Mesoscale Discussion 0836
NWS Storm Prediction Center Norman OK
0636 AM CDT Sat May 17 2025
Areas affected...Upstate New York and northern Vermont
Concerning...Severe potential...Watch unlikely
Valid 171136Z - 171400Z
Probability of Watch Issuance...20 percent
SUMMARY...Thunderstorms will continue moving northeast this morning.
Additional thunderstorms will develop later this morning and
afternoon and a watch may eventually be needed.
DISCUSSION...As a strong mid-level low slowly moves east across the
Great Lakes today, multiple rounds of thunderstorms are anticipated
across upstate New York, Vermont, and New Hampshire. These storms
will be aided by increasing large-scale forcing from a number of
sources: increasing upper-level divergence, lobes of positive
vorticity advection, and the left exit region of a mid-level jet.
As diurnal heating increases this morning, cold mid-level
temperatures will overspread the region. This, coupled with surface
dewpoints ranging from the mid 50Fs to mid 60Fs will result in a
largely unstable, uncapped environment, primed for thunderstorm
development in association with one of the myriad of large-scale
forcing mechanisms.
One such mechanism is already producing thunderstorms across far
eastern portions of Lake Ontario. These thunderstorms should
continue to rapidly move northeast into northern Vermont this
morning. These thunderstorms will be capable of producing gusty
winds and small hail.
The likelihood for a watch in the short-term is relatively low.
However, as instability increases, and more widespread forcing for
ascent moves into the area, a watch or watches may be needed across
portions of the area by midday into early afternoon.
..Marsh/Bunting.. 05/17/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BTV...ALY...BGM...BUF...
LAT...LON 43927225 43087390 42527564 42277680 42567763 43377876
43787863 43687688 44287631 44637567 45097477 45097330
45147184 44537152 43927225
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
Category: Watches, Warnings, Advisories, & Hazards