John Homenuk

2016 Summer Forecast

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Over the past several months, our forecasters have monitored several extremely important variables, indices, and the trends in their behavior. We will be utilizing those variables and indices throughout our summer forecast. These variables reflect the atmospheric circulation patterns for certain geographical areas. For example, the AO refers to patterns within the Arctic Circle. The NAO refers to pattern characteristics in the North Atlantic, the PNA in the western part of North America, the PDO in the Pacific Ocean, and the EPO in the Northern and Eastern Pacific Ocean.

Typically, negative AO, NAO and EPO values correlate to enhanced high latitude blocking and high pressure to our north while lower pressure areas and troughs usually form underneath that high latitude ridging in the middle latitudes. In contrast, positive AO, NAO and EPO values generally yield lower pressure and less blocking to our north, while higher pressure and more ridging tends to build into the middle latitudes.

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Miguel Pierre

Coastal storm further south, some showers still possible

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Most of the region is under overcast skies this afternoon with low pressure organizing along the Virginia or North Carolina coast.. We had anticipated a closer track to region with this storm with more rainfall today.. However latest models have this low tracking further south and east of the area. A balloon launched sounding over Brookhaven, NY this morning also showed very dry air and subsidence in lower to middle levels. This is causing rain from the southwest to evaporate or fall apart before reaching New York City metro area.

Clouds will still dominate rest of the day. Some showers are still possible with this afternoon and through tonight with the shortwave energy with the 500mb trough swing through region and coastal storm brushing the area. But heavy rainfall is no longer anticipated for the most of the region. For Mets fans, Mets vs Brewers game at Citifield later today should go with only a slight chance of rain delay from a shower. Visit our Sportcast page for more information.

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John Homenuk

Premium: Intricate phase will determine magnitude of coastal storm

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The details of a phase between a mid level disturbance over the Ohio Valley, one with surprising vigor, and a second disturbance dropping southward from Southeast Canada into the Northeast, will have significant impacts on the eventual evolution of a coastal storm system this weekend. The atmospheric evolution in the mid and upper levels is actually quite complex, and reminiscent of some of the storm systems that impact our area in the winter season.

The pattern actually begins becoming amplified and energetic today (Friday), as a large trough in the Western United States amplifies. This will force a large ridge axis to build to its east, over the Central Plains states. This ridge drives northward, amplifying into Central Canada. This sets the stage for a large and amplifying trough over the Eastern United States this weekend.

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John Homenuk

Coastal storm may bring heavy rain, wind on Saturday

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Amazingly, we’re still talking about coastal storms during the middle weeks of May. A period long discussed as one that may favor a cutoff low or coastal storm seems to be coming to fruition, as forecast models have keyed in on a potential storm this weekend. Energy over the Ohio Valley will move eastward toward the Mid Atlantic, as additional shortwave energy drops southeastward from Canada toward the Mid Atlantic as well.

The resulting interaction will result in the development of a coastal storm, with a low pressure at the surface moving eastward towards the Mid Atlantic coast. But the exact track and intensity of the storm system will depend on the evolution in the mid and upper levels of the atmosphere. As the two pieces of energy interact and potentially phase, the surface low pressure will deepen — resulting in areas of heavy rain and strong winds developing to the north and northwest of the low pressure center.

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