRONG TORNADOES WILL BE ENHANCED. 
     
    STRONG HEATING IS EXPECTED TO OCCUR ALONG THE DRYLINE LATER THIS 
    AFTERNOON AND EARLY EVENING OVER WESTERN KS INTO WESTERN OK.  MODEL 
    SOLUTIONS SUGGEST THE CAP WILL BE WEAK BUT CONSIDERABLE UNCERTAINTY 
    REMAINS REGARDING THE EXTENT OF LARGE SCALE FORCING THIS EVENING.  
    AREAL COVERAGE OF STORMS COULD BE WIDELY SPACED.  HOWEVER... 
    PARAMETERS TO THE EAST OF THE DRYLINE WILL BE EXTREMELY FAVORABLE 
    FOR TORNADIC SUPERCELLS CAPABLE OF LONG-TRACK... DAMAGING/VIOLENT 
    TORNADOES /4000 J/KG MLCAPE...50-60 KNOTS OF EFFECTIVE SHEAR...AND 
    0-3KM SRH VALUES OF 300-500 M2/S2/.  THOSE STORMS THAT FORM MAY 
    PERSIST FOR SEVERAL HOURS AND TRACK ACROSS CENTRAL KS/OK AND INTO 
    SOUTHERN NEB. 
     
    FARTHER SOUTH...CONVECTIVE INITIATION BECOMES INCREASINGLY 
    UNCERTAIN.  HOWEVER...WEAK CONVERGENCE ALONG THE DRYLINE COUPLED 
    WITH A WEAK CAP AND STEEP LOW LEVEL LAPSE RATES SUGGEST SOME THREAT 
    OF ISOLATED SEVERE STORMS ACROSS PARTS OF WESTERN NORTH TX. 
     
    ..HART/COHEN.. 04/14/2012

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


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Particularly Dangerous Situation (PDS) Tornado Watch 165


http://www.spc.noaa.gov/products/watch/ww0165.html


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Particularly Dangerous Situation (PDS) Tornado Watch 166


http://www.spc.noaa.gov/products/watch/ww0166.html


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Severe Weather and Flash Flood Warnings
http://kamala.cod.edu/svr/


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http://radar.weather.gov/Conus/uppermissvly_loop.php


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http://radar.weather.gov/Conus/southplains_loop.php


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to note -- I will be offline later as I set up a new computer; have set this up as a reference post to carry through this event -- for later watches and outlooks, go to the Storm Prediction Center at http://www.spc.noaa.gov/ -- for warnings go to http://kamala.cod.edu/svr/ (third above) -- the radar loops above will stay current to provide an overview of the activity -- and to anyone and everyone in the risk area, stay alert and stay safe