Mesoscale Discussion 0665
NWS Storm Prediction Center Norman OK
1114 AM CDT Sat May 03 2025

Areas affected...parts of the Northeast and southern New England

Concerning...Severe potential...Severe Thunderstorm Watch likely 

Valid 031614Z - 031815Z

Probability of Watch Issuance...80 percent

SUMMARY...An increasing severe threat is expected through the
afternoon across a confined corridor of the Northeast and southern
New England. A mix of at least isolated damaging winds and hail is
anticipated. A severe thunderstorm watch issuance appears likely.

DISCUSSION...Bulk of morning guidance, outside of the HRRR and
parent RAP, suggest a favorable corridor of at least isolated severe
storms should develop from the PA/NJ/NY border northeastward across
parts of interior southern New England. Robust boundary-layer
heating is underway ahead of the minor lobe of ascent over eastern
PA and south of the quasi-stationary front. The differential heating
across the front will aid in strengthening the baroclinic zone.
While mid-level lapse rates are weak and will temper overall storm
intensity, nearly unidirectional southwesterly wind profiles with
moderate speed shear will foster occasional updraft rotation. A mix
of cells and small clusters should support both a severe hail/wind
threat in a confined corridor through the afternoon.

..Grams/Gleason.. 05/03/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GYX...BOX...OKX...ALY...PHI...BGM...

LAT...LON   41187498 42107438 42727332 43327208 43437130 43187092
            42597125 41777276 41177389 40647457 40437498 40537542
            41187498 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0750 AM CDT Sat May 03 2025

Valid 031300Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CAROLINAS...MID-ATLANTIC STATES...AND NEW ENGLAND...

...SUMMARY...
Strong to severe storms are possible this afternoon into evening
from parts of the Carolinas into the Mid-Atlantic and Northeast. An
isolated severe threat may develop across the Southeast, and also
across parts of the Great Basin.

...Carolinas/Mid-Atlantic States to Southern New England...
Thinking remains that the primary severe risk will focus today
across parts of the Mid-Atlantic into southern New England,
including western/northern Virginia and parts of West
Virginia/Maryland into southern/eastern Pennsylvania to southeast
New York and southern New England. Even with higher-level cloud
cover spreading into the region, ample heating will occur within the
prefrontal warm sector, generally coincident with near 60/lower 60s
F surface dewpoints in the lee of the Appalachians, with upwards of
1000 J/kg MLCAPE possible especially across parts of
Virginia/Delmarva into southeast Pennsylvania and New Jersey. A belt
of moderately strong mid-level southwesterly flow in advance of the
slow-moving mid/upper trough will provide sufficient deep-layer
shear for some storm organization, coincident with the moderately
buoyant warm sector.

Organized cells/clusters should develop during the afternoon from
the Mid-Atlantic into southern New England, as a frontal wave
and modestly enhanced low-level jet move northeastward across the
region. These storms will pose a threat of damaging winds and
isolated hail, and possibly some localized tornado potential. 

Farther south, scattered storm development is expected during the
afternoon near/east of the Blue Ridge. Moderate buoyancy/shear and
relatively steep low-level lapse rates will support a threat of
damaging wind and hail with the strongest storms.

...Southeast States/Tennessee Valley...
Several linear bands of storms and possibly multiple weak MCVs are
ongoing this morning across the Florida Panhandle, eastern Alabama,
into western/northern Georgia. An isolated severe risk may exist
early today primarily across the Florida Panhandle with an ongoing
linear cluster of storms. Otherwise, subsequent later-day
destabilization is uncertain in the wake of this convection. Some
increase in deep-layer shear and cooling temperatures aloft will
accompany the approaching mid/upper trough, and adequate
heating/destabilization could result in redevelopment of strong to
locally severe storms along the cold front during the afternoon and
evening. This could potentially include parts of Alabama, eastern
Tennessee, northern Georgia and eastern Mississippi.

...Nevada into Oregon/Idaho...
Scattered thunderstorms are expected this afternoon across the
northern Great Basin and vicinity, as favorable large-scale ascent
and steep mid-level lapse rates overspread the region. Buoyancy will
generally remain modest (MLCAPE around 500 J/kg or less), but
moderate deep-layer shear and steep low-level lapse rates could
support a few stronger storms capable of localized severe wind gusts
and small to marginally severe hail. 

...Parts of the Texas Big Bend/Trans-Pecos region...
Very isolated storm development is possible during the afternoon and
evening, within a post-frontal regime across parts of west Texas.
Guidance varies somewhat regarding the magnitude of destabilization
across the region, though MLCAPE may remain rather modest (around
500 J/kg). Veering wind profiles will support sufficient deep-layer
shear for storm organization, and if somewhat greater instability
materializes, severe probabilities might need to be introduced for
isolated supercell/related hail potential.

..Guyer/Jewell.. 05/03/2025

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1117 AM CDT Sat May 03 2025

Valid 031700Z - 041200Z

...NO CRITICAL AREAS...

No changes are needed to the D1 Fire Weather Outlook. See previous
discussion below for more information.

..Thornton.. 05/03/2025

.PREV DISCUSSION... /ISSUED 0101 AM CDT Sat May 03 2025/

...Synopsis...
Fire weather concerns are expected to remain limited across the
country for today. Dry conditions will prevail across the Southwest,
but weak low-level pressure gradient winds will limit the potential
for dry and windy conditions. Isolated to scattered thunderstorms
are expected from central NM westward across AZ and into central NV
this afternoon. Very dry boundary layer conditions sampled in 00 UTC
soundings may support occasional dry lightning strikes away from
slow-moving rain cores across western NM into central AZ. Similar
thermodynamic conditions and storm motions were observed yesterday
(Friday) and resulted in pockets of wetting rainfall as well as a
few dry lightning strikes. However, the coverage of dry lightning
over receptive fuels remains too limited to warrant a risk area
based on latest CAM guidance and fuel analyses.

...Please see www.spc.noaa.gov/fire for graphic product...