One year ago, a significant pattern change began to develop and affect southern New Jersey. This pattern change, which was supported by a growing La Nina weather pattern, has produced a significant drought over southern New Jersey. With May, 2008 being the one year anniversary, it is time to look back at what has caused this daught and what the future may hold.
A year ago, a significant change began to develop over the Pacific. Ocean waters cooled in the central and east-central equatorial Pacific, which lead to stronger than average easterly winds across the entire equatorial Pacific. The changes in these upper level winds lead to whole scale changes in the pattern. One of those changes was the development and sustained presence of a ridge off and over the Southeast coast. The development of this ridge of high pressure is extremely important.
La Nina grew to become very strong and as an indirect result, supported a strong ridge off the Southeast coast. Through May, 2007 up to May, 2008 the Southeast ridge (SER) has forced the overall storm track to the north and west of southern New Jersey. At the height of La Nina in the winter months, the SER was able to literally deflected most fluctuations away from southern New Jersey leading to significant deficits in rainfall. As seen on NY NJ PA Weather daught page, rainy shortcomings from May to December of 2007 were 7.35 "below normal.
Additionally, through December to March (the winter months) the overall influence of La Nina produced a rapidly progressive weather pattern. With a lack of a negative north Atlantic Oscillation (NAO) and a strong SER, the storm track generally remained north and west of southern New Jersey. For each storm, the anticipation continued was focused over central Pennsylvania, the Hudson Valley, and New England. While, New England experienced a very snowy and harsh winter, the Mid Atlantic remained reliably dry and warm.
Many strong disturbances and closed lows this Spring that have bought heavy precipitation and severe weather have rapidly weakened and dissipated as the fluctuations moved north and east. Once again, the progressive nature of this pattern combined with a storm track focused to the north of southern New Jersey has led to a deficit in 2008 of 2.16. "This has pushed the deficit for the entire period to 9.51" below normal.
There is good news though! La Nina is starting to show signs of weakening and the forecasts from the Climate Prediction Center suggest that La Nina will continue to weaker despite linger through June. Going toward the Summer and Fall, the ENSO could potentially go neutral or toward an El Nino state, which will bring a much higher chance for precipitation. However, in order to break the significant grip that this La Nina enhance drought has on the region, several months of above normal rainy will likely be needed. Heavy tropical rains from tropical systems may also aid in alleviating the drought, although heavy downpours will do more harm than good as flooding and a washing away of top soil will be the result.
The Drought over southern New Jersey, though under reported in the media, continues to have significant impacts on the communities of southern New Jersey. Although improvement in the drought conditions are expected, significant rainfall will be needed to replenish the lack of rain seen over this year. NY NJ PA Weather will continue to track and cover this daught and give the latest news and impacts through the summer.