Sep 20, 2023 0100 UTC Day 1 Convective Outlook
Updated: Wed Sep 20 00:59:46 UTC 2023 (20230920 0100Z Day 1 shapefile | 20230920 0100Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20230920 0100 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 56,885 8,619,223 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Plano, TX...
MARGINAL 53,146 3,486,781 Tulsa, OK...Mesquite, TX...San Angelo, TX...Fort Smith, AR...Fayetteville, AR...
Probabilistic Tornado Graphic
20230920 0100 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
2 % 31,752 2,214,859 Oklahoma City, OK...Abilene, TX...Norman, OK...Wichita Falls, TX...Lawton, OK...
Probabilistic Damaging Wind Graphic
20230920 0100 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 % 56,634 8,561,831 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Plano, TX...
5 % 53,463 3,541,602 Tulsa, OK...Mesquite, TX...San Angelo, TX...Fort Smith, AR...Fayetteville, AR...
Probabilistic Large Hail Graphic
20230920 0100 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 36,568 2,404,492 Oklahoma City, OK...Abilene, TX...Norman, OK...Wichita Falls, TX...Lawton, OK...
15 % 46,762 3,779,108 Oklahoma City, OK...Abilene, TX...Norman, OK...Wichita Falls, TX...Denton, TX...
5 % 47,588 7,447,670 Dallas, TX...Fort Worth, TX...Tulsa, OK...Arlington, TX...Plano, TX...
   SPC AC 200059

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0759 PM CDT Tue Sep 19 2023

   Valid 200100Z - 201200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   WEST AND NORTH TEXAS...INTO OKLAHOMA...

   ...SUMMARY...
   Thunderstorms, associated with large hail (possibly greater than two
   inches in diameter) and wind damage, will be likely from parts of
   west and north Texas, into Oklahoma this evening.

   ...West and North Texas/Oklahoma...
   Latest water vapor imagery shows evidence of a shortwave trough over
   the central High Plains. RAP analysis has several vorticity maxima,
   associated with the trough, located from western Oklahoma into
   western Kansas. At the surface, a 1003 mb low is analyzed over
   northwest Texas, with backed southeasterly flow over much of
   Oklahoma and south-central Kansas. A pocket of maximized low-level
   moisture is present in this area where surface dewpoints are
   generally in the 60s F. This is contributing to a north-to-south
   corridor of moderate instability, with the RAP estimating MLCAPE in
   the 1500 to 2500 J/kg range. Thunderstorms are ongoing near the
   instability axis from west-central Oklahoma south-southwestward into
   west-central Texas. Isolated storms are also located in
   south-central Kansas. MCS development will be likely this evening as
   the storms move east-southeastward across the southern Plains.

   In addition to moderate instability, shear profiles across much of
   the southern Plains appear favorable for severe storms. The 00Z
   sounding from Norman, Oklahoma has 0-6 km shear near 45 knots with
   strong directional shear from the surface to 700 mb. In addition,
   700-500 mb lapse rates are near 8.5 C/km. This moderate deep-layer
   shear, combined with steep mid-level lapse rates, will support
   supercells with large hail this evening. Hailstones of greater than
   two inches in diameter will be possible with the most intense
   updrafts, mainly across southwest Oklahoma and northwest Texas. A
   wind-damage threat will also be likely with supercells, and with
   organized multicells. The severe threat is expected to continue
   through much of the evening.

   ..Broyles.. 09/20/2023

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