WW 490 SEVERE TSTM NH NY VT 150500Z - 151100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 490
NWS Storm Prediction Center Norman OK
100 AM EDT Wed Jul 15 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southern New Hampshire
Northern New York
Southern Vermont
* Effective this Wednesday morning from 100 AM until 700 AM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...A cluster of strong to severe thunderstorms will continue
to move quickly southeast and into the Watch area tonight. A couple
of the stronger storms may be supercells posing a risk for isolated
large hail. Scattered damaging gusts 55 to 70 mph are possible with
the more intense storms, especially if a small cluster can evolve
later tonight.
The severe thunderstorm watch area is approximately along and 25
statute miles north and south of a line from 65 miles west northwest
of Glens Falls NY to 15 miles southeast of Concord NH. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU0).
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 488...WW 489...
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
31045.
...Smith
WW 0490 Status Updates
STATUS REPORT ON WW 490
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WSW GFL
TO 20 S SLK.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1622
..GLEASON..07/15/26
ATTN...WFO...GYX...ALY...BTV...
STATUS REPORT FOR WS 490
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NHC005-011-013-019-150840-
NH
. NEW HAMPSHIRE COUNTIES INCLUDED ARE
CHESHIRE HILLSBOROUGH MERRIMACK
SULLIVAN
NYC113-115-150840-
NY
. NEW YORK COUNTIES INCLUDED ARE
WARREN WASHINGTON
VTC003-021-025-027-150840-
VT
. VERMONT COUNTIES INCLUDED ARE
BENNINGTON RUTLAND WINDHAM
WW 0489 Status Updates
STATUS REPORT ON WW 489
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 S SLK TO
30 WSW MPV TO 10 E LCI TO 15 E CON.
WW 489 WILL BE ALLOWED TO EXPIRE AT 150800Z.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1622
..GLEASON..07/15/26
ATTN...WFO...GYX...BTV...
STATUS REPORT FOR WS 489
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NHC001-150800-
NH
. NEW HAMPSHIRE COUNTIES INCLUDED ARE
BELKNAP
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.
WW 0488 Status Updates
STATUS REPORT ON WW 488
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 70 NNE BIL
TO 15 SSE GGW TO 15 NNW OLF.
WW 488 WILL BE ALLOWED TO EXPIRE AT 150700Z.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1620
..SMITH..07/15/26
ATTN...WFO...TFX...GGW...BYZ...
STATUS REPORT FOR WS 488
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC033-055-079-087-103-105-150700-
MT
. MONTANA COUNTIES INCLUDED ARE
GARFIELD MCCONE PRAIRIE
ROSEBUD TREASURE VALLEY
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.
MD 1622 CONCERNING SEVERE THUNDERSTORM WATCH 489...490... FOR NORTHERN NY...SOUTHERN VT...SOUTHERN NH
Mesoscale Discussion 1622
NWS Storm Prediction Center Norman OK
0156 AM CDT Wed Jul 15 2026
Areas affected...northern NY...southern VT...southern NH
Concerning...Severe Thunderstorm Watch 489...490...
Valid 150656Z - 150830Z
The severe weather threat for Severe Thunderstorm Watch 489, 490
continues.
SUMMARY...The risk for large hail (1 to 1.5 inches in diameter) and
damaging gusts (55 to 70 mph) will likely move southeast into
southern parts of VT/NH over the next couple of hours.
DISCUSSION...Radar mosaic at 0655 UTC shows a couple of severe
thunderstorms moving southeast along a remnant baroclinic zone
draped across New England. Surface temperatures have been slow to
cool with upper 70s to lower 80s F being maintained beneath
thunderstorm anvil cloud canopy. Ample mid to high-level flow
increasing with height on area WSR-88Ds VADs (75-kt at 8km MSL) will
continue to support storm venting and promote a cellular storm mode.
Although MUCAPE has decreased into the overnight, around 2000 J/kg
is indicated by HRRR-based objective analysis. As a result,
episodic intensification of storms will probably continue with
supercellular structure. Isolated large hail and damaging gusts
will be the primary threats with this activity over the next few
hours as it shifts southeastward into southern parts of VT/NH.
..Smith.. 07/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BOX...BTV...ALY...
