RSS Mesoscale Discussions from Storm Prediction Center
WW 471 SEVERE TSTM NY PA 281550Z - 290000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 471
NWS Storm Prediction Center Norman OK
1150 AM EDT Sat Jun 28 2025
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southern New York
Western and Central Pennsylvania
* Effective this Saturday morning and evening from 1150 AM until
800 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
SUMMARY...Thunderstorms will increase in coverage and intensity
through the day across the watch area, ahead of an approaching cold
front. The strongest cells will pose a risk of locally damaging
wind gusts.
The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 15 miles north of
Latrobe PA to 50 miles east northeast of Binghamton NY. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU1).
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 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 500. Mean storm motion vector
24025.
...Hart
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WW 0471 Status Updates
STATUS REPORT ON WW 471
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 N LBE TO
30 SSE DUJ TO 30 NNW UNV TO 35 ESE BFD TO 50 NE BFD.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1491
..SQUITIERI..06/28/25
ATTN...WFO...BUF...BGM...PBZ...CTP...
STATUS REPORT FOR WS 471
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NYC003-007-011-015-017-023-053-065-067-097-099-101-107-109-123-
281940-
NY
. NEW YORK COUNTIES INCLUDED ARE
ALLEGANY BROOME CAYUGA
CHEMUNG CHENANGO CORTLAND
MADISON ONEIDA ONONDAGA
SCHUYLER SENECA STEUBEN
TIOGA TOMPKINS YATES
PAC005-009-013-015-021-027-035-037-041-043-055-057-061-063-067-
069-079-081-087-093-097-099-105-107-109-111-113-115-117-119-127-
129-131-281940-
PA
. PENNSYLVANIA COUNTIES INCLUDED ARE
ARMSTRONG BEDFORD BLAIR
BRADFORD CAMBRIA CENTRE
CLINTON COLUMBIA CUMBERLAND
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MD 1492 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR EASTERN ND AND FAR NORTHWEST MN
Mesoscale Discussion 1492
NWS Storm Prediction Center Norman OK
0151 PM CDT Sat Jun 28 2025
Areas affected...eastern ND and far northwest MN
Concerning...Severe potential...Watch possible
Valid 281851Z - 282015Z
Probability of Watch Issuance...60 percent
SUMMARY...Isolated large hail and locally strong gusts may initially
develop along a cold front in eastern North Dakota, and could be
sustained through late afternoon. A Severe Thunderstorm Watch
issuance is possible.
DISCUSSION...Early storm development is underway along the weak
surface cold front, likely aided by a minor mid-level impulse
upstream over central ND. Recent HRRR runs have trended towards this
earlier and farther north regime, unlike the bulk of 12Z HREF
guidance which indicated that far northeast SD into west-central MN
will be the genesis region later today. With influence of a decayed
MCS likely delaying that latter regime until evening, the short-term
severe threat into late afternoon may be confined to a portion of
eastern ND into far northwest MN. Low-level winds should remain weak
and generally veered, yielding minimal hodograph curvature. But this
combined with moderate buoyancy/deep-layer shear should result in
primarily a large hail threat. Overall storm coverage could be
fairly isolated, especially given the lack of cumulus ahead of the
front this early in the afternoon.
..Grams/Hart.. 06/28/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...BIS...
LAT...LON 47409879 48039857 48469814 48429711 48139666 47619648
46729635 46349652 46129671 46109842 46589912 47139894
47409879
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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MD 1491 CONCERNING SEVERE THUNDERSTORM WATCH 471... FOR PORTIONS OF CENTRAL PENNSYLVANIA INTO CENTRAL NEW YORK
Mesoscale Discussion 1491
NWS Storm Prediction Center Norman OK
0133 PM CDT Sat Jun 28 2025
Areas affected...Portions of central Pennsylvania into central New
York
Concerning...Severe Thunderstorm Watch 471...
Valid 281833Z - 282000Z
The severe weather threat for Severe Thunderstorm Watch 471
continues.
