Sunday Night-Monday December 29-30, 2019
Heavy Rain - Elevation Ice Storm Event

A long duration complex storm unleashed moderate to heavy storm total precipitation on eastern New York and western New England from late Sunday afternoon December 29 through Monday evening December 30 with additional scattered light precipitation through Tuesday December 31 (mostly drizzle, freezing drizzle or very light snow) before all parts of the storm cleared the region. The result was liquid equivalent precipitation amounts, which largely fell as plain rain in valley areas, ranging from 0.75" to 1.50" on average.

At elevations of 1000' and higher, much of the precipitation fell as sleet and freezing rain with ice storm conditions from late Sunday night through Monday in parts of the Catskills, Schoharie County, the Mohawk valley, Adirondacks, Vermont, the Taconics, Berkshires and Litchfield hills. A general 0.25" to 0.50" of ice accumulated with some pockets in the Taconics, Berkshires and Litchfield County CT, especially at elevations of 1800' and higher, coming in with up to 3/4" of ice on average. Considerable tree and power line damage occurred in these pockets where the heaviest icing occurred. Power outages were scattered with up to 12,000 utility customers out through Monday across the CBS6 coverage area.

Temperatures in the valleys, including the Glens Falls, Saratoga, Capital Region and points south as well as west into the Amsterdam area remained a few degrees above freezing through the event, just warm enough to allow for predominantly rain through the heaviest portion of the storm. A change to sleet and light patchy snow did occur late in the afternoon and through the evening continuing into the 31st as the atmosphere aloft cooled. A bonus round of heavy snow squalls, mixed with rain in the valleys, and producing lightning and thunder culminated the entire event from roughly 6pm through 9:30pm on Tuesday the 31st as the parent potent upper level low pressure system moved through.

Heavy Icing on top of Mount Raimer in Petersburg (Elevation 2520') in the Taconics on the NY-MA Border: Photo taken on Tuesday December 31 - Photo Credit: Shawn Puzio

Heavy Icing in the Taconics (elevation of 2520') in Petersburg

Icing Zones : The map depicts a rough estimate of where significant icing of 1/4" or greater occurred. Due to the highly elevation dependent nature of this event and the limited resolution of this map (which is hand drawn, not computer generated) the icing zones are likely exaggerated as many lower elevation areas in the shaded zones had little icing. Icing was generally confined to elevations of 1000' and higher. NOTE: This map depicts pure ice accretion only, not accumulations of sleet and snow which most areas had at least a coating of with a few inches in some higher elevation areas.

Outline of where significant icing of a quarter inch or greater occurred, mainly at elevations of 1000' and higher 

STORM SET-UP
A complex and very large low pressure system both at the surface and aloft, tracked well to our region's west, up through the Midwest, creating the set-up for a strong northward gulf moisture transport into the Northeast on a deep mid and upper level warming southerly flow. This would have entirely been a rainstorm for the Northeast due to the lack of cold air aloft had it not been for a cold Canadian surface high pressure system, characterized by a pool of shallow colder, sub-freezing air, banked across the border prior to the onset of precipitation. The low level cold air, being shallow and dense, easily bled south, in response to air pressure falls along the coast, effectively wedging into eastern New York and New England. This shallow cold air was further chilled by a wet bulb process as precipitation began which caused evaporative cooling of the air mass dropping the temperature a few more degrees and is largely what set the stage for mixed precipitation and icing.

But, the air was only marginally cold, with temperatures in valley areas generally holding in the mid 30s (and even briefly the upper 30s around Albany) through the bulk of the event, coupled with the warm air aloft, to support plain rain. Higher elevation locations, however, hovered at freezing or a little below allowing for the rain to freeze on contact with surfaces creating the ice storm in the higher terrain both east and west of the Hudson valley as well as in the Mohawk valley, Adirondacks, and higher terrain in Vermont.

