SPC May 9, 2025 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0801 PM CDT Thu May 08 2025

Valid 090100Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTH TEXAS...THE TENNESSEE VALLEY...SOUTHERN APPALACHIANS AND
SOUTHEAST...

...SUMMARY...
Scattered thunderstorms with severe wind gusts and large hail will
continue this evening over parts of the Tennessee Valley, southern
Appalachians and Southeast. Severe wind gusts and large hail are
also expected across parts of south Texas, where hailstones of
greater than 2 inches in diameter will be possible.

...Tennessee Valley/Southern Appalachians/Southeast...
Latest water vapor imagery shows a positively-tilted mid-level
trough over the Ohio Valley, with an east-to-west oriented plume of
mid-level moisture from the mid Mississippi Valley into the south
and central Appalachians. At the surface, a quasi-stationary front
is analyzed in the Ohio Valley. To the south of the front over the
Ohio and Tennessee Valleys, surface dewpoints are in the mid 50s to
the mid 60s F. The RAP has moderate instability in place from the
Tennessee Valley eastward into the southern Appalachians and
southward into the Gulf Coast states. Scattered thunderstorms are
ongoing, concentrated along the northern edge of moderate
instability from Kentucky and Tennessee eastward into western North
Carolina. RAP forecast soundings in this vicinity early this evening
have 0-6 km shear ranging from 35 to 45 knots, mostly due to speed
shear in the mid-levels. This, combined with 0-3 km lapse rates in
the 7.5 to 8 C/km range, should be favorable for severe gusts with
the stronger cells. The shear will also support supercell
development with large hail possible. The severe threat should
become more isolated later this evening as instability decreases
across the region.

...South Texas...
A shortwave trough, with multiple vorticity maximums, appears to be
located in the lower Rio Grande Valley, according to water vapor
imagery. Scattered strong to severe thunderstorms are ongoing ahead
of the trough from near Laredo extending eastward onto the Texas
Coastal Plain. From the storms southward, moderate instability is
analyzed by the RAP, with MLCAPE estimated to be in the 1000 to 2000
J/kg range. The airmass is very moist with surface dewpoints in the
lower to mid 70s F. Within this moist airmass, RAP forecast
soundings early this evening have 0-6 km shear near 50 knots, with
700-500 mb lapse rates near 7.5 C/km. This environment will support
supercells with large hail, and hailstones greater than 2 inches in
diameter will be possible within the more intense cores. Isolated
severe gusts may also occur within the stronger downdrafts. The
ongoing severe storms will track southeastward across the remainder
of south Texas this evening...see MCD 749.

..Broyles.. 05/09/2025

Read more