SUMMARY...Multiple strong, damaging gusts may still occur with an
eastward-advancing MCS, as well as with other strong storms that
manage to materialize over the next few hours.
DISCUSSION...An MCS, with a history of producing multiple damaging
gusts, continues to advance eastward across central PA. Ahead of
this MCS, strong surface heating amid minimal convective inhibition
is supporting up to 2000 J/kg MLCAPE. Given marginal vertical wind
shear in the region, the MCS should continue eastward with a
damaging gust threat for a few more hours. However, the presence of
billow clouds, along with mesoanalysis output, suggest that stable
conditions exist downstream over eastern PA toward NJ. While airmass
modification should occur through the remainder of the afternoon, it
is unclear how residual stability would impact the downstream
damaging gust threat.
..Squitieri/Hart.. 06/28/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ALY...PHI...BGM...BUF...CTP...PBZ...
LAT...LON 39927947 40977866 41687796 42197748 43347580 43547539
43537519 43227498 42587497 41987502 41347538 40827592
40407637 40087699 39847758 39807851 39927947
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
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MD 1490 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHERN AND EASTERN OHIO...WESTERN WEST VIRGINIA...FAR SOUTHWESTERN PENNSYLVANIA
Mesoscale Discussion 1490
NWS Storm Prediction Center Norman OK
0114 PM CDT Sat Jun 28 2025
Areas affected...Portions of southern and eastern Ohio...western
West Virginia...far southwestern Pennsylvania
Concerning...Severe potential...Watch unlikely
Valid 281814Z - 281945Z
Probability of Watch Issuance...5 percent
SUMMARY...A couple of strong/damaging wind gusts may occur with the
stronger storms this afternoon. A WW issuance is unlikely given the
sparse nature of the overall severe threat.
DISCUSSION...Scattered thunderstorms have developed ahead of a weak
frontal boundary, amid a modifying airmass behind an earlier MCS.
Here, surface temperatures are rising into the upper 80s F, that
combined with low 70s F dewpoints and 8 C/km 0-3 km lapse rates, are
boosting MLCAPE to 2500 J/kg. However, modest deep-layer westerly
flow is resulting in weak vertical wind shear, and with buoyancy
constrained to tall/narrow profiles, the main concern is for
damaging gusts originating from the stronger storm cores. The severe
threat should remain quite isolated, so a WW issuance is not
expected.
..Squitieri/Hart.. 06/28/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PBZ...RLX...CLE...ILN...
LAT...LON 40028274 40408229 40738155 40818107 40728061 40418018
39967993 39557988 39238005 38968044 38758097 38628159
38578201 38718243 38868271 38988289 40028274
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1126 AM CDT Sat Jun 28 2025
Valid 281630Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
FROM CENTRAL PENNSYLVANIA INTO SOUTHEAST NEW YORK. OTHER SEVERE
STORMS WILL OCCUR FROM THE BLACK HILLS REGION INTO PARTS OF
MINNESOTA AND WESTERN WISCONSIN....
...SUMMARY...
Scattered severe thunderstorms are possible across portions of the
Upper Midwest into the north-central Great Plains. All severe
hazards are possible centered on southern Minnesota and eastern
South Dakota. Scattered damaging gusts are possible across parts of
New York into Pennsylvania.
...Eastern SD/MN/WI...
Current radar loops show a persistent MCS slowly weakening across
southern MN. This feature has driven an associated outflow boundary
into northwest IA and eastern SD. Morning model solutions are in
general agreement that the low-level air mass will rapidly recover
in the wake of the MCS, leading to rapid and intense thunderstorm
development by late afternoon over western MN. It is unclear if the
models are handling the lingering effects of the morning convection,
but the eventual re-development of storms poses risks of tornadoes,
very large hail, and damaging winds. An upgrade to ENH risk over
parts of central/southern MN for this evening was considered, but
will defer to the 20z outlook, after further evaluation of the
ongoing convection and trends in destabilization.
