When I was writing the daily forecast Thursday it was about 25 degrees warmer than this morning and a lot more humid.  As you step outside today, heading to work, school or walking the dog, you’ll quickly notice fall is here.

The air mass in place is cool and dry and feels more typical of the final days of September.  As we look back at most of the month in the rearview mirror, it’s been very warm and very much on the dry side, but this weekend will be cool with some rainfall.

Average rainfall is just around three-quarters of an inch each week.   If we don’t receive that amount then it starts to become dry rather quickly.  A week with a lot of rain can keep things moist for a week that follows with no rain, but beyond that the landscape quickly dries.

The drier-than-average weather is most notable along the coastline where the drought monitor is picking this up.  In Maine, much of the area from Portland north along the coast is still in drought conditions.  The heat this week exacerbated all of this.

Drought continues along much of the Maine coast.

On Saturday it will rain at least a bit, and although the ground may become wet, it won’t be nearly enough.  An inch or more of rain would be ideal; we’ll be fortunate to see a 10th of that in many places.

The map below shows how much rainfall is expected Saturday.  This is based on all the models and is an average.  The exact amounts are rarely correct, but the pattern of very little overall rain likely is.  Notice the rain barely makes it to Portland.

Low pressure will be too weak and too far south to alleviate our drought with rainfall. Dave Epstein

Temperatures on Saturday with the clouds and the raw breeze off the water will be very chilly.  Highs won’t reach the 60-degree mark for one of the coolest days in a long time.

The reason for the showers is a low-pressure system to our west that will track just south of the region.  The low is starved for moisture, thus the prediction of meager total rainfall.

As the low passes, clearing will take place and sets up a fantastic Sunday.  This will be a typical fall day with highs in the 60s and lows in the 40s.  If you want to see some early foliage, head to the higher elevations for a good show.

Next week there’s going to be a another warmup – not as warm or humid as this week by any measure, but it will turn unseasonably mild with highs well into the 70s and a few 80-degree readings are likely.  It will feel like fall this weekend, but summer-like conditions haven’t given up just yet.

Temperatures average below normal this weekend, but above next week. WeatherBell

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