Mesoscale Discussion 1180
NWS Storm Prediction Center Norman OK
0658 AM CDT Thu Jun 18 2026
Areas affected...Northwest Pennsylvania...Western New York
Concerning...Severe potential...Watch unlikely
Valid 181158Z - 181400Z
Probability of Watch Issuance...20 percent
SUMMARY...An isolated tornado and wind-damage threat may continue
for much of the morning across parts of northwestern Pennsylvania
and western New York. The threat area is expected to remain
marginal, and weather watch issuance appears unlikely.
DISCUSSION...A line of strong thunderstorms is currently ongoing
along the eastern edge of Lake Erie, near a pocket of maximized
low-level convergence. The storms are also located near a moist axis
which extends northeastward from far northwestern Pennsylvania into
far western New York. From near the moist axis eastward into central
New York, a 50 to 60 knot low-level jet is analyzed by the RAP. In
addition, the RAP shows the nose of an 80 to 100 knot mid-level jet
that is moving into the central Appalachians. The two jets are
greatly enhancing lift and shear across the Lower Great Lakes
region. Forecast soundings this morning in far western New York have
long and looped hodographs with 0-3 km storm-relative helicity above
400 m2/s2. This will support an isolated tornado threat with
low-topped supercells this morning. In addition, an isolated threat
for severe wind gusts will also be possible.