Valid 130100Z – 131200Z
…THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID MISSISSIPPI…OHIO AND TENNESSEE VALLEYS…
Severe storms capable of an isolated tornado threat, damaging winds
and large hail, remain possible into the nighttime hours from the
Arklatex northeastward across the mid Mississippi Valley into parts
of the Ohio and Tennessee Valleys.
…Arklatex/Mid Mississippi Valley/Ohio and Tennessee Valleys…
Several clusters of strong to severe thunderstorms are ongoing from
the Ohio Valley southwestward into the Ozarks. The storms are
located along a corridor of maximized surface dewpoints generally
from near 60 F in the Ohio Valley to the mid 60s F in the Ozarks.
The RAP is analyzing a small pocket of moderate instability in the
Arklatex. A couple strong line segments are ongoing along the
northeastern end of this instability in western and northern
Arkansas where MLCAPE is estimated of 1000 to 1200 J/kg. This is
combined with 0-6 km shear near 50 kt, evident on the Little Rock
00Z sounding. This environment should continue to support a severe
threat this evening as the activity moves eastward into eastern
Arkansas. An isolated tornado threat along with wind damage and hail
will be possible.
A couple line segments are also ongoing across central and
southeastern Kentucky. These storms are located near and to the
south of a warm front where instability is weak. In spite of this,
the Nashville 00Z sounding shows 0-6 km shear of 55 kt with a
looping hodograph. This environment could be enough to support
supercells with an isolated tornado threat for another hour or two.
The more organized parts of the line segments may also have a
wind-damage threat this evening.
An upper-level low will continue to move slowly eastward toward the
coast of southern California. Large-scale ascent associated with the
low will spread eastward across the Desert Southwest this evening.
An axis of instability is currently analyzed by the RAP in southeast
California and western Arizona where a line of thunderstorms is
ongoing. This line will move slowly eastward across southwest
Arizona this evening. Although instability is relatively weak ahead
of this convection, the large-scale ascent associated with the
upper-level low and strong deep-layer shear will be sufficient for a
marginal severe threat, with wind damage and hail possible.