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
Read more
WW 0495 Status Updates
STATUS REPORT ON WW 495
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NNW SBY
TO 20 SSW ACY TO 20 NE ACY TO 15 ENE NEL.
..HART..07/18/26
ATTN...WFO...PHI...LWX...
STATUS REPORT FOR WT 495
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NJC001-009-029-190040-
NJ
. NEW JERSEY COUNTIES INCLUDED ARE
ATLANTIC CAPE MAY OCEAN
ANZ431-450-451-452-453-454-455-190040-
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
DELAWARE BAY WATERS SOUTH OF EAST POINT NJ TO SLAUGHTER BEACH DE
COASTAL WATERS FROM SANDY HOOK TO MANASQUAN INLET NJ OUT 20 NM
COASTAL WATERS FROM MANASQUAN INLET TO LITTLE EGG INLET NJ OUT 20
NM
COASTAL WATERS FROM LITTLE EGG INLET TO GREAT EGG INLET NJ OUT 20
NM
COASTAL WATERS FROM GREAT EGG INLET TO CAPE MAY NJ OUT 20 NM
Read more
WW 0494 Status Updates
STATUS REPORT ON WW 494
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 WSW ELM
TO 10 NNW ELM TO 30 SE UCA.
..HART..07/18/26
ATTN...WFO...BUF...BGM...
STATUS REPORT FOR WS 494
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NYC007-015-017-023-025-077-097-101-105-107-109-190040-
NY
. NEW YORK COUNTIES INCLUDED ARE
BROOME CHEMUNG CHENANGO
CORTLAND DELAWARE OTSEGO
SCHUYLER STEUBEN SULLIVAN
TIOGA TOMPKINS
PAC015-069-079-103-115-127-131-190040-
PA
. PENNSYLVANIA COUNTIES INCLUDED ARE
BRADFORD LACKAWANNA LUZERNE
PIKE SUSQUEHANNA WAYNE
WYOMING
LEZ020-LOZ030-190040-
CW
Read more
WW 0492 Status Updates
STATUS REPORT ON WW 492
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 SE MFD TO
25 S CAK TO 10 WSW FKL TO 15 ENE DUJ TO 30 WNW AVP.
..HART..07/18/26
ATTN...WFO...CLE...PBZ...CTP...
STATUS REPORT FOR WS 492
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
OHC013-019-031-059-067-075-081-083-111-117-119-121-157-190040-
OH
. OHIO COUNTIES INCLUDED ARE
BELMONT CARROLL COSHOCTON
GUERNSEY HARRISON HOLMES
JEFFERSON KNOX MONROE
MORROW MUSKINGUM NOBLE
TUSCARAWAS
PAC001-003-005-007-009-013-019-021-027-031-033-035-037-041-043-
051-055-057-059-061-063-065-067-071-073-075-081-085-087-093-097-
099-107-109-111-113-119-125-129-133-190040-
PA
. PENNSYLVANIA COUNTIES INCLUDED ARE
ADAMS ALLEGHENY ARMSTRONG
BEAVER BEDFORD BLAIR
BUTLER CAMBRIA CENTRE
CLARION CLEARFIELD CLINTON
COLUMBIA CUMBERLAND DAUPHIN
FAYETTE FRANKLIN FULTON
Read more
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
Read more
WW 0493 Status Updates
STATUS REPORT ON WW 493
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 WSW VPZ
TO 15 NNW LAF TO 10 SSE DNV.
..HART..07/18/26
ATTN...WFO...LOT...IWX...GRR...DTX...
STATUS REPORT FOR WS 493
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ILC053-075-091-182340-
IL
. ILLINOIS COUNTIES INCLUDED ARE
FORD IROQUOIS KANKAKEE
INC007-111-182340-
IN
. INDIANA COUNTIES INCLUDED ARE
BENTON NEWTON
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0501 PM CDT Sat Jul 18 2026
Valid 201200Z - 261200Z
...Synopsis...
