Multiple Round, Long Duration Severe T-Storm Episode
Saturday-Tuesday July 3-6, 1999

The 1999 severe weather season had been tranquil across the Northeast until this time period.  A hot and oppressively humid air mass pushed into the Northeast on Saturday the 3rd and continued through Tuesday, the 6th.  Temperatures pushed through the upper 80's on the 3rd, 90 on the 4th, and into the mid 90's on the 5th and 6th at Albany.  Dewpoint temperatures surged through the mid 70's producing a volatile combination of heat and moisture.  Moderate to at times strong wind fields in the mid levels of the atmosphere, coupled with weak mid level atmospheric disturbances (cool pools of air aloft) and the high heat and humidity at the surface produced four separate outbreaks of severe thunderstorms across parts of New York and New England.  I've grouped the four separate events together in this summary because the causal factors were linked together by the uniform air mass and lack of large scale triggers.

July 3-4:
Hot, humid, and dry weather prevailed through the region during the afternoon on Saturday, July 3.  Thunderstorms erupted in the eastern Great Lakes late in the afternoon, triggered by a weak upper level disturbance.  Moderately strong mid level winds blowing from northwest to southeast across New York and New England helped organize the thunderstorms into a complex which quickly pushed through New York.  The storms effected the Mohawk valley, Capital Region, Catskills, and Mid Hudson valley between 9:00pm and 11:30pm.  Strong wind gusts and frequent lightning as well as torrential downpours occurred with this batch of strong and severe thunderstorms.   The following table is a listing of damage reports for the local area associated with this group of thunderstorms.


Town, State County Time Damage Report
Burlington, NY Otsego 9:00pm Wind damage, trees down
Colchester, NY Delaware 9:25pm Wind damage, trees down
West Winfield, NY Herkimer 9:30pm Wind damage, trees down
Cobleskill, NY Schoharie 9:30pm Wind damage, trees down
Canajoharie, NY Montgomery 10:00pm Wind damage, trees and wires down
Prattsville, NY Greene 10:30pm Wind damage, trees and wires down
New Scotland, NY Albany 10:35pm Wind damage, trees and wires down


A second round of severe thunderstorms developed a bit further north than the initial batch over southeastern Canada around midnight on Sunday the 4th and traveled in the same moderately strong mid level flow through upstate New York and parts of western New England.  This second round of thunderstorms produced gusty winds and exceptionally heavy rain.  The combination of the two thunderstorm complexes produced up to seven inches of rain in parts of the Mohawk valley and Adirondacks where extensive flooding occurred.   Severe thunderstorm warnings were issued for Herkimer, Hamilton, Fulton, Montgomery, and Schoharie counties at 3:00am effective until 4:30am.  Some wind damage occurred over rural areas.  The thunderstorms began back building over the same areas which resulted in the excessive rainfall.  Flash flood warnings were issued for Southern Herkimer, Fulton and Montgomery counties until noon on Sunday.  Flooding also occurred in Otsego county between 7:30am and 9:30am with numerous roads washed out in the town of Cooperstown.  Severe weather flared up again between 7:00am and 9:30am in Schoharie, Otsego, and Delaware counties.  A tornado warning was issued in Delaware county at 8:43am due to rotation within the thunderstorm that was detected by Doppler radar.  A tornado did not occur, but extensive flooding in Roxbury, Stamford, and Margaretville did occur after four inches of rain fell from the storm.  Wind damage occurred in Summit in Schoharie county at 7:26am.  Concurrently severe flash flooding in Ilion in southern Herkimer county was on-going with many roads and bridges reported closed.  Thunderstorms cleared the area  by late morning leaving a hot and oppressively humid afternoon with no additional thunderstorms.


July 5:
Once again the same atmospheric set-up which produced the two thunderstorm clusters on July 3 and 4, produced another round of thunderstorms at night on July 5.  Hot and oppressively humid weather occurred on the 5th with high temperatures in the mid 90's through the region and no thunderstorms during the day.  Increasing low level inflow winds and a moderately strong mid level wind field again tripped by a weak upper level cool pool of air traveling across southern Canada fired off a round of strong and severe thunderstorms over northern New York between 10pm and midnight.  The storms  tracked across northern New York into northern New England where they intensified.  Wind damage and torrential rain occurred north of the Capital region through the Adirondacks and Green mountains.   The storms were at there most severe as they pushed into New Hampshire and Maine during the morning of the 6th, developing into a full fledged derecho (highly organized thunderstorm complex which produces prolonged periods of damaging wind.)  Extensive wind damage occurred across northern New England.

July 6:
The most significant severe weather event of the series for the Capital Region and western New England occurred on the sixth.  A combination of temperatures in the mid 90's, dewpoint temperatures in the mid 70's, a strong cold front, strong mid level winds, a batch of dry air in the mid levels of the atmosphere, and a strong cool pool of air aloft, all came together to produce widespread severe thunderstorms across eastern New York and western New England.  High wind was the primary type of severe weather with several downburst of 80 to 100 mph occurring through the region.   T-storms began producing damage in the Channel 6 viewing area at 2:00pm.  The last damage report out of Litchfield county, CT, the far southeastern viewing area occurred at 10:08pm.  This was a prolonged severe weather event affecting most counties in upstate eastern New York and western New England. The following table is a listing of NWS damage reports throughout the local area.

