Mesoscale Discussion 2243
   NWS Storm Prediction Center Norman OK
   0628 PM CST Sun Dec 29 2019

   Areas affected...Northeast New York...Vermont...Southern New
   Hampshire...and northern Massachusetts

   Concerning...Freezing rain 

   Valid 300028Z - 300430Z

   SUMMARY...A long duration icing event has started for portions of
   the Northeast.

   DISCUSSION...A large area of light to moderate precipitation
   associated with broad isentropic ascent has overspread much of the
   Northeast. Initially, most of this precipitation has fallen as rain
   with temperatures in the mid 30s, but drier air is in place across
   northeast New York, Vermont, southern New Hampshire, and northern
   Massachusetts. Therefore, wet-bulbing has led to significant
   temperature drops as precipitation begins. Current surface wet-bulb
   temperatures suggest upper 20s to low-30s can be expected across
   most of this region. Given the warm air aloft (~5C per ALB 00Z
   RAOB), and a shallow surface cold layer, expect precipitation type
   across this region to quickly change to freezing rain as surface
   temperatures drop. Light to moderate precipitation is expected to
   continue into the overnight hours when diurnal temperature trends
   will assist maintenance of sub-freezing temperatures across this
   region. A strong surface high in eastern Canada will help maintain
   east-northeast surface flow and advect cold air into the region
   through the overnight hours and into the day tomorrow. Light to
   moderate precipitation rates, temperatures a few degrees below
   freezing, and increasing surface winds (10 to 15 mph by Monday
   morning) will provide a favorable environment for efficient ice
   accretion (0.05"-0.1"/hr). The most significant icing in the next 12
   hours is expected late this evening into the early morning hours
   before precipitation rates lighten somewhat near daybreak.

   Localized terrain effects and subsequent temperature differences
   will affect icing across the region with lesser icing expected at
   lower elevations where temperatures may remain more marginal.

   ..Bentley.. 12/30/2019

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF...

   LAT...LON   44367591 44677567 44997511 45047473 45087368 44807289
               44377227 43917171 43527110 43247083 43057082 42827108
               42607154 42377202 42357231 42597288 42767315 42857361
               42897385 43037457 43277505 44087592 44367591