A large upper air trough dug across the western Great Lakes on Monday, July 21. At the surface, a deep low pressure area moved across the eastern Great Lakes, driving a warm front across eastern New York and adjacent New England. The air became very unstable in the warm air mass behind the front. The combination of the unstable air and strong wind shear aloft, produced the most significant severe outbreak of the season across the region, and the largest tornado outbreak since May 31, 1998.   	The first line of thunderstorms worked across the region during the afternoon hours. These produced spotty wind damage, mainly downed trees and wires across portions of Albany, Greene, Rensselaer, Schenectady, Saratoga and Schoharie Counties. Torrential rains falling in a very short interval of time caused flash flooding in the city of Schenectady. North Jay Street suddenly flooded and a woman had to be rescued from her car as it became submerged in about three feet of moving water. 	An even stronger line of storms moved east from central New York, into eastern New York during the evening hours. This squall line produced wind damage of its own, with spotty downed trees and wires across portions of Albany and Washington counties. Wind damage was more concentrated in Ulster and Dutchess counties. In Saugherties, Ulster County, downed trees flattened three cars. In Dutchess County, a large swath of trees were downed in the town of East Fishkill and in the town of Tivoli, a state of emergency was declared.    	One cell broke loose from the line, and became a supercell as it reached the Mid Hudson Valley. This storm ultimately spawned a long lived significant tornado. The twister initially touched down in southeastern Greene County, and produced a  discontinous path of 17 miles in Greene County, 12.2 miles in northwestern Columbia County and 4.8 miles in southern Rensselaer County.  The tornada left a swath of destruction including hundreds, if not thousands of trees uprooted and snapped away, along with lots of power and telephone wires. Many roads in each of these counties were impassable due to debris. 	The first confirmed touchdown was in the town of Palenville, Greene County. The tornado was ranked as F1 with a 50 yard wide path and on the ground for a half mile. An unoccupied home had its siding ripped off. Several other homes were severely damaged including a trailor. The tornado next touched downed in the hamlet of Kiskatom, in the town of Catskill, where it increased to F2 intensity and cut a path 150 yards wide and over a mile long. Several homes were destroyed along with seven injuries right off Route 32 in the Brookside Camp Grounds.  Four people were trapped inside one of the trailer homes. Another lady was trapped inside a mobile home as it was lifted into the air then smashed into the ground. The woman was badly bruised but survived the ordeal. The next touchdown was in Athens with a rating of F0, and the last touchdown in Greene County was in Coaxsackie where a manufactured home was hoisted off its foundation, and had insulation pasted to the siding on the downwind side, which is typical of F1 damage.  	The tornado ripped across Columbia County with two touchdowns confirmed in the towns of Kinderhook, the Newtown Hook section in the town of Stuyvesant and the town of Niverville. The touchdown at Kinderhook Lake the strongest, with a ranking of F2. A barn was completely destroyed and the unfortunate farmer stated that some of his haywagons ended up in Kinderhook Lake. A garage was completely leveled and a car was tossed onto the tops of a blown-down tree. Another building had its metal roof partially peeled back. In Niverville, 11 people were given shelter as they were afraid to stay in their damaged homes. Straight-line thunderstorms produced additional tree and wire damage in the towns of Chatham, Hudson and Valatia. A state of emergency was declared throughout Columbia County. There was one injury reported by the newspaper in that county. The only hail reported with these storm took place in Stockpart, where golf ball size stones where reported. A state of emergency was declared in all of Columbia County right after the tornado past on by. 	The supercell and resultant tornado next touched down in the town of Nassua in Rensselaer County, near Route 20 with a rating of F1. The average width of the twister was between 75 and 100 yards and a discontinous path length of more than four miles. More homes and a garage were severly damaged but no injuries were reported. The roof on the Agway was blown off and a gazebo landed across the state highway in a  pile of splintered wood. The NWS Survey team noted that the twister had multiple vortices in this area.  Additional straight line damage was also noted in the same town. The last touchdowns were in the town of Schaghticoke with an F1 rating.  	During the height of the storms, as many as 63,000 customers were reported to have lost power in eastern New York, nearly 7,000 of those in Greene County alone. Power restoration was not completed until the following Friday.

Thunderstorm Wind in SCHOHARIE, NEW YORK
From 21-JUL-03 14:17:00 to 21-JUL-03 14:17:00 (EST)
Location: MIDDLEBURG
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in GREENE, NEW YORK
From 21-JUL-03 14:46:00 to 21-JUL-03 14:46:00 (EST)
Location: LEXINGTON
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in SCHENECTADY, NEW YORK
From 21-JUL-03 15:00:00 to 21-JUL-03 15:00:00 (EST)
Location: SCHENECTADY
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ALBANY, NEW YORK
From 21-JUL-03 15:11:00 to 21-JUL-03 15:11:00 (EST)
Location: COLONIE
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in SARATOGA, NEW YORK
From 21-JUL-03 15:25:00 to 21-JUL-03 15:25:00 (EST)
Location: CLIFTON PARK
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Tornado in GREENE, NEW YORK
From 21-JUL-03 19:14:00 to 21-JUL-03 19:15:00 (EST)
Location: PALENVILLE
Tornado F-scale: F1
Property damage: 25K
Reported by: TRAINED SPOTTER

