Wednesday 10 a.m.
Temperatures a mile overhead in the Northeast today would support afternoon ground-level temperatures well up in the 80s today... if this were July. In July, the sun climbs high in the sky. Mornings warm quickly; soon it is very warm or hot. Not so fast in October, though. The longer nights allow more time for the temperature to drop to the saturation point, and soon fog forms.
The fog prevents much solar energy from the reaching the ground to cause warming. If there are higher clouds around like there are at many places today. the warming process is delayed further... and before we know it the sun is sinking back toward the horizon. The changing amounts of clouds and fog can wreak havoc on temperature forecasts. Despite this, we can say confidently that temperatures in Middle and North Atlantic states will run higher than the long-term averages for this time of year.
Fog may redevelop late tonight and longer tomorrow morning. On Friday, however, slightly drier air will advance from the west and southwest... and with the breeze picking up, it could turn out to be the warmest day of the week. A cold front will arrive and be followed by noticeably cooler air for the weekend. The cold front is associated with a low pressure area that will cause heavy snow across parts of the far North Central states and adjacent Canada. This video shows the expected progression of events:
Dense fog has often proven to be very challenging for painters and photographers. You can see why with this image from a webcam overlooking the area between the Statue of Liberty and the buildings of Manhattan.
If the ridge was the only thing involved, it would just be sunny hot and humid day after day. As it is though, there are various minor disturbances rippling through the ridge. One such disturbance has allowed cooler air to spread down the coast.
This map shows where the storms were at 10:18 AM ET. That cluster of storms may hold together, but in response to daytime heating, new ones can pop up at other places this afternoon.
On this map, two such features (short waves) stand out today. The one in Ohio caused some thunderstorms in Michigan and Indiana yesterday. The other short wave is causing thunderstorms this morning from western Wisconsin to northern Missouri.
Scotty the Dog will be four-months-old in four days. On walks during hot weather, he is quick to seek out shady spots. He has yet to experience any cold weather, but he looks like he will be ready when it arrives (not any time soon!).
Erika's heavy rainfall separated into two areas yesterday. This is the Morehead City, North Carolina, radar, showing an area of heavy rain and thunderstorms that dumped more 4 inches of rain on parts of the coastal Carolinas this morning.
Tropical Storm Erika could eventually affect Florida and other sections of the Gulf Coast or Southeast, but for now it poses no threat for the Northeast. This map shows the storm as of early this morning.