Four Part Severe Weather Outbreak including a Major Supercell T'Storm Event
Late Sunday night, May 23-Monday, May 24, 2004

Within a twenty four hour period from 10pm Sunday night, May 23, to 10pm Monday night May 24, four separate and distinct outbreaks of severe thunderstorms developed and produced reports of wind damage, large hail, and flash flooding throughout eastern New York and western New England.

Set Up For T'Storm Event #1, 11:15pm/23rd-2:00am/24th:
Sunday Afternoon, May 23: A warm front briefly lifted north of the Capital Region allowing dewpoints to climb into the 60s and air temperatures to push into the low 80s in the Capital Region and to around 90 degrees around Poughkeepsie.  Concurrently, temperatures around Glens Falls and Rutland, VT remained in the 50s and low 60s through the day.  The front moved south as a cold front during the evening, dropping temperatures and dewpoints across the majority of the region, eventually stalling along the New York-Pennsylvania line.  Similar to the event early in the morning on the 23rd, another vigorous thunderstorm complex, originating in the Midwest, traveled along the northern periphery of the warm front into upstate New York.  A strong low level jet again transported very warm and humid air northward up and over the warm front to create a favorable environment aloft for thunderstorms despite the very chilly temperatures and low dewpoints at the surface.  A more dramatic turning of the wind and increase in speed with height was present in the vicinity of the front than was the case during the pre-dawn 23rd event.  This "Wind Shear" created a favorable environment for a discrete supercell thunderstorm to form which went on to produce wind and hail damage over Herkimer county.  A tornado warning was issued on the storm which showed strong rotation between 11:20pm and midnight.  The cell tracked northeast into Hamilton county and gradually weakened.  A line of very strong thunderstorms then moved down the Mohawk valley into the Capital Region with radar signatures of strong wind.   However, little wind was able to make it down to the ground due to a strong temperature inversion that resulted from the warm air being transported by the low level jet up an over the chilly air at the surface.  Had the thunderstorms been occurring in the warm sector of the front, much more mixing of the atmosphere would have occurred causing considerable damaging wind to make it down to the ground.  Therefore, very little severe weather occurred with this thunderstorm complex.  However, the lightning with the supercell was reported to be continuous for almost two hours in the Adirondacks.   Lightning with the other clusters of thunderstorms was also frequent through the Mohawk Valley and Capital Region.   Torrential rains occurred over the Adirondacks setting the stage for flooding from subsequent rounds of thunderstorms. 

This is a listing of severe weather reports from this event:
Poland, Herkimer County, 1" diameter Hail, 10:30pm
Russia, Herkimer County, T'Storm Wind Damage, Trees Down, 10:30pm
Cold Brook, Herkimer County, T'Storm Wind Damage, Trees Down, 10:55pm
Poland, Herkimer County, T'Storm Wind Damage, 10:55pm

Set Up For T'Storm Event #2, 5:00am-8:00am/24th:
Another in a series of disturbances tracked along the stationary front to the south of the region, accompanied by a continuous strong low level jet of moisture and warmth overrunning the front, to produce another round of torrential and locally severe T'storms during the very early morning of the 24th.  Frequent lightning and crashes of thunder rocked many out of bed early as the line of storms moved through the Capital Region. Torrential rain on saturated ground in the Adirondacks lead to flash flooding in several communities in Herkimer and Hamilton counties.  Rainfall estimates from Doppler radar ranged from 1"-5" across the Adirondacks from the two thunderstorm events.

This is a listing of severe weather and flash flood reports from this event:
Glenville, Schenectady County, T'Storm Wind Damage, Trees Down and power out, 5:48am
Schaghticoke, Rensselaer, T'Storm Wind Damage, Trees Down, 6:15am
Little Falls, Herkimer County, Flash Flood, The Mohawk river flowed out of its banks in low lying areas between Herkimer and Little Falls
Middleville, Herkimer County, Flash Flood, Multanner Creek out of its banks, 7:00am
Herkimer, Herkimer County, Flash Flood, West Canada Creek out of its banks in low lying areas between Newport and Herkimer
Hope, Hamilton County, Flood, flooding along the Sacandaga River

Set Up For T'Storm Event #3, 11:00am-1:00pm/24th:
A strong mesoscale convective complex, which formed over western New York early in the morning as the second line of thunderstorms was tracking through the Capital Region, intensified as it approached the region during the middle to late morning.  A notable twist in the northern extent of the thunderstorm line indicated a very organized complex.   However, the region remained north of the warm front, which meant very warm and moist air remained aloft over the chilly air near the ground, precluding widespread damaging wind gusts from propagated to the ground as the complex arrived.   Nevertheless, the strength of some of the downdrafts was sufficient to bring some strong gusts down creating damage.  Large hail also fell from a few of the stronger storms.  Frequent lightning and torrential rain again accompanied this complex of thunderstorms as it tracked through most of the region from the Mohawk valley on south and into Berkshire county. A severe thunderstorm watch was issued to cover this event from the late morning until 4pm.

