Mesoscale Discussion 0646
NWS Storm Prediction Center Norman OK
0237 PM CDT Tue May 05 2026

Areas affected...parts of northwestern into north central Texas

Concerning...Severe potential...Watch possible 

Valid 051937Z - 052230Z

Probability of Watch Issuance...40 percent

SUMMARY...The initiation of strong thunderstorms appears possible to
the west of Dallas/Forth Worth within the next couple of hours. 
This may include the evolution of an intensifying supercell or two,
which could pose potential for producing large, damaging hail
impacting at least parts of the Metroplex by 5-7 PM.  If/when this
becomes more certain, a severe weather watch probably will be
needed.

DISCUSSION...Just ahead of a southward advancing cold front, now
southeast of the Wichita Falls TX vicinity, stronger surface heating
and deeper boundary-layer mixing are ongoing in a narrow corridor
roughly focused along I-20 across the Abilene into Fort Worth
vicinity.  At least attempts at deepening convective development are
underway within this regime to the west-north of Mineral Wells,
where low-level forcing for ascent may be aided by weak low-level
warm advection and locally enhanced convergence, near the general
intersection of the cold front and dryline.

This is occurring beneath larger-scale mid/upper ridging
overspreading much of the southern Great Plains.  However, based on
various model output, including convection allowing guidance, 
further insolation, coupled with subtle mid-level height falls and
cooling, might become supportive of thunderstorm initiation within
the next few hours.  How long this activity is sustained before
tending to be undercut by the southward advancing cold front, and
whether this occurs prior to acquiring inflow of higher
boundary-layer moisture content along and to the east of the
dryline, remain unclear.

Even in the drier more strongly heated boundary-layer just to the
west/southwest of the cold front/dryline intersection, initial
thunderstorm development may become capable of producing large hail
and a locally strong downburst, in the presence of steep-lapse rates
and strong deep-layer shear.  If convection is able to acquire
inflow of boundary-layer air with dew points near 70F, which may be
maintained across eastern portions of the Metroplex, the potential
for much larger and damaging hail will become considerably greater.

..Kerr/Smith.. 05/05/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FWD...SJT...

LAT...LON   33289903 33379822 33019639 32189747 32399914 32829950
            33289903 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0246 PM CDT Tue May 05 2026

Valid 052000Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTH TEXAS INTO
WESTERN TENNESSEE...

...SUMMARY...
Widely scattered severe storms are possible this afternoon through
this evening from north Texas, much of Arkansas, and into western
Tennessee.  Large to very large hail, severe gusts, and a few
tornadoes are possible.

...20z Update...
The previous forecast largely remains on track with only minor
adjustments made. Recent GOES imagery shows gradual clearing across
northern TX into northwest LA and western AR with slow
warming/moistening noted in surface observations. A stable layer
remains evident in visible imagery across western AR, and a recent
18 UTC SHV RAOB sampled a stronger capping inversion at 850 mb
compared to what is depicted by latest high-res guidance. This casts
some uncertainty on convective coverage across southwest AR;
however, trends in time-lagged ensemble guidance and early high-res
WoFS solutions continue to show reasonably high confidence in
thunderstorm development along and north of the I-40 corridor in AR
and downstream into northern MS, middle TN, and northwest AL later
tonight. Although storm mode will likely transition to clusters and
embedded semi-discrete cells after 06 UTC, some severe threat will
likely persist into the early morning hours given adequate buoyancy
and ample deep-layer wind shear. The eastern extent of the 5%
wind/hail contours have been adjusted accordingly. 

Elsewhere, the forecast remains on track. See the previous
discussion below and recently issued MCD #646 for additional
details.

..Moore.. 05/05/2026

.PREV DISCUSSION... /ISSUED 1131 AM CDT Tue May 05 2026/

...Northeast TX into the Mid-South...
Radar mosaic shows an MCV moving east across far western KY with a
band of weak thunderstorms extending south and west across western
TN.  Convective outflow associated with the showers/thunderstorms
extends from east-west near I-40 across AR into eastern OK where it
intersects a triple point over central OK.  A cold front is draped
southwest to northeast along the I-44 corridor from western north TX
northeastward into the Ozarks.  

Visible-satellite imagery late this morning shows extensive cloud
cover from northeast TX northeastward into AR and the lower OH
Valley.  A plume of richer moisture at the surface is denoted by mid
to upper 60s deg F dewpoints protruding north from east-central TX
into north TX and southeast OK.  Further moistening of low levels
via southerly return flow is forecast beneath a capping inversion
around 850 mb sampled by the 12 UTC Forth Worth, TX raob.  

