The rise and return of a strengthening El Nino

El Nino has arrived, and it continues to strengthen, with increasing potential to become a powerhouse by Autumn and Winter.

Computer models and meteorologists are growing more confident that a strong El Nino will develop by this Autumn and Winter, with some computer modeling even suggesting that it could rival the 1997-98 “Super El Nino” which remains the strongest on record.

El Nino refers to the periodic warming of waters in the central and eastern Equatorial Pacific, which has a cascading effect on weather systems around the globe. In normal years, the atmospheric circulation allows trade winds to converge around the equator in the Pacific, blowing from east to west. But this year, trade winds are pushing in the opposite direction, bursting from west to east. This helps transport warmer waters, which typically lie in the Western Pacific, farther east — and dramatically changes the atmospheric circulation.

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Afternoon Update: Enhanced risk of severe weather in PA, NJ

Strong to severe thunderstorms remain a distinct possibility this afternoon and evening across much of Eastern Pennsylvania and New Jersey. As a low pressure system moves quickly through New York State today, southerly and southeasterly winds will draw in warmer, more moist and unstable air. The incoming atmospheric disturbance will act to touch off thunderstorms, and these storms will form in an environment featuring instability and favorable shear. Accordingly, they may organize to strong and severe levels. The main threat with these storms will be damaging wind gusts, but an isolated tornado cannot be ruled out given the aforementioned atmospheric shear.

The threat for storms is much less as one travels farther east. Marine air near the coast will make New York City the dividing line for strong storms and weak storms — with thunderstorm complexes expected to weaken as they approach New York City and move toward Long Island. Still, thunder/lightning and heavy rain are likely over these areas. Highlights from today are included below:

  • The Storm Prediction Center has placed Western NJ and Eastern PA in an “Enhanced Risk” for severe storms this afternoon. An Enhanced Risk is issued when organized thunderstorms are possible, with the potential to produce locally damaging winds, hail, or isolated tornadoes. The Enhanced Risk is meant to signify the area where more concentrated severe weather may occur relative to its surroundings.
  • The risk for severe weather decreases as you head farther east. More stable air will be in place near the coast, thanks to south/southeasterly winds off the water. Still, some thunderstorms and a period of heavy rain is expected in New York City later tonight.
  • The weather will dramatically improve Friday into the weekend. As this storm system slides off the coast, a high pressure will build in. Temperatures will remain warm, with lots of sun, and very little chance for any precipitation.

*This post will update throughout the afternoon with details and information on thunderstorms. 

Morning Overview: Strong storms possible this evening

An approaching mid level disturbance will aid in the development of a low pressure system today, which will track from Pennsylvania to Southeast New York during the afternoon hours. Southeasterly winds at the surface will help to advect in warmer, more moist and unstable air during the afternoon hours. Near the coast, this low level wind flow will bring in a marine layer that will keep the air more stable. So, naturally, as the disturbance approaches the best chance for severe weather will be away from the coast and west of New York City. In those areas, from Pennsylvania to New Jersey, strong to severe thunderstorms will be possible. We’ve included some details and information below, but stay tuned for an updated article later today if any watches or warnings are issued:

  • A Slight Risk of severe weather today from the Storm Prediction Center for much of Pennsylvania, Western New Jersey and the Mid Atlantic States. A risk of strong winds and isolated tornadoes exists in those areas.
  • Hot and humid once again today. Highs approach the upper 80’s after a cloudy start. Southerly winds will draw in a more moist and humid airmass, with more clouds along the coast and near the area beaches and local waters.
  • A disturbance approaching the area will bring the potential for strong to severe thunderstorms, mainly west of New York City. These storms will be capable of producing strong winds, lightning, flooding rains and possibly an isolated tornado.
  • A period of heavy rain is likely during the evening hours, even in New York City and near the coast. As the storms weaken and spread east, localized flooding will be possible with heavy rains.
  • Much nicer conditions are expected for Friday and into the weekend, as high pressure settles in. Temperatures will remain warm with plenty of sun and a very minimal chance of any precipitation.

Afternoon Roundup: Threat of storms stays in the forecast

A warm, humid, and moist airmass remains in place today ahead of a cold frontal boundary. Clouds have inhibited the development of widespread atmospheric instability, but enough has developed to suggest that some storms this afternoon could be strong. Weak shear in the mid and low levels of the atmosphere will keep storms somewhat unorganized, and moving slowly. So given the moisture content in the atmosphere, these storms could be capable of producing localized flooding in very rain. These storms will eventually slip to the east/northeast of our area tonight as the frontal boundary slips east as well. Here’s a roundup of news and information from the meteorology:

  • Strong thunderstorms and periods of heavy rain will again be possible later on Thursday. A stronger atmospheric disturbance approaching the area could force the development of storms with greater coverage and intensity than the past few days. Models, however, continue to waffle back and forth with this feature’s exact track.
  • Much more pleasant weather is expected for the weekend. A high pressure will build southward and keep the very moist and humid airmass to our south. Highs in the 80’s with sunshine are expected with only minimal chances of showers and storms.

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