 

Town, State County Time Damage Report
Poland, NY Herkimer 1:50pm Trees down
Herkimer, NY Herkimer 2:00pm Street Flooding, trees, wires, and polls down
Newport, NY Herkimer 2:00pm Trees and wires down
Salisbury, NY Herkimer 2:00pm Wind damage, wires down
Warrensburg, NY Warren 2:12pm Wires and large branches down
Diamond Point, NY Warren 2:20pm Trees down, two people injured
Fort Plain, NY Montgomery 2:23pm Trees down
Mayfield, NY Fulton 2:29pm Trees down
Lake George, NY Warren 2:29pm Numerous trees down
Broadalbin, NY Fulton 2:30pm Trees down
Fort Plain, NY Montgomery 2:30pm Trees/Wire down from a second storm
Lake George, NY Warren 2:35pm Tree down killing a camper on Unkiss Island
Dresden, NY Washington 2:36pm Trees and large limbs down
Putnam, NY Washington 2:37pm Wind damage, 400 to 500 trees down, trailer blown on its side
Hagaman, NY Montgomery 2:41pm Wind damage, wires down
Fort Edward, NY Washington 2:41pm Large tree limbs and wires down
Moreau, NY Saratoga 2:41pm Wind damage, trees down
Greenfield, NY Saratoga 2:41pm Trees and wires down
Charlton, NY Saratoga 2:45pm Trees and wires down
Burnt Hills, NY Saratoga 2:47pm Wind damage, tree limbs and wires down
Granville, NY Washington 2:47pm Trees and wires down
Argyle, NY Washington 2:47pm Trees and wires down
Rotterdam, NY Schenectady 2:53pm Large trees down blocking multiple streets
Glenville, NY Schenectady 2:54pm Trees and wires down, described as a "War Zone"
Schenectady, NY Schenectady 2:56pm Wind damage, roof off a building, signs blown down
Niskayuna, NY Schenectady 2:58pm Branches and wires down
Clifton Park, NY Saratoga 2:58pm Wind damage, many trees down due to an 80-90 mph microburst
Salem, NY Washington 3:02pm Trees down
Cobleskill, NY Schoharie 3:04pm Trees down
Jackson, NY Washington 3:04pm Wind damage, 50 uprooted or broken trees
Cambridge, NY Washington 3:10pm Hundreds of trees down
Manchester, VT Bennington 3:15pm Large trees down
Sunderland, VT Bennington 3:15pm Wind damage, trees down
Cohoes, NY Albany 3:15pm Large branches down
Raymertown, NY Rensselaer 3:17pm Trees down and uprooted
Pittstown, NY Rensselaer 3:20pm Extensive wind damage, thousands of trees down, roofs off of storage buildings due to an estimated 100mph downburst
Cobleskill, NY Schoharie 3:20pm Trees down from a second storm
Rensselaer, NY Rensselaer 3:22pm Trees down, power out
Grafton, NY Rensselaer 3:26pm Trees down, no power
Hoosick Falls Rensselaer 3:28pm Large tree limbs down
Arlington, VT Bennington 3:30pm Wind damage
Bennington, VT Bennington 3:30pm Trees down, frequent cloud to ground lightning
Pownal, VT Bennington 3:35pm Trees and power lines down
Stamford, VT Bennington 3:45pm Trees down
Florida, MA Berkshire 3:45pm Wind gust to 65mph
South Berne, NY Albany 4:57pm Trees and wires down at Warner's Lake
Greenville, NY Greene 5:03pm Trees down
Ravena, NY Albany 5:14pm Power out due to downed lines
Delmar, NY Albany 5:14pm Small trees down
Rensselaer, NY Rensselaer 5:18pm Trees and power lines down, several homes struck by lightning, several roofs off
North Chatham Columbia 5:33pm Trees down
Chatham Center Columbia 5:35pm Trees down across route 66
Little Falls, NY Herkimer 6:26pm Trees and wires down due to a 90mph microburst
Kerhonkson, NY Ulster 9:07pm Trees and wires down
Accord, NY Ulster 9:11pm Trees and wires down
New Paltz, NY Ulster 9:19pm Wind damage, due to 70 mph gust
Hyde Park, NY Dutchess 9:30pm Numerous trees down along route 9
Rhinebeck, NY Dutchess 9:30pm Numerous large trees down along route 9G
Pleasant Valley Dutchess 9:30pm Wind damage
New Milford, CT Litchfield 10:00pm Trees down
Pawling, NY Dutchess 10:04pm Trees down
Litchfield, CT Litchfield 10:08pm Trees down