Tuesday 10 a.m.
The major storm that caused heavy rain in the I-95 corridor and heavy snow in parts of western and central New York, western Pennsylvania and West Virginia is slowly winding down. The upper-air pattern shows a strong ridge over the Rockies and a strong through in the East. By the weekend, a split flow pattern is predicted. One current will come in from the Pacific, then drop into a trough that moves across the Southwest and South Central states. Another current will move through western Canada, climb over a ridge in Manitoba, then head southeast to the northeastern part of the country. This will set up a huge temperature difference from north to south. This weekend's flow toward Virginia will start out over Arizona, while the flow coming to New York state starts over Hudson Bay! The video shows one of several outcomes.
Around accuweather.com headquarters, we saw snow, but the nearest significant accumulation was on the ridge tops. The camera peers out toward the ridge top and sees what was left of the snow on Tuesday morning.
There were numerous thunderstorms yesterday. This is the lightning stroke map covering the period from 8 ET yesterday morning to 7:30 ET this morning. Thunderstorms will be less numerous today, but any that do form can cause briefly strong and gusty winds.
One area of concern is Lake Erie, where unprepared boaters could suddenly be blasted by 60-mph winds. The National Weather Service Storm Prediction Center has outlined a large area where the threat of strong wind exists. The map is below today's forecast video.
Tomorrow, a cold front will cross the Great Lakes, then reach the Northeast by the end of Wednesday. Today, a southwesterly current of very warm air is evident on the surface pressure map.
The center of Arthur (shown here at noon ET) should pass less than 50 miles southeast of Nantucket this evening, causing heavy rain and gusty winds across much of eastern New England. Meanwhile, the Great Lakes and much of the Appalachian region have a lovely Fourth (but take a jacket or sweater as you head out to the fireworks).
This map, which is updated frequently, showed our track forecast and main impact notes as of 10 AM ET.
This detailed pressure map can be helpful in identifying boundary zones along which clouds, showers and thunderstorms can form.