Gradual boundary layer heating will result in surface temperatures
warming into the upper 80s over north TX with muted heating farther
northeast over AR where persistent cloud cover will inhibit stronger
heating.  Model guidance shows MLCAPE ranging from 500-1500 J/kg
from northeast AR southwestward into southwest AR, and upwards of
3000 J/kg MLCAPE across north TX by mid-late afternoon.  Convergence
along the front will be modest and large-scale height rises are
anticipated.  However, thinning clouds near the OK/AR border and the
erosion of convective inhibition as convective temperatures are
breached over north TX will result in isolated to scattered storms
developing during 20-23 UTC period.  Initial supercell mode is
forecast over north TX with some clustering expected during the
evening.  The tornado risk over north TX will likely be limited by
relatively weak low-level shear but strong mid to high-level flow
will promote large to very large hail growth (1 to 3 inches in
diameter).  Farther northeast, isolated to scattered storms are
forecast to develop east of the eastward-migrating surface low and
near the front by the mid-late afternoon.  HRRR time-lagged runs
this morning show a few supercells with one more longer track storms
moving developing and moving east across central AR in a larger SRH
environment.  An all hazards severe risk may accompany the stronger
storms in AR beginning later this afternoon and possibly persisting
through the evening as this activity moves east towards the MS
River.  A strong tornado is possible with a sustained discrete
supercell.  Upscale growth into a cluster or band of storms is
expected as moderately strong southwesterly 850 to 700-mb flow is
maintained across the Mid South.  Damaging gusts and perhaps a
lingering tornado risk will possibly spread east tonight before
storms weaken late. 

...Lower Great Lakes into northern New England...
A marginally moist airmass will advect northeastward into the Lower
Great Lakes and Northeast ahead of an eastward-moving cold front,
with low 50s dewpoints likely reaching as far north as ME.  This
low-level moisture coupled with afternoon temperatures in the 70s
will support modest buoyancy, despite poor lapse rates. 
Thunderstorms are anticipated along and ahead of the
eastward-progressing front as it moves into the destabilized airmass
from the Lower Great Lakes into northern ME. 

Strong deep-layer vertical will be in place, supported by relatively
deep southwesterly flow, suggesting the potential for organized
storms.  However, this flow will be largely parallel to the
boundary, with linear structures favored.  Damaging gusts will be
possible with the strongest storms, although transient updraft
strength should keep the overall coverage and intensity modest.
Isolated hail is possible with a few storms as well.  Predominantly
linear mode should keep the tornado risk low, although a
low-probability threat still exists, particularly if a pocket of
strong buoyancy can develop across Upstate NY.

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1245 PM CDT Tue May 05 2026

Valid 061200Z - 071200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN
LOUISIANA ARCROSS PARTS OF MISSISSIPPI AND ALABAMA...

...SUMMARY...
Scattered severe thunderstorms are expected Wednesday afternoon and
evening from eastern Texas into the lower Mississippi and Tennessee
Valleys/southern Appalachians. Tornadoes appear most likely from
Mississippi into Alabama. Corridors of damaging winds may occur from
Texas into Georgia.

...Synopsis...
Strong mid to high level winds will intensify across the MS/OH/TN
Valleys on Wednesday as a positive-tilt upper trough moves out of
the Plains. Midlevel winds up to 50 kt will extend as far south as
the Gulf Coast, with 70+ kt sweeping across the TN Valley to the
Appalachians late.

At the surface, a cold front will extend from central TX into
northern MS and AL by 00Z, with a very moist air mass ahead of it.
Dewpoints in the 70s F will be common from TX into MS, with mid 60s
F into western GA by evening. Instability will be greatest from TX
into MS during the day, but will develop eastward across AL and into
western GA due to persistent west/southwest winds in the low levels.

The expansive area of strong deep-layer shear atop the very moist
air mass will support scattered to widespread thunderstorms
beginning late afternoon and spreading during the evening and
overnight. Corridors of tornado and wind damage potential appear
likely, with hail from TX into LA/MS.

...Eastern TX across much of the Southeast...
Early day storms are possible across TN and into northern MS/AL/GA,
possibly elevated due to and e-w outflow. A marginal wind threat
cannot be ruled out at that time.

The primary severe risk will develop during the late afternoon after
21Z and into the early evening, as instability builds. Supercells
may develop along and ahead of the cold front. The deep moist layer
combined with strong mid and high level flow should support
supercell mode with minimal cold downdraft initially. The severe
risk may persist during the evening into GA as the southwesterly
low-level jet brings instability into that area. Corridors of
damaging winds may evolve as well, especially along the cold front
late as storms become more numerous.

Farther west into TX, supercells producing hail and locally damaging
gusts are also likely near the front.

..Jewell.. 05/05/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0214 PM CDT Tue May 05 2026

Valid 071200Z - 081200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ...

...SUMMARY...
A few strong to severe thunderstorms are possible on Thursday across
portions of the central Gulf coast into South Carolina.

...Synopsis...
A strong upper-level speed max will move across the Southeast to Mid
Atlantic Thursday as the parent upper trough moves across the Great
Lakes and into the Northeast. A cold front will extend roughly from
the central Carolinas to the north-central Gulf Coast by late
afternoon, with 60s F dewpoints ahead of it.

Scattered thunderstorms may be ongoing Thursday morning across much
of this region ahead of the cold front, within the 850 mb theta-e
plume. A few strong gusts will be possible. Thereafter, the rapid
progression of the upper trough will foster midlevel drying, with
veering low-level winds. As such, the greatest potential for a few
strong storms appear to be from morning through midday prior to the
front moving offshore. Forecast soundings show very strong
deep-layer shear, but also increasing midlevel subsidence which may
counteract additional late afternoon development. Any additional
late day development should be quite isolated and marginal in
nature.

..Jewell.. 05/05/2026