ACUS11 KWNS 220433
SWOMCD
SPC MCD 220432=20
NYZ000-220630-

Mesoscale Discussion 1397
NWS Storm Prediction Center Norman OK
1132 PM CDT Sat Jun 21 2025

Areas affected...North-central Upstate New York

Concerning...Severe potential...Watch possible=20

Valid 220432Z - 220630Z

Probability of Watch Issuance...40 percent

SUMMARY...Some risk for large hail and damaging winds may accompany
a cluster moving into Upstate New York out of Ontario. Given limited
spatial extent of a favorable environment, the need for a watch is
not clear. Trends will continue to be monitored.

DISCUSSION...A cluster of storms continues to move southeastward
through southern Ontario towards Upstate New York. This cluster is
moving at about 40 kts. Storms initially developed on the southern
flank of a compact shortwave trough and are now being further
maintained by a 50 kt low-level jet (evident on the KBUF VAD).
Regional observed soundings from this evening show a fairly sharp
gradient in mid-level lapse rates with BUF showing near 8 C/km and
ALB showing only around 5 C/km. A belt of strong northwesterly flow
aloft is promoting over 50 kts of effective shear.

Some model guidance from earlier this evening showed some potential
for a greater expansion of convection farther east. This, however,
should be limited by rapidly decreasing buoyancy. It is more likely
that the strongest activity remains on the western flank of the
cluster as mid-level lapse rates and elevated buoyancy will slowly
increase with time from the northwest. Long hodographs along with
the steep mid-level lapse rates will mean some risk of large hail.
Damaging winds remain possible as well, but this may only be an
isolated threat given at least some low-level CIN exists and
potential influence from cooler lake boundary layer.

The need for a watch is not certain given the limited area of
greater instability downstream of the current activity and that
convection may outpace the slow increase in buoyancy through
tonight. Trends will be monitored over the next few hours.

..Wendt.. 06/22/2025

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_AqIuUh-LOoxCXPYWbUPuh79SkpZNNOsDFx1KZoaVlps3OsFyTUrPssPhoONQ_lx7X8Xj21Wh= aEX2CJaEY6EAdXuuXo$ for graphic product...

ATTN...WFO...BTV...ALY...BGM...BUF...

LAT...LON 43027692 42947763 43367831 44027842 44357698 44577584
44517501 44117472 43427510 43237577 43027692=20

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


=3D =3D =3D
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