Dec 29, 2020 1730 UTC Day 2 Convective Outlook
Updated: Tue Dec 29 17:30:27 UTC 2020 (20201229 1730Z Day 2 shapefile | 20201229 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20201229 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 35,887 8,230,563 Houston, TX...Austin, TX...Corpus Christi, TX...Pasadena, TX...College Station, TX...
Probabilistic Tornado Graphic
20201229 1730 UTC Day 2 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 2 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 15,199 5,331,870 Houston, TX...Corpus Christi, TX...Pasadena, TX...Sugar Land, TX...Missouri City, TX...
Probabilistic Damaging Wind Graphic
20201229 1730 UTC Day 2 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 2 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 15,367 5,383,595 Houston, TX...Corpus Christi, TX...Pasadena, TX...Sugar Land, TX...Missouri City, TX...
Probabilistic Large Hail Graphic
20201229 1730 UTC Day 2 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 2 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 36,114 8,364,697 Houston, TX...Austin, TX...Corpus Christi, TX...Pasadena, TX...College Station, TX...
   SPC AC 291730

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1130 AM CST Tue Dec 29 2020

   Valid 301200Z - 311200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE TEXAS COASTAL PLAIN AND VICINITY...

   ...SUMMARY...
   Thunderstorms -- and limited severe potential -- will affect
   portions of the Texas Coastal Plain and Hill Country from late
   afternoon Wednesday into the overnight hours.

   ...Synopsis...
   A highly amplified, split flow pattern will prevail across the U.S.
   Wednesday.  In the northern stream, a trough initially over the
   upper Midwest is forecast to move quickly east-northeastward across
   the Great Lakes, reaching New England late.  Meanwhile, a second,
   eastern Pacific short-wave trough will move inland over the Pacific
   Northwest early, and dig southeastward toward the Great Basin
   through the period.

   Meanwhile in the southern stream, an upper low is forecast to move
   across northern Mexico.

   At the surface, a cold front will move eastward across the Great
   Lakes region and into New England, and southeastward across the
   Ohio/mid and lower Mississippi/Tennessee Valleys, and southern
   Plains.

   Meanwhile, in response to the Mexican upper low, cyclogenesis is
   expected to occur during the second half of the period near the
   lower/middle Texas coast, eventually becoming commingled with the
   southeastward-moving cold front.

   ...Texas Coastal Plain and portions of the Hill Country...
   Showers and embedded thunderstorms -- ongoing at the start of the
   period -- are forecast to spread southeastward across the southern
   Plains Wednesday, along and behind the advancing cold front. 
   Meanwhile, pre-frontal shower activity is forecast to increase ahead
   of the front, with scattered thunderstorms evolving from within this
   activity by evening as warm advection increases ahead of the
   advancing upper system.

   Limited CAPE is expected in the vicinity of the front as it advances
   across Texas, with warm mid-level air/modest lapse rates limiting
   convective intensity.  Still, given ample flow aloft that may aid in
   sustenance of a few stronger updrafts, a 5% risk for hail appears
   warranted.

   Later, as a surface low develops near the southeast Texas coast, an
   increase in convection just ahead of the advancing front is
   expected.  With favorable low-level veering/shear, beneath amply
   strong mid-level flow, a few rotating storms may evolve overnight. 
   As such, very limited potential for a tornado (2%) and locally
   gusty/damaging winds (5%) will be included in this outlook, centered
   over the middle Texas Coastal Plain.

   ..Goss.. 12/29/2020

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