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 140538
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1138 PM CST Mon Dec 13 2021
Valid 141200Z - 151200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few thunderstorms are possible from portions of the West Coast to
the Four Corners region, as well as across parts of eastern and
southern Florida.
...Western US...
Strong 500mb speed max will rotate through the base of the
progressive western US trough into southern CA after 18z then
intensify as the short-wave trends toward negative tilt over the
Four Corners region by sunrise Wednesday. 180m 12hr mid-level height
falls will overspread southern CA early as exit region of the
aforementioned speed max approaches. Forecast soundings around the
LA basin suggest buoyancy will increase through 18z with modestly
steep lapse rates in the lowest 3-4km. This is where the majority of
instability will reside thus frontal convection may struggle to
attain heights necessary for appreciable lightning. Even so, 50+kt
850mb southwesterly LLJ may contribute to gusty winds with a shallow
band of frontal convection. At this time it appears convective winds
will remain below severe levels but activity should be organized
with the surging cold front.
Isolated thunderstorms are expected to spread/develop east across
portions of the southern Great Basin into the Four Corners region by
the end of the period as very cold mid-level temperatures and steep
lapse rates overspread this region late.
...FL Peninsula...
Isolated thunderstorms remain possible across eastern/southern FL in
advance of the weak short wave trough that is drifting southeast.
Weak low-level convergence along with moist easterly flow into this
region suggest a few updrafts may produce lightning.
..Darrow/Squitieri.. 12/14/2021
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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