Dec 26, 2021 0600 UTC Day 1 Convective Outlook
Updated: Sun Dec 26 05:23:10 UTC 2021 (20211226 1200Z Day 1 shapefile | 20211226 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20211226 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
20211226 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
20211226 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
20211226 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 260523

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1123 PM CST Sat Dec 25 2021

   Valid 261200Z - 271200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated, weak thunderstorms are possible along the Pacific
   Northwest Coastline and across portions of the Inter-Mountain West
   during the day, and over parts of the Midwest late in the day and
   overnight. Severe weather appears unlikely.

   ...Synopsis and Discussion...
   A large area of cyclonic flow aloft will be situated over the West 
   early in the day, with an intense mid/upper jet streak over the Four
   Corners region. This feature will move quickly across the central
   Plains during the day, and will lift northeastward across the upper
   Mississippi Valley overnight.  Meanwhile, a secondary upper low will
   remain over the Pacific Northwest, with a jet max nosing south
   offshore Washington and Oregon.

   At the surface, low pressures will exist over much of the West early
   in the day, with a leading low developing over the central and
   northern Plains late in the day, in concert with the leading
   shortwave trough. A broad area of strong southwesterly low-level
   winds will develop over the Plains and into the Mississippi Valley,
   resulting in low 60s F dewpoints as far north as southern Missouri
   by 00Z. Moisture will continue to stream northeastward toward the
   lower Ohio Valley overnight, with the bulk of the lift from warm
   advection north of a surface warm front. As such, it is likely that
   only elevated thunderstorms will result, forming after 00Z over
   Missouri, and spreading east/northeast overnight. Although shear
   profiles will be very strong, only a few hundred J/kg of MUCAPE is
   forecast, thus severe hail is not expected.

   Elsewhere, only isolated, weak convection is anticipated over the
   coastal Pacific Northwest, and from the Great Basin into parts of
   Wyoming and Colorado, beneath cold air aloft and aided by daytime
   heating. Instability in these areas will be quite weak, at or below
   100 J/kg.

   ..Jewell/Moore.. 12/26/2021

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