Jul 21, 2024 0600 UTC Day 1 Convective Outlook
Updated: Sun Jul 21 05:24:37 UTC 2024 (20240721 1200Z Day 1 shapefile | 20240721 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20240721 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 89,947 6,476,104 Phoenix, AZ...Tucson, AZ...Mesa, AZ...Colorado Springs, CO...Glendale, AZ...
Probabilistic Tornado Graphic
20240721 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
20240721 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
5 % 67,713 5,492,925 Phoenix, AZ...Tucson, AZ...Mesa, AZ...Glendale, AZ...Chandler, AZ...
Probabilistic Large Hail Graphic
20240721 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
5 % 40,278 1,172,527 Colorado Springs, CO...Pueblo, CO...Prescott, AZ...Prescott Valley, AZ...Cimarron Hills, CO...
   SPC AC 210524

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1224 AM CDT Sun Jul 21 2024

   Valid 211200Z - 221200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
   SOUTHWEST...

   ...SUMMARY...
   Isolated, marginally severe thunderstorms are possible this
   afternoon into early evening across parts of central and southern
   Arizona, and from southern Colorado to northeast New Mexico.

   ...Southwest...
   Scattered to widespread thunderstorms are expected this afternoon
   through sunset within a generally modest north-northwesterly
   mid/upper flow regime between an anticyclone over the western Great
   Basin and a low-amplitude trough in the central states. The most
   likely corridors for thunderstorm development will be across the
   southern Rockies and the Mogollon Rim.

   For the CO/NM portion, more favorable wind profiles will exist here,
   but buoyancy will largely remain weak owing to below-normal surface
   temperatures. Convection will probably struggle to greatly
   intensify, but a few updrafts may acquire transient supercell
   structure and be capable of marginally severe hail during the
   afternoon. Storms should largely consolidate into multicell clusters
   moving south-southeastward, with mainly a strong-gust threat over
   southeast CO and northeast NM that subsides closer to sunset.

   For the AZ portion, deep-layer shear will remain weak, but a more
   northerly orientation to the mid/upper flow should foster convection
   over the Rim spreading south into the lower deserts. Buoyancy south
   of the Rim should be moderate, with MLCAPE of 1000-2000 J/kg amid
   hot temperatures and low to mid 60s surface dew points. Loose
   multicell clustering may occur as outflows spread
   south-southwestward. While small to marginally severe hail is
   possible along the Rim, strong to isolated severe gusts will be the
   main hazard before convection weakens after sunset.

   ..Grams/Lyons.. 07/21/2024

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z