Tuesday 9 a.m.
A storm moving northeastward through the upper Great Lakes will move to Labrador by Thursday. South winds sent temperatures into the 40s from Chicago to Buffalo ahead of the storm, but the cold front whipping around the south side of the storm quickly put an end to any semblance of mildness. In Chicago, the temperature was 47 degrees at 7 last night, but only 16 degrees at 7 a.m. today. The change won't be quite as drastic when the cold front clears the East Coast last tonight, but tomorrow and Thursday will feel quite a bit chillier than today in the I-95 corridor.
Despite the warming trend, snow, sleet and freezing rain broke out this morning from the higher elevations of southwestern New York on south through the middle of Pennsylvania and into West Virginia. In State College, Pa., an icy assortment of sleet, freezing rain and snow came in quickly enough to cause school delays. This picture taken outside the accuweather.com employee lounge clearly shows evidence of rain mixed with snow. For the I-95 corridor, mostly rain is likely later today.
map shows predicted rainfall between now and next Wednesday. This will need to be watched in order to assess the risk of flooding.
Looking farther ahead, it appears a summer version of THE POLAR VORTEX will send much cooler air into the Great Lakes and then the Northeast. The first map shows the flow aloft next Tuesday night. The second map shows what could be a heat wave a week and a half later!
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).