RSS Mesoscale Discussions from Storm Prediction Center
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
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WW 489 SEVERE TSTM ME NH NY VT 150025Z - 150800Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 489
NWS Storm Prediction Center Norman OK
825 PM EDT Tue Jul 14 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southwest Maine
Central and Northern New Hampshire
Northern New York
Northern Vermont
* Effective this Tuesday night and Wednesday morning from 825 PM
until 400 AM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
A tornado or two possible
SUMMARY...Thunderstorms are forecast to develop and intensify this
evening across the Watch and also move into the Watch area from the
west. A couple of supercells are possible with large hail and
severe gusts accompanying these storms. A tornado is also possible.
Later tonight, additional storms will probably evolve into a small
thunderstorm cluster with large hail and severe gusts the main
hazards with this activity.
The severe thunderstorm watch area is approximately along and 55
statute miles north and south of a line from 25 miles west northwest
of Massena NY to 40 miles east of Mount Washington NH. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU9).
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...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 400. Mean storm motion vector
30040.
...Smith
Read more
WW 488 SEVERE TSTM MT 142335Z - 150700Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 488
NWS Storm Prediction Center Norman OK
535 PM MDT Tue Jul 14 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Central into Northeast Montana
* Effective this Tuesday afternoon and Wednesday morning from 535
PM until 100 AM MDT.
* Primary threats include...
Scattered damaging winds and isolated significant gusts to 75
mph possible
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Thunderstorms are forecast to develop and intensify
through this evening across central Montana. A few supercells
yielding a risk for large hail and severe gusts will be possible
with the initial thunderstorm activity. By mid evening, additional
storms are forecast with an organized cluster potentially evolving
and moving east across portions of the Watch. Severe gusts will
probably become the main hazard by mid to late evening coincident
with this expected transition to an organized thunderstorm cluster.
The severe thunderstorm watch area is approximately along and 70
statute miles north and south of a line from 25 miles northwest of
Helena MT to 45 miles east southeast of Glasgow MT. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).
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 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
26025.
...Smith
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WW 0490 Status Updates
STATUS FOR WATCH 0490 HAS NOT BEEN ISSUED YET
Read more
WW 0489 Status Updates
STATUS REPORT ON WW 489
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 WNW MSS
TO 40 NNW BTV TO 15 SW PWM.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1621
..SMITH..07/15/26
ATTN...WFO...GYX...BTV...
STATUS REPORT FOR WS 489
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MEC031-150630-
ME
. MAINE COUNTIES INCLUDED ARE
YORK
NHC001-003-009-017-150630-
NH
. NEW HAMPSHIRE COUNTIES INCLUDED ARE
BELKNAP CARROLL GRAFTON
STRAFFORD
NYC019-031-033-089-150630-
NY
. NEW YORK COUNTIES INCLUDED ARE
CLINTON ESSEX FRANKLIN
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WW 0488 Status Updates
STATUS REPORT ON WW 488
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 WSW BIL TO
65 ENE HVR.
..LYONS..07/15/26
ATTN...WFO...TFX...GGW...BYZ...
STATUS REPORT FOR WS 488
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC033-055-065-069-071-079-087-103-105-150540-
MT
. MONTANA COUNTIES INCLUDED ARE
GARFIELD MCCONE MUSSELSHELL
PETROLEUM PHILLIPS 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.
Read more
MD 1621 CONCERNING SEVERE THUNDERSTORM WATCH 489... FOR PORTIONS OF NORTHERN NEW YORK INTO VERMONT AND NEW HAMPSHIRE.
Mesoscale Discussion 1621
NWS Storm Prediction Center Norman OK
1144 PM CDT Tue Jul 14 2026
Areas affected...portions of northern New York into Vermont and New
Hampshire.
Concerning...Severe Thunderstorm Watch 489...
Valid 150444Z - 150615Z
The severe weather threat for Severe Thunderstorm Watch 489
continues.
SUMMARY...Strong to severe storms are expected to persist across the
western portions of WW489 into the overnight hours. Hail and
damaging winds are the most likely hazards.
DISCUSSION...As of 0440 UTC, a cluster of severe storms, including a
robust supercell over St Lawrence County NY, are ongoing across
western portions of WW489. Moderate buoyancy and strong deep-layer
shear remain in place ahead of this convection, and new storm
development just across the ON border. Hail is the most likely
threat tonight, especially with the aforementioned supercell showing
peak MRMS MESH of 2+ inches and a persistent cellular storm mode.
Damaging winds are also possible with the stronger cells, though
upscale growth appears limited given the very strong deep-layer
shear. A tornado also cannot be ruled out given the ongoing
supercells and strong vertical shear.
With the favorable parameter space likely to persist tonight, severe
potential should be maximized across parts of northern NY, into VT
and southern NH. Storm should begin to weaken late tonight as they
approach a more stable air mass into southern New England.
..Lyons.. 07/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BTV...ALY...
LAT...LON 44537274 44167218 43637149 43287141 42997161 42977210
43277331 44137519 44527574 45027513 45177451 44997374
44537274
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
Read more
MD 1620 CONCERNING SEVERE THUNDERSTORM WATCH 488... FOR EAST-CENTRAL MT
Mesoscale Discussion 1620
NWS Storm Prediction Center Norman OK
1123 PM CDT Tue Jul 14 2026
Areas affected...east-central MT
Concerning...Severe Thunderstorm Watch 488...
Valid 150423Z - 150600Z
The severe weather threat for Severe Thunderstorm Watch 488
continues.
SUMMARY...Scattered to widespread severe gusts (60-80 mph) will
likely continue with an eastward-moving linear cluster for the next
couple of hours.
DISCUSSION...Radar-mosaic and IR composite imagery show a mature
linear cluster with 50-kft echo tops over Petroleum into Yellowstone
counties moving east. Surface observations indicate temperatures
are still warm and in the 80s F with lower to mid 60s F dewpoints
over Garfield into northern Rosebud counties in eastern MT.
HRRR-based objective analysis implies MUCAPE 2000-3000 J/kg over
eastern MT with an easterly 40-kt 850-mb LLJ maintaining a moist
fetch into the area immediately east of the linear cluster. Given
the strengthening low-level flow with height veering to weaker
southwesterly flow in the midlevels (yielding 50-kt effective
shear), the resultant wind profile will continue to strongly promote
a linear storm mode. Severe gusts will be the primary severe
hazard, but there may be a localized threat for large hail occurring
intermittently with southern flanking updrafts as this complex moves
east during the early overnight.
..Smith.. 07/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...
LAT...LON 46040845 46400828 46820835 47200852 47410790 47360666
47030617 46560611 46020626 45860692 45880810 46040845
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
Read more
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Tue Jul 14 2026
Valid 150100Z - 151200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
PARTS OF NEW YORK...VERMONT...AND NEW HAMPSHIRE...AND A SMALL PART
OF WESTERN MAINE...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN NORTHERN AND
CENTRAL MONTANA AND SURROUNDING THE ENHANCED RISK IN NORTHERN NEW
YORK AND NORTHERN AND CENTRAL NEW ENGLAND...
...SUMMARY...
Severe thunderstorms capable of producing damaging winds, large
hail, and a few tornadoes are expected tonight across parts of
northern New York and New England. Thunderstorms with scattered
severe winds and hail will also be possible across portions of
Montana.
...New England and the northern Mid-Atlantic...
The glancing influence of a shortwave trough and associated
mid/upper-level jet streaks moving through Quebec have contributed
to a recent increase in storm coverage and intensity from portions
of the St. Lawrence Valley into northern parts of VT and NH. Owing
to considerable clouds and wildfire smoke, a baroclinic zone is
analyzed from northern VT through central NH to the Southern Coast
of ME. The 00z observed soundings across the region indicate the
presence of a capping inversion at the base of a relatively warm and
dry EML, which casts some uncertainty on updraft intensity and
duration, owing to the deleterious effects of entrainment and
existing convective inhibition.
However, any storms that can become sustained will do so within a
kinematic environment featuring strong deep-layer shear, which will
conditionally support the potential for large hail, damaging winds
with significant gusts to 70-75 mph possible, and perhaps a couple
of tornadoes. The best potential for that threat to be realized may
be with the rapidly intensifying storms across portions of eastern
Ontario, which are projected to reach northern NY within the next
2-3 hours. As such, severe probabilities have been adjusted in
portions of NY to account for the Ontario storms.
...Montana...
A cluster of supercells capable of large hail has developed this
evening over central MT within a relatively moist, post-frontal
upslope regime within MLCAPE as high as 2000-3000 J/kg, per latest
objective analysis. With time, the presence of large
temperature-dewpoint spreads and a resultant, well-mixed boundary
layer will enhance downdraft potential, leading to a cold-pool
driven convective system with an attendant risk for damaging winds
with gusts up to 75 mph.
For additional near-term guidance, see MCD 1617.
..Mead.. 07/15/2026
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