If you took Monday’s weather map and didn’t show me the temperatures, you could easily fool me into thinking it was from the middle of winter.  We can go several years without seeing the atmosphere produce low pressure like this in July.

A winter-like weather map in mid-July is quite unusual. (Dave Epstein)

 

A double-barreled storm to our south and west, with the flow around these systems, is keeping much of New England on the near-record cool side of average. In the summer, air masses in this part of the world typically don’t have the contrast in temperature to produce these types of weather systems.  Midday temperatures were in the mid-60s in southern Maine on Monday.

Typical highs in the upper 70s and lower 80s will not be reached until later this week. NOAA

NOT MUCH RAIN

Although it is cool and cloudy, we are not looking at a lot of rain in Maine. Coastal Maine actually needs rain.

The heaviest and steadiest rain remains west and south of Maine. NOAA-Gray

ATMOSPHERIC CHILL

The atmosphere is like a big layer cake and when it’s warm the cake’s layers are thicker.  In colder weather the layers become more compressed.

In the loop below, the map is showing how one of the layers, at around 18,000 feet, will behave in the coming days.  In our current pattern, this layer is lower in height than normal and thus coded in blue.   Notice how the blue disappears and is replaced by warmer colors as things return to more typical July weather later this week.

The atmosphere at 500 millibars or roughly 18,000 feet will undergo several changes this week. Tropical Tidbits

The good news is this abnormal pool of cool air will only stick around for a couple of days before being replaced by much warmer conditions later this week.  

If you are on vacation this week, Monday and Tuesday are definitely days to read or go shopping, leaving the beach for Wednesday and Thursday.  

The meteogram from one model shows our cool damp weather at the beginning of the week and then a warm-up at the end.   

The greatest risk of significant rain comes Friday this week. WeatherBell Analytics

Another round of showers and perhaps some downpours are likely on Friday as a cold front approaches. If this front keeps moving, we will see a nice weekend, but a slower passage will keep clouds around for Saturday.

UNLIKE LAST SUMMER

The chilly weather may feel especially cold for New Englanders because last summer was a doozy in terms of heat and dryness.  A year ago this week, much of New England was in the middle of plenty of humidity and heat.  Even Portland reached the mid-90s.  

AUGUST TO BE WARM, BUT JUST HOW WARM?

Beyond this week the weather looks warmer to start August. Early August can bring some very hot weather to the region, but we will need to wait a bit longer to see just how warm next month is going to be.

You can follow Dave Epstein on Twitter @growingwisdom

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