RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Wed Jul 22 17:54:02 UTC 2026.
MD 1709 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE MID-ATLANTIC
Mesoscale Discussion 1709
NWS Storm Prediction Center Norman OK
1240 PM CDT Wed Jul 22 2026
Areas affected...portions of the Mid-Atlantic
Concerning...Severe potential...Watch unlikely
Valid 221740Z - 221945Z
Probability of Watch Issuance...20 percent
SUMMARY...Strong to occasionally severe thunderstorms will bring the
potential for isolated damaging wind gusts and perhaps a brief
tornado through this evening.
DISCUSSION...A prefrontal band of precipitation with embedded
thunderstorms remains ongoing across southern Virginia as of early
afternoon, with an area of denser cloud cover extending downstream
from this precipitation along the VA/NC border. This ongoing
thunderstorm activity is expected to spread eastward through this
afternoon, eventually interacting with greater buoyancy across far
eastern NC where dewpoints are in the upper 70s F. Additional
development is also anticipated along/ahead of an approaching cold
front across central and eastern Virginia where a relative lack of
cloud cover has allowed for stronger surface heating. This activity
will occur along the southern periphery of stronger mid/upper flow,
with effective shear of 30-40+ kts (greater with northward extent)
supporting a mixed mode of clusters and supercells. The primary risk
with this activity will be for isolated damaging wind gusts, with
the greatest potential likely to exist where low-level lapse rates
can appreciably steepen. A brief tornado also cannot be ruled out
given modestly enhanced low-level flow (~30 kts sampled by the
AKQ/MHX VAD profiles). However, veered low-level flow across the
region, poor mid-level lapse rates, and the likelihood that
low-level lapse rates will be at least somewhat tempered by the
aforementioned cloud cover suggest that convective
severity/intensity are likely to remain limited. Thus, watch
issuance appears unlikely at this time.
..Chalmers/Thompson.. 07/22/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PHI...AKQ...MHX...LWX...RAH...RNK...
LAT...LON 37417886 37977838 38507757 38697702 38747588 38647511
38487495 38227501 37577542 37187569 36947580 36647579
36317561 36097556 35917577 35707689 35627859 35707904
35967931 36387933 36697931 37417886
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
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MD 1708 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR A LARGE PORTION OF MAINE
Mesoscale Discussion 1708
NWS Storm Prediction Center Norman OK
1214 PM CDT Wed Jul 22 2026
Areas affected...A large portion of Maine
Concerning...Severe potential...Watch possible
Valid 221714Z - 221845Z
Probability of Watch Issuance...40 percent
SUMMARY...A gradual increase in storm coverage and intensity is
expected through the afternoon. A watch may be needed.
DISCUSSION...Storms have started to develop across western Maine
where temperatures are in the mid 70s with dewpoints in the mid 60s
F. Continued heating ahead of this activity will result in greater
destabilization this afternoon and additional storm coverage. 35 to
40 knots of shear is in place (per SPC mesoanalysis and regional
VWPs) which will aid in storm organization including some supercell
structures. The relatively weak instability casts some doubt on the
total coverage of severe storms, but if several severe storms can
develop, a severe thunderstorm watch may need to be issued.
..Bentley/Thompson.. 07/22/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CAR...GYX...
LAT...LON 45997046 46667011 47246951 47576918 47406882 47446820
47066765 45776774 45246834 44026955 42957076 43327092
44587112 45477085 45997046
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1121 AM CDT Wed Jul 22 2026
Valid 221630Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR MAINE AND THE MID-ATLANTIC...
...SUMMARY...
Scattered storms are expected across the Carolinas and southern
Mid-Atlantic, as well as New England this afternoon and early
evening, with damaging winds as the primary concern. Isolated strong
to severe wind gusts are also possible in the central High Plains,
southeast Texas and central Oregon, where isolated large hail will
also be possible.
...Northern New England this afternoon...
Per water vapor imagery and morning upper air observations, a
pronounced midlevel trough will progress east-northeastward from
PA/NY/Saint Lawrence Valley toward New England through this
afternoon. An associated surface cold front will likewise move
eastward and provide a focus for thunderstorm development by early
afternoon into Maine. A few cloud breaks developing from
west-to-east through the afternoon will allow surface temperatures
to warm into the 70s with boundary-layer dewpoints in the mid 60s,
resulting in MLCAPE in the 1000-1500 J/kg range. Deep-layer,
south-southwesterly shear will be sufficient for a mix of clusters
and supercells with a primary threat for occasional wind damage.
...Mid-Atlantic this afternoon/evening...
A pre-frontal band of convection is ongoing across southern VA, with
a narrow zone of stronger surface heating/destabilization to the
north of the thicker clouds from northern VA into MD/DE in advance
of a cold front moving across PA. The southern fringe of the
stronger (35-50 kt) midlevel flow extends to near the VA/NC border
on the south side of the thicker cloud band. The ongoing convection
is likely persist through the afternoon while spreading slowly
southward. Midlevel lapse rates will remain poor, but deep-layer
vertical shear will be sufficient for embedded/organized storms with
occasional wind damage. Low-level shear will be marginally
favorable for rotating storms and perhaps an isolated tornado.