Severe Weather Reports from the 11:00am-1:00pm Event

Town Name

County

Severe Weather Report

Time of Severe WX
Middleburgh Schoharie

T'Storm Wind damage, Trees Down

11:00am
Berne Albany

0.75" Diameter Hail

11:10am
Lake Hill Ulster

0.75" Diameter Hail

11:44am
Ashland Greene

T'Storm Wind damage, trees down on road

11:30am
Livingston Columbia

T'Storm Wind damage, Large Tree Limbs down

12:14pm
Fishkill Dutchess

0.75" Diameter Hail

12:30pm

Major Supercell Severe Thunderstorm Outbreak: 3:30pm-10:00pm/24th
Set Up:
After enduring three rounds of torrential and locally severe thunderstorms already, the main event was yet to occur across the region.  As the midday complex of thunderstorms moved out of the area, rapid drying of the mid levels of the atmosphere occurred as sinking air resulted in the wake of the departing thunderstorms.  Clouds dissipated and the sun came out strongly by 1:00pm across much of eastern New York.   A weak low pressure system, simultaneously, tracked into western New York on a path that would take it up through the St. Lawrence valley.  The combination of the circulation around the low pressure system and the sunshine, caused the warm front lying south of the region to jump north, into the Mohawk valley.  Subsequently, temperatures climbed into the mid and upper 70s and dewpoints climbed into the low and mid 60s.  In conjunction with these developments, a mid level pocket of cold air was moving into the Northeast and strong low level wind shear was developing along and south of the warm front and ahead of an advancing cold front.  The increase in sheer resulted as surface winds came up out of the southeast while the upper level winds veered to the southwest and west with height.  As the atmosphere became more unstable with surface heating and falling temperatures aloft, the ingredients were coming together for a major outbreak of severe thunderstorms with a slight possibility of tornadoes.   Low level moisture, although sufficient for severe thunderstorms, with dewpoints in the low to mid 60s, was just low enough, to preclude a major tornado outbreak across the region.  Had dewpoint temperatures climbed to near 70 degrees,  and air temperatures moved into the low or mid 80s, the level of instability would have been much higher, creating a more favorable environment for tornadoes. 

As it was, numerous supercell thunderstorms (thunderstorms with rotating updrafts) formed and went on to produce huge amounts of hail, some reports of damaging straight line winds, torrential amounts of rain, and frequent cloud to ground lightning.  Although several tornado warnings were issued for some of the stronger supercells, only one tornado was confirmed in far western Delaware county.  A severe thunderstorm watch was reissued over the region effective until 9pm to cover the developing outbreak.

Thunderstorms began developing rapidly across central New York around 3pm and moved into eastern New York by 3:30pm, rapidly becoming severe.   A particularly long lived supercell formed just west of Herkimer county and took a very familiar track down the Mohawk valley through Fulton county, where a tornado warning was issued and wall clouds sighted.  The storm then moved into Saratoga county, through the towns of Round Lake, Ballston Spa, Stillwater, then to northern Rensselaer and southern Washington counties, through Buskirk Eagle Bridge, and Cambridge, and finally into south central Bennington county, VT between Shaftsbury and Bennington.  It took the storm approximately three hours to track through the region, producing almost continuous lighting, bursts of straight line damaging winds, and hail ranging in size from small peas, to over an inch and a half in diameter.  So much hail fell on Buskirk in northern Rensselaer county that it accumulated up to several inches in places, defoliated trees, smashing out windows in houses and cars, and requiring snow plows to clear the roads.  Flooding in Malta's Luther Forest development in Saratoga county occurred with the passage of the supercell as well as in parts of Washington and Bennington counties.  Localized wind damage also occurred along the supercell's path.   Many other supercells went on to produce long hail paths and wind damage, as well as torrential rains through 10:00pm before most of the activity finally moved out of the region.  Storms in this event effected every county in the Channel 6 coverage area, with the exception of Rutland county, VT, with some counties being hit with up to three separate supercells in this outbreak.

According to the Albany National Weather Service the amount of hail dumped on the region from the outbreak was the most extensive since an outbreak of hail storms in early July, 1992.

Flooding was extensive as well in parts of the Adirondacks as a result of the combined effects of the four rounds of thunderstorms.  Flash flooding was scattered throughout much of the remainder of the region as up to six inches of rain was reported in spots after the thunderstorms finally had ended.

This is a sampling of local photographs sent in from Channel 6 viewers from this event.

A supercell thunderstorm wall cloud over Johnstown, NY, late afternoon, Monday, May 24, 2004. The wall cloud is the lowest part of the storm's rotating updraft and is the area a tornado would form.