The extended forecast period exhibits a critical fire weather
pattern for the Pacific Northwest and parts of northern California.
A broad mid-level ridge will dominate over much of Intermountain
West through early next week as troughing across the northeastern
U.S. amplifies midweek. Model guidance suggests better chances of
dry thunderstorm impacts for the Pacific Northwest emerging as early
as Day 3/Monday as moisture from tropical storm Elida gets wrapped
up along the northwestern periphery of the upper ridge. Beyond Day
5/Wednesday, an incoming upper trough and influence from tropical
storm Elida are expected to contribute to the breakdown of the upper
ridge, encouraging dry air and gusty winds to overlap portions of
the Northwest where lightning activity is forecast early in the
forecast period.
...Days 3-5/Monday-Wednesday...
The thunderstorm threat across CA and the Pacific Northwest remains
very sensitive to the expected track of a subtropical moisture plume
from tropical storm Elida. Thunderstorms could threaten
central/northern CA as early as Day 3/Monday, moving into the
Pacific Northwest by Days 4-5/Tuesday-Wednesday. While forecast
PWATs range from 0.9-1.3", fast storm motions may limit
precipitation efficiency, generating greater ignition potential as
the fuelscape remains receptive. For this outlook, 10% dry
thunderstorm probabilities were introduced on Day 3/Monday for the
initial surge of subtropical moisture into northern CA and southern
OR. Additional probabilities and adjustments may be needed in future
outlooks as the upper pattern is better resolved.
...Days 6-8/Thursday-Saturday...
Following several days of mixed wet/dry thunderstorm potential,
longer term ensemble guidance suggests a return to dry and breezy
conditions across portions of CA and the Pacific Northwest beginning
Day 6/Thursday. Ensemble cluster analysis suggests a more inland
push of an upper-trough into the Pacific Northwest on Day 7/Friday,
with broader 40% Critical probabilities expanded (and introduced on
Day 8/Saturday) across WA/OR into far southwest ID.
..Elizalde-Garcia.. 07/18/2026
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0501 PM CDT Sat Jul 18 2026
Valid 201200Z - 261200Z
...Synopsis...
The extended forecast period exhibits a critical fire weather
pattern for the Pacific Northwest and parts of northern California.
A broad mid-level ridge will dominate over much of Intermountain
West through early next week as troughing across the northeastern
U.S. amplifies midweek. Model guidance suggests better chances of
dry thunderstorm impacts for the Pacific Northwest emerging as early
as Day 3/Monday as moisture from tropical storm Elida gets wrapped
up along the northwestern periphery of the upper ridge. Beyond Day
5/Wednesday, an incoming upper trough and influence from tropical
storm Elida are expected to contribute to the breakdown of the upper
ridge, encouraging dry air and gusty winds to overlap portions of
the Northwest where lightning activity is forecast early in the
forecast period.
...Days 3-5/Monday-Wednesday...
The thunderstorm threat across CA and the Pacific Northwest remains
very sensitive to the expected track of a subtropical moisture plume
from tropical storm Elida. Thunderstorms could threaten
central/northern CA as early as Day 3/Monday, moving into the
Pacific Northwest by Days 4-5/Tuesday-Wednesday. While forecast
PWATs range from 0.9-1.3", fast storm motions may limit
precipitation efficiency, generating greater ignition potential as
the fuelscape remains receptive. For this outlook, 10% dry
thunderstorm probabilities were introduced on Day 3/Monday for the
initial surge of subtropical moisture into northern CA and southern
OR. Additional probabilities and adjustments may be needed in future
outlooks as the upper pattern is better resolved.
...Days 6-8/Thursday-Saturday...
Following several days of mixed wet/dry thunderstorm potential,
longer term ensemble guidance suggests a return to dry and breezy
conditions across portions of CA and the Pacific Northwest beginning
Day 6/Thursday. Ensemble cluster analysis suggests a more inland
push of an upper-trough into the Pacific Northwest on Day 7/Friday,
with broader 40% Critical probabilities expanded (and introduced on
Day 8/Saturday) across WA/OR into far southwest ID.
