Forecast: Chance Of Hitting 90 In Boston, Only 5th Time This Summer

One more day of heat Wednesday with a chance of highs reaching 90 in Boston for only the 5th time this summer. Boston's Logan Airport hasn't broken 85 the entire month of August.

A southwest flow of air will continue to bring the heat and the humidity into the area ahead of a cold front to our west. As this front marches east, some thunderstorm activity could pop up. Any storms that do form will be isolated. The best opportunity for any storms comes in the afternoon, when temperatures are warmest and the air is less stable.

A southwest flow means Cape Cod and the Islands will be significantly cooler than areas north of Plymouth where readings could reach 90 or higher. Humidity is going to be noticeable Wednesday, but drier air will arrive by Thursday.

Thursday through Saturday looks warm and dry with abundant sunshine. Temperatures will be seasonable during this period, which means 70s to near 80.

There are still a lot of questions around the forecast for Sunday and Monday. It doesn't appear we will have a washout either day, but showers could occur. The warmest day will be Sunday, with humidity and highs in the 80s. Temperatures in the 70s will return for Monday, but still the risk of some shower activity. I'll be updating the timing of the showers and the amount of possible rain as we get closer to the weekend.

On a side note, seas will increase offshore and rip currents will be an issue late Wednesday and more likely Thursday as hurricane Cristobal passes offshore, so be careful if you are headed to the beach.

Wednesday: Mostly Sunny and hot with a slight risk for some isolated thunderstorms, which won't last too long. Highs 86 to 91 with cooler temperatures in the south coast.

Wednesday Night: An early evening thunderstorm otherwise clearing and turning drier by morning with lows in the lower 60s.

Thursday: Sunny, with a high in the upper 70s.

Friday: Sunny, with a high near 75. Winds will be light and humidity will be low.

Saturday: Partly sunny, with a high near 80.

Sunday: Warm and muggy with clouds and some sunny breaks. Showers possible with highs in the 80s.

Follow updates from David Epstein on Twitter @growingwisdom.