RSS Mesoscale Discussions from Storm Prediction Center
WW 497 SEVERE TSTM MT 182140Z - 190400Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 497
NWS Storm Prediction Center Norman OK
340 PM MDT Sat Jul 18 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Central Montana
* Effective this Saturday afternoon and evening from 340 PM until
1000 PM MDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Scattered large hail events to 1.5 inches in diameter possible
SUMMARY...Thunderstorms will continue to develop off the mountains
of western Montana and spread northeastward. High-based storms
capable of damaging winds and hail are possible.
The severe thunderstorm watch area is approximately along and 80
statute miles east and west of a line from 50 miles east southeast
of Dillon MT to 45 miles north northeast of Great Falls MT. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU7).
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...WW 496...
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
26030.
...Hart
Read more
WW 0497 Status Updates
STATUS REPORT ON WW 497
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..HART..07/19/26
ATTN...WFO...TFX...BYZ...
STATUS REPORT FOR WS 497
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC005-007-013-015-027-031-041-043-045-049-051-057-059-067-073-
097-099-107-190140-
MT
. MONTANA COUNTIES INCLUDED ARE
BLAINE BROADWATER CASCADE
CHOUTEAU FERGUS GALLATIN
HILL JEFFERSON JUDITH BASIN
LEWIS AND CLARK LIBERTY MADISON
MEAGHER PARK PONDERA
SWEET GRASS TETON WHEATLAND
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
WW 0496 Status Updates
STATUS REPORT ON WW 496
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SSW GSO
TO 30 WSW AVC TO 10 S AVC TO 15 NW GSB.
WW 496 WILL BE ALLOWED TO EXPIRE AT 190100Z.
..HART..07/19/26
ATTN...WFO...LWX...AKQ...RAH...RNK...
STATUS REPORT FOR WS 496
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NCC001-037-063-069-077-135-151-181-183-190100-
NC
. NORTH CAROLINA COUNTIES INCLUDED ARE
ALAMANCE CHATHAM DURHAM
FRANKLIN GRANVILLE ORANGE
RANDOLPH VANCE WAKE
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
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 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
WW 0492 Status Updates
STATUS REPORT ON WW 492
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNE PKB
TO 30 SW DUJ TO 40 ESE IPT.
WW 492 WILL BE ALLOWED TO EXPIRE AT 190100Z.
..HART..07/19/26
ATTN...WFO...CLE...PBZ...CTP...
STATUS REPORT FOR WS 492
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
PAC001-005-009-013-021-027-037-041-043-051-055-057-059-061-063-
067-071-075-087-093-097-099-107-109-111-119-125-129-133-
190100-
PA
. PENNSYLVANIA COUNTIES INCLUDED ARE
ADAMS ARMSTRONG BEDFORD
BLAIR CAMBRIA CENTRE
COLUMBIA CUMBERLAND DAUPHIN
FAYETTE FRANKLIN FULTON
GREENE HUNTINGDON INDIANA
JUNIATA LANCASTER LEBANON
MIFFLIN MONTOUR NORTHUMBERLAND
PERRY SCHUYLKILL SNYDER
SOMERSET UNION WASHINGTON
WESTMORELAND YORK
WVC049-051-061-069-077-103-190100-
WV
. WEST VIRGINIA COUNTIES INCLUDED ARE
Read more
MD 1656 CONCERNING SEVERE THUNDERSTORM WATCH 497... FOR PARTS OF WESTERN/CENTRAL MT
Mesoscale Discussion 1656
NWS Storm Prediction Center Norman OK
0635 PM CDT Sat Jul 18 2026
Areas affected...Parts of western/central MT
Concerning...Severe Thunderstorm Watch 497...
Valid 182335Z - 190130Z
The severe weather threat for Severe Thunderstorm Watch 497
continues.
SUMMARY...Some increase in severe-wind potential is possible through
the evening. Isolated hail also remains possible.
DISCUSSION...As of 2330 UTC, widely scattered storms are ongoing
across parts of western MT. In the short term, the severe threat may
remain rather isolated, with moderate buoyancy and steep lapse rates
supporting a threat of localized hail and severe gusts. With time,
as both midlevel flow and storm coverage gradually strengthen over
the region, one or more outflow-driven clusters may evolve and pose
an increasing severe-wind threat into this evening. Some severe
threat may eventually develop north of WW 497, and trends will
continue to be monitored regarding the need for local watch
expansion.
..Dean.. 07/18/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...TFX...MSO...
LAT...LON 45761352 47971301 48971205 49031139 49061025 49020950
48980903 47650881 46560952 45941010 45511068 45151132
44971202 45101278 45761352
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 CORR 1
NWS Storm Prediction Center Norman OK
0809 PM CDT Sat Jul 18 2026
Valid 190100Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ...
CORRECTED FOR INCORRECT CATEGORICAL LINES
...SUMMARY...
Storms capable of wind damage may continue for another hour or so
across central Pennsylvania before dissipating. Additional
strong-to-severe thunderstorms capable of damaging winds and hail
will be likely across portions western Montana
... 01Z Update ...
Overall thunderstorm intensity continues to wane across much of the
northeast with the loss of daytime heating and multiple rounds of
thunderstorms acting to stabilize the airmass. However, a few
damaging thunderstorm wind gusts will be possible from far eastern
Ohio into southern New England for perhaps another hour or two. The
most likely area for wind damage is across central Pennsylvania
where the most intense thunderstorms are currently found. These
storms should weaken further in the next couple of hours, bringing
an end to the organized severe threat.
Across western Montana, sufficient buoyancy is in place to support
ongoing convection, some of which has produced severe wind gusts
this afternoon. Steep lapse rates coupled with gradually
strengthening mid-level flow will support an ongoing severe threat,
including a couple of outflow-driven convective clusters. Please see
MCD #1656 for more details.
..Marsh.. 07/19/2026
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
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