No watches are valid as of Wed Jul 15 23:26:02 UTC 2026.MD 1629 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL INTO SOUTHEAST LOWER MICHIGAN
Mesoscale Discussion 1629
NWS Storm Prediction Center Norman OK
0623 PM CDT Wed Jul 15 2026
Areas affected...central into southeast lower Michigan
Concerning...Severe potential...Watch unlikely
Valid 152323Z - 160130Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated occurrences of damaging wind and/or marginally
severe hail appear possible with thunderstorms developing across the
discussion area. A watch is not currently expected.
DISCUSSION...Thunderstorms have recently developed along a cold
front from Gratiot and Clinton Counties into Oakland County.
Although smoke and some high cloudiness are likely reducing diabatic
warming, latest surface observations indicate temperatures in the
low 90s south of the front, which coupled with dewpoints in the low
to mid 70s, is resulting in a moderately to strongly unstable air
mass with MLCAPE as high as 2500-3000 J/kg, per latest objective
analysis. However, closer inspection of RAP-based soundings
indicates the presence of relatively warm mid-level temperatures,
which are reducing lapse rates through the 700-500 mb layer. That
coupled with a considerable amount of dry air through that layer and
the absence of appreciable forcing for ascent, it's quite possible
that the available parcel buoyancy may be less than what objective
analysis suggests.
The presence of 30-40 kt of northwesterly deep-layer shear may
offset some of the thermodynamic limitations, potentially leading to
episodic supercell structures with an associated risk for locally
damaging winds and marginally severe hail. Given the expected areal
coverage and magnitude of the threat, a watch is not currently
expected.
..Mead/Guyer.. 07/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DTX...GRR...
LAT...LON 42468376 42698453 43018491 43278505 43388473 43208368
42868312 42668279 42298304 42468376
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
MD 1628 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL AND SOUTHERN ARIZONA
Mesoscale Discussion 1628
NWS Storm Prediction Center Norman OK
0617 PM CDT Wed Jul 15 2026
Areas affected...portions of central and southern Arizona
Concerning...Severe potential...Watch unlikely
Valid 152317Z - 160115Z
Probability of Watch Issuance...5 percent
SUMMARY...Sporadic strong to severe gusts are possible with
scattered thunderstorms into this evening. Organization potential is
very limited and a watch is unlikely.
DISCUSSION...As of 2310 UTC, regional radar imagery showered
scattered to numerous thunderstorms ongoing over portions of central
and southern AZ. Over the last 2 hours, storm coverage has slowly
increased over the northwestern and southeastern portions of the
Mogollon Rim. While very warm surface temperatures are present,
buoyancy is fairly limited owing to modest moisture and mid-level
lapse rates. Still, it remains sufficient for occasional stronger
multicell updrafts within the weak easterly flow aloft. This should
keep storm organization potential very limited. However, dry
sub-cloud layers could support sporadic severe gusts with the
stronger downdrafts.
Expectations are for storm coverage to continue to increase first
over the higher terrain of central and southeast AZ. Eventually
these storms should spread westward into the lower deserts this
evening with some damaging gusts potential. While some severe
potential is possible, the lack of broader storm organization amid
weak vertical shear and modest buoyancy should preclude the need for
a watch.
..Lyons/Guyer.. 07/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TWC...FGZ...PSR...VEF...
LAT...LON 31811048 32011195 32331292 32881370 33371421 34271424
35031413 35211368 35101314 34961206 34481163 34291113
34021046 32940985 32281012 31811048
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MD 1627 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTH-CENTRAL TEXAS...INCLUDING THE SAN ANTONIO METRO AREA
Mesoscale Discussion 1627
NWS Storm Prediction Center Norman OK
0523 PM CDT Wed Jul 15 2026
Areas affected...south-central Texas...including the San Antonio
metro area
Concerning...Severe potential...Watch unlikely
Valid 152223Z - 160030Z
Probability of Watch Issuance...20 percent
SUMMARY...A localized brief tornado threat may evolve this evening
in the San Antonio metro area. A watch is not currently expected.
DISCUSSION...Low-level warm advection/isentropic ascent to the north
of an outflow boundary situated to the immediate south of the San
Antonio metro area is fostering recurring shower and thunderstorm
development with some weak rotation evident in radar data. The
current KEWX VWP, located to the north of the boundary, exhibits
pronounced veering of winds through the lowest 1 km AGL with
estimated SRH of 150-200 m2/s2 through that layer.
The air mass to the immediate north of the outflow boundary is quite
moist with dewpoints in the lower 70s, which are largely
contributing to MLCAPE of around 1000 J/kg. However, given the
cooler boundary-layer temperatures, low-level lapse rates are
relatively weak, which may limit parcel accelerations in the lower
part of the storms. Nonetheless, the presence of modest low-level
shear and a moist/low LCL environment indicates some potential for a
brief tornado this evening. Given the localized and brief nature of
the tornado threat, a watch is not currently expected.
..Mead/Guyer.. 07/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...EWX...
LAT...LON 29199881 29559898 29849871 29929831 29879790 29769764
29439757 29139771 28929827 29199881
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 PM CDT Wed Jul 15 2026
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC...NORTHERN NEW ENGLAND...NORTHERN ROCKIES/HIGH
PLAINS...PACIFIC NORTHWEST...ARIZONA...AND SOUTH-CENTRAL TEXAS...
