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 181945
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0145 PM CST Tue Dec 18 2018
Valid 182000Z - 191200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not forecast through tonight across the
contiguous United States.
...20Z Update...
A small general thunderstorm area has been added to parts of
southwest TX, where a focused area of mid-level ascent is evident on
visible satellite imagery ahead of a shortwave trough. Isolated
lightning strikes may occur with this elevated convection mainly
through the rest of the afternoon. Otherwise, only minor adjustments
have been made to the general thunderstorm area across central/east
TX for later this evening and overnight.
A couple of low-topped thunderstorms have developed this afternoon
off the WA Coast in a post-frontal environment. Veered low-level
flow and weak instability should continue to preclude a meaningful
severe threat across this region.
..Gleason.. 12/18/2018
.PREV DISCUSSION... /ISSUED 1005 AM CST Tue Dec 18 2018/
...Western WA...
A powerful upper jet max and associated surface cold front are
moving ashore along the WA coast, resulting in widespread
precipitation. Several lightning strikes have been noted well
offshore. Forecast soundings suggest the unstable layer will be
sufficiently deep to support isolated lightning through much of the
afternoon in vicinity of the WA coastal ranges. There is a low
potential for a lightning strike farther inland across WA into ID,
but that risk appears to be less than 10%.
...Southeast TX...
A second strong shortwave trough is digging southeastward across
southern NM. Strengthening southerly low level winds ahead of the
system will help to moisten/destabilize the air mass over southeast
TX. This will lead to increasing coverage of showers and a few
embedded thunderstorms later tonight. No severe storms are
expected.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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