The storm that originally looked like it could bring heavy snow from Ohio and Pennsylvania to southern New England moved south of the track that would have produced that result. Instead, the heaviest snow today is in Virginia, parts of Maryland and Delaware and extreme southern New Jersey.
So why did this happen to make the forecast so wrong? When the main energy from the storm was over the Pacific last week, the data that was fed into the models had less detail than that available over a continent where data sources are more densely packed. This problem has been somewhat reduced in recent years, but not eliminated, by an increase in satellite and aircraft-based observations.
All along, it was perceived that the heaviest precipitation would fall in a narrow stripe. As it turned out, we were off on the exact position of this band. As the storm storm came ashore and we knew more about its nature, the forecasts improved. However, if you heard a foot of snow was in the forecast Friday and didn't check for updates, then woke up to see no snow this morning, you'd think no storm ever formed. One thing I can assure you is that this will happen again sometime. That's why it is important to look at updates as often as possible whenever you have a weather sensitive decision to make. Here is today's video.
This map shows accumulations as of 8 a.m. They have continued to increase since then in Delaware, Maryland and Virginia.
The NWS Storm Prediction Center issued this outlook for today and tomorrow: A preliminary area of showers may advance from the Carolinas as far as southeastern Pennsylvania and southern New Jersey by tonight.
For the almost 24 hours between 10 a.m. ET Tuesday and 9:20 a.m. ET today, here is a the lightning recap. The dry pattern from the Midwest will now advance across New York and New England.
Cooling aloft and heating moist air closer to the ground should trigger strong thunderstorms from eastern New York and much of New England southwest through parts of the Middle Atlantic states.
The front will move into a region with high humidity as it approaches the I95 corridor tomorrow. This is the basis for SPC's forecast of thunderstorms approaching severe limits tomorrow.
Tropical Storm Colin is caught in the southern stream while the northern stream is helping to send unseasonably cool air out of central Canada.
Then, as the cold front arrives, there may be violent thunderstorms. This map shows the early morning SPC assessment of the severe weather risk on Sunday: