June 10, 2013: More Rain Tonight, Thursday

Forecast Highlights:


Another rain event affected the region today with moderate to heavy rainfall, adding more onto what is already a wetter than average June due to the remnants of tropical storm Andrea a few days ago. More rain will continue to fall tonight with scattered thunderstorms possible on Tuesday; a strong low pressure is likely on Thursday which has the potential to produce yet another round of heavy rain, followed by drier conditions returning for the weekend.

Tonight – Wednesday: More Storms, Warmer

northeast12As of 11 PM, the rain temporarily stopped over the immediate NYC area while still continuing over southern CT. So far, rain totals are at least 1/2 to 3/4 inch in NW NJ and southern CT, 3/4 to 1.25 inch in northeast NJ, SE NY
and NYC, and 1 to 2 inches in Long Island. As the radar posted to the left shows, another line of moderate to heavy rain will move through the area during the next few hours, moving out after 2-4 AM. Storm totals are expected to end up around 1 to 2 inches across most of the area with locally higher totals east of NYC. With today’s rainfall on top of what fell with the remnants of Andrea, rain totals for the month are already above average for most of the area, with Central Park already over 7 inches. With additional rain events in the outlook, this June is on track to be one of the wettest Junes on record.

The warm front, currently south of the area over New Jersey, will continue to advance northeast, moving through the area later tonight with low temperatures staying steady in the low to mid 60s and wind direction shifting to the southwest. Mostly cloudy skies are expected for Tuesday with temperatures rising into the mid 70s to low 80s across the area with showers and thunderstorms likely in the late afternoon and evening, mainly after 3-5 PM. Rain totals will be lower with this round compared to today, with less than 1/4 to 1/2 inch except for locations under the heavier thunderstorms, where locally higher totals are possible.

Dry conditions will briefly return for Wednesday as the low pressure exits, with mostly sunny skies, a NW wind at 5-15 mph, and highs reaching the mid to upper 70s inland and the upper 70s to low 80s for the rest of the area. Cloud cover is expected to increase overnight as the next storm approaches, with overnight lows falling into the 50s away from the coast.

Thursday – Friday: Significant Storm, Heavy Rain Possible

scenario3Uncertainty in the outlook increases on Thursday as the next low pressure approaches. Most of the operational model runs show a low pressure developing over the Ohio Valley with a MCS (Mesoscale Convective System) developing, later intensifying into an unusually strong non-tropical low pressure for this time of the year, with a minimum pressure around 992-996 mb, moving through the region on Thursday afternoon into Friday morning. If this low pressure was to materialize as currently modeled, it would produce significant impacts across the region, with widespread heavy rain near or over 2 inches and chilly temperatures to its north, and hot temperatures with a severe weather outbreak, possibly significant, to its south.

Assuming the strong low pressure does materialize, it would be relatively compact, with uncertainty regarding the impact in the NYC area. Depending on the track of the low, possible scenarios range from a chilly heavy rain, to warmth and severe weather, to the storm staying south of the area. At this time, I do not think the storm stays south and misses the area, and increased rain probability to 80% for the Thursday afternoon to Friday morning time frame. The main question at this time is regarding the track and intensity of the low pressure and how it affects the area; at this time, my latest thinking is for moderate to heavy rain with chilly temperatures and the potential for 1-2 inches of rain, although as previously mentioned, there is still a lot of uncertainty for this time frame and the outlook is subject to change; it is a possibility that the low pressure is weaker than modeled with only minimal impacts in the area, and the track of the low pressure will also be monitored in case it stays south with light rain at most, or ends up further north and introduces a severe weather risk for the area. Stay tuned for more information on this storm potential over the next few days.

Weekend Outlook: Dry, Seasonable

Despite the uncertainty on the Thursday-early Friday storm, there is higher confidence on the low pressure exiting the region in time for more sunshine and drier conditions to return for Friday and the weekend. There is some minor uncertainty regarding the exact temperatures, although they should remain cooler than average, likely around the 70s, and gradually warming up later into the weekend back into the 80s. Continuing with the theme of the current pattern for limited warmth and frequent rain events, another rain event is possible around early-mid next week, but with specific details still uncertain at this time. Stay tuned for more information on the longer range outlook.

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