Tornado in COLUMBIA, NEW YORK
From 21-JUL-03 19:35:00 to 21-JUL-03 19:36:00 (EST)
Location: NEWTON HOOK
Tornado F-scale: F0
Property damage: 5K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in WASHINGTON, NEW YORK
From 21-JUL-03 15:30:00 to 21-JUL-03 15:30:00 (EST)
Location: HUDSON FALLS
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHINGTON, NEW YORK
From 21-JUL-03 15:30:00 to 21-JUL-03 15:30:00 (EST)
Location: CAMBRIDGE
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in RENSSELAER, NEW YORK
From 21-JUL-03 15:41:00 to 21-JUL-03 15:41:00 (EST)
Location: HOOSICK
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ULSTER, NEW YORK
From 21-JUL-03 19:00:00 to 21-JUL-03 19:00:00 (EST)
Location: SAUGERTIES
Magnitude: 75 ES
Property damage: 10K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in SCHOHARIE, NEW YORK
From 21-JUL-03 19:00:00 to 21-JUL-03 19:00:00 (EST)
Location: SCHOHARIE
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in DUTCHESS, NEW YORK
From 21-JUL-03 19:15:00 to 21-JUL-03 19:15:00 (EST)
Location: COUNTYWIDE
Magnitude: 75 ES
Property damage: 10K
Reported by: LAW ENFORCEMENT

Tornado in GREENE, NEW YORK
From 21-JUL-03 19:23:00 to 21-JUL-03 19:25:00 (EST)
Location: KISKATOM
Tornado F-scale: F2
Property damage: 1M
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in ULSTER, NEW YORK
From 21-JUL-03 19:20:00 to 21-JUL-03 19:20:00 (EST)
Location: ESOPUS
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ALBANY, NEW YORK
From 21-JUL-03 19:16:00 to 21-JUL-03 19:16:00 (EST)
Location: BETHLEHEM CENTER
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in COLUMBIA, NEW YORK
From 21-JUL-03 19:25:00 to 21-JUL-03 19:25:00 (EST)
Location: HUDSON
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Tornado in RENSSELAER, NEW YORK
From 21-JUL-03 19:45:00 to 21-JUL-03 19:51:00 (EST)
Location: NASSAU
Tornado F-scale: F1
Property damage: 50K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in WASHINGTON, NEW YORK
From 21-JUL-03 20:15:00 to 21-JUL-03 20:15:00 (EST)
Location: EASTON
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER

Tornado in COLUMBIA, NEW YORK
From 21-JUL-03 19:40:00 to 21-JUL-03 19:40:00 (EST)
Location: STUYVESANT
Tornado F-scale: F0
Property damage: 5K
Reported by: NWS STORM SURVEY

Hail in COLUMBIA, NEW YORK
From 21-JUL-03 19:30:00 to 21-JUL-03 19:30:00 (EST)
Location: STOCKPORT
Magnitude: 1.75 
Property damage: 1K
Reported by: TRAINED SPOTTER

Tornado in GREENE, NEW YORK
From 21-JUL-03 19:24:00 to 21-JUL-03 19:25:00 (EST)
Location: ATHENS
Tornado F-scale: F1
Property damage: 10K
Reported by: NWS STORM SURVEY

Tornado in GREENE, NEW YORK
From 21-JUL-03 19:30:00 to 21-JUL-03 19:31:00 (EST)
Location: COXSACKIE
Tornado F-scale: F1
Property damage: 100K
Reported by: NWS STORM SURVEY

Tornado in COLUMBIA, NEW YORK
From 21-JUL-03 19:38:00 to 21-JUL-03 19:39:00 (EST)
Location: STUYVESANT
Tornado F-scale: F0
Property damage: 10K
Reported by: NWS STORM SURVEY

Tornado in COLUMBIA, NEW YORK
From 21-JUL-03 19:40:00 to 21-JUL-03 19:42:00 (EST)
Location: KINDERHOOK
Tornado F-scale: F0
Property damage: 20K
Reported by: NWS STORM SURVEY

Tornado in COLUMBIA, NEW YORK
From 21-JUL-03 19:43:00 to 21-JUL-03 19:45:00 (EST)
Location: KINDERHOOK
Tornado F-scale: F2
Property damage: 200K
Reported by: NWS STORM SURVEY

Tornado in COLUMBIA, NEW YORK
From 21-JUL-03 19:32:00 to 21-JUL-03 19:34:00 (EST)
Location: NIVERVILLE
Tornado F-scale: F1
Property damage: 150K
Reported by: NWS STORM SURVEY

Flash Flood in SCHENECTADY, NEW YORK
From 21-JUL-03 15:00:00 to 21-JUL-03 16:00:00 (EST)
Location: SCHENECTADY
Reported by: NEWSPAPER

Thunderstorm Wind in COLUMBIA, NEW YORK
From 21-JUL-03 19:40:00 to 21-JUL-03 19:40:00 (EST)
Location: VALATIE
Magnitude: 60 ES
Property damage: 10K
Reported by: NEWSPAPER

Thunderstorm Wind in COLUMBIA, NEW YORK
From 21-JUL-03 19:40:00 to 21-JUL-03 19:40:00 (EST)
Location: CHATHAM
Magnitude: 60 ES
Property damage: 10K
Reported by: NEWSPAPER

Thunderstorm Wind in DUTCHESS, NEW YORK
From 21-JUL-03 18:05:00 to 21-JUL-03 18:05:00 (EST)
Location: EAST FISHKILL
Magnitude: 60 ES
Property damage: 1K
Reported by: TRAINED SPOTTER