Jan 11, 2018 0600 UTC Day 1 Convective Outlook
Updated: Thu Jan 11 05:49:45 UTC 2018 (20180111 1200Z Day 1 shapefile | 20180111 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180111 1200 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
20180111 1200 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
20180111 1200 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
20180111 1200 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 110549

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1149 PM CST Wed Jan 10 2018

   Valid 111200Z - 121200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated to scattered thunderstorms are expected across parts of the
   Gulf Coast and Mississippi Valley today and tonight.  Elsewhere,
   isolated thunderstorms will be possible across parts of the
   Carolinas and Mid-Atlantic.

   ...Synopsis...
   A large-scale mid-level trough over the central U.S. will slowly
   move eastward from the Great Plains into the MS Valley by Friday
   morning.  A shortwave trough located in the base of the larger-scale
   trough will translate east from the TX Rio Grande Valley to the
   central Gulf Coast.  Concurrently, a cold front extending from low
   pressure over the upper Great Lakes southwestward through the
   southern Plains will slide east-southeastward and push through much
   of the Great Lakes/OH Valley and through the western Gulf Basin
   during the period.

   ...TX/LA Sabine Valley eastward into the lower MS Valley...
   Southerly low-level flow ahead of the approaching front will advect
   moisture northward into the Gulf coastal plain during the day.  As
   stronger large-scale ascent/DCVA associated with the shortwave
   trough encounters a moist/weakly unstable airmass, showers and
   isolated thunderstorms are expected to develop over parts of
   southeast/east TX during the late morning.  Forecast soundings show
   moist profiles in the lowest several km with weak lapse rates.  Some
   weak diurnal destabilization will occur and yield scant buoyancy
   (50-250 J/kg MLCAPE).  As the mid- to high-level flow/forcing for
   ascent strengthens, the thunderstorms are forecast to grow upscale
   into a broken band during the afternoon near the Sabine River and
   develop east.  Model guidance is showing only a modest LLJ (850mb
   flow around 30-35 kt) with the stronger flow largely above 600mb. 
   As such, it appears some weak organization to the convective band
   may occur, which could lead to a stronger storm (localized strong
   gust).  However, the presence of weak lapse rates and relatively
   modest strength of flow in the low levels (available for momentum
   transport) appear as limiting factors for an otherwise relatively
   greater risk in thunderstorm (marginally severe) potential.  This
   activity will move east across the central Gulf Coast during the
   overnight amidst weak lapse rates.

   ..Smith.. 01/11/2018

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