May31 Severe Thunderstorm and Tornado Outbreak

During the morning of May 31, 1998 a warm front moved quickly north across the region. Rapid destabilization occurred during the afternoon as a cold front pressed south toward the region. Lines of severe thunderstorms formed and moved rapidly east across New York and Western New England. Several of these storms became tornadic over Saratoga, Albany, Rensselaer, and Washington counties in New York and Bennington county Vermont. Straight line wind damage occurred in most counties of NWSFO Albany's County Warning Area. Cloud to ground lightning rates over the region reached 15,000 strokes per hour, rates not observed before over this region.

These storms resulted 68 injuries but no fatalities, tens of millions of dollars in damage to homes and businesses, and extensive forest damage. Power was out to over 130,000 customers at the storm's peak, while 12,000 were without power for over three days.

NWS warnings and advance notice of severe potential was recognized by the media and New York Governor George Pataki as playing a major role in no loss of life in Eastern New York with the event. NWS warnings were relayed via Emergency Alert System and NWR. However after NOAA weather radio station WXL34 failed WGY radio, the primary EAS relay point, read NWS warnings and prepared EAS messages and activation manually. Warnings were also relayed to Emergency Operations Centers (EOC) via HAM radio.

On June 1st and 2nd a total of 9 survey teams from NWSFO Albany traveled across the affected areas to assess damage, identify storm tracks and characteristics. Aerial surveys were performed with WNYT Television and the New York State Police.

Several factors contributed to the low loss of life in this event. NWS forecasts began highlighting the severe potential as early as Saturday afternoon. The potential for tornadoes was highlighted further early Sunday morning in statements and a watch. During the event a total of 48 warnings were issued, 46 warnings have verified although many of the tornado warnings have verified with straight line winds. The warning for the Stillwater-Mechanicville tornado in Saratoga county had a lead time of 42 minutes.

The 48 warnings issued for this event is the greatest for a single event by this office in the last 20 years. Average lead time for all tornado warnings was 21 minutes, and for all warnings was 22 minutes. Local media effectively used program break ins and crawlers for the numerous warnings further highlighting public awareness.

Meteorological Background

In the morning hours Sunday May 31, 1998 a warm front moved rapidly north across New York and Western New England. During the day upper level divergence rapidly increased, the 850 hPa jet increased to over 50 kts, helicity values increased to 500 to 800 m2 sec-2 in the highly sheared environment. Low level moisture increased rapidly as dew points rose from 8C to 22C during the day, resulting in rapid atmospheric destabilization.

During the morning Sunday May 31, 1998 a Derecho moved across southern Ontario and decayed as it moved into the Adirondacks. It established boundaries which focused later convection. During the afternoon a cold front pressed south into western New York and a series of lines of thunderstorms formed ahead of it.

Thunderstorms developed explosively as they moved east across the region. Several of these storms became tornadic. The most long lived tornadic thunderstorm produced a series of tornadoes starting with an F3 tornado that moved across the Saratoga County Communities of Stillwater and Mechanicville, and moved into the Rensselear County town of Schaghticoke. The tornado continued east across Hoosic Falls into the Washington County town of White Creek and into Bennington County Vermont. It was mainly an F2 and skipped occasionally from Rensselaer county into Vermont.

An F2 tornado occurred in East Schodack, while an F1 tornado occurred across the Albany International Airport.

The tornados of May 31, 1998 were caused by scattered supercell thunderstorms along a squall line in a highly sheared environment. Most of the other severe thunderstorm wind damage was associated a series of squall lines which moved across the region at speeds of 40 to 60 mph.

Major severe weather outbreaks such as this are not uncommon across the Northeast. Major severe events have occurred in the recent past, including July 3, 1997, July 15, 1995, May 29, 1995, July 5, 1992, May 2, 1992, August 28 1990, and July 10, 1989.

