WW 496 SEVERE TSTM DC MD NC VA WV CW 181815Z - 190100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 496
NWS Storm Prediction Center Norman OK
215 PM EDT Sat Jul 18 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
District Of Columbia
Much of Maryland
North central and northeats North Carolina
Central and eastern Virginia
The eastern West Virginia Panhandle
Coastal Waters
* Effective this Saturday afternoon and evening from 215 PM until
900 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Scattered thunderstorms have formed along and immediately
east of the higher terrain. These storms will spread eastward
through late evening with the potential to produce wind damage and
isolated large hail.
The severe thunderstorm watch area is approximately along and 80
statute miles east and west of a line from 30 miles northeast of
Hagerstown MD to 20 miles southwest of Raleigh NC. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU6).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 492...WW 493...WW
494...WW 495...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
27020.
...Thompson
WW 495 TORNADO DE MD NJ PA CW 181755Z - 190100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 495
NWS Storm Prediction Center Norman OK
155 PM EDT Sat Jul 18 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Delaware
Eastern Maryland
New Jersey
Southeast Pennsylvania
Coastal Waters
* Effective this Saturday afternoon and evening from 155 PM until
900 PM EDT.
* Primary threats include...
A few tornadoes possible
Widespread damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Scattered thunderstorms are forming east of the higher
terrain and will spread eastward into the watch area through this
evening. The storm environment favors some supercell structures
with the potential to produce a few tornadoes in addition to wind
damage and isolated large hail. Additional storms will likely
spread into this same area from the northwest this evening with a
primary threat of damaging winds.
The tornado watch area is approximately along and 65 statute miles
east and west of a line from 25 miles north of Wilkesbarre PA to 35
miles south of Dover DE. For a complete depiction of the watch see
the associated watch outline update (WOUS64 KWNS WOU5).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 492...WW 493...WW 494...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 28030.
...Thompson
WW 494 SEVERE TSTM NY PA LE LO 181735Z - 190100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 494
NWS Storm Prediction Center Norman OK
135 PM EDT Sat Jul 18 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Western and central New York
Far northeast Pennsylvania
Lake Erie
Lake Ontario
* Effective this Saturday afternoon and evening from 135 PM until
900 PM EDT.
* Primary threats include...
Widespread damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
A tornado or two possible
SUMMARY...Clusters of storms and line segments are expected to
spread east-southeastward across western and central New York
through this evening. Damaging gusts of 60-70 mph will be the
primary severe threat, though embedded circulations could produce an
isolated tornado or two. Isolated large hail of 1.1.5 inches in
diameter may also occur with the strongest storms.
The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 30 miles south
southeast of Utica NY to 50 miles northwest of Jamestown NY. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 492...WW 493...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
30035.
...Thompson
WW 493 SEVERE TSTM IL IN MI OH LE LH 181720Z - 190000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 493
NWS Storm Prediction Center Norman OK
120 PM EDT Sat Jul 18 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Extreme northeast Illinois
Northern Indiana
Southeast Lower Michigan
Northwest Ohio
Lake Erie
Lake Huron
* Effective this Saturday afternoon and evening from 120 PM until
800 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 65 mph possible
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Bands of thunderstorms are forming along and immediately
ahead of a cold front, and storm coverage is expected to increase
through the afternoon. The more intense storms will be capable of
producing damaging winds up to 65 mph and isolated large hail of
1-1.5 inches in diameter.
The severe thunderstorm watch area is approximately along and 55
statute miles north and south of a line from 20 miles south
southeast of Mount Clemens MI to 45 miles north of Danville IL. For
a complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU3).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 492...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
31025.
...Thompson
WW 492 SEVERE TSTM OH PA WV LE 181700Z - 190100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 492
NWS Storm Prediction Center Norman OK
100 PM EDT Sat Jul 18 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northern and eastern Ohio
Western and central Pennsylvania
Far northern West Virginia
Lake Erie
* Effective this Saturday afternoon and evening from 100 PM until
900 PM EDT.
* Primary threats include...
