Sept 11, 2011: Dry Conditions To Continue

Today brought mostly cloudy skies across the area, and even though widespread showers and thunderstorms were observed in places such as Pennsylvania and western New York, the NYC tri-state area stayed dry with only a few isolated showers. High temperatures were colder than the last few days due to a SE wind, only reaching the lower to mid 70s across the entire area, which was close to the forecast but slightly colder than expected in the immediate NYC area.

With temperatures aloft warming up ahead of a strong cold front, temperatures across the area will start to warm up as well, reaching the mid 80s in NYC by Tuesday. This surge of warmth will be short lived, however, as a mostly dry cold front will pass through the area on Wednesday, bringing scattered thunderstorms. Behind this cold front, a strong trough will move in from Canada, bringing much more fall-like temperatures into the area for Friday into next weekend.

Tomorrow’s Outlook:

Tomorrow will bring less cloud cover across the area, with partly cloudy skies expected, though an isolated shower still cannot be ruled out. Temperatures aloft will slightly warm up, with 850 mb temperatures near 12-14 degrees celsius. When combined with a SW wind and more sunshine, warmer temperatures are expected, reaching the upper 70s to 80 degrees inland, lower 80s across most of the immediate NYC area, and the mid 70s to 80 degrees in Long Island and southern Connecticut. A few mid 80s may be possible in parts of NE NJ.

Tuesday – Thursday: Cold Front Moves Through

On Tuesday, 850 mb temperatures will continue to warm up as a warmer air mass moves in from the west. Temperatures at the surface will continue to warm up, with high temperatures reaching the lower 80s inland, mid 80s in most of the immediate NYC area, and the upper 70s to lower 80s in Long Island and southern Connecticut due to a SW wind.

By Wednesday, however, the short lived warm spell will come to an end. A weak low pressure expected to move east along the US/Canada border tomorrow will intensify and pull northward on Tuesday, which combined with a strong trough to the west of the storm, will bring a strong cold front through the region. The majority of the models indicate a dry frontal passage with little to no rain, though I kept a chance of scattered thunderstorms in place in the 5-Day Forecast page, especially for Wednesday afternoon and night. Warm temperatures are still expected on Wednesday, reaching the upper 70s to lower 80s inland, lower to mid 80s in the immediate NYC area, and the upper 70s to lower 80s in Long Island/S CT with a SW/WSW wind.

The cold front will be to the east of the area on Thursday. As a result, clearing skies with a breezy NNW wind is expected. Temperatures will be colder than those of Wednesday, only reaching the mid to upper 60s inland and the upper 60s to lower 70s in the immediate NYC area, Long Island, and southern Connecticut. With the cold air mass only entering the area on Thursday, however, the coldest temperatures have yet to come.

Thursday Night – Sunday: Fall-Like Temperatures

The strong trough moving into the US will bring the coldest air mass into the central and eastern United States since the spring, with 850 mb temperatures dropping below 0 degrees celsius across most of the Great Lakes. The colder air mass will bring colder overnight temperatures into the area, dropping into the mid 40s in NW NJ and Orange county in NY, mid to upper 40s in the immediate north/west suburbs of NYC and in southern Connecticut, upper 40s to lower 50s in Long Island, and in the lower to mid 50s in NYC. These low temperatures are colder than average, but are not unusual for mid-late September.

With a strong high pressure moving into the region, clearing skies are expected on Friday as well, with mostly sunny skies expected. Colder high temperatures are expected, reaching the lower to mid 60s inland, mid to potentially upper 60s in the immediate NYC area, and the mid 60s across most of Long Island and southern Connecticut. Friday night will be the coldest night, with temperatures slightly colder than those of Thursday night, reaching the lower 40s in NW NJ. Saturday will bring high temperatures similar to those of Friday, and by Sunday, temperatures will begin to slightly warm up.

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