Tornado Alley (PROG)

[F6]

Public Severe Weather Outlook (PWO)

    ZCZC SPCPWOSPC ALL 
    WOUS40 KWNS 221302 
    ALZ000-FLZ000-GAZ000-221800- 
  
    PUBLIC SEVERE WEATHER OUTLOOK   
    NWS STORM PREDICTION CENTER NORMAN OK 
    0702 AM CST SUN JAN 22 2017 
  
    ...Outbreak of tornadoes and severe thunderstorms expected over 
    parts of the north Florida and south Georgia today... 
  
    * LOCATIONS... 
      South Georgia 
      North Florida 
      Extreme southeast Alabama 
  
    * HAZARDS... 
      Numerous tornadoes, several intense and long track 
      Scattered damaging winds 
      Scattered large hail 
  
    * SUMMARY... 
      A severe thunderstorm and tornado outbreak is expected today 
      across north Florida and south Georgia, with the significant 
      severe threat also expected to extend southward into central 
      Florida and northeastward into South Carolina this evening. A 
      few long-track, strong tornadoes will be possible. 
  
    Preparedness actions... 
  
    Review your severe weather safety procedures for the possibility 
    of dangerous weather today. Stay tuned to NOAA Weather Radio,  
    weather.gov, or other media for watches and warnings. A tornado 
    watch means that conditions are favorable for tornadoes to form 
    during the next several hours. If a tornado warning is issued for 
    your area, move to a place of safety, ideally in a basement or 
    interior room on the lowest floor of a sturdy building. 
  
    && 
  
    ..Thompson.. 01/22/2017 
  
    $$

http://www.spc.noaa.gov/products/outlook/pwo.html [will update when the next PWO is issued, probably later today]


*


Jan 22, 2017 1300 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.


Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point.


Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.

    SPC AC 221253 
  
    Day 1 Convective Outlook   
    NWS Storm Prediction Center Norman OK 
    0653 AM CST Sun Jan 22 2017 
  
    Valid 221300Z - 231200Z 
  
    ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS TODAY ACROSS SOUTH 
    GEORGIA...NORTH FLORIDA...AND EXTREME SOUTHEAST ALABAMA... 
  
    ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS SURROUNDING THE 
    HIGH RISK AREA...FROM CENTRAL FLORIDA TO SOUTH CAROLINA... 
  
    ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SURROUNDING THE 
    MODERATE RISK AREA...FROM SOUTH FLORIDA TO SOUTHERN NORTH 
    CAROLINA... 
  
    ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE 
    ENHANCED RISK AREA... 
  
    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE 
    SLIGHT RISK AREA IN THE SOUTHEAST STATES... 
  
    ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY ACROSS THE 
    CENTRAL CALIFORNIA COAST... 
  
    ...SUMMARY... 
    A severe thunderstorm and tornado outbreak is expected today across 
    north Florida and south Georgia, with the significant severe threat 
    also expected to extend southward into central Florida and 
    northeastward into South Carolina this evening. 
  
    ***Significant tornado outbreak expected today across north Florida 
    and south Georgia*** 
  
    ...Synopsis... 
    An amplifying mid-upper trough over TX/OK this morning will continue 
    eastward to MS/AL by this afternoon.  The initial synoptic cyclone 
    near Texarkana will likely be replaced by cyclogenesis today at the 
    triple point of the effective warm front across southern AL, and the 
    eastward-surging cold front/trough from LA/MS.  This new cyclone 
    will deepen and move north-northeastward today across AL/GA in 
    association with the strong height falls/ascent within the exit 
    region of a 100-130 kt mid-upper jet.  Likewise, very strong 
    deep-layer tropospheric flow is expected within the warm sector, 
    where boundary layer dewpoints in the 65-70 F range and a lingering 
    steep lapse rate plume will support moderate buoyancy.  The net 
    result of these factors will be the potential for a significant 
    tornado episode today across north FL into south GA. 
  
    ...AL/FL/GA today to the Carolinas this evening/tonight... 
    A broken band of severe storms that formed overnight persists this 
    morning across south GA.  This convective band was associated with 
    low-level warm advection, as well as an ejecting midlevel trough 
    that is now over north GA and east TN.  It is not clear if this 
    convection will weaken this morning, or if it will persist until new 
    thunderstorms begin to form farther to the west across south AL and 
    the FL Panhandle.  Regardless the boundary should begin to move 
    northward by midday as cyclogenesis proceeds across AL.  Likewise, 
    as the synoptic midlevel trough approaches from the west, 
    strengthening vertical shear is expected within the unstable warm 
    sector.  Observational data confirm the most important aspects of 
    the thermodynamic and kinematic profiles, thus confidence is high in 
    the unusual combination of ingredients today.  Forecast soundings 
    suggest the potential for MLCAPE of 1000-1500 J/kg, with effective 
    bulk shear in excess of 70 kt, and effective SRH in excess of 
    300-400 m2/s2.  The orientation of deep-layer shear vectors across 
    the cold front/trough will favor broken bands of tornadic 
    supercells. 
  
    Aside from the ongoing storms across south GA, the severe/tornado 
    risk will likely ramp up again later this morning across south AL 
    and the FL Panhandle along the residual rain-cooled boundary/warm 
    front, and then spread east-northeastward across north FL and GA 
    through the day.  Long-tracked, strong tornadoes will be possible 
    with fast moving supercells, in addition to damaging winds and large 
    hail.  The severe/tornado risk will spread northeastward into the 
    Carolinas this evening as the cyclone deepens and moves 
    northeastward to the southern Appalachians.  There are some concerns 
    regarding the degree of near-surface destabilization with 
    northeastward extent into the Carolinas.  However, very strong 
    low-level shear would favor maintenance of any supercells that 
    mature a bit farther southwest in the warm sector, with the risk for 
    tornadoes persisting after dark into SC and perhaps southern NC.  
    Farther south, the band of storms with the cold front will reach 
    south FL overnight, with a continued risk for damaging winds and a 
    couple of tornadoes. 
  
    ...Central CA coast today... 
    Another strong shortwave trough will move inland today over CA.  As 
    the left exit region of the mid-upper jet overspreads the coast and 
    near-surface flow becomes onshore with frontal passage, weak 
    surface-based buoyancy will develop.  There will be some potential 
    for low-topped thunderstorms with isolated damaging gusts in this 
    regime. 
  
    ..Thompson/Cohen.. 01/22/2017 
  
    CLICK TO GET WUUS01 PTSDY1 PRODUCT 
  
    NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z

http://www.spc.noaa.gov/products/outlook/day1otlk.html [will update in the normal course]


*


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

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

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