Widespread damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
A tornado or two possible
SUMMARY...Thunderstorms will increase in coverage and intensity
through late afternoon/evening in multiple corridors/bands along and
well ahead of a cold front. The storm environment will favor a mix
of multicell clusters, line segments and supercells with a primary
threat of wind damage. Supercells close to the warm front could
pose the threat for a tornado or two in central Pennsylvania.
The severe thunderstorm watch area is approximately along and 70
statute miles north and south of a line from 45 miles southeast of
Williamsport PA to 50 miles west southwest of Akron OH. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU2).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
29030.
...Thompson
WW 0496 Status Updates
STATUS FOR WATCH 0496 HAS NOT BEEN ISSUED YET
WW 0495 Status Updates
STATUS FOR WATCH 0495 HAS NOT BEEN ISSUED YET
WW 0494 Status Updates
STATUS FOR WATCH 0494 HAS NOT BEEN ISSUED YET
WW 0493 Status Updates
STATUS FOR WATCH 0493 HAS NOT BEEN ISSUED YET
WW 0492 Status Updates
STATUS FOR WATCH 0492 HAS NOT BEEN ISSUED YET
MD 1649 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR ORTIONS OF SOUTHERN VIRGINIA...WESTERN NORTH CAROLINA...FAR NORTHEAST TENNESSEE...SOUTHEASTERN WEST VIRGINIA
Mesoscale Discussion 1649
NWS Storm Prediction Center Norman OK
1256 PM CDT Sat Jul 18 2026
Areas affected...ortions of southern Virginia...western North
Carolina...far northeast Tennessee...southeastern West Virginia
Concerning...Severe potential...Watch likely
Valid 181756Z - 181900Z
Probability of Watch Issuance...80 percent
SUMMARY...Scattered to numerous thunderstorms will continue to
increase in intensity this afternoon with a risk for damaging wind
gusts. Trends are being monitored and a Severe Thunderstorm Watch
is likely.
DISCUSSION...Thunderstorms continue to develop across the higher
terrain of WV, NC and VA at 1755z, and also along a confluence zone
extending from northern VA into western NC. Despite weak mid-level
lapse rates, diurnal heating of a moist boundary layer has
contributed to MLCAPE of 2000 to 3000 J/kg and low-level lapse rates
of 8.5 to 9 deg/C. In the presence of minimal CINH, storms should
continue to increase in coverage through the afternoon and move
generally east. Shear in the cloud-bearing layer will average 20-25
kts across northern portions of the discussion area and 15-20 kts
farther south, sufficient for updraft organization and a risk for
damaging wind gusts.
Trends are being monitored and a Severe Thunderstorm Watch will be
needed shortly.
..Bunting/Thompson.. 07/18/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...LWX...RAH...RNK...RLX...GSP...MRX...
LAT...LON 36938187 37458132 37957998 38207909 38197842 37907734
37557681 36927645 36077666 35487802 35237929 35118087
35298160 35678207 36228209 36938187
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
MD 1647 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHERN MICHIGAN INTO NORTHEAST ILLINOIS...NORTHERN INDIANA...AND NORTHWEST OHIO
Mesoscale Discussion 1647
NWS Storm Prediction Center Norman OK
1137 AM CDT Sat Jul 18 2026
Areas affected...Southern Michigan into northeast
Illinois...northern Indiana...and northwest Ohio
Concerning...Severe potential...Watch possible
Valid 181637Z - 181830Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorms developing along a cold front will continue
to intensify and pose a risk for large hail and severe winds through
the afternoon across portions of the Great Lakes/Midwest. Watch
issuance is being considered and may be needed within the hour.
DISCUSSION...Latest radar mosaics and GOES imagery shows maturing
convection along and just ahead of a southeastward moving cold front
with a few deeper, more robust updrafts noted across eastern lower
MI and southwest lower MI. Downstream of this developing convection,
temperatures continue to warm into the 80s within a moist air mass.