LAT...LON 42677097 42677146 42757197 43847448 44217454 44397436
44437398 43167080 42817080 42677097
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1252 AM CDT Wed Jul 15 2026
Valid 151200Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NEW ENGLAND...THE MID-ATLANTIC...NORTHERN ROCKIES...AND ARIZONA...
...SUMMARY...
There is a conditional risk for severe storms capable of large hail
and damaging winds in the Mid-Atlantic Wednesday afternoon and
evening. Isolated occurrences of mainly damaging wind gusts appear
possible in northern New England, the northern Rockies, and Arizona.
...Synopsis...
A high-over-low blocking pattern will remain anchored over central
North America with an embedded shortwave trough and associated 70 kt
mid-level jet streak translating through New England and the
northern Mid-Atlantic Wednesday afternoon. That system will be
attended by a surface front, which will settle south into the
central Mid-Atlantic during the peak of the diurnal heating cycle.
...Mid-Atlantic...
Temperatures in the 90s to around 100 are forecast south of the
front, which coupled with dewpoints in the upper 60s to low 70s,
will contribute to a moderately unstable air mass by afternoon with
MLCAPE of 1500-2500 J/kg. The strongest height falls/forcing for
ascent associated with the shortwave trough are expected to remain
north of the surface frontal zone, and as a result, the extent of
thunderstorm development along the boundary remains uncertain.
Another factor that could limit storm development is the potential
for instability reduction along the front due to the existence of
wildfire smoke, as depicted in recent HRRR runs.
Given the uncertainty in storm initiation and sustenance, a level
1/Marginal Risk will be maintained with this forecast. However, on
the condition that surface-based storms develop, the presence of
seasonably strong mid-level winds and resultant 40-50+ kt of
effective bulk shear will support supercells capable of large hail
and damaging winds.
...Northern New England...
Within the zone of strongest forcing for ascent associated with the
shortwave trough, a band of low-topped showers and thunderstorms is
expected to develop during the afternoon amidst a marginally
unstable environment. Steepening low-level lapse rates and a
unidirectional wind profile with 35-40 kt winds as low as 1.5-2.0 km
AGL will support the potential for locally damaging wind gusts.
...South-central Montana and north-central Wyoming...
Heating along the high terrain coupled with the glancing influence
of a subtle disturbance is expected to foster widely scattered
afternoon thunderstorms amidst a moderately unstable air mass
featuring a relatively deep, well-mixed boundary layer. A number of
the 00Z CAMs indicate the potential for some cold pool organization
with an attendant risk for isolated severe wind gusts into the
evening.
...Arizona...
Scattered afternoon and evening thunderstorms are expected from the
Colorado and San Francisco Plateaus into the Sonoran Desert amidst a
moderately unstable air mass with a deep and well-mixed boundary
layer. That thermodynamic environment will be supportive of isolated
strong downbursts; however, more organized severe wind gust
potential is expected to be limited by the weak vertical shear that
is forecast.
..Mead/Lyons.. 07/15/2026
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Wed Jul 15 2026
Valid 161200Z - 171200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN MONTANA...
...SUMMARY...
Strong-to-severe thunderstorms will be possible across portions of
western Montana Thursday afternoon and evening.
... Synopsis ...
An expansive mid-level ridge will remain in place across much of the
CONUS on Thursday. On the western side of the ridge, a closed
mid-level low will lift northward, helping to raise mid-level
heights northward into Canada. On the eastern side of the ridge, a
strong mid-level trough will move across New England, within the
basal region of a long-wave trough centered across northern Quebec
and extending southward along the east coast of North America.
At the surface, a frontal boundary across the northern Mid-Atlantic
region will delineate a moist airmass to the south from a slightly
less moist airmass to the north. A secondary front will push south
across New England associated with the passing mid-level wave. This
secondary front will bring a reinforcing shot of seasonably cool,
dry air.
... Western Montana ...
This area will be on the eastern periphery of a zone of large-scale
ascent associated with the lifting eastern Pacific mid-level low.
This large-scale ascent will combine with surface dewpoints in the
mid 50Fs and surface temperatures in the upper-80Fs to low-90Fs to
support scattered thunderstorm development in the afternoon.
Relatively long hodographs and MUCAPE between 1000-2000 J/kg will
support a marginal threat for large hail and gusty thunderstorm
outflows. Should the number of thunderstorms be greater than
currently anticipated, higher severe probabilities may become
necessary.
