Nov 7, 2017 1300 UTC Day 1 Convective Outlook
Updated: Tue Nov 7 12:44:29 UTC 2017 (20171107 1300Z Day 1 shapefile | 20171107 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20171107 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20171107 1300 UTC Day 1 Tornado Probabilities Graphic
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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20171107 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Large Hail Graphic
20171107 1300 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 071244

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0644 AM CST Tue Nov 07 2017

   Valid 071300Z - 081200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Thunderstorms are possible from the coastal Carolinas/Delmarva to
   parts of east Texas today.

   ...Synopsis...
   In mid/upper levels, a broad belt of zonal flow will cover most of
   the central and eastern U.S., downstream from a positively tilted
   shortwave trough now located over the northern Plains, northern
   Rockies and Great Basin.  That trough is forecast to elongate and 
   shift east-southeastward, and by 00Z, should reach southern Lake
   Michigan, northern IA, northern NE, southern WY, to an anchoring
   vorticity lobe over eastern UT.  The trough will continue to stretch
   overnight, extending from the Mid-Atlantic across much of the Corn
   Belt to the main vorticity max over CO by 12Z.  Though lacking
   substantial embedded shortwaves, the downstream/zonal pattern across
   the Southeast will be characterized by height falls. 

   At the surface, a weak low was analyzed at 11Z over eastern Middle
   TN, with cold front southwestward across northern MS, northern LA,
   and central/southwest TX.  The low should migrate across the
   mountains and NC, along a slower-moving to stationary segment of the
   front to its east.  Meanwhile, by 00Z, the cold front should reach
   northern GA, central MS, and southeast/south-central TX.  By 12Z,
   the front should be located from southern SC across southern parts
   of MS/AL to the northwestern Gulf, and deep south Texas. 

   ...Northern GA, southeastern TN, western/central Carolinas...
   Isolated to widely scattered thunderstorms are possible today near
   the surface cold front as the boundary crosses the region. 
   Destabilization for surface-based parcels becomes more uncertain
   with northward extent across the southern Appalachians region, in
   the wake of ongoing non-severe thunderstorms crossing the region. 
   To their south, a combination of diurnal/diabatic surface heating
   and dew points in the 60s F may yield a southwest-northeast plume of
   MLCAPE reaching 500-1000 J/kg from midday through late afternoon. 
   Weak lapse rates/instability aloft, and veered prefrontal winds in
   the boundary layer, cast doubts on strength of lift needed to
   sustain convection, and thus on convective coverage/strength, even
   though forecast soundings suggest 40-50 kt effective-shear
   magnitudes are possible.  Isolated damaging gusts approaching severe
   limits, or small hail, cannot be definitively ruled out from a
   thunderstorm or two in this environment; however, the potential
   still appears too conditional to warrant categorical-level
   probabilities at this time.

   ..Edwards/Mosier.. 11/07/2017

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