RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1153 PM CDT Tue Apr 28 2026
Valid 291200Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF TEXAS AND THE GULF COAST STATES INTO SOUTHERN GEORGIA AND SOUTH
CAROLINAS...AND ACROSS THE CENTRAL APPALACHIANS/SOUTHERN
MID-ATLANTIC...
...SUMMARY...
Widely scattered strong to severe storms may impact a corridor from
south of the Texas Big Bend into the Gulf coast states and southern
Georgia/South Carolina Wednesday afternoon into evening. Additional
strong storms are expected across the central Appalachians and
southern Mid-Atlantic.
...Synopsis...
An upper trough will pivot across the Great Lakes and Midwest today.
Within southern stream flow, a weak shortwave impulse will migrate
through westerly flow aloft from Texas to the GA/SC coast. This will
result in enhanced westerly flow across the southern U.S. and the
Midwest to the Mid-Atlantic. At the surface, a cold front is
forecast to extend from northern IN southwestward into central TX
this morning. This front will develop southward across TX and
southeastward across the Lower MS Valley and Southeast through the
period. The northern extent of the front will shift east across the
Midwest to the Mid-Atlantic. This surface boundary will be a focus
for strong to severe thunderstorm development during the
afternoon/evening.
...TX to GA/SC Coast...
A moist airmass will be in place ahead of the surface front,
particularly across TX where dewpoints in the 70s are common.
Heating into the 80s and 90 of this very moist airmass will result
in a corridor of moderate to strong MLCAPE. The surface boundary
will be the main forcing mechanism for convection across TX and
storm coverage may remain isolated. Further east into the Lower MS
Valley/Southeast, a shortwave impulse will provide modest forcing
for ascent in addition to the southeast sagging cold front.
Isolated supercells across central TX will pose a risk for large
hail, with some potential for 2+ inch hail. Uncertainty concerning
storm coverage and capping across TX precludes an upgrade to Sight
risk at this time. Additional storms are expected to develop closer
to the Sabine Valley and Lower MS Valley this afternoon. Initial
thunderstorm clusters may congeal into one or more linear segment
and move across MS/AL/GA during the late afternoon into evening
hours. Hail and strong wind gusts will be possible with this
activity.
...Central Appalachians/Mid-Atlantic vicinity...
An upper shortwave trough emanating from the Great Lakes/Midwest
upper trough will overspread the region during the afternoon/evening
in tandem with the eastward advancing cold front. Modest boundary
layer moisture is forecast across the region, with dewpoints
generally in the 50s to near 60 F. Modest heating will result in
weak destabilization (generally 500-750 J/kg or less). Despite weak
instability, supercell wind profiles are evident in forecast
soundings. This should aid in at least transient organization of
stronger updrafts with a wind and hail risk. While instability and
moisture will be marginal, 0-1 SRH will approach 150 m2/s2 in
proximity to a weak surface low and a brief tornado could also
occur.
..Leitman/Moore.. 04/29/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1152 PM CDT Tue Apr 28 2026
Valid 301200Z - 011200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THURSDAY
AFTERNOON AND EVENING ACROSS PARTS OF THE RIO GRANDE NEAR THE TEXAS
BIG BEND...
...SUMMARY...
A couple of strong storms may impact the Rio Grande River vicinity
near the Texas Big Bend late Thursday afternoon and evening, perhaps
accompanied by at least some risk for severe hail.
...Discussion...
It still appears that an elongated area of lower mid-level heights
will continue a slow east-southeastward progression across much of
the upper Mississippi Valley through northern Atlantic Seaboard,
with an embedded cyclonic circulation redeveloping southeastward
through the Great Lakes region. In its wake, split westerlies
likely will remain confluent across and east of the Rockies, as a
short wave perturbation emerges from the subtropical eastern
Pacific.
There appears a much better consensus within latest model output
concerning the inland progression of this perturbation, which is now
generally forecast to accelerate across northern Mexico and adjacent
portions of the U.S. Southwest, toward the Texas Big Bend vicinity
Thursday through Thursday night. Downstream short wave ridging is
forecast to gradually shift east of the southern Rockies, across the
southern Great Plains through Gulf Coast, while subtropical ridging
centered across southern Mexico undergoes further suppression.