With further diurnal heating expected through late afternoon, MLCIN
will continue to erode as MLCAPE increases into the 2500-3000 J/kg
range. Additionally, regional VWPs are sampling 35-40 knot mid-level
flow over MI/OH with decreasing winds with westward extent. This
flow should remain in place through the day as a mid-level wave
continues to progress east/southeast towards the lower Great Lakes.
Given these convective and environmental trends, the expectation is
for additional thunderstorm development through the next few hours
with a steady uptick in intensification. Sufficient deep-layer shear
will promote organized storm modes, including the potential for a
few supercells initially (especially across MI) before frontal
ascent promotes increased clustering through late afternoon.
Consequently, some hail threat will likely materialize before
damaging/severe winds become the predominant threat through time
across IN and OH. Convective trends are being monitored, and watch
issuance will is probable as thunderstorm coverage continues to
increase.
..Moore/Thompson.. 07/18/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...
LAT...LON 40098729 40398838 40788880 41218885 41608871 41788841
41898744 42108638 42438516 42748447 43278358 43518288
43448249 43248225 42738223 41768210 41038228 40438264
40088349 40098729
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
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1120 AM CDT Sat Jul 18 2026
Valid 181630Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
THROUGH LATE EVENING FROM THE LOWER GREAT LAKES INTO THE
MID-ATLANTIC...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON EVENING FOR PARTS OF WESTERN MONTANA...
...SUMMARY...
Severe thunderstorms are expected across portions of the Ohio Valley
and Lower Great Lakes into the Mid-Atlantic and Northeast this
afternoon and evening. Damaging gusts will be the primary threat,
but a few tornadoes are possible, including perhaps a strong
tornado.
...Mid-Atlantic to the lower Great Lakes this afternoon/evening...
Ongoing convection across central PA/NY will continue to spread
eastward through early afternoon within a warm advection zone along
and north of a surface warm front. The warm front will move
northward today in advance of a surface cyclone and associated
midlevel trough now in the vicinity of Lake Huron. In the wake of
the ongoing convection, destabilization will occur as boundary-layer
dewpoints rise to near 70 F and surface temperatures into the 80s,
resulting in moderate buoyancy in the warm sector. Destabilization
will occur earlier immediately south-through-west of the ongoing
storms across eastern PA/NJ, and a little later this afternoon into
central NY.
Additional thunderstorm development is beginning in southwest PA and
vicinity as of 16z and a continued increase in storms is expected
into early-mid afternoon along a cold front and along pre-frontal
confluence zones/lake-enhanced boundaries. A mixed convective mode
(line segments and clusters) is expected, with embedded bowing
segments and a chance for pre-frontal supercells in PA/NY/NJ where
vertical shear and hodograph curvature will be larger along the warm
front. Wind damage will be the primary severe threat with both the
frontal convection and pre-frontal storms, with a few tornadoes
possible with supercell structures and/or embedded mesovortices.
...Northern Rockies late this afternoon/evening...
Scattered thunderstorm development is expected later this
afternoon/evening across western MT and vicinity, within the
northwest fringe of the midlevel ridge and monsoonal moisture plume.
Midlevel flow will be somewhat enhanced to the immediate southeast
of a midlevel trough moving over southeast BC, thus some organized
storm structures will be possible with faster storm motions compared
to yesterday. Occasional severe outflow gusts and large hail up to
1.5 inches in diameter will be the main threats.
..Thompson/Bunting.. 07/18/2026
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Sat Jul 18 2026
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
VIRGINIA INTO NORTH CAROLINA...AND OVER THE NORTHERN PLAINS...
...SUMMARY...
Scattered strong to severe thunderstorms may pose a risk for
damaging wind gusts over the Carolinas and southeast Virginia, and
over the Tennessee Valley Sunday afternoon. Strong to severe storms
may also develop across parts of eastern Montana into North Dakota
and Minnesota from late afternoon into the overnight period.
