SPC MD 2243



MD 2243 CONCERNING FREEZING RAIN FOR NORTHEAST NEW YORK…VERMONT…SOUTHERN NEW HAMPSHIRE…AND NORTHERN MASSACHUSETTS

MD 2243 Image

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 

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