Mesoscale Discussion 2184
NWS Storm Prediction Center Norman OK
0445 AM CST Sun Dec 01 2019
Areas affected...Portions of western/central PA...far western
MD...and southwestern NY
Concerning...Freezing rain
Valid 011045Z - 011645Z
SUMMARY...Freezing rain, with rates in excess of 0.05 inch per three
hours, will become increasingly likely through the morning.
DISCUSSION...A band of precipitation being aided by strengthening
low-level warm and moist advection will develop across much of the
Mid-Atlantic this morning. This precipitation will overrun a
residual near-surface sub-freezing layer that extends across much of
the Northeast and into parts of western/central PA and the higher
terrain of far western MD. As surface temperatures cool to the wet
bulb temperature with continued low-level moistening, freezing rain
will become increasingly likely across much of this region. Freezing
rain rates in excess of 0.05 inch per three hours appear probable,
although substantial ice accretion may be limited by near-freezing
surface temperatures. Somewhat better potential for both higher
rates and ice accretion will likely exist across the higher terrain
of western PA/central and far western MD, where surface temperatures
in the upper 20s to around 30 F should be present. With the
exception of the higher terrain, freezing rain should gradually
transition to rain from southwest to northeast across western PA
through the morning as low-level warm advection continues.