See the linked diary for background information on today's severe weather outbreak.
There is a major severe weather outbreak ongoing across the eastern part of the United States right now, from Missouri to New York. The line of storms in Pennsylvania and New York has already produced a long swath of damage, including possible tornado damage in Elmira, NY, where Governor Cuomo reports significant damage.
Reports of significant damage in Elmira, possible tornadic activity, state assessment crews on the way #stormwatch— Andrew Cuomo (@NYGovCuomo) July 26, 2012
There are other reports of significant damage to a mall and country club in Elmira, along with people being trapped in cars.
Tens of millions of people are under some sort of weather watch right now, the blue boxes indicating severe thunderstorm watches, and the red box indicating a tornado watch. The watches will be in effect until the storms pass your area.
As forecast, there are several lines of storms developing. The most intense is in Pennsylvania and New York:
With another one forming in central Ohio:
If these storms approach your area, don't take them lightly. 80+ MPH winds are possible, and I even saw a 92 MPH radar indicated wind velocity a little while ago in New York.
I'll continue to update the diary below the fold in liveblog format.
— Adam Joensen (@Adam_Joensen) July 26, 2012
2:17 PM PT: The Baltimore/DC area needs to watch the line of storms in Ohio. If, and that's a big IF, the storms survive crossing the Appalachian Mountains, they could pose a problem for the DC area. The mountain ridges like ripping apart lines of storms, though, so it's questionable right now. It's worth watching.
2:32 PM PT: Satellite view of the storms:
2:44 PM PT: The derecho is approaching eastern Pennsylvania and the NYC metro area. If you live in Maryland, Philly, New Jersey, and the NYC area, prepare for this nasty line of storms with a history of producing a ton of damage.
2:57 PM PT: A new watch has been issued for parts of WV, MD, VA, Washington DC, DE, and NJ. They haven't made the watch graphic yet, but I'll post it when it's available.
3:00 PM PT: Here's the new watch (for the counties highlighted in blue), effective until 100AM EDT. 70 MPH winds, 1.50" hail, dangerous lightning, and heavy rain are possible.
3:18 PM PT: Warnings are encroaching on the northwestern NYC suburbs. 70+ MPH winds and quarter sized hail possible. The worst winds -- radar estimated about 75-85 MPH -- will stay north of the immediate NYC area and impact the area around Poughkeepsie, NY. This is an incredibly dangerous situation.
3:35 PM PT: Just a reminder...if you give a report (i.e. "I just saw three flying cows!"), give a general area if you're comfortable doing so. It'll help people down the line from you get an idea of how bad it'll be once it gets to them.
4:22 PM PT: Here we go I-95 corridor. 70+ MPH moving into the NYC metro right now:
Same with Philadelphia and southern/southeastern Pennsylvania:
4:27 PM PT: Facebook won't let me update my page anymore for some reason. Damn you, Zuckerberg!
4:48 PM PT: This webcam is INCREDIBLE. It's on top of the Statue of Liberty, and listening to the wind, rain, and hail whip the statue is just unbelievable. Manhattan has disappeared behind the rain.
4:56 PM PT: The derecho should be right over Philadelphia right now, moving into New Jersey.
5:02 PM PT: Animated GIF I created of the EarthCam webcam from the Statue of Liberty, looking into Manhattan as the derecho moved in. Incredible.
5:07 PM PT: Quiet again in Manhattan:
STATE OF EMERGENCY IN ELMIRA; CURFEW IN EFFECT
THE CITY OF ELMIRA IS UNDER A STATE OF EMERGENCY, DUE TO STRONG STORMS THAT PASSED THROUGH THE AREA. A CURFEW IS IN EFFECT FROM 8PM UNTIL 8AM FRIDAY. PEOPLE CAUGHT VIOLATING THE CURFEW MAY BE ARRESTED.
h/t to EcosseNJ in the comments for posting the link to this.
5:59 PM PT: The storms didn't hold together crossing the Appalachian Mountains as they moved towards the DC area. The storms in DC right now are not severe, but they bear watching given the unstable soupy airmass.
9:22 PM PT: It's over. Over 400 reports of severe weather so far, and the total will climb as people get out and about tomorrow to survey the damage. It was definitely a derecho -- the line's damage path went from Lake Erie to the Atlantic, well over the 240 mile limit that separates a derecho from a bad squall line.
The reports in the image are from about 1221AM EDT Friday.