For the last several days, all the buzz has been about the development of a potent Nor’easter that would spread heavy rain and strong wind gusts to the Hudson Valley and Northeast. While this Nor’easter will contain rain… it has many characteristics of a winter storm. One major similarity, is the unpredictable nature of the storm. And as of Friday night we’re seeing the beginning signs of some changes to the timing and potential impacts
These two graphics compare our European model data forecasting Sunday’s Nor’easter. On the left is is the storm data from Thursday…. and on the right is what the storm looks likely to do now (Friday night).
In the first image is the forecast map for Sunday afternoon. Notice how on Thursday, the low pressure was more organized and tucked in right along the east coast. That scenario spread a swath of soaking rain from Baltimore, up the Hudson Valley on Sunday afternoon.
But notice as of Friday night… the storm development looks much different. Instead of a more organized system along the coastline, one piece of energy lingers off the coast of South Carolina, and another weak piece of energy moves well off shore. The impact on the Hudson Valley (circled) is night and day. Our original data suggested a windswept rain on Sunday in the Hudson Valley. The new data suggests that the Hudson Valley is mainly dry during the day on Sunday… with some rain looking more likely Sunday PM into Monday AM as the storm stalls out.
The second image shows the expected rainfall from these two scenarios between Sunday and Monday. On the left is our old data… projecting 1 to 2 inches of rain in the Hudson Valley. Our new data on the right, shows total rainfall amounts less than 0.25″ in the Hudson Valley… with the heavy rain being kept off the coast of Long Island. We will need to monitor for additional changes but most of this threat of heavy rain has shifted into overnight Sunday into Monday AM. So a period of moderate to heavy rain is still possible but its arrival has shifted significantly.
This data is supported by all our other computer guidance (GFS, NAM)… meaning we have a growing confidence that Sunday look much less stormy than originally forecasted. Instead the potential of heavier rain may occur much later into overnight Sunday and Monday AM. Winds still look to continue to build into the region Sunday afternoon into Monday, with the
potential for a period of stronger gusts early Monday morning.
To Recap– There is still a slow moving and impactful coastal storm developing this weekend, but we caution the forecast confidence. If this were a winter storm, in this exact setup, we would say this has a high bust potential. We are still seeing large inconsistencies in the model data which at this time frame is a sign the models are struggling with the evolution of the storm and how the ingredient will play into one another. So far the big change is the timing being pushed back from noon Sunday, to now impacts arriving overnight Sunday. Wind and rain are STILL in the forecast, but more changes are possible, keep an eye on the forecast as we continue to monitor how the storm begins to develop.