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
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
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 240517
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1117 PM CST Thu Dec 23 2021
Valid 241200Z - 251200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunder is possible along the Pacific Coast as well as over
portions of the southern Great Basin and Colorado Plateau.
...Western US...
Early-day low-latitude short-wave trough will eject inland across
the lower CO River Valley then into the southern Rockies by late
afternoon. This feature will deamplify as it tracks into the OH
Valley by the end of the period. While some elevated convection may
be noted across portions of the mid MS Valley during the overnight
hours, possibly producing a lightning flash or two, the primary risk
for isolated thunderstorm activity will be across the western US,
north of the associated mid-level jet. Steep lapse rates and
large-scale forcing for ascent are expected to encourage deeper
updrafts that could generate lightning from southern CA into the
Great Basin/western CO.
Secondarily, exit region of a digging speed max will approach
northern CA by mid day. Height falls and cooling lower-tropospheric
profiles suggest weak low-topped convection is once again expected
to focus near/offshore of the WA/OR/northern CA Coast, north of this
digging jet. Forecast soundings suggest adequate buoyancy within a
steep low- mid-level lapse rate environment such that lightning
should be generated within the strongest updrafts.
..Darrow/Moore.. 12/24/2021
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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