..Elizalde-Garcia.. 07/18/2026
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0501 PM CDT Sat Jul 18 2026
Valid 201200Z - 261200Z
...Synopsis...
The extended forecast period exhibits a critical fire weather
pattern for the Pacific Northwest and parts of northern California.
A broad mid-level ridge will dominate over much of Intermountain
West through early next week as troughing across the northeastern
U.S. amplifies midweek. Model guidance suggests better chances of
dry thunderstorm impacts for the Pacific Northwest emerging as early
as Day 3/Monday as moisture from tropical storm Elida gets wrapped
up along the northwestern periphery of the upper ridge. Beyond Day
5/Wednesday, an incoming upper trough and influence from tropical
storm Elida are expected to contribute to the breakdown of the upper
ridge, encouraging dry air and gusty winds to overlap portions of
the Northwest where lightning activity is forecast early in the
forecast period.
...Days 3-5/Monday-Wednesday...
The thunderstorm threat across CA and the Pacific Northwest remains
very sensitive to the expected track of a subtropical moisture plume
from tropical storm Elida. Thunderstorms could threaten
central/northern CA as early as Day 3/Monday, moving into the
Pacific Northwest by Days 4-5/Tuesday-Wednesday. While forecast
PWATs range from 0.9-1.3", fast storm motions may limit
precipitation efficiency, generating greater ignition potential as
the fuelscape remains receptive. For this outlook, 10% dry
thunderstorm probabilities were introduced on Day 3/Monday for the
initial surge of subtropical moisture into northern CA and southern
OR. Additional probabilities and adjustments may be needed in future
outlooks as the upper pattern is better resolved.
...Days 6-8/Thursday-Saturday...
Following several days of mixed wet/dry thunderstorm potential,
longer term ensemble guidance suggests a return to dry and breezy
conditions across portions of CA and the Pacific Northwest beginning
Day 6/Thursday. Ensemble cluster analysis suggests a more inland
push of an upper-trough into the Pacific Northwest on Day 7/Friday,
with broader 40% Critical probabilities expanded (and introduced on
Day 8/Saturday) across WA/OR into far southwest ID.
..Elizalde-Garcia.. 07/18/2026
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Sat Jul 18 2026
Valid 182000Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
LOWER GREAT LAKES AND MID-ATLANTIC...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
WESTERN TO CENTRAL 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.
...20z Update...
The previous forecast remains on track with only minor adjustments
required based on recent convective trends. Lingering clouds and
stratiform precipitation across northern NY and into VT/NH continues
to limit confidence in the degree of destabilization that will occur
through the remainder of the day. Latest high-res ensemble guidance
has captured recent trends and depicts limited potential for intense
convection through this evening. Severe wind/hail probabilities have
been reduced to reflect the decreasing potential. For additional
short-term forecast details across the lower Great Lakes see MCD
#1650.
Further west, the 5/15% wind probabilities have been expanded
slightly eastward to account for trends in recent guidance that
depict some threat for severe winds across central MT later tonight
as thunderstorms begin to cluster. Given building buoyancy, strong
shear across the region (per recent mesoanalysis estimates), and
building cumulus within the terrain, environmental trends appear to
support the eastward expansion. See MCD #1651 for additional
short-term details.
..Moore.. 07/18/2026
.PREV DISCUSSION... /ISSUED 1120 AM CDT Sat Jul 18 2026/
...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.
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Sat Jul 18 2026
Valid 182000Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
LOWER GREAT LAKES AND MID-ATLANTIC...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
WESTERN TO CENTRAL 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.
...20z Update...