... Mid-Atlantic Region ...
This evening's (20260715 00UTC) HREF shows afternoon temperatures
riding to near 100F in the presence of surface dewpoints in the
mid-to-upper 60Fs. This combination results in ensemble mean MLCAPE
between 1500-2000 J/kg. As the aforementioned surface boundary moves
south during the afternoon and evening, isolated thunderstorms may
develop along the front. Steep low-level lapse rates would support
some wind damage potential should these storms develop.
However, the 20260715 00UTC HRRR vertically integrated smoke
forecasts show a dense ribbon of smoke stretching from the Upper
Midwest southeast into the Mid Atlantic. Should this ribbon of dense
smoke materialize, afternoon high temperatures would likely be lower
than expected, and low- and mid-level lapse rates weaker than
forecast. This in turn would lower atmospheric buoyancy and may
limit thunderstorm coverage and/or intensity.
Given the already marginal nature of the severe potential absent the
presence of smoke, the uncertainty introduced by the presence of
smoke results in too much uncertainty to introduce unconditional
severe probabilities at this time. This area will continued to be
re-evaluated with subsequent forecasts.
..Marsh.. 07/15/2026
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Wed Jul 15 2026
Valid 171200Z - 181200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms will be possible across much of the country on Friday.
Although a few strong storms may occur, areas of organized severe
weather are not currently forecast.
... Synopsis ...
Enhanced mid-level flow will persist across the Pacific Northwest
and the Great Lakes/Northeast US along the periphery of a large
mid-level anticyclone centered across the central US. Across the
Northwest, strong southwesterly mid-level flow and embedded
vorticity/speed maxima will contribute to shower and thunderstorm
development during Friday afternoon and evening. Farther east,
northwesterly mid-level flow will be in place across the Upper
Midwest into the Mid-Atlantic and Northeast regions. A strong trough
will be departing the Northeast at the start of the forecast period,
and several smaller mid-level waves will be traversing the enhanced
mid-level flow during the day. A stronger mid-level wave is forecast
to approach the Upper Great Lakes overnight Friday into Saturday.
At the surface, a residual synoptic boundary will stretch from the
Upper Peninsula of Michigan southeast toward the vicinity of
Washington D.C. early on Friday. By late morning, this boundary will
begin lifting northeast across the Great Lakes region in response to
the approaching mid-level trough. Farther southeast, this boundary
will still be slowly sagging southward during the morning before
stalling during the afternoon and quickly lifting northeast during
Friday night into Saturday morning.
A weak surface low will develop along this boundary across northern
Minnesota by Friday morning. This low will slowly move
east-southeast during the day, dragging a secondary cold front
southeast across the Dakotas and into Wisconsin/southern Minnesota
by Saturday morning.
... Upper Midwest southeast into the Mid-Atlantic ...
Subtle/small vorticity maxima moving through the mid-level flow will
yield modest large-scale ascent along portions of the frontal
boundary. Strong diurnal heating of the moist airmass along and
south of the boundary should support at least widely scattered
thunderstorms. The surface boundary will be on the southwest fringe
of the better mid-level flow, with effective-layer shear being
generally less than 30 knots. This should limit any
sustained/organized severe threat.
One complicating factor/unknown will be the extent smoke plumes from
northern Minnesota are advected into/across the region and their
density. A thicker smoke plume may limit the degree of surface
heating and impact the overall number of thunderstorms.
There is a secondary potential for thunderstorms to develop along
the secondary cold front late Friday into early Saturday as stronger
large-scale ascent overspreads the Upper Great Lakes. The
uncertainty as to whether this convection will be able to produce
severe weather is quite large owing to the impacts of both smoke
plumes and the cooler waters of Lake Superior.
At this time the uncertainty associated with afternoon convection
and the overnight convection is too great to introduce unconditional
severe weather probabilities with this outlook, however, this region
will be evaluated further with subsequent forecasts.
..Marsh.. 07/15/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Wed Jul 15 2026
Valid 151200Z - 161200Z
...Synopsis...
Mid-level ridging will remain firmly over the CONUS Great Plains
while a surface trough in southeastern MT brings dry and breezy
conditions to portions of the northern High Plains. An upper trough
and associated increasing southerly mid-level flow approaching the
Pacific Northwest will support fast moving isolated thunderstorms
with limited rainfall along and east of the Cascades in WA and OR.