   
     Preliminary damage report. This is not an all inclusive
     list, rather it is a general list of damage reports 
     received by NWSFO Albany. (This list was last updated
     at 700 pm June 3, 1998)
     
     
COUNTY         TIME Location - Severe event

Herkimer (S)   338  Frankfort,Dolgeville,
                    Cedarville - trees down       

Montgomery     342  Fonda -    trees down                        

Montgomery     342  Fonda - trees down       
               344  Amsterdam -tornado west       
          
Herkimer (S)   345  Mohawk -   wind damage        

Fulton         345  Gloversville - Trees and wires down     
                    3 houses /  2 cars damaged, some 
                    may have occurred in later storms  

Saratoga       415  Milton - 1" hail              
               416  Mechanicville - 60 mph        
               425-435   Stillwater - F2 - F3 Ttornado 
                    Extensive structural damage
                    28 injured sent to hospital
                    40 injured treated on scene
                    20 homes destroyed
                    25 homes with severe damage
                    10+ with moderate damage
               420  Saratoga Springs - 1.75' hail 
               425-435   Mechanicville - tornado       
               435  Malta, Ballston Spa .75" hail 

Schoharie (N)  410  Schoharie Village             
               430  Blenheim - trees down (time aprx)            
               432  Middleburg - wind damage      

Albany         438  Bethlehem Center - wind damage               
               440  Albany Airport - 82 mph gust  
               450  Colonie - wind damage         

Schenectady    450  Rotterdam - trees down             
               450  Schenecaty - trees down       

Washington     430  Southern portion - trees down 
               445-500   White Creek - F1 Tornado

Bennington     432  Arlington - trees down        
               455  N Bennington - F1 Tornado     
               505  Bennington - trees down       

Rennselaer (N) 445  East of Hoosic Falls- F2 Tornado      
                    at NY and VT border
               450  Schaghticoke - trees down          
                    Trailers flipped over
                    Damage also at Hoosick, Pittstown
               500  Brunswick - trees down        
               505  E. Green bush -trees down               

Albany         438  Bethlehem Ctr. - wind damage  
               440  Albany Airport - gusts 82 mph 
               440-445 Colonie - F0 Tornado       
                    2 mile path length.  Discontiuous
                    wind damage. Funnel cloud 
                    obsevered by FAA personel.
               450  Colonie - trees down          

Schoharie      430  Blenheim - trees down         

Schenectady    450  Rotterdam - trees down        
               450  Schenectady - tree down       

Saratoga       450  Mechanicville - trees down         

Greene         500  Greenville - quarter size hail     

Windam         542  Brattleboro - tornado observed        
 
Columbia       510  Stuyvesant - 0.75" hail            
               510  Kinderhook- trees down       
               520  Chatham - trees down          
               526  Niverville - tree on house         
               531  Stuyvesant -1" hail           

Berkshire      545  Pittsfield - 1.75" hail       

Rensselaer     535  Nassua - trees down      

 
Herkimer       625  Mohawk  - trees down          

Fulton         630  Gloversville - Trees and wires down     
     
Montgomery     620-630   Root, Ames, Fort Plain        
                         Fonda, Amsterdam, Charleston -     
                         trees down

Schoharie      635  Richmonville - roof damage   
               645  Blenheim - dime size hail          
               647  Breekabeen               

Saratoga       708  Mechanicville - wind damage   

Schenecrady    700  Duanesburg - trees down       

Albany         716  Guilderland - tornado observed     

               708  Clarksville  - tree down      
               711  New Scotland             

Greene         733  Greenville - tree d                     
               745  Catskill - dime size hail          

Rennselaer     725  East Schodack - F2 Tornado    
                    4 miles of tree damage. 
                    2 barns destroyed
                    2 homes with severe damage
               742  Stephentown - wind damage     

Bennington     715  W Shaftsbury - 0.88 - 1.75" hail  

Washington     735  Greenwich - numerous trees down

Albany         730  New Scotland - trees down          

Schoharie      735  Schoharie- widespread damage  

Ulster         800  Saugerties and other locations
                    Wires down               
                    Time uncertain

Windham        755  Brattleboro - wind damage               
 
Columbia       830  Hillsdale - wind damage       

Berkshire      755  N.Adams - gusts 70 mph        
               800  Great Barrington - hail       
               803  Pittsfield - wind damage                  

Greene         823  Catskill - 0.75" hail         
               827  Catskill - 1.0" hail               

Bennington     830  Pownal, Shaftsbury - trees down    
   
Ulster         900  Gardiner and other locations
                    Wires down - time uncertain    

Columbia       900  Copake - trees down 
     
Berkshire      940  South Lee - wind damage       
          
Ulster         900  Gardiner and other locations
                    Wires down - time uncertain
     
Dutchess   900-1000 Widespread reports of
                    downed trees, including towns of
                    Rhinebeck, Red Hook, Clinton
                    Corners, Stanford, Wappingers 

Litchfield     950  New Milford - large limbs down

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