...SUMMARY...
There is a conditional risk for severe thunderstorms capable of
producing large hail and damaging winds across parts of the
Mid-Atlantic this afternoon and evening. Isolated damaging winds
appear possible for portions of northern New England, the northern
Rockies/High Plains, Pacific Northwest, and Arizona. A brief tornado
or two may also occur across parts of south-central Texas.
...20z Update...
The previous forecast remains on track with only minor adjustments
made, predominately across southern Montana where guidance has
trended towards a slightly higher coverage of thunderstorms within
an environment favorable for strong/severe winds. These trends are
supported by recent MRMS mosaics which depict convection developing
along the WY/MT border (see MCD #1624 for additional information).
...Texas...
Although thunderstorm coverage has been decreasing since late
morning across portions of central/southern TX, recent VWP
observations continue to show a strongly sheared environment across
the greater San Antonio area with 0-1 km SRH on the order of 100-200
m2/s2. Additionally, clearing skies and warming temperatures are
contributing to destabilization across parts of the region, and lift
associated with a departing mid-level wave continues to influence
the region. Consequently, some potential remains for organized
convection through late afternoon. Diminishing wind fields through
the evening should gradually diminish the severe threat tonight.
See MCD #1625 and the previous discussion below for additional
forecast details.
..Moore.. 07/15/2026
.PREV DISCUSSION... /ISSUED 1131 AM CDT Wed Jul 15 2026/
...Northern Mid-Atlantic into the Northeast...
Recent surface analysis places a cold front from northern ME
southwestward into northern NY before arcing westward across
southeastern Ontario and west-northwestward across northern MI and
far northern WI into central MN. Eastern portion of this front is
expected to push southeastward through the Northeast today, moving
ahead of a low-amplitude and progressive shortwave trough currently
moving through eastern Ontario into far southern Quebec. Large-scale
ascent associated with this wave will spread across the region, but
warm temperatures aloft will likely limit thunderstorm coverage
across much of the region. A band of low-topped showers and
isolated/brief thunderstorms may develop during the afternoon
across northern New England, where forcing for ascent will be the
strongest. Overall buoyancy will be modest, but steepening low-level
lapse rates, a unidirectional/westerly wind profile with height
through mid levels, and 30-40 kt of flow around 1-2 km AGL will
support the potential for locally damaging wind gusts.
Farther south in the northern Mid-Atlantic, warm and moist
conditions will persist south of the front. However, warm mid-level
temperatures may prevent the airmass from fully destabilizing, with
lingering convective inhibition likely. Given this inhibition and
displacement farther south of the stronger forcing for ascent,
robust convective development remains highly uncertain.
Additionally, residual smoke could also limit heating, keeping
convective inhibition in place. That being said, strong deep-layer
westerly flow and steep mid-level lapse rates would support strong
outflow and perhaps even isolated hail with any storms that can
develop and mature.
...Northern Wyoming into Southern Montana...
Recent satellite imagery shows a weak vorticity maximum over eastern
ID. This vorticity max is forecast move northeastward today across
the northern Rockies and into the adjacent northern High Plains.
Diurnal heating across the higher terrain coupled with
the glancing influence of this subtle disturbance should foster the
development of scattered afternoon thunderstorms. Weak to moderate
instability is forecast, with a relatively deep and well-mixed
boundary layer across lower elevations. Scattered thunderstorm
coverage could result in some upscale growth into a loosely
organized cluster with cold pool organization, and a risk for
isolated severe wind gusts into the evening. However, the overall
severe threat should be tempered by modest deep-layer shear and
limited storm duration.
...Pacific Northwest...
Multiple rounds of isolated to scattered thunderstorms are possible
this afternoon along and east of the Cascades from central OR into
southern WA. The first round during the afternoon will be aided by
orographic influences and a weak shortwave trough preceding a closed
upper low off the coast of the Pacific Northwest. High cloud bases
and a deeply mixed boundary layer will support the potential for a
few strong gusts with this activity. Another round of storms is
possible later this evening/overnight as another weak shortwave
trough rounds the upper low as the low itself also drifts closer to
the coast. Very dry low to mid-levels will persist throughout the
evening/overnight, with the potential for isolated strong gusts
remaining possible.
...South-Central Texas...
Weak mid-level low over south-central TX will only drift slightly
westward today, remaining largely in place within the very moist
airmass over the region. Recent EWX VAD profiles show about 30 kt of
southerly flow between 1-3 km along the eastern periphery of this
low. Resulting hodographs show just enough low-level curvature to
support brief tornadoes given the tropical airmass in place.
...Arizona...
Weak east-northeasterly mid-level flow is forecast today across AZ,
which is on the southern periphery of upper ridging extending across
much of the central CONUS. Daytime heating of a seasonably moist
low-level airmass across southern/central AZ will yield modest
instability by mid afternoon. Initial development is anticipated
over the Mogollon Rim and higher terrain of southeast AZ, before
subsequently spreading westward into the lower deserts. A deeply
mixed boundary layer across the lower elevations could support
isolated strong to severe gusts.
|