Hot and dry conditions in the CA Central Valley coupled with breezy
onshore flow and downslope drying will promote a fire weather threat
across portions of the CA coastal ranges and adjacent Central
Valley.
...California Coastal Ranges and Central Valley...
Onshore flow, downslope drying and higher winds through favored
terrain will support elevated fire weather conditions across the
central CA coastal ranges, adjacent Central Valley and portions of
the southern CA coast. Winds from the west/northwest at 10-15 mph
(locally 20-25 mph in favored terrain gaps), combined with RH of
15-20% in the coastal ranges to as low as 10% in the Central Valley,
will promote elevated fire weather conditions this afternoon.
Elevated highlights were extended southward to include the Santa
Barbara Coast where localized sundowner winds of 20-30 mph will
enhance the fire weather threat late this afternoon and evening.
...Northern High Plains...
Hot, above normal temperatures and dry conditions will persist
across much of the Northern Plains under a broad mid-level ridge
over the central U.S. A surface trough across southeastern MT will
support breezy southeast winds of 10-15 mph across the northern High
Plains with more of an easterly component across central WY. Minimum
RH of 15-20% (closer to 10% in central WY) combined with sustained
winds of 15 mph will promote elevated fire weather conditions during
peak heating. Only minor changes were needed to the existing
highlighted area.
...Central Washington and Oregon...
An upper trough will impinge upon the Pacific Northwest coast today,
introducing increasingly southerly mid-level flow and shear into
central WA and OR. A complimentary monsoon moisture plume will also
be in place aiding in instability and isolated thunderstorm
development. Although PWATs in the 0.7-1.0" range will enable a
mixed wet/dry thunderstorm mode, faster northerly storm motions
could limit precipitation efficiency and increase ignition
probability over an increasingly receptive fuelscape. Swift moving
nocturnal thunderstorms are possible as the mid-level jet pushes
into the WA/OR coast overnight, with isolated dry thunderstorm
highlights extended into the northern WA Cascades to cover this
potential threat.
..Williams.. 07/15/2026
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Wed Jul 15 2026
Valid 161200Z - 171200Z
...Synopsis...
An upper-level trough entering the Pacific Northwest along with a
lee surface trough in interior WA and OR will support dry and breezy
conditions across northeastern CA, south-central OR and far
northwestern NV Thursday. A dry thunderstorm threat will also exist
across much of interior WA as the trough pushes through the region.
Farther south, dry and breezy onshore flow will continue to bring a
fire weather threat to portions of the central and southern coastal
ranges of CA and adjacent Central Valley.
...Northeastern California, northwestern Nevada and south-central
Oregon...
Increasing mid-level flow attributed to the Pacific Northwest trough
atop an increasingly dry boundary layer via exiting monsoon
moisture, will bring dry and breezy conditions to northeastern CA,
south-central OR and far northwestern NV Thursday. Southwest winds
of up to 15 mph and relative humidity of 10-15% will result in
several hours of elevated fire weather conditions during the
afternoon.
...Portions of central California and Central Valley...
Dry and breezy westerly/northwesterly flow and resultant fire
weather threat will once again impact portions of the central CA
coastal ranges, southward into the southern Central Valley and
adjacent Sierra Madre and San Rafael ranges. Wind speeds of up to 15
mph (up to 20-25 mph in terrain gaps) combined with RH in the 15-20%
range will lead to elevated fire weather concerns Thursday
afternoon.
...Washington and far northern ID Panhandle...
A dynamic upper low and attendant 50-60 knot mid-level jet will push
into the OR/WA Cascades Thursday. Residual monsoon moisture with
PWATs ranging from 0.70-1.0", daytime heating and resultant
instability over higher terrain, will bring a dry thunderstorm
threat to much of central/eastern WA and northern ID Panhandle.
Fuels continue to dry with forecast ERC values remaining near the
90th percentile as minimal rainfall is expected during the
D1/Wednesday time period. LCL-EL layer northeastward velocities of
30-35 knots suggests reduced residence time of rain cores which will
enhance ignition potential. Gusty outflow thunderstorm winds are
also possible aided by a dry, sub-cloud layer. Highlighted area may
need future adjustments if localized heavier rains occur
D1/Wednesday.
..Williams.. 07/15/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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