Valid 261300Z – 271200Z
…NO SEVERE THUNDERSTORM AREAS FORECAST…
The risk of severe thunderstorms appears negligible across the U.S.,
today through tonight.
A low-amplitude midlevel trough, with embedded speed maxima near
Texarkana and Laredo, will continue east-southeastward to the lower
MS/TN Valleys and the northwest Gulf of Mexico, respectively. Warm
advection on the north edge of a modifying Gulf air mass has
supported a few elevated thunderstorms overnight along the upper TX
coast. This zone of ascent will shift eastward today and weaken
gradually, though the threat for isolated elevated thunderstorms may
persist into tonight along the northern Gulf coast.
Otherwise, multiple midlevel shortwave troughs will move inland over
the Pacific Northwest and from CA to the southern Great Basin.
Steep midlevel lapse rates will accompany the southern trough, and
very isolated lightning flashes may occur from the CA central valley
today to NV this evening and northern AZ overnight. However,
buoyancy will remain quite weak (MUCAPE generally 100 J/kg or less),
and the threat for thunderstorms appears too small to justify a
relatively large outlook area. A separate shortwave trough will
move inland over OR/WA this evening. Some lightning has been noted
with this wave about 400 miles west of the OR coast, but forecast
soundings suggest buoyancy this evening may remain too weak/shallow
for any appreciable lightning threat over land.