The previous forecast remains on track with only minor adjustments
required based on recent convective trends. Lingering clouds and
stratiform precipitation across northern NY and into VT/NH continues
to limit confidence in the degree of destabilization that will occur
through the remainder of the day. Latest high-res ensemble guidance
has captured recent trends and depicts limited potential for intense
convection through this evening. Severe wind/hail probabilities have
been reduced to reflect the decreasing potential. For additional
short-term forecast details across the lower Great Lakes see MCD
#1650.
Further west, the 5/15% wind probabilities have been expanded
slightly eastward to account for trends in recent guidance that
depict some threat for severe winds across central MT later tonight
as thunderstorms begin to cluster. Given building buoyancy, strong
shear across the region (per recent mesoanalysis estimates), and
building cumulus within the terrain, environmental trends appear to
support the eastward expansion. See MCD #1651 for additional
short-term details.
..Moore.. 07/18/2026
.PREV DISCUSSION... /ISSUED 1120 AM CDT Sat Jul 18 2026/
...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.
Read more
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0239 PM CDT Sat Jul 18 2026
Valid 191200Z - 201200Z
...NO CRITICAL AREAS...
Hot daytime temperatures amid marginally dry and breezy conditions
are expected across north-central Montana on Day 2/Sunday afternoon.
Such meteorological conditions would typically provoke Elevated
highlights; however, expansive green-up and sparse fuels alleviate
broader fire concerns.
..Elizalde-Garcia.. 07/18/2026
.PREV DISCUSSION... /ISSUED 1251 AM CDT Sat Jul 18 2026/
...Synopsis...
An upper ridge will build over the Northwest in the wake of a
departing midlevel trough. While a continuation of warm and dry
conditions are expected, weaker surface winds will limit
fire-weather concerns regionally compared to previous days. However,
locally elevated conditions are still possible in wind-prone areas,
given the continuation of warm/dry conditions and receptive fuels.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 PM CDT Sat Jul 18 2026
Valid 201200Z - 211200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE UPPER MIDWEST AND GREAT LAKES...
...SUMMARY...
Severe thunderstorms are probable across portions of the Upper
Midwest and Great Lakes vicinity on Monday. Swaths of damaging winds
will be the most likely hazard, with isolated large hail as well.
Isolated strong to damaging gusts may occur over parts of the
Carolinas.
...From Lake Superior to Iowa...
A strong shortwave trough will move southeastward across the
northern Plains and upper MS Valley on Monday, with 50-60 kt 500 mb
winds across MN/IA/WI enhancing deep-layer shear. Early day storms
may occur within the warm advection regime, with at least some
threat of severe wind or hail. This activity may weaken during the
day and give way to diurnal destabilization, with areas of strong
instability developing. Notably, mid to high level winds will be
quite strong, with highly elongated hodographs favoring both
supercells and severe bows. Corridors of significant wind will be
possible, with some models indicating a bimodal distribution
(northern WI, and IA). However, the environment across the entire
area ahead of cold front will conditionally support severe storms.
Despite some uncertainties, the synoptically evident upper wave and
ample instability support an upgrade to Enhanced Risk.
...North Carolina...
A weak surface low will develop over NC with strong daytime heating
beneath modest northwest flow aloft. Mid 70s F dewpoints will
contribute to MLCAPE over 2000 J/kg, with clusters of storms
developing during the afternoon. Multicellular clusters appear
likely, moving generally eastward with potential for locally
damaging outflow winds.
..Jewell.. 07/18/2026
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0442 PM CDT Fri Jul 17 2026
Valid 191200Z - 251200Z
...Discussion...
A broad mid-level ridge will dominate over much of Intermountain
West through next week as troughing across the northeastern U.S.
amplifies midweek. Monsoon moisture trapped within weak flow under
the ridge and afternoon instability will support daily afternoon
showers and thunderstorms over higher terrain across the Colorado
River Basin and eastern Great Basin. This higher RH environment and
slow moving, terrain anchored convection will mitigate ignition
potential. Mainly dry conditions will persist across the interior
portions of the Pacific Northwest and CA through Day 4/Monday. Short
wave impulses on the western periphery of the upper ridge could
bring thunderstorms back into CA as early as Monday. Longer term
model guidance suggests better chances of dry thunderstorm impacts
for the Pacific Northwest emerging for the latter part of next week
as moisture from tropical storm Elida gets wrapped up in a
mid-latitude trough.
