This map shows where the cold front was at 7 a.m. ET. The flow north of there can be traced all the way back to Greenland.
Once the leading edge of the change to colder weather -- the cold front -- reaches North Carolina, low pressure area will develop. That storm will head to the Virginia coast, then out past New England. Things can still changes as the storm takes shape, but here is our draft map as of daybreak today.
Next weather change: Sharp blasts of face-freezing breezings, thumbnumbing bitter blusters with the low winter sun a hapless bystander who gives up in disgust after 5 p.m. The feeble sun can do little to stem the freezer-full of air from the arctic snowfields when the Hudson Bay wind tunnel is open. We'll certainly be in winter's kingdom this week. We are in a time when cold and wind are constant companions; times when barren tree limbs snap brittly in the unforgiving blusters of winter's dim domain... the cold night ahead of us with the melancholy moon standing silent sentinel over the frozen ground. Icy needles of wind are marauding through the Midwest, whistling through Wisconsin, irritating Illinois, icing Iowa & mesmerizing Michigan. Now too, the cold penetrates Pennsylvania, nips New Jersey, cools Connecticut, rushes through Rhode Island, marches through Massachusetts and Maryland, dashes through Delaware, and torques thru New York (not to mention vaulting into Vermont, turning temperatures negative in New Hampshire, and minusing Maine). Then it ventures through Virginia, considerably cools the Carolinas, As we feel the chill driving us to January's gelid jailhouse, our thoughts might wander to spring. One day, some day, the sun will coax us back toward milder times. One day, some day, the cautious crocus and daring daffodil will show their bright flowers to the first tender warm breezes. But those times will seem all too remote and inaccessible the next few days, with mornings for the mittens and scarves, parkas and hoods, a wintry wakeup inside the gates of January's jailhouse. We still sail on the iceberg strewn great gulf of winter, its uncharted waters of cold waves loom larger this morning, the ice water plenty deep. We heading off into the midst of a classic bitter cold ice bound winter cold snap, when face freezing winds run rampant across the winterscape as the sun is just a feeble bystander an eternity away.
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:
Farther east on Sunday, rain is likely to be more extensive, and there is a severe thunderstorm threat from the Middle Atlantic region on south.
With the second front, shower activity may be spotty at first as the system comes through Chicago on Saturday but could be wetter and more stormy than the first front by time it reaches the I-95 corridor Sunday.
A pocket of dry air covers most of the area from the Great Lakes to the back edge of the East Coast clouds. This suggests sunshine will be the rule across the Northeast until the next frontal system approaches later in the week.
Here is the severe weather outlook for today from the NWS Storm Prediction Center. Note at the bottom the population in each alert area is listed. Keep in mind that in any given severe weather situation, the number of individuals directly affected is far less than the number of people potentially threatened.