Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
342 PM EDT Sat Mar 16 2019

Valid 00Z Sun Mar 17 2019 - 00Z Wed Mar 20 2019


A weak surface wave moving east from the mid Mississippi valleys
into the Ohio Valley into Sunday combines with modest low-mid
level frontogeneiss and 850 mb convergence to produce a band of
light snow.  The 12z NAM, GFS and several hi-res members are in
good agreement showing a stripe of light accumulations from
eastern Iowa to northern Indiana and Ohio tonight to Sunday,
continuing east into southeast Ohio and southwest PA and western
MD/northern WV Sun evening before ending as the wave moves east of
the mountains into the mid Atlantic.

The limited moisture and the progressive nature of the system
should keep accumulations light, with WPC probabilities for
accumulations of 4-inches or more at less than 10 percent.   

Elsewhere, enhanced moisture and low level frontogenesis
associated with a series of low amplitude 700 mb shortwave sliding
southeast along the central to southern Rockies and High Plains is
largely responsible for some scattered low end probabilities for
accumulations of 4-inches or more across the central to southern
Rockies and high Plains Monday into Tuesday.  Temperatures become
too warm for snow further east on the central to southern Plains,
keeping the threat minimal.

The probability of 4 or more inches of snow iss less than 10
percent day 3.

The probability of significant freezing rain is less than 10
percent days 1-3.

Petersen