The building ridge aloft and lack of robust surface pressure
features across the West will keep winds relatively light across the
western coastal states where fuels are more receptive. Longer term
ensemble guidance suggests a return to breezy conditions across
portions of CA and the Pacific Northwest beginning Day 7/Thursday
where 40 percent critical probabilities have been added to
northeastern CA/southern OR. Ensemble cluster analysis suggests a
more inland push of an upper-trough into the Pacific Northwest on
Day 8/Friday, with a broader 40 percent critical probability area
introduced into much of central OR, northeastern CA and adjacent
northwest NV. The thunderstorm threat across CA and the Pacific
Northwest remains very sensitive to the expected track of a
subtropical moisture plume from tropical storm Elida. Thunderstorms
could threaten central/northern CA as early as Day 5/Tuesday, moving
into the Pacific Northwest by Day 7-8/Thursday-Friday. For this
outlook, introduced a 10 percent dry thunderstorm probability for
initial surge of subtropical moisture into northern CA and southern
OR, although this could change based on future model guidance.
..Williams.. 07/17/2026
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
MD 1642 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WEST AND SOUTHWEST MONTANA AND EXTREME NORTHEAST IDAHO
Mesoscale Discussion 1642
NWS Storm Prediction Center Norman OK
0312 PM CDT Fri Jul 17 2026
Areas affected...West and southwest Montana and extreme northeast
Idaho
Concerning...Severe potential...Watch unlikely
Valid 172012Z - 172215Z
Probability of Watch Issuance...20 percent
SUMMARY...Scattered thunderstorms are expected to form through
mid-late afternoon with a gradual increase in the threat for
isolated severe outflow gusts and large hail.
DISCUSSION...Visible satellite imagery reveals deepening convection
over the high terrain across southwest and western MT where surface
temperatures have warmed well into the 80s with dewpoints in the
mid-upper 50s. The 18z soundings from TFX and BOI suggest that
surface temperatures need to warm to 90+ F to eliminate convective
inhibition for the lower elevations, though inhibition has
diminished over the higher terrain. Though forcing for ascent will
remain subtle, there are embedded perturbations rotating northward
over ID/western MT around the northwest periphery of the midlevel
ridge. These perturbations, in combination with additional surface
heating, will support scattered thunderstorm development the next
few hours. Steepening low-level lapse rates will favor
strong-severe outflow gusts as the main threat in an environment
with moderate buoyancy. Isolated large hail may also occur with any
more organized/supercell storms, given effective bulk shear of 30-35
kt.
..Thompson/Guyer.. 07/17/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...TFX...MSO...OTX...
LAT...LON 46011013 45580943 45210931 45080955 45271109 45631269
45671368 46071469 47121509 48091510 48921488 48951402
48931310 47981257 47041194 46431126 46011013
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Fri Jul 17 2026
Valid 172000Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
IDAHO INTO MONTANA...THE GREAT LAKES...AND THE OHIO VALLEY INTO THE
SOUTHEAST...
...SUMMARY...
Strong to potentially severe storms are possible today across parts
of western Montana and northern Idaho, and also across parts of the
Upper Midwest and northern Great Lakes. More isolated strong to
severe storms with damaging wind gusts are possible over parts of
the Ohio Valley and Southeast.
...20z Update...
