May 20, 2013: Warmth, Humidity Continue

Forecast Highlights:

Much warmer temperatures were observed today with a warmer and more humid air mass in place, surging well into the 70s away from the coast. The warmth will continue on Tuesday and Wednesday with partly to mostly cloudy skies, a slight risk of thunderstorms, and highs in the 80s away from the coast. A cold front will produce widespread thunderstorms on Thursday into at least early Friday, likely clearing in time for Memorial Day Weekend.

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Tonight - Friday: Warm, Humid, Stormy

Over the next few days, a frontal boundary will remain over the Northeast region, extending west towards a low pressure in the north central US that has been producing a significant severe weather outbreak. Originally, this boundary appeared to drop south of the area, but probability is increasing for this boundary to remain entirely to the north, with the warm and humid air mass staying in place through Tuesday and Wednesday. By Thursday, the low pressure will gradually track towards the region, with widespread thunderstorms, possibly strong or severe, expected on Thursday into early Friday.

Partly sunny skies are expected for Tuesday with a light south wind and highs peaking in the low to mid 80s from NYC and further north/west and the mid 70s to near 80 degrees in Long Island and southern CT. Dew points will be in the mid to upper 60s, resulting in heat index values in the 85-90 degree range. Scattered thunderstorms are possible overnight, especially north of NYC, with temperatures cooling down into the mid to upper 60s from NYC and further west and the upper 50s to low 60s east of NYC. During this time frame, the back door cold front will likely approach Connecticut, and while the southward extent is subject to some changes, the front is likely to retreat back north on Wednesday.

A warmer air mass will be present on Wednesday, with highs likely reaching the low to mid 80s from NYC and further north/west and the mid 70s to low 80s in Long Island and southern CT. More cloud cover is expected compared to Tuesday, with a risk of scattered thunderstorms especially north/west of NYC. The cold front will approach the region on Thursday, likely moving through overnight, with widespread thunderstorms expected, possibly strong or severe. High temperatures will not be as warm due to the cloud cover and storms, likely peaking in the mid 70s to near 80 degrees across the area. There is uncertainty regarding the timing of the cold front, with rain possibly sticking around into Friday as well, although temperatures should continue to cool down on Friday, likely back to near average in the low to mid 70s, although the late week outlook is still subject to some changes.


Memorial Day Weekend: Cooler, Drier

A trough will drop into the region behind the late week cold front, providing the area with sunshine, dry conditions and cooler temperatures for Memorial Day Weekend. High temperatures are generally expected to be slightly below average, in the upper 60s to low 70s for most of the area, with overnight lows in the low 50s in NYC and the coast and the 40s elsewhere. More information will be posted on the Memorial Day Weekend outlook as details become clearer.