Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0254 PM CDT Mon Jun 10 2024
Valid 102000Z - 111200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
NORTHERN/CENTRAL HIGH PLAINS...SOUTHEAST GA/COASTAL SC...AND WEST
TX...
...SUMMARY...
Severe thunderstorms with large hail and severe wind gusts should
continue across parts of the northern/central High Plains into early
evening. Other strong to severe thunderstorms with large hail and
damaging winds will remain possible across portions of the Southeast
States and west Texas through this evening.
...20Z Update...
Prior forecast reasoning remains largely on-track across the CONUS.
Primary categorical change has been to sever parts of the southern
High Plains level 1-MRGL risk area to the north/west of the
mid-level impulse drifting east-southeast. Here, abundant
cloudiness/rain has limited afternoon destabilization. In
conjunction with weak deep-layer shear, the potential for an
organized severe storm appears negligible. Please see MCD 1228 for
in-depth discussion on the severe potential ahead of this impulse in
the Permian Basin and TX South Plains.
Minor adjustments have also been made across the northern/central
High Plains area based on latest convective and observational
trends. No changes have been made to the severe threat area in the
Southeast States.
..Grams.. 06/10/2024
.PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Jun 10 2024/
...Northern/Central High Plains...
A mid-level shortwave trough noted on water vapor satellite imagery
over the northern Rockies will continue to advance eastward today
over the northern High Plains. A related weak surface low over
eastern MT should consolidate and shift into Saskatchewan through
early afternoon, while a separate surface low develops over the
central High Plains. A cold front is progged to move eastward
through the afternoon and early evening over the northern High
Plains. Low-level moisture will remain fairly limited ahead of the
front, with surface dewpoints generally in the mid to upper 50s.
But, steep mid-level lapse rates and daytime heating will aid in the
development of weak to locally moderate instability in a narrow
corridor by mid afternoon. Although mid-level flow is not expected
to be overly strong, sufficient veering/strengthening of the flow
with height through mid levels will still support generally 35-45 kt
of deep-layer shear. Current expectations are for thunderstorms to
develop along or just ahead of the front in the 18-20Z time frame.
Initial supercells should pose a threat for mainly severe hail, but
quick upscale growth into one or more small clusters will probably
lead to a greater severe/damaging wind risk as convection moves
quickly eastward. A tornado or two also appears possible. The
relatively narrow warm sector suggests that thunderstorm intensity
should decrease through the early evening with eastward extent
across the northern/central High Plains.
...Southeast...
Latest surface observations show a weak cold front situated across
southern AL/GA into coastal SC. The presence of a moist low-level
airmass and robust daytime heating along/south of this boundary will
likely promote moderate to locally strong instability developing by
early afternoon. Weak low-level convergence along the front, coupled
with modest ascent on the southern fringe of an upper trough over
the eastern CONUS, should support robust convective development by
18-20Z along/near the front in south/central GA and coastal SC. Weak
westerly low-level flow is forecast to gradually increase with
height through mid levels, which is expected to foster sufficient
deep-layer shear to support supercells. Large hail should be a
concern with this initially discrete activity, and some guidance
shows potential for splitting supercells given a relatively
long/straight westerly hodograph aloft. Occasional damaging winds
will also be a concern with any small bowing clusters that can
develop and spread eastward towards the coast through early evening.
Weaker low-level convergence with southward extent into southern AL
and the FL Panhandle suggests that overall thunderstorm coverage
will remain more isolated across these areas.
...Southern Plains...
A convectively augmented vorticity maximum/shortwave trough is
evident late this morning over NM and west TX. An MCV is also noted
in recent radar imagery across parts of northwest TX into the TX
Panhandle. A surface cold front is in place over the southern High
Plains. Although convective evolution remains somewhat uncertain
later today, scattered thunderstorms will probably develop on the
southern flank of the shortwave trough along and southwest of the
front, and where better daytime heating can occur. Mid-level flow
and related deep-layer shear should be a little stronger compared to
yesterday, mainly owing to the influence of the MCV and mid-level
shortwave trough. Latest high-resolution guidance continues to
variability in whether an MCS will develop and become organized
across west TX later today. Severe/damaging winds may occur if this
scenario is realized, along with some hail with any isolated
supercells that can develop.
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