...VA/Carolinas into the TN Valley...
An upper trough will lift out of the Northeast on Sunday, with a
trailing cold front extending from southern VA westward toward the
KY/TN border during the afternoon. Ahead of the front, low 70s F
dewpoints and heating will lead to 1500-2000 J/kg MLCAPE despite
warmer air aloft. Modest west to northwest flow aloft will persist,
with 500 mb speeds around 20 kt near the VA/NC portion of the front.
Farther west into TN and AL, winds will be weaker but more northerly
at 10-15 kt.
Storms are likely to develop along the length of the front by early
afternoon, moving in a southeasterly direction. The most favorable
combination of mean wind speeds and deep-layer shear will be from VA
into NC, and corridors of damaging wind gusts may occur as various
clusters form along the front.
Farther west, the very moist and uncapped air mass should lead to
southward-moving storm clusters developing from TN into northern GA
and AL through the afternoon. At least isolated damaging gusts
appear likely.
...Northern Plains...
An upper ridge over the area will break down as a shortwave trough
moves across MT and into the northern Plains late. Deep-layer shear
will increase through the period with 40-50 kt. Storms should
develop near the surface trough coincident with peak heating from ND
into southeast MT, and forecast soundings show elongated hodographs
and steep lapse rates favorable for a few supercells producing large
hail and locally severe gusts. The severe risk will continue
east/southeastward into SD and MN through the evening and overnight,
as storm coverage increases with a southwesterly low-level jet and
height falls. Damaging winds should be the main concern, though a
large hail threat may persist if cellular modes should persist.
..Jewell.. 07/18/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1121 AM CDT Sat Jul 18 2026
Valid 181700Z - 191200Z
The forecast remains on track for elevated fire weather conditions
across portions of the Pacific Northwest and the northern High
Plains today. Current (16z) observations depict RH values quickly
plummeting beneath mostly clear skies -- apart from areas of dense
smoke in central-eastern OR/WA -- and a few wind gusts of 20+ mph in
terrain-favored areas. This afternoon, high temperatures across the
risk areas will approach 90-95 degrees (locally higher) yielding
better boundary layer mixing, allowing for RH values to decline to
less than 20% amid sustained winds of 10-15 mph (west-southwesterly
in the Northwest, southeasterly in the northern High Plains).
Despite several days of thunderstorms across OR/WA/ID, fuels remain
very dry with ERCs at or above the 90th percentile. Combined
meteorological conditions and a dry fuelscape will promote an
Elevated fire risk, especially in the Northwest where an abundance
of lightning strikes over the last several days has led to the
emergence of numerous wildfires.
..Elizalde-Garcia.. 07/18/2026
.PREV DISCUSSION... /ISSUED 1250 AM CDT Sat Jul 18 2026/
...Synopsis...
Along the northwestern periphery of an expansive upper ridge over
the West, a midlevel trough will advance eastward across BC and the
Northwest during the day. Within the base of the trough, strong
midlevel southwesterly flow will overspread WA, OR, northern CA, and
northwest NV. Associated downslope flow in the lee of the Cascades
and northern Sierra will aid in deep boundary-layer mixing into the
strengthening flow aloft. This will yield a broad area of 15 mph
sustained west-southwesterly surface winds (with higher gusts) amid
10-15 percent RH. Locally stronger surface winds can be expected in
terrain-favored/gap-flow areas through the Cascades. Given
dry/receptive fuels across region, elevated fire-weather conditions
are expected.
Farther east, lee troughing over the northern High Plains will
promote 10-15 mph sustained easterly surface winds across parts of
southeastern WY during the afternoon. These winds, combined with
15-20 percent RH and dry fuels, will favor elevated fire-weather
conditions.
...Please see www.spc.noaa.gov/fire for graphic product...
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