Sept 12, 2013 Storm Updates

Below, occasional storm updates will be posted on the heavy rain and thunderstorms affecting the area this afternoon. Updates are being posted both on the blog and on Twitter.

This Morning’s Forecast Discussion
5-Day Forecast


8:55 PM: Storms Persist Over LI, CT, Weakening Elsewhere

0038While most of the storms have weakened across the area, with rain collapsing as it entered southern Long Island, a strong thunderstorm managed to remain intact over central-northern Suffolk county extending across the Long Island Sound into south central CT. This storm is producing heavy rainfall and frequent lightning, and will continue to move east through Long Island and SE CT over the next hour, with light to moderate rain gradually decreasing in intensity behind it. West of central LI/CT, rain will mostly end within the next hour.

The cold front will move through the area tonight with isolated storms still possible, with clearing skies, a breezy NW wind and highs in the low 70s inland and the mid 70s elsewhere as cooler temperatures return for the weekend and early-mid next week. More information will be posted with the next forecast discussion and 5-day forecast update, on Friday afternoon.


7:50 PM: Strong Storms Moving Into NYC, SW CT

2338North NJ/SE NY – The strong line of storms moved east, having produced heavy rainfall up to 1/2 to 1 inch, frequent lightning and gusty winds. Light to moderate rain and thunder will continue through at least 10-11 PM before tapering off. NYC – Strong storm located over Bronx with heavy rain/frequent lightning, to move NE out of the city with light to moderate rain and thunder continuing through at least 10-11 PM. Southern CT – heavy storms remain stalled over coastal Fairfield county, spreading E into New Haven county. Rain of 1/2 inch, locally higher, is expected with frequent lightning and gusty winds, continuing through at least 11 PM. Long Island – Heavy storms entering western Long Island, focusing mostly on the north shore near northern Nassau county. Further south, light to moderate rain and thunder will begin shortly and continue through at least 11 PM.


7:15 PM: Flash Flooding Over North NJ

2258North NJ – A strong line of thunderstorms has developed over northern NJ over the last half hour, with flash flooding occurring in west Bergen and E Passaic counties, where radar estimates indicate 1 to 2 inches of rain fell in a short period of time. NYC – The new line of strong storms will affect the rest of NE NJ and NYC by 8 PM, with heavy rain up to 1″ and localized flash flooding, frequent lightning and gusty winds expected. Another strong storm over Staten Island is tracking NE, and will affect Brooklyn, lower Manhattan, and Queens by 7:30-7:45 PM. Interior – The line of storms is SW CT is shifting southeast towards the coast, with Bridgeport, CT expected to get into the heavy rain shortly as well, while the strong storm that produced flash flooding in NE NJ is entering Rockland and N Westchester counties, where more heavy rain is expected over the next hour up to 1/2″ to 1″.

Long Island – With the redeveloped line, strong storms may spread into western Long Island as well, gradually weakening as they spread further east by 9 PM, but may still be capable of moderate to locally heavy rain and gusty winds for some. Otherwise, storms will continue for the rest of the area through the early overnight hours, gradually ending with drier conditions likely after midnight.


6:35 PM: Strong Storms Developing Over North NJ

2218Widespread thunderstorms, some of them strong to severe, are developing across northern NJ where instability remains high, with several areas of concern. Area 1 is NE NJ into Westchester and Fairfield counties, where a line of heavy storms is training in place. At least 1/2 inch of rain or locally higher is expected with these storms with gusty winds as well. Area 2 is NW NJ, near Sussex and Morris counties, where a severe storm producing heavy rainfall up to 1″/hour with localized flash flooding, frequent lightning and strong wind gusts over 50 mph is moving NE. This storm will spread NE into W Passaic, W Bergen and SW Rockland counties within the next hour. Area 3 is southern parts of NYC, primarily Staten Island/Brooklyn/Queens, where storms currently exiting off the eastern NJ coast may reach in 1/2 to 1 hour with heavy rain and gusty winds possible.


6:10 PM: Second Round Entering NYC Area

2148Note: Storm updates were suspended earlier due to a loss of internet connection. Storm updates will continue through the rest of the evening.

Since the last update, additional strong to severe thunderstorms continued in the Northeast, with most of the area dry aside from a strong storm currently located over Rockland county, NY, which will spread NE into northern Westchester and NW Fairfield counties within the next hour. The radar to the left shows a squall line over eastern PA moving east towards the area; this line has slightly weakened over the last hour, with reports from that area showing heavy rainfall and gusty winds. Instability has generally been decreasing, with CAPE down to 2000 J/kg from 3000 two hours ago, and lift index down to -3 while the CIN has slightly increased. Some additional weakening of the line is likely later this evening as it spreads into NYC towards 8 PM and Long Island later on, with moderate to locally heavy rain and gusty winds, but with strong thunderstorms likely to spread into NW NJ and Orange county in NY as the line enters within the next hour.


2:10 PM: Storms Moving Into NYC, Long Island

1748Over the last 2 hours, a line of moderate to heavy thunderstorms affected northern NJ, SE NY and NYC, with radar estimates showing totals locally up to 1.5 inch in Morris, W Bergen and Rockland counties. These storms are weakening as they continue to move east into Long Island and SW CT, where brief moderate to locally heavy rain is expected over the next 1-2 hours. Otherwise, dry conditions are likely to return through the late afternoon.

As the latest radar shows, there is a developing squall line over western Pennsylvania and New York. This line will continue to move east through the afternoon and evening hours, producing heavy to locally strong/severe thunderstorms with heavy rainfall and strong wind gusts the main risk. These storms will enter western parts of the area towards the evening, likely after 6-7 PM, then approaching the rest of the area, but with the strongest storms likely remaining to the north and west of the area. More updates will be posted later this afternoon.

7 thoughts on “Sept 12, 2013 Storm Updates

    • NYC Area Weather Post authorReply

      The squall line is expected to spread into Long Island after at least 8 PM; while it should weaken due to the marine layer and decreasing instability and is unlikely to be as strong as it currently is in Pennsylvania, it may still be capable of producing moderate to possibly locally heavy rainfall.

    • NYC Area Weather Post authorReply

      The front will be east of the area tomorrow, although scattered storms are still likely in Long Island this evening and possible again Friday morning. Friday itself should be dry other than an isolated sprinkle or two possible.

  1. Eduardo Berroa Reply

    That’s one of the most greatest line of non-severe T-storms I ever had on Fordham and I caught on tape however. The line of strong storms has gotten excessively numerous CG lightning flashes and It’s definitely frightening but perfect! I am still witnessing couple of CG flashes.

  2. Anonymous Reply

    Could you please tell me if there are any more showers expected for NYC and Long Island later today?

    • NYC Area Weather Post authorReply

      Shower coverage was a bit more widespread than forecast inland, but otherwise isolated showers should continue this afternoon, possibly including Long Island, before ending this evening.

Leave a Reply to Anonymous Cancel reply