203
AWUS01 KWNH 061552
FFGMPD
NYZ000-PAZ000-062130-

Mesoscale Precipitation Discussion 0404...Corrected
NWS Weather Prediction Center College Park MD
1152 AM EDT Thu Jun 06 2024

Corrected for DISCUSSION SECTION FIXED

Areas affected...Central and Eastern Upstate New York...Far
Northeast PA...

Concerning...Heavy rainfall...Flash flooding possible

Valid 061545Z - 062130Z

SUMMARY...Deep moisture flux convergence along/ahead of frontal
zone and mid-level wave should allow for efficient rainfall
production.  Places of localized back-building/cell hanging up may
result in spotty 2-3" totals and possible flash flooding through
late afternoon.

DISCUSSION...GOES-E WV suite depicts very strong negatively tilted
long wave trough across the Great Lakes with well defined warm
conveyor belt well east near effective triple point low/complex in
the New York Bight.  However, the broadness of the trough and
influence of easterly component winds over the last few days has
resulted in a residual secondary moisture plume axis across the
eastern Great Lakes/NY as main vorticity center drives eastward
through Lake Huron.  Additionally, upper-level diffluent part of
the highly cyclonically curved 90-100kt polar jet over S Ontario
leaves much of the area of concern within large scale ascent
pattern and favorable environment to maintain/strengthen 500-700mb
inflection/wave currently seen along the central PA/NY border
pressing east.  Given the DPVA, low level flow as backed slightly
with 15-20kts, deep layer moisture has pooled to over 1.75" along
and northeast of the inflection across Eastern Lake Ontario into
SE Ontario/SW Quebec.

Modest clearing is providing good insolation to support building
instability axis along and east of the deep moisture confluence
axis.  MLCAPES have already climbed into the 750-1000 J/kg and
likely to increase to 1250 J/kg.  The combination of deep layer
convergence, enhanced downshear of the MCV will allow for
increased convection over the next few hours.  A few cells may
even break through capping in the warmer air along the increasing
terrain slopes north of the Mohawk valley into the Adirondack
Mountains. Given flux convergence, moisture availability, rates of
1.5-1.75" will becoming increasingly frequent and if cells are
slow to move initially could pose spots of 2-3".  Additionally,
favorable north-northeast cell motions along the deformation zone
into southern Canada may support some short-term repeating for
isolated spots of 2-3", as well.

Slowly, with some mid-level steepening of lapse rates along/south
of the shortwave in NE PA, deeper, more intense thunderstorms may
evolve with rates over 2"/hr...though forward propagation may
mitigate overall totals, sub-hourly rates/totals may induce some
low end flash flooding concerns in the lower FFG/complex terrain
of the Poconos/Catskills, and so has been included in this area of
concern through late afternoon.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

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

ATTN...RFC...MARFC...NERFC...NWC...

LAT...LON   45017500 44837398 43557381 42217354 41617433
            41517562 41967661 42327725 42897723 43377691
            43627642 44187634