Icing was most severe at elevations of 1800' and higher and significant down to about 1000' and a little lower in some places like the Glenville hill in Schenectady County where up to 1/4" of ice brought down some branches and trees. A switch to some light sleet and snow did occur everywhere as the atmosphere cooled late in the day and through the night of the 30th into the morning of the 31st. At this point in the storm, however, the heavy precipitation had ended as a coastal low which had formed pushed the deeper moisture across New England through the night. Occasional drizzle, freezing drizzle and light snow occurred through Tuesday morning with little additional accumulation of either snow or ice, outside of a coating.

LOCALIZED STRONG WIND GUSTS (So. Vermont, Berkshires, eastern Hudson valley and Taconics)

A period of strong east to southeast winds occurred from the mid to late morning into the mid afternoon on the 30th in pockets across western New England, the Taconics and parts of Columbia County and to a lesser extent across the Adirondacks. Localized wind gusts of 40-50 mph occurred in response to the strong low level ESE jet going over and through the passes in the Berkshires, southern Green mountains and the Taconics where the flow was channeled to the ground in localized strong gusts. North Adams, MA gusted to 51 mph at 1:01pm, 50 mph at Old Bennington, VT at 12:29pm, 46 mph at Bennington, VT at 11:34am, 46 mph @ Copake at 11:35am, and 41 mph at Stephentown at 12:50pm
.

AFTERNOON T'STORM EVENT
A pocket of elevated instability developed in advance of an occluded front to support scattered shallow convection from the mid to late afternoon which rolled through parts of Delaware, Ulster, Greene, Albany, Columbia, Rensselaer, southern Bennington, Berkshire, and Litchfield counties. The thunderstorms produced occasional cloud to ground lightning and pockets of hail. Large hail fell in Norfolk, CT, Litchfield County, measuring 1" in diameter, unusual for the time of the year. The strong low level jet produced a zone of strong easterly flow which was topped by strong westerly flow setting up a strong shear environment which coupled with the shallow instability supported the convection which is not unprecedented in winter storms, especially winter storms that produce mixed precipitation. The fact that the precipitation was mixed, with heavy sleet reported with the thunderstorms, aided in charge separation creating the lightning, despite the very shallow nature of the convection.

Hoosick Falls - Rensselaer County - Small Hail - Photo credit: Derek Gardner

Small hail in Hoosick Falls Monday December 30, 2019 


NWS Ice Storm Reports Monday December 30, 2019: Note, these reports are used to verify the NWS ice storm warnings which were issued for this event and therefore do not represent an accounting for all of the associated damage produced by the moderate to heavy icing.

Town County Severe Weather Report Time
Knox Albany Multiple reports of downed power lines due to ice 8:00am
Berne Albany Multiple trees and wires down due to ice 11:00am
Grafton Rensselaer Trees and wires down due to ice 12:00pm
Hoosick Falls Rensselaer Ice Storm: Large tree down blocking Route 22, Utility pole taken out 12:30pm
Berlin Rensselaer Ice Storm: Trees and wires down 1:00pm
Westerlo Albany Ice Storm: Wires and trees down throughout town 1:30pm
Rensselaerville Albany Ice Storm: Multiple reports of branches and trees down due to ice 2:00pm
Petersburg Rensselaer Trees and wires down due to heavy icing 2:00pm
Duanesburg Schenectady Ice Storm: Multiple reports of downed trees, branches and lines 2:30pm
Summit Schoharie Tree limbs down on roadways due to heavy icing 4:00pm
Jefferson Schoharie Ice Storm: downed trees and branches 4:00pm
Town County Ice Accumulation Reports Time of Report
Torrington, CT Litchfield 0.75" 4:54pm
Norfolk, CT Litchfield 0.30" 2:46pm
Windsor, MA Berkshire 0.50" 11:15am
Savoy, MA Berkshire 0.50" 11:15am
Peru, MA Berkshire 0.25" 3:00pm
Becket, MA Berkshire 0.25" 11:30am
Sandisfield, MA Berkshire 0.25" 9:02am
Altamont Albany 0.25" 7:25am
Delanson Schenectady 0.50" 11:02am
Breakabeen Schoharie 0.50" 11:52am
Speculator Hamilton 0.25" 7:00am
Piseco Hamilton 0.25" 7:00am
Long Lake Hamilton 0.19" 7:00am
Danube Herkimer 0.50" 8:00am
Ilion Herkimer 0.40" 12:30pm
Salisbury Herkimer 0.24" 8:00am
Lake Desolation Saratoga 0.50" 5:00pm
Hessville Montgomery 0.30" 8:34am
Amsterdam Montgomery 0.10" 7:45am
Hartford Washington 0.14" 7:33am
Hebron Washington 0.10" 8:10am
Readsboro, VT Bennington 0.30" 9:00am
Londonderry,VT Bennington 0.25" 9:00am
Wilmington, VT Windham 0.20" 6:41am
Danby, VT Rutland 0.19" 11:00am