Photographs By: Matthew Nichols
Hail in Buskirk, Northern Rensselaer County. 
The hail in Buskirk defoliated trees, smashed out windows in homes and automobiles and accumulated to sufficient depths that the snow plows had to be called out to clear the roads.  So much hail fell, that eighteen hours after the storm, some remained in piles along the sides of the road.

Buskirk Hail, May 2004

Photographs By: Jere Baker
Hail Stones From Maplecrest, NY Greene County

The following is a listing of the National Weather Service Storm Reports for the May 24, 2004 Supercell Thunderstorm Outbreak

Town Name

County

Severe Weather Report

Time of Severe WX
Frankfort Herkimer

1.75" Diameter Hail

4:00pm
North Ilion Herkimer

1.75" Diameter Hail

4:00pm
Wappingers Falls Dutchess

0.88" Diameter Hail

4:02pm
Herkimer Herkimer

0.88" Diameter Hail

4:02pm
South Ilion Herkimer

1.00" Diameter Hail

4:05pm
Herkimer Herkimer

T'Storm Wind Damage, Trees Down

4:17pm
Frankfort Herkimer 0.88" Diameter Hail 4:17pm
Ilion Herkimer Flash Flood, Acme Rd. Between Ilion & Frankfort 4:18pm
4 Miles W. of Awosting Ulster 1.00" Diameter Hail 4:30pm
New Paltz Ulster 1.00" Diameter Hail 4:45pm
1 Mile ENE of Canajoharie Montgomery 0.75" Diameter Hail 4:50pm
Poughkeepsie Dutchess 0.88" Diameter Hail 4:58pm
Coxsackie Greene 0.75" Diameter Hail 5:10pm
Caroga Lake Fulton 0.75" Diameter Hail 5:10pm
Salt Point Dutchess 0.88" Diameter Hail 5:15pm
Johnstown Fulton 1.00" Diameter Hail 5:18pm
Niverville Columbia 0.75" Diameter Hail 5:23pm
Cooperstown Otsego T'Storm Wind Damage 5:32pm
1 Mile NE of Deposit Delaware F-1 Tornado, winds 73-112 mph, 6 miles long path lengths, 100 yards wide, numerous downed trees, demolished a trailer, damaged siding on a house and destroyed a barn, 5 mile wide swath of hail damage in Sanford 5:35pm
Dolgeville Herkimer 0.75" Diameter Hail 5:36pm
Dorloo Schoharie T'Storm Wind Damage 5:57pm
Ballston Spa Saratoga 0.75" Diameter Hail 6:00pm
Malta Saratoga 0.88" Diameter Hail and Flash Flood 6:02pm
Round Lake Saratoga T'Storm Wind Damage, Trees and lines down on Eastline Road 6:05pm
Pittsfield, MA Berkshire 0.88" Diameter Hail 6:11pm
East Greenbush Rensselaer 0.88" Diameter Hail 6:12pm
North Greenbush Rensselaer 0.75" Diameter Hail 6:16pm
Saratoga Lake Saratoga 0.75" Diameter Hail 6:18pm
Malta Saratoga 1.00" Diameter Hail 6:18pm
Glen Montgomery 1.00" Diameter Hail 6:23pm
Near Batchellerville Saratoga 0.75" Diameter Hail 6:28pm
Amsterdam Montgomery 1.00" Diameter Hail 6:30pm
Stillwater Saratoga 1.00" Diameter Hail, two to three inches deep on Blizzard Road 6:33pm
Easton Washington 1.00" Diameter Hail 6:37pm
Buskirk Rensselaer 0.88"-2" Diameter Hail, covering the ground several inches deep, broken windows, dented cars, damaged vinyl siding, defoliated trees, hail storm lasted twenty minutes 6:49pm
Malta Ridge Saratoga Flash Flood 6:58pm
4 Miles SSE Acra Greene 0.75" Diameter Hail 7:10pm
Bennington, VT Bennington 0.88" Diameter Hail 7:15pm
Richmondville Schoharie 1.25" Diameter Hail 7:15pm
Greenfield Center Saratoga Heavy Rain, 2.6" of rain in twenty minutes 7:20pm
Greenport Center Columbia 0.88" Diameter Hail 7:25pm
Delhi Delaware 2.00" Diameter Hail 7:25pm
Easton Washington T'Storm Wind damage, trees down 7:40pm
Easton Washington Flash Flood 7:40pm
Pittsfield, MA Berkshire T'Storm Wind Damage 7:45pm
Providence Saratoga Flash Flood, ten inches of water on Clark Road 7:55pm
Great Barrington, MA Berkshire 0.75" Diameter Hail 8:00pm
Saugerties Ulster 0.88" Diameter Hail 9:05pm