The tropics have been more active recently. This map shows various entities that area being tracked and analyzed. Hurricane Gonzalo stands out clearly.
A couple of days ago, the storm entering the East had a stronger circulation than it does now. Here is the pressure analysis from earlier this morning. Several minor disturbance can be seen, and trough lines representing those have been sketched on the map. Note that there is little difference in temperature from western Pennsylvania to Wisconsin.
The rain band is only 100-200 miles wide, but it is moving slowly. This map shows its location at 10 a.m. today. Once the main rain band passes, it won't be quite as warm as it was when the rain started. However, by mid-October standard, it will still be mild.
On some days, there are so many "little things" that it is difficult to identify the players. Today, we see two systems dominating: the low pressure area on the left (west) and the high pressure area to the right (east). The cold front associated with the low pressure area is helping to support bands of rain.
One branch of the flow will go from Oregon and northern California eastward to the Plains, then it will go around the south side of the storm we have been talking about. A second branch of the flow will run from British Columbia northeastward to northern Hudson Bay. Cold air will be north of that current...which means it won't be anywhere near the eastern U.S. later this week.
It seems late in the season for tropical storm activity, but remember Sandy came late in October two years ago, causing heavy snow in the West Virginia and western Maryland mountains and disastrous effects from New Jersey to southern New England.
It is easy to see how people could become very concerned about the first map, while complacency would be the rule after looking at the second map. At this point, we know either solution could be totally wrong and so can both of them! I am using the benign forecast as the thumbnail for this post because I don't want to cause undue concern.
Many times we look at the sky and it may be pretty, or gray and gloomy, or whatever. However, a time-lapse movie can really bring the scene to life. This movie, taken on the afternoon of Oct. 1, shows clouds northwest of my house (in the middle of Pennsylvania).
During summer, you have to be pretty ambitious to take many sunrise photos... because sunrise is so early. That's not the case now. Often, the best color is seen when the sun is just below the horizon. At that point, it is not yet bright from our gran-based viewpoint, but the undersides of the clouds may be well illuminated. In this picture, alto cumulus clouds are lit up on their forward edges.
While there can be a thunderstorm and a period of heavy rain with the cold front all the way to the East Coast, it may not rain for more than a few hours at most places east of the Appalachians. Thunderstorms have been widespread with this system as it moved across the middle of the country. We expect the storms to become less numerous as the front continues eastward. This map shows the lightning strokes from 9 a.m. ET yesterday through 8:25 a.m. ET today.