Mar 24, 2021 2000 UTC Day 1 Convective Outlook
Updated: Wed Mar 24 19:50:46 UTC 2021 (20210324 2000Z Day 1 shapefile | 20210324 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20210324 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 30,159 3,556,344 Dallas, TX...Mesquite, TX...Waco, TX...Killeen, TX...Tyler, TX...
SLIGHT 86,601 9,143,345 Austin, TX...Fort Worth, TX...Arlington, TX...Plano, TX...Garland, TX...
MARGINAL 157,989 14,411,496 San Antonio, TX...Memphis, TN...New Orleans, LA...Birmingham, AL...Baton Rouge, LA...
Probabilistic Tornado Graphic
20210324 2000 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
5 % 29,244 3,244,487 Mesquite, TX...Waco, TX...Killeen, TX...Tyler, TX...Temple, TX...
2 % 176,144 18,314,700 San Antonio, TX...Dallas, TX...Austin, TX...Fort Worth, TX...New Orleans, LA...
Probabilistic Damaging Wind Graphic
20210324 2000 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
15 % 92,445 12,055,202 Dallas, TX...Austin, TX...Fort Worth, TX...Arlington, TX...Plano, TX...
5 % 161,536 13,444,559 San Antonio, TX...New Orleans, LA...Birmingham, AL...Baton Rouge, LA...Montgomery, AL...
Probabilistic Large Hail Graphic
20210324 2000 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
SIG SEVERE 31,191 6,792,838 Dallas, TX...Fort Worth, TX...Arlington, TX...Plano, TX...Garland, TX...
30 % 30,159 3,556,344 Dallas, TX...Mesquite, TX...Waco, TX...Killeen, TX...Tyler, TX...
15 % 71,982 8,620,178 Austin, TX...Fort Worth, TX...Arlington, TX...Plano, TX...Garland, TX...
5 % 170,867 14,645,655 San Antonio, TX...Memphis, TN...New Orleans, LA...Birmingham, AL...Baton Rouge, LA...
   SPC AC 241950

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0250 PM CDT Wed Mar 24 2021

   Valid 242000Z - 251200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   CENTRAL INTO NORTHEAST TEXAS...

   ...SUMMARY...
   Severe thunderstorms capable of large hail, damaging winds, and
   isolated tornadoes will be possible over parts of the southern
   Plains into the Arklatex, mainly this evening into tonight.

   ...20Z Update...
   Based on latest short-term guidance, the Slight and Enhanced Risk
   areas for hail have been expanded a little west-southwestward in
   central TX. Potential for multiple supercells developing this
   evening into tonight ahead of a mid-level shortwave trough and
   surface cold front remains apparent, with scattered large hail and a
   couple tornadoes possible. With steep mid-level lapse rates
   supporting moderate instability and very strong deep-layer shear,
   isolated very large hail may occur early in the convective life
   cycle before storms potentially grow upscale into one or more small
   bowing clusters with more of a damaging wind threat.

   ..Gleason.. 03/24/2021

   .PREV DISCUSSION... /ISSUED 1118 AM CDT Wed Mar 24 2021/

   ...North-Central TX this afternoon...
   Latest visible satellite loop shows relatively clear skies across
   much of north-central and northeast TX, with temperatures warming
   through the 60s.  Meanwhile, a surface warm front is lifting
   northward into this area, with 50s dewpoints now as far north as
   ACT.  This destabilizing process will continue through the
   afternoon, yielding MLCAPE values over 1000 J/kg.  Forecast
   soundings show little cap, and CAM guidance indicates the likely
   development of scattered thunderstorms across the warm sector and in
   vicinity of the warm front.  Supercell structures are expected with
   large hail being the main threat.  As the low-level moisture
   continues to improve through the evening, isolated tornadoes will
   also be possible as activity spreads into northeast TX.

   ...Central TX tonight...
   Water vapor imagery shows a shortwave trough over northern Mexico
   rounding the base of the larger-scale trough.  This feature will
   emerge into southwest TX after dark, leading to the development of
   scattered thunderstorms.  Similar to farther north, supercells
   capable of large hail and a tornado or two appears to be the main
   threat, although the potential for damaging winds could also
   increase with time.  This cluster of storms is expected to track
   east-northeastward through the pre-dawn hours into east TX, with a
   continued severe risk.

   ...Southern AR/northwest MS...
   A surface warm front is forecast to become better defined by evening
   over central MS/LA and lift northward overnight.  Thunderstorms are
   expected to develop along and north of this boundary after midnight.
   Meanwhile, model guidance is consistent in a strengthening low-level
   jet late tonight across this region - yielding enlarged hodographs
   and considerable low-level shear.  It is unclear if the convection
   along the immediate warm front will be surface-based.  However, if
   these storms can be rooted in the boundary-layer, the potential
   exists for supercells and bowing structures capable of damaging
   winds or an isolated tornado.

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