The previous forecast remains largely on track based on latest
trends in ensemble guidance. Recent runs of the RRFS/HRRR
time-lagged ensemble continue to show some potential for organized
convection across northern WI and into the U.P. of Michigan later
this evening, and latest trends in GOES imagery show building
cumulus that seem to support these solutions. However, the overall
ensemble signal for widespread severe convection on the U.S. side of
the international border remains limited. Similarly, a corridor of
more focused wind potential may emerge across west-central MT this
evening, but given low ensemble probabilities for severe winds,
coupled with modest low-level lapse rates in latest RAP mesoanalyses
and forecast soundings, limits confidence in a widespread severe
wind threat. See the previous discussion below and MCD #1641 for
additional details.
..Moore.. 07/17/2026
.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Jul 17 2026/
...Northern Rockies and northern High Plains...
The region will be influenced by an increasingly progressive
shortwave trough moving northeastward from off the Washington coast
and over southern British Columbia. The preceding upper ridge will
flatten/shift eastward particularly near the international border,
with a plume of rich monsoonal moisture extending into the region,
highlighted by prevalent middle 50s to lower 60s F dewpoints along
the Continental Divide. Orographic lift and heating will promote the
development of scattered thunderstorms this afternoon, especially
across eastern/northern Idaho and western Montana. Steepened
low-level lapse rates will potentially yield storms capable of
isolated severe wind gusts beginning this afternoon and continuing
into mid-late evening. Isolated large hail may occur with the
stronger thunderstorm cores, especially over northwest Montana where
deep-layer shear may exceed 30 kt.
...Upper Midwest and northern Great Lakes...
A decaying cluster of storms continues to spread southeastward
across northern Michigan, and smoke will continue to be a factor
regionally, albeit with some west-to-east abatement later today. A
cold front associated with the upper wave will push southeastward
across the Upper Midwest and provide a focus for thunderstorm
redevelopment late this afternoon, and more so into this evening.
Forecast model guidance shows moderate buoyancy developing today
within a belt of 25-40 kt west-northwesterly 500-mb flow as upstream
shortwave trough amplification occurs.
A few of the stronger thunderstorms could evolve into supercells and
organized multicell clusters, although uncertainty persists
regarding the overall magnitude/extent of today's severe potential.
Isolated large hail and damaging gusts are the primary hazards,
although a brief tornado risk may also develop in the areas
surrounding Lake Superior. One or more clusters of strong to severe
storms may persist into the overnight along the warm front.
...Ohio Valley to the southern Appalachians and Florida...
A moist and diurnally destabilizing airmass will support scattered
to numerous storms developing by the mid afternoon. Some of the
stronger water-loaded downdrafts will potentially be capable of
50-60 mph gusts and isolated wind damage.
...West-central Texas...
A weak mid- to upper-level low over west Texas will move little
during the day while a warm/moist conveyor persists across southern
into central parts of Texas. Despite very moist low levels and some
enlargement of the low-level hodograph, weak flow in the mid levels
should limit storm organization and meaningful supercell potential,
more so favoring a heavy rain threat.
Read more
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0245 PM CDT Fri Jul 17 2026
Valid 181200Z - 191200Z
...Southeastern Wyoming...
Elevated highlights have been added to portions of southeastern WY
for Saturday. A large scale upper ridge over the central U.S. and
Intermountain West will promote unseasonably warm temperatures and
dry surface conditions to portions of the central and northern
Plains. A surface low developing in southwestern WY will aid in
stronger easterly low-level flow of 10-15 mph across eastern WY.
These winds along with minimum RH of 15-20% will support elevated
fire weather conditions over exceptionally dry fuels (ERC values
around the 95-98th percentile) Saturday afternoon.
...Columbia Basin, Idaho Panhandle, interior Oregon and adjacent
areas of California and Nevada...
Stronger mid-level southwest flow will linger over the Pacific
Northwest as an upper trough moves northeastward into British
Columbia. Dry, downslope flow in the lee of the Cascades and
northern Sierra Nevada will support RH of 15-20 percent by
mid-afternoon Saturday. These dry conditions along with receptive
fuels will support an elevated fire weather concern for the region
with impacts to active wildfires in the Pacific Northwest expected.
