May 28, 2011 Morning: Hot Memorial Day

Note: The next update will be posted on Sunday night. The 5-Day Forecast has been updated once again for the entire area.


The same cold front that brought damaging and deadly severe weather outbreaks from the central US to Pennsylvania/New York state will finally reach the area today with some thunderstorm, but it has significantly weakened over the last two days, and will bring nothing more than scattered showers and thunderstorms from NYC and further west today.

By tomorrow, however, a very warm air mass bringing temperatures today as high as 110 degrees in Texas will begin to spread into the central and eastern United States, bringing hot temperatures on Memorial Day, reaching the mid 90s in parts of the immediate NYC area. A cold front will bring an end to the heat by Wednesday/Thursday, but with the cold front comes a risk of severe weather.

Weekend Outlook:

Scattered showers and thunderstorms are expected today, mostly from NYC and further west. These storms will stay below severe levels. Otherwise, partly to mostly cloudy skies are expected today, with high temperatures in the upper 70s to lower 80s from NYC and further west and the lower 70s to lower 80s in Long Island and southern Connecticut. A few mid 80s are possible in the immediate NYC area if there is enough sunshine.

Sunday will bring drier conditions to the area, with a low risk of an isolated shower or thunderstorm from NYC and further west. Temperatures will begin to warm up, reaching the lower to mid 80s from NYC and further west, with Long Island and southern Connecticut expected to see temperatures similar to those of today.

Next Week: Heat, Then Severe Storm Potential

The warm air mass will reach the area on Monday, bringing 850 mb temperatures as high as 18c-20c. Under sunshine and dry conditions, these 850 mb temperatures can support temperatures well into the 90s. Monday will bring partly sunny skies across the area, though as some models have been suggesting, isolated showers and thunderstorms cannot be ruled out in the evening hours from NYC and further north. With a SW/SSW wind expected, temperatures will warm up across the entire area, with temperatures in Long Island/southern Connecticut ranging from the mid 70s along the coast to the mid to potentially upper 80s closer to New York City. From NYC and further west, widespread lower 90s are expected, with mid 90s in parts of the immediate NYC area. With dew points in the mid to upper 60s, the heat index may reach the mid to upper 90s.

A back door cold front will reach the area by Tuesday, but will only barely move through before being pushed out again. An onshore SE wind is expected for Long Island and southern Connecticut, which will keep temperatures mostly in the 70s. Temperatures from NYC and further west will be slightly cooler than Monday, with mid to upper 80s expected in NYC and upper 80s to lower 90s expected west of NYC.

As the cold front approaches the area on Wednesday, temperatures will warm up once again, with more widespread lower 90s possible once again from NYC and further west. There is some slight timing uncertainty with this cold front, but there is a risk of scattered thunderstorms from Wednesday evening into the early overnight hours. The models are suggesting a risk of potentially significant severe weather on Wednesday, with the GFS showing high lapse rates as well as extreme CAPE and Lift Index values. Bulk shear, however, may be an issue, especially from the area and further south. Should these storms reach the area during the time frame mentioned above with no major changes in the modeled parameters, Wednesday evening may bring a severe weather risk to the area. Stay tuned for more information on the next update regarding Wednesday’s severe weather potential.

A gradual cool down is expected by the late week, with Thursday’s temperatures lowering back into the 70s to mid 80s. On Friday, the models have started to trend towards a weaker cold air mass, and I continue to expect temperatures to drop into the lower to mid 70s by Friday and Saturday. Temperatures will begin to warm up by Sunday.

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