here The map for Aug. 7, 1918 is below." />
Tuesday 8:30 a.m.
Drier air advanced into the northeast quarter of the nation yesterday, but its tenure is temporary and will be quickly terminated. As a high pressure area moves off the East Coast and a low pressure area forms near the lower Great Lakes, more humid air will be drawn northward... and the chance of showers and thunderstorms will increase. This looks like the kind of setup that can unleash 1-2 inches of rain in some areas. However, until we see exactly where the storm forms and how the moisture becomes arranged around it, forecasting rainfall amounts for various places is risky. The video has more.
On this date in 1918, Philadelphia had a high temperature of 106, the highest official reading ever for that city. What did the weather map look like that day? NOAA maintains an archive of weather maps for each day back to 1871. You can view them here The map for Aug. 7, 1918 is below. The map time is 1 a.m., and you may be able to see the 80-degree isotherm for that hour.
In those days, weather records were kept at the Customs House in Center City, Philadelphia. In later years, the observation site was shifted to Philadelphia International Airport. Airport locations are typically somewhat cooler than the middle of our big cities.
In the Northeast, a high pressure area now in control will be reinforced by another high from northeastern Canada. In the "what could go wrong?" department, a batch of cloudiness has appeared east of New England and has been spreading southwestward toward the New Jersey coast this morning.
The clouds over parts of the region are starting to break up, a sign that the predicted drier air from the northeast is making progress.
Cloudiness covers a large area. A few pockets of clearing show up where south winds ride downhill from mountains to lowlands. Air warms and dries with descent. Notice clearing downwind (northwest of) the Smoky Mts.
So, there could be more showers at times late next week as forest we can tell. For now we are stumped. But, it is our beleaf that this weekend you will like being outside. I know a dogwood. It may be a little cool for the beech, but you can take your dog for walk in the bark. What about next weekend? Don't ax.
If the pattern turns out damp as suggested by this map for Sunday, it could turn gray and drizzly from D.C. to New York City for early next week. If the high does not move offshore and no disturbance approaches from the west, it would be sunny and warm.
Two things stand out: (1) a warmup this weekend and early next week (the top graph), and (2) the overall dryness for the weekend and early next week. This graph is for Philadelphia.