...Western SD Vicinity...
Full sun will lead to strong heating and deep mixing across much of
eastern WY today. High-based convection will develop by late
afternoon in this region and spread eastward into a progressively
more moist and unstable air mass over western SD. Scattered intense
storms are expected to develop, posing a risk of large hail and
damaging wind gusts. These storms may persist through the evening
and grow upscale, with a risk of damaging winds into southern
SD/northern NE.
...NY/PA/Mid-Atlantic...
A surface cold front is sagging southward into NY and western PA
today. Thunderstorms have begun to intensify along/ahead of the
front, with locally damaging wind gusts expected through the
afternoon. Low clouds are limiting heating/destabilization over
eastern NY/PA and the Mid-Atlantic region. However, heating should
commence by mid/late afternoon, allowing storms approaching from the
west to maintain a damaging wind threat into the early evening.
..Hart/Squitieri.. 06/28/2025
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Sat Jun 28 2025
Valid 291200Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MIDWEST INTO THE LOWER MISSOURI VALLEY...
...SUMMARY...
Scattered strong to severe storms are possible Sunday from the
central Plains into the upper Great Lakes region, with some
potential for the evolution of a large, organized severe storm
cluster across parts of the mid into lower Missouri Valley and
central Great Plains late Sunday through Sunday night.
...Synopsis...
An amplifying midlevel trough will advance east-southeastward from
the north-central Plains toward the Upper MS Valley through the
period. Related large-scale ascent will overspread the Middle/Upper
MS Valley, while a related cold front moves southeastward across the
region.
...Upper Midwest...
In the wake of several overnight storm clusters and related cloud
debris, gradual clearing should support boundary-layer
destabilization and the development of moderate-strong surface-based
buoyancy. As the cold front intercepts this increasing buoyancy,
around 30 kt of deep-layer shear should favor a few organized
clusters capable of producing widely scattered damaging wind gusts
during the afternoon.
...Central Plains to the Middle/Lower Missouri Valley...
A separate area of thunderstorms is expected along the front in IA
and the Lower MO Valley during the late afternoon into the overnight
hours. Ahead of these evolving storms, lower/middle 70s dewpoints
beneath steep midlevel lapse rates will contribute to strong-extreme
surface-based buoyancy. Initial storms will be capable of producing
isolated large hail and locally severe wind gusts. However,
strengthening deep-layer shear accompanying the digging midlevel
trough, coupled with an increasing low-level jet, will support the
development of a southward-moving MCS into the overnight hours. The
Slight risk was expanded southward to account for this scenario, and
higher wind probabilities may eventually be needed as the scenario
becomes more clear.
Farther west, semi-discrete storms are expected over the central
High Plains during the afternoon. Elongated/straight hodographs and
moderate surface-based buoyancy should favor large hail with any
supercell structures that can develop.
...Mid-Atlantic...
Despite marginal deep-layer flow/shear, diurnal heating amid deep
tropospheric moisture (around 2 inch PW) will favor wet microbursts
and the potential for wind damage with the stronger thunderstorms.
..Weinman.. 06/28/2025
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0228 PM CDT Sat Jun 28 2025
Valid 301200Z - 011200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE OHIO VALLEY...MIDWEST...AND MID-ATLANTIC...
...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of the Ohio Valley, Midwest and the Mid-Atlantic on Monday.
...Synopsis...
An amplifying midlevel trough and accompanying jet streak will
advance eastward across the Midwest and Great Lakes on Monday. At
the same time, a related cold front will overspread the OH Valley
through the afternoon.
...Ohio Valley and Midwest...
Widely scattered thunderstorms are expected along/ahead of the
eastward-moving cold front in the OH Valley, aided by large-scale
ascent preceding the midlevel trough. While midlevel lapse rates
will be modest over the warm sector, diurnal heating of a moist air
mass (lower 70s dewpoints) will still contribute to moderate-strong
surface-based buoyancy (highest over the lower OH Valley). Around 30
kt of deep-layer shear and the destabilizing air mass will favor
organized multicell clusters capable of producing wind damage
through the afternoon.
