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 201221
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0621 AM CST Mon Nov 20 2017
Valid 201300Z - 211200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for severe thunderstorms appears negligible across the U.S.
today through tonight.
...Synopsis...
Gradual amplification of the western ridge/eastern trough pattern is
expected through Tuesday. An embedded shortwave trough over the Rio
Grande Valley will progress to the central Gulf of Mexico by
tonight, with some potential for very weak surface cyclogenesis
across the eastern Gulf in association with ascent preceding the
wave and air mass modification over the loop current. Isolated
lightning flashes have been observed this morning with convection
crossing the Rio Grande, and 12z soundings from CRP/BRO confirm
sufficient buoyancy rooted near or above 700 mb to sustain a
thunderstorm threat through the morning across deep south TX.
Otherwise, low-level moistening/destabilization is expected across
the southeast FL coast as a front stalls and then retreats back to
the north tonight. Only shallow convective showers are expected
today across southeast FL, but moistening could become sufficient
for deeper convection and isolated lightning flashes overnight.
..Thompson.. 11/20/2017
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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