Photographs

Heavy Icing in Carlisle - Schoharie County - Photo Credit: Connie Bradt via facebook

Heavy icing in Carlisle Schoharie County 

Heavy icing in Carlisle Schoharie County

Heavy Icing in Carlisle - Schoharie County (Elevation 1365') - Photo Credit: Shelly Cacciolfi via facebook

Icing in Carlisle - Schoharie County - Elevation of 1350'

Heavy Icing in Cherry Valley - Otsego County - Photo Credit: Dave Fritts via facebook

Heavy icing in Cherry Valley - Otsego County 

Heavy icing in Cherry Valley - Otsego County 

Moderate Icing on Bleecker Mountain - Fulton County - Photo Credit: Dave and Stacy Winnie via facebook

Moderate icing on Bleecker Mtn. Fulton County Monday Morning December 30, 2019 

Icing and tree damage in Glenville - Schenectady County - Photo Credit: Peter Hutchins via email

Icing and tree damage in Glenville Schenectady County

Icing in Delanson - Schenectady County - Photo Credit: Kristin Amy via facebook

Moderate icing in Delanson - Schenectady County 


Icing in Galway - Saratoga County -
Photo Credit: Teri Eastwood via facebook

Moderate to heavy icing in Galway - Saratoga County

Heavy Icing in Norfolk, CT - Litchfield County - Photo taken on Jan 1, 2020, Photo Credit: Jim Meehan, WxNet 6

Heavy ice still on the trees on January 1, 2020, Norfolk, CT Litchfield County

WeatherNet 6 Rainfall Reports from Sunday Evening December 29-Monday December 30, 2019
(Most Reports are Not Storm Totals but close)


NOTE: Rainfall reporting was not consistent or particularly accurate in this event due to the mixed precipitation nature of the storm. Therefore you should consider the values listed close estimates

Town County Rainfall Report Town County Rainfall Report
Great Barrington, MA Berkshire 1.01" Hancock, MA Berkshire 0.88"
Savoy, MA Berkshire 6" Snow 29th-31st      
           
Albany (ASOS) Albany 1.36" Westmere Albany 0.65"
Delmar Albany 0.70" Colonie Albany 1.42"
           
Taghkanic Columbia 0.88" Spencertown Columbia 1.04"
Livingston Columbia 1.34"      
           
Margaretville Delaware 0.59" Roxbury Delaware 0.66"
           
Staatsburg Dutchess 1.09" Red Hook Dutchess 1.30"
           
Catskill Greene 1.05" to 1.17" Cairo Greene 1.20" to 1.50"
Greenville Greene 0.72"      
           
Fonda Montgomery 1.49" Amsterdam Montgomery 1.69"
           
Speigletown Rensselaer 1.20"      
           
Galway Saratoga 1.20" Saratoga Springs Saratoga 1.20"
           
Rotterdam Schenectady 1.34" Glenville Schenectady 1.29"
           
Granville Washington 1.00" Greenwich Washington 1.10"
Cossayuna Washington 0.72"      
           
Warrensburg Warren 1.00"      
           
Ulster Park Ulster 1.02" West Shokan Ulster 1.56"
Phoenicia Ulster 1.09"      
           
West Rutland, VT Rutland 0.83"