Farther west, large-scale ascent in the left-exit region of the
midlevel jet will promote isolated thunderstorms across the Midwest
during the afternoon. Sufficient post-frontal moisture beneath steep
midlevel lapse rates, and elongated/straight hodographs (30-40 kt of
deep-layer shear), will support isolated severe hail in the stronger
cells.
...Mid-Atlantic...
Despite weak deep-layer flow/shear, a few wet microbursts will be
possible east of the Appalachians during the afternoon, where steep
low-level lapse rates will develop amid deep/rich tropospheric
moisture (PW around 2 inches).
..Weinman.. 06/28/2025
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1153 AM CDT Sat Jun 28 2025
Valid 281700Z - 291200Z
...Snake River Plain...
A broad area of elevated mid-level winds on the southern periphery
of a mid-level trough along with daytime boundary layer mixing will
support breezy winds across the Snake River Plain this afternoon.
Elevated highlights were trimmed across portions of the Magic Valley
Region owing to a now marginal overlap of winds and low relative
humidity based on the latest model guidance consensus.
...Southwestern Wyoming...
Only minor changes were noted to Elevated highlights across
southwestern Wyoming. Increased mid-level flow coupled with lee
troughing farther east will enhance westerly winds across the area.
The breezy winds combined with dry fuels and relative humidity
dropping into the 15-20 percent range will promote elevated fire
weather conditions this afternoon.
..Williams.. 06/28/2025
.PREV DISCUSSION... /ISSUED 0203 AM CDT Sat Jun 28 2025/
...Synopsis...
Subtle mid-level troughing on the northern periphery of the sub
tropical ridge will continue over the northern Rockies and Northwest
today. A belt of stronger mid-level flow will remain in place over
parts of the Intermountain West, supporting dry downslope flow ahead
of a weak cold front over the Northwest. Lee troughing and the
increased flow aloft will encourage breezy westerly flow amid dry
conditions, conducive for elevated fire-weather conditions.
...Snake River Plain into western WY...
Increasing mid-level flow attendant to a passing mid-level shortwave
trough will overspread a dry and well-mixed boundary layer across
portions of ID and western WY this afternoon. Aided by lee
troughing, elevated surface winds are expected across the
central/eastern portions of the Snake River Plain and through the
Red Desert in southwest WY. Westerly winds of 15-20 mph, combined
with warm afternoon temperatures and relative humidity in the 15-20
percent range, will support elevated fire weather conditions this
afternoon and evening.
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0236 PM CDT Sat Jun 28 2025
Valid 291200Z - 301200Z
A departing mid-level trough will aid in sustaining breezy northwest
winds of 15-20 mph across the Interstate 80 corridor in southwest
Wyoming Sunday. The winds overlapping with relative humidity in the
15-20 percent range amid a very dry fuelscape will support elevated
fire weather conditions across southwest Wyoming. Otherwise, fire
weather concerns across much of the western U.S. will be mitigated
by a building upper-level ridge bringing warming temperatures and
generally light, terrain-driven winds.
..Williams.. 06/28/2025
.PREV DISCUSSION... /ISSUED 0203 AM CDT Sat Jun 28 2025/
...Synopsis...
Upper ridging is forecast to steadily build over the West Coast
Sunday, as weak troughing shifts eastward. As heights continue to
rise, weakening the flow aloft over the northern Rockies, a cold
front will move out of the Northwest ushering in a cooler and higher
humidity air mass. Some residual mid-level flow will linger across
WY and western CO Sunday, but surface winds are expected to be much
weaker and will shift to northwesterly. The weaker winds, along with
increasing humidity should limit broader fire-weather potential.
Some localized dry and breezy conditions will remain possible over
southwest WY, but widespread fire-weather concerns are not expected.
...Please see www.spc.noaa.gov/fire for graphic product...
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