Latest model guidance suggests stronger surface winds across the ID
Panhandle Saturday under the 50-55 knot mid-level jet. This should
promote sustained winds of around 15 mph (locally higher favorable
terrain gaps) across the ID Panhandle Saturday. Due to potential for
impact from lightning ignitions from Day 1/Friday, extended elevated
highlights into ID Panhandle to cover this fire weather threat.
..Williams.. 07/17/2026
.PREV DISCUSSION... /ISSUED 0150 AM CDT Fri Jul 17 2026/
...Synopsis...
Between a midlevel trough moving across BC and an expansive
large-scale ridge over the central/western CONUS, enhanced
deep-layer south-southwesterly flow will overspread a deep/dry
boundary layer (around 10-15 percent RH) in the lee of the northern
Sierra and Cascades. These dry conditions combined with around 15
mph sustained west-southwesterly surface winds will favor elevated
fire-weather conditions during the afternoon, given dry/receptive
fuels.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 PM CDT Fri Jul 17 2026
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CAROLINAS INTO SOUTHEAST VIRGINIA...
...SUMMARY...
Isolated to widely scattered strong to severe thunderstorms may pose
a risk for damaging wind gusts across portions of the southern
Appalachians to the coastal Carolinas/southeast Virginia vicinity on
Sunday. Strong to severe storms may also develop across parts of
eastern Montana into North Dakota and Minnesota.
...Southern Appalachians into the Coastal Carolinas/southern VA...
A broad mid/upper-level trough will remain in place across much of
the eastern CONUS on Sunday. A weakening cold front may become
nearly stationary by afternoon somewhere across southern VA.
Scattered storm development is expected during the afternoon
along/ahead of the remnant frontal zone, and also near the higher
terrain of the southern Appalachians.
Deep-layer flow/shear will generally be weak to modest, but large
PW, steepening low-level lapse rates, and moderate to locally strong
buoyancy will support vigorous updrafts and localized downbursts. In
addition, low/midlevel flow may be sufficient for one or two
outflow-driven clusters to evolve with time and move southeastward
into the early evening, with wind-damage potential.
...Parts of eastern MT into ND/MN...
A vigorous shortwave trough may evolve into a mid/upper-level low as
it moves eastward across the Canadian Prairies on Sunday. An
attendant surface low is forecast to gradually intensify as it moves
toward Lake Winnipeg. A surface trough/weak cold front will move
into northeast MT during the day and across parts of the Dakotas
during the evening.
A conditionally favorable environment is expected to evolve across
parts of far eastern MT into ND and northwest MN during the
afternoon/evening, as a 40-50 kt midlevel jet and steep lapse rates
overspread a warm and relatively moist boundary layer. However, with
the strongest height falls and ascent expected to remain north of
the international border, capping may inhibit diurnal storm
development. Any storms that are able to develop and mature during
the afternoon and early evening could evolve into organized cells or
clusters with severe wind and hail potential.
Even if surface-based diurnal development is suppressed, there will
be some potential for elevated convection to develop Sunday evening
into the overnight. Steep lapse rates, moderate elevated buoyancy,
and sufficient effective shear could support a hail threat with the
strongest elevated storms, and severe-wind potential with any
forward-propagating clusters that can develop Sunday night.
The Level-1/Marginal Risk has been expanded westward across ND and
far eastern MT to account for the conditional threat in these areas,
though confidence in the details of storm coverage and evolution
remains low at this time.
..Dean.. 07/17/2026
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1229 PM CDT Fri Jul 17 2026
Valid 181200Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
THE LOWER GREAT LAKES INTO THE MID-ATLANTIC...
...SUMMARY...
Severe thunderstorms are expected across portions of the Ohio Valley
and Lower Great Lakes into the Mid-Atlantic and Northeast, mainly
Saturday afternoon into the evening. Some threat may linger into
late Saturday night.