In lower levels, to the east of the Rockies, cool surface ridging
will be maintained across much of the Great Plains and
Mississippi Valley into Southeast. Most guidance now indicates that
the frontal zone on the leading edge of this air mass will make
slow, but steady, southward progress into and across the Texas Big
Bend and Hill Country, immediate upper Texas/Louisiana coastal
vicinity, and northern Florida.
Forcing for ascent associated with lower/mid-tropospheric warm
advection, downstream of the approaching subtropical perturbation,
may contribute to multiple rounds of thunderstorm development
above the stable surface-based air across parts of the Permian Basin
and Texas South Plains through much of central Texas by late
Thursday night. Based on latest model output, including Rapid
Refresh and NAM forecast soundings, thermodynamic profiles seem
unlikely to support severe hail. One exception might develop within
moist upslope flow into a more strongly heated environment across
the higher terrain near and south of the Texas Big Bend. Beneath
moderate to strong mid-level flow, the initiation of a couple of
supercells appears possible. However, this activity is expected to
weaken as it acquires less unstable updraft inflow to the east of
the higher terrain.
Otherwise, the front might provide a general focus for widely
scattered thunderstorm activity near the Gulf coast vicinity, while
destabilization beneath cool mid-level air across the Great Basin
into southern Rockies supports scattered, mostly diurnal
thunderstorm activity.
..Kerr.. 04/29/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Wed Apr 29 2026
Valid 011200Z - 021200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY AFTERNOON
INTO FRIDAY NIGHT ACROSS PARTS OF MIDDLE TEXAS COASTAL
AREAS...SOUTHEASTERN LOUISIANA...THE FLORIDA BIG BEND VICINITY AND
ADJACENT PORTIONS OF SOUTHWESTERN GEORGIA...
...SUMMARY...
Isolated severe thunderstorm development is possible across middle
Texas coastal areas, parts of southeastern Louisiana and the Florida
Big Bend region Friday afternoon through Friday night.
...Discussion...
Latest model output suggests that there will be substantive
amplification within the split westerlies emanating from the
mid-latitude Pacific during this period, with ridging building to
the west of 140W longitude into the higher latitudes of western
Canada, and on a larger-scale eastward across the Canadian Prairies
and northern U.S. Rockies. Within this ridging, a modest mid-level
trough and embedded low are forecast to slowly dig to the west of
the U.S. Pacific coast, while broad upper ridging gradually builds
across the subtropical eastern Pacific.
Downstream, a confluent mid-level regime will be maintained across
and east of the Rockies, enhanced across the Great Plains into
middle Mississippi Valley, in the wake of short wave troughing
forecast to dig to the southwest of an elongated area of lower
heights slowly shifting eastward through the Ontario/Quebec/Great
Lakes and Northeast vicinity.
A short wave perturbation reaching the Texas Big Bend vicinity by
12Z Friday is likely to undergo shearing as it progresses through
the confluence to the south of the digging trough. However, as a
reinforcing cool surge noses southward to the lee of the southern
Rockies, across and south/southeast of the Texas Big Bend, guidance
suggests a notable lingering impulse may support a developing wave
along a stalled frontal zone, across middle Texas coastal areas
through the eastern Gulf coast vicinity Friday afternoon through
Friday night.
...Middle Texas coastal plain through Florida Big Bend region...
Large-scale forcing for ascent aided by warm advection along and to
the cool side of the front may support a swath of mostly weak
thunderstorm activity across much of the Gulf into southern Atlantic
coast during this period. Among other model output, forecast
soundings from the NAM and RRFS indicate thermodynamic profiles with
little potential for severe hail and/or wind. One exception may be
across middle Texas coastal areas, where loaded gun type soundings,
probably based above a stable surface-based layer, may become
conducive to supercell development in the presence of strong shear,
as mid-level forcing for ascent overspreads the region by late
afternoon.
Late Friday evening across southeastern-most parishes of Louisiana,
through the Florida Big Bend region by 12Z Saturday, forecast
soundings suggest modest boundary-layer destabilization is possible
in a pre-frontal corridor coincident with strengthening deep-layer
shear and enlarging, clockwise-curved low-level hodographs. It is
possible that this will become supportive of supercells, accompanied
by the risk for a tornado or two, in addition to large hail and
localized damaging wind gusts.
..Kerr.. 04/29/2026
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