A cold front cutting into the extreme heat across the mid-Atlantic and Northeast is leading to the development of strong to severe thunderstorms.
Thunderstorms will continue to fire up into this evening from the mid-Atlantic into the Ohio Valley and for that reason, severe thunderstorm watch boxes are in effect through this evening.
According to Meteorologist Meghan Evans, "The battlegrounds for severe storms on Saturday afternoon and evening will span from southern New England to the Ohio Valley. The best shot for cities such as State College, Pa., Scranton, Pa., Newark and New York City appears to be through the evening hours. Harrisburg, Allentown, Philadelphia and Lancaster will be at risk during the late evening and part of the overnight."
The biggest threats from these storms will be damaging wind gust in excess of 60 mph along with torrential, flooding downpours.
The strongest storms will also be capable of producing large hail to the size of quarters.
Additional thunderstorms will continue to develop over the next few hours over the Ohio Valley, bringing a strong storm threat to the cities of Columbus and Dayton, Ohio, along with Indianapolis, Ind., and Evansville, Ill.
Storms from the Ohio Valley through the mid-Mississippi River Valley will be much more isolated in nature compared to what is expected over the mid-Atlantic.
Thunderstorms will rattle even farther south overnight into Sunday morning. Dover, Baltimore and Washington, D.C., may be in the path of damaging thunderstorms.
Stay tuned to AccuWeather.com as we continue to update the severe weather potential for the mid-Atlantic and parts of the Ohio Valley.
7:26 P.M. EDT: A call to the Chester County, Pa. 911 reported lightning struck a transformer and set a utility pole on fire.
7:09 P.M. EDT: Light struck a house and fire is visible near the Waynesborough Country Club in Chester County, Pa., according to the Chester Co. Police, Fire and EMS scanner.
7:01 P.M. EDT: Chester Co., Pa., Police, Fire and EMS scanner report a woods fire due to lightning strike on Darby Rd.
6:46 P.M. EDT: Storms near Philadelphia, Pa. and Trenton, N.J. now.
6:39 P.M. EDT: Line of thunderstorms entering Lancaster, Pa.
5:31 P.M. EDT: Centre County police scanner reported a lightning strike to a house on Brush Valley Rd. with smoke in the attic.
5:16 P.M. EDT: Numerous trees down in Ford City, Pa.
4:27 P.M. EDT: 58-mph wind gust in Williamsport, Pa.
4:20 P.M. EDT: Telephone poles and tree limbs down near Grove City, Pa.
4:05 P.M. EDT: Numerous trees down along state route 8 near Butler, Pa.
3:25 P.M. EDT: Numerous trees down in and around New Castle, Pa.
3:05 P.M. EDT: 75-mph wind gusts knocked down trees near Ulysses, Pa.
3:00 P.M. EDT: 1.75-inch diameter hail fell near Turtlepoint, Pa.
2:58 P.M. EDT: Large tree limbs and powerlines were knocked down near Salem, Ohio.
2:30 P.M. EDT: Three trees were knocked down near Streetsboro, Ohio.
2:25 P.M. EDT: 2.00-inch diameter hail reported near Belmont, N.Y.
2:25 P.M. EDT: 0.75-inch diameter hail reported in Wellsville, N.Y.
2:18 P.M. EDT: 1.00-inch diameter hail near Silo, N.Y.
2:15 P.M. EDT: New severe thunderstorm watch now in effect from northeast Ohio through western Pennsylvania until 7 P.M. as thunderstorms continue to intensify near the PA/NY border. and over eastern Ohio.
1:30 P.M. EDT: Thunderstorms continue to weaken as they pass north and east of New York City. Watching for additional development farther north and west which may affect the mid-Atlantic coast late this afternoon or this evening.
11:50 A.M. EDT: Severe thunderstorm watch now in effect until 7 P.M. from northeastern Pennsylvania through southwestern Connecticut. Including Scranton, Pa., New York City, Long Island, Bridgeport, Ct. and White Plains, N.Y.
11:35 A.M. EDT: Numerous trees reported down in the town of Horseheads, N.Y. Wires down in the city of Elmira as well.
11:16 A.M. EDT: Numerous trees and power poles reported down in the village of Watkins Glen, N.Y.
10:40 A.M. EDT: Strong storms were tracking through central New York state, expected to approach the Binghamton area over the next hour.
9:46 A.M. EDT: Thunderstorms tracking through Buffalo, N.Y., produced a wind gust to 41 mph.
See how far away severe thunderstorms are as we monitor the severe weather with these radar images.
Heavy rain returning to the northern Plains will generate a renewed flood threat for the Red River.
Mount Saint Helens has erupted several times since the destructive 1980 eruption, and likely will again in the future.
Seven homes have been red tagged, meaning do not occupy, and six others are under a voluntary evacuation order.
Though recovery continues from Superstorm Sandy, residents and homeowners on the Atlantic coast should prepare for another active season in 2013.
While there is a threat for a shower in spots in Baltimore, Md., today, it will not be a washout like the day of the Kentucky Derby.
Houston, TX (2000)
6.80" of rain.
New England (1763)
"The 19th day of May, 1793, a bad storm of hail and rain and very cold following which froze the ground and puddles of water." by Ebenser Byles, Town Clerk of Ashford.
Moorcroft, WY (1978)
27 inches of snow (17th-20th), bringing total for the month to 92 inches.