...Ohio Valley/Lower Great Lakes into the Mid-Atlantic/Northeast...
An active severe-weather day is expected Saturday from parts of the
Ohio Valley and Lower Great Lakes into the Mid-Atlantic, as
scattered to widespread storms move through an increasingly
favorable environment. A 45% wind area has been added, resulting in
a categorical upgrade to Level-3/Enhanced Risk. The Enhanced Risk
area is a combination of multiple regimes which may eventually
overlap, with some areas potentially seeing multiple rounds of
strong to severe storms.
A mid/upper-level shortwave trough is forecast to move across the
northern Great Lakes vicinity through the day, before approaching
New England by evening. In conjunction with this shortwave trough, a
deepening surface low is expected to move across southern Quebec
toward northern Maine, as a trailing cold front moves through the
Great Lakes and eventually parts of the Mid Atlantic and Northeast.
A remnant surface front initially draped from southern NJ into
western PA will lift northeastward as an effective warm front, in
advance of the surface low and cold front.
As strengthening deep-layer wind fields overspread increasingly rich
moisture, a broad region from the Ohio Valley and Lower Great Lakes
into the Mid-Atlantic and parts of the Northeast will become
supportive of organized convection and severe-thunderstorm
potential. HRRR-based forecasts suggest that smoke will become less
prominent from west to east by afternoon, which should allow for
relatively strong diurnal heating and moderate destabilization in
areas not affected by early-day convection. Effective shear of 35-45
kt will support organized clusters and possibly occasional
supercells from the Lower Great Lakes into the northern Mid-Atlantic
and Northeast, while strong heating and steep low-level lapse rates
will result in a favorable wind-damage environment within the
somewhat weaker flow regime across the southern Mid-Atlantic and
parts of the Carolinas.
Elevated convection may be ongoing or else develop during the
morning across parts of PA/NY, within a warm-advection regime
associated with the returning warm front. Depending on the timing of
this convection and downstream heating/destabilization, some
intensification of ongoing convection may occur by early afternoon.
Additional development may occur along the southwest flank of
early-day convection and related outflow, which may intensify and
move across the northern Mid-Atlantic during the afternoon. In
addition to a wind-damage threat, some hail and tornado potential
may also evolve with any supercell development, given the presence
of favorable effective SRH.
Farther north, a broken band of storms is expected to develop along
the cold front and move across the Lower Great Lakes region,
eventually reaching a larger part of OH/PA/NY by late afternoon or
early evening. Additional storms may develop ahead of the frontal
convection, depending on the extent of heating in the wake of
early-day storms. Multiple wind-damage swaths may accompany this
convection, along with some potential for isolated hail. Rich
moisture and some enhancement to low-level SRH may also support a
tornado threat with any discrete or embedded supercells, especially
near the effective warm frontal zone or any remnant outflow
boundaries from morning convection.
An initially separate regime of storm development and severe
potential is expected to develop along/east of a surface trough
across parts of the southern Mid-Atlantic into NC. While deep-layer
flow will tend to weaken with somewhat southward extent, strong
heating and steepening of low-level lapse rates will provide a
favorable thermodynamic environment for downbursts and damaging
outflow winds.
Depending on the extent of outflow from prefrontal storms, frontal
convection may continue to pose at least an isolated severe threat
through the evening as it spreads southeastward.
...Parts of ID/MT...
A mid/upper-level low initially near Vancouver Island is forecast to
move east-northeastward as a shortwave trough across southern BC/AB
on Saturday. This shortwave will only have a glancing influence on
parts of the Northwest and northern Rockies, but modestly enhanced
midlevel southwesterlies will be maintained across the region
through the day/evening. Widely scattered storm development is again
expected during the afternoon, with MLCAPE increasing to near 1000
J/kg and effective shear of 30+ kt supporting a threat of isolated
hail and localized strong to severe gusts.
..Dean.. 07/17/2026
Read more