...Southeast TX late this afternoon through late evening...
Strong surface heating is underway with a general confluence zone
near the TX/LA border well to the west of highly-sheared Tropical
Storm Bertha. As Bertha continues westward, this confluence zone
should support thunderstorm development into southeast TX late this
afternoon. Steering flow from the northeast at ~35 kt will favor
storm clusters moving southwestward into a hot, deeply mixed
boundary layer where buoyancy will be sufficient to maintain the
storm clusters into late evening. A few strong-severe outflow gusts
will be the main threats.
...Northeast CO and vicinity this afternoon/evening...
Low-level upslope flow on the cool side of a surface front, combined
with weak perturbations rotating around the northwest periphery of
the southern Plains midlevel high, will support afternoon
thunderstorm development over the foothills. The storms will spread
east-southeastward onto the plains, with a tendency for clustering
with the potential for isolated severe outflow gusts.
...OR this afternoon/evening...
Along the northwest edge of the monsoonal moisture plume, a midlevel
shortwave trough will move northward from northern CA into OR. Weak
forcing for ascent combined with daytime heating over the higher
terrain will support scattered thunderstorms later this
afternoon/evening from the Cascades into central OR. An environment
with MLCAPE of 500-1000 J/kg, steepening low-level lapse rates and
effective bulk shear near 25 kt will support isolated strong outflow
gusts and marginally severe hail.
..Thompson/Chalmers.. 07/22/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1220 PM CDT Wed Jul 22 2026
Valid 231200Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL HIGH PLAINS...
...SUMMARY...
Isolated severe storms capable of damaging wind will be possible the
central High Plains on Thursday.
...Synopsis...
A weak mid-level shortwave trough will move through the flow across
the central High Plains within the region between the amplified
western ridge and eastern trough Thursday afternoon. At the surface,
weak low pressure will develop across the Oklahoma/Texas Panhandles
with a stationary front/boundary in place from eastern Colorado into
the southern Plains. Thunderstorm development is likely across the
Front Range in Colorado, with an increase in coverage spreading into
the lower plains with the influence of the passing shortwave.
...Central High Plains...
Southerly to southeasterly flow across the southern/central High
Plains will bring moisture northward into portions of the
Oklahoma/Texas Panhandles and into western Kansas/eastern Colorado.
This in combination with steep mid-level lapse rates and heating
will yield a moderately unstable air mass from eastern Colorado into
western Kansas by the afternoon. Initially, storms are expected to
develop along the Front Range before moving into the lower plains
and western Kansas by the evening. Shear profiles across Colorado
will be fairly weak tempering severe potential. Nonetheless, deeply
mixed profiles may support some strong to severe outflow gusts. As
the shortwave shifts southward through the period, mid-level flow
will increase across western Kansas with resulting modest deep layer
shear increase. As storms/clusters move east through the late
afternoon/evening an organized cluster or two will have the
potential to produce damaging wind.
..Thornton.. 07/22/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1020 AM CDT Wed Jul 22 2026
Valid 221700Z - 231200Z
Minor modifications were made to the IsoDryT area based on the
latest observations and forecast guidance. The forecast remains on
track, and please see the previous discussion for more details.
..Nauslar.. 07/22/2026
.PREV DISCUSSION... /ISSUED 1201 AM CDT Wed Jul 22 2026/
...Synopsis...
Upper-level troughing will remain in place across the eastern U.S.
as a southward progressing cold front promotes widespread chances of
rainfall along the Eastern Seaboard today. Meanwhile, tropical
remnants will continue to translate northward along the western
periphery of a large-scale ridge across the western CONUS. As high
pressure shifts towards the Four Corners, additional monsoonal
moisture will advect into the Pacific Northwest.
A mix of wet/dry thunderstorms are expected across the IsoDryT area,
with overall coverage likely exceeding 50% across central/southern
Oregon--perhaps approaching 80% in central Oregon. PWAT values are
expected to approach 0.9-1.3" amid southerly flow induced training
of storms, indicating wetting rain is likely across portions of the
area. However, given a drought-stressed fuelscape and numerous
ongoing wildfires, lightning-induced ignitions will remain a concern
on the periphery of heavier precipitation. The lightning threat will
then shift northward into southwestern WA through the evening and
overnight hours. Forecast soundings depict dry sub-cloud layers up
to 700 mb, ample instability (MUCAPE greater than 500 J/kg), and
15-25 kt storm motions. This meteorological setup greatly increases
fire weather concerns as several days of dry and windy conditions
are expected to follow, potentially impacting nascent wildfires born
from thunderstorm activity.
...Please see www.spc.noaa.gov/fire for graphic product...
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