Aug 17, 2013: 90 Degrees Possible Again

Forecast Highlights:

northeastA slow warming trend continues with temperatures today back into the low to mid 80s. A brief cool down is expected for Sunday as a wave of low pressure produces clouds and some showers, but average and eventually above average temperatures will return for next week as a warmer and more humid air mass returns, with highs climbing into the mid 80s to low 90s until a cold front moves through on Friday, bringing some rain and a temporary cool down.




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Friday, August 16 Observations:

8.16.13Mostly sunny skies continued across the area as a high pressure remained in place with a cooler than average air mass in place. Morning temperatures fell into the upper 40s to low 50s inland and the mid 50s for most of the area away from NYC and the immediate coast. With the air mass slightly moderating, temperatures were slightly warmer than those of Thursday, peaking in the upper 70s to low 80s across the area. The highest temperature was 82 degrees in Teterboro, NJ and Central Park, and the coolest high temperature was 76 degrees in Montauk, NY.



Today – Monday: Increasing Clouds, Few Showers Possible

The high pressure currently over the region will continue to slowly slide east as temperatures continue to moderate, with mostly sunny skies today and highs in the upper 70s to low 80s across the area. A frontal boundary will continue to slowly advance north in the Mid Atlantic, although the high pressure in place will keep most of the rain suppressed below central-southern New Jersey. A wave of low pressure is forecast to develop along this boundary; most models are fluctuating with the exact location and northern extent, ranging from the GFS showing widespread rain and highs only in the upper 60s to the NAM with sunshine and low 80s, although this wave of low pressure should result in mostly cloudy skies across the area on Sunday along with a risk of scattered showers, especially east and south of NYC. Due to the cloud cover, shower potential and a NE wind at 5-15 mph, cooler high temperatures are expected, peaking in the low 70s in Long Island, mid 70s in the immediate NYC area and coastal CT, and the upper 70s inland. There remains some uncertainty regarding the exact northern extent of the wave of low pressure, and the temperature outlook is subject to minor changes as well as the rain outlook, with the possibility for more widespread showers than currently forecast.

The wave of low pressure is expected to exit on early Monday morning, with a high pressure building back into the region but this time from the south. This will result in a southwest flow which will gradually spread a warmer and more humid air mass into the eastern half of the US. Humidity will be slightly higher on Monday compared to previous days, with partly sunny skies expected and highs climbing into the low to mid 80s.

Tuesday – Next Weekend: Warm And Humid, Then Cooling Down

The warmer and more humid air mass will continue to spread through the region, with 850mb temperatures rising to about 16-18 degrees Celsius along with dew points in the mid 60s, supporting high temperatures rising back into the mid to upper 80s with areas of low 90s especially in the immediate NYC area, and overnight lows ranging from the low 60s inland to the low 70s near NYC and the coast. These conditions are expected to last from Tuesday through Thursday with mostly sunny skies and a relatively light southwest wind.

Changes are taking place in the upper level pattern compared to the first half of August, with ridging becoming centered over the central US, keeping the region under a W-NW flow aloft. A relatively strong trough will be located over southern Canada in the midweek, diving southeast under the NW flow aloft as it amplifies, and is expected to reach the region on Friday. This will bring a cold front through the region; models vary regarding the exact timing, although showers and thunderstorms are possible, if not likely, along with slightly cooler temperatures. The front is expected to move through overnight with cooler temperatures returning for the weekend, likely bringing high temperatures back into the low 80s and possibly the 70s, but with uncertainty regarding exactly how far the trough digs into the region and how long it persists. With the ridge centered over the central US, another warm air mass is likely to start surging east towards next weekend, although depending on the position and setup of the trough, it could reach the region in a moderated form with another warmth surge in the following week, or it could be suppressed to the south especially if a trough pattern develops in southeast Canada. Stay tuned for more information on the longer range outlook.

5 thoughts on “Aug 17, 2013: 90 Degrees Possible Again

  1. Anonymous Reply

    Could you please tell me if NYC expected to see any rain tomorrow ( Sunday)?

    • NYC Area Weather Post authorReply

      The models are somewhat divided with the NAM showing nothing and the GFS with over 1/4 inch of rain. It is likely at this time that NYC stays mostly cloudy with a few isolated showers at times but with most of the rain staying south; there is a low possibility of a little more rain than forecast though.

  2. Anonymous Reply

    Could you please tell me how much rain is NYC expected to see today as of now?

    • NYC Area Weather Post authorReply

      As I noted with my latest update, scattered shower coverage is expected across most of the area, which is further north than originally indicated, although rainfall amounts are expected to remain light with under 0.1 inch, locally higher south and east of NYC.

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