Relief is on the way tomorrow evening.  A cold front that is just making its way into parts of Northern New England will be crossing through Southern New England tomorrow.  I am still confident in the finer details that I laid out a couple of days ago.  The only thing that has changed is the potential strength in any storms that form tomorrow afternoon.  As you can see from the image posted with this blog, the Storm Prediction Center is forecasting a 30% chance of severe storms for most of Southern New England tomorrow.

As I said a couple days ago, tomorrow should break down as follows.  The cold front should be located in Southern New Hampshire and Vermont by tomorrow morning.  Meaning that Northern New England will be allowed to enjoy a beautiful day.  By early afternoon, the cold front should be located just south of the Mass/New Hampshire border.  Allowing for day time temperatures to reach up into the upper 80s for most, possibly low 90s for parts of Connecticut and Rhode Island.  The atmosphere will have sufficient time to destabilize and showers and thunderstorms should be forming by about 2 pm.  Some storms can and will be strong to severe producing damaging winds and hail.

By saying “the atmosphere will have sufficient time to destabilize”; what I mean is this:  Simply put, when looking at how unstable the atmosphere is, there are two parameters that can be looked at. (Yes there are many many more, but a broad forecast can be made off of just two) They are what is known as CAPE and CIN.  CAPE = Convective Available Potential Energy.  Simply put, it is the amount of energy that a parcel of air would have if lifted a certain height into the atmosphere.  CIN = Convective Inhibition.  Which is just the opposite of CAPE.  It is the amount of energy in the atmosphere that is trying to prevent the same air parcel from rising.

For tomorrow afternoon, as the surface temperatures increase, so will the amount of CAPE.  By the afternoon, most places south of the Mass Pike will have CAPE values of over 2000 J/kg.  Which is more than enough to support thunderstorms and potentially strong ones.  Also by tomorrow afternoon, CIN values for most of the same areas will be decreasing towards 0.  Setting the stage for widespread thunderstorms.

Finally by taking a look at what the storms have produced in Northern New England today, it would appear that damaging winds will be our main threat.  So, just keep a eye to the sky during the afternoon hours tomorrow.

By Thursday morning, the front has cleared the south coast and we usher in the return of some much more bearable weather as highs to finish out the week will hover around 80.  Our next chance of precipitation after Wednesday isn’t until Sunday afternoon.

7 DAY FORECAST

Tonight: Hot and sticky, overnight “lows”  around 75.  Air conditioning working overtime tonight.

Tomorrow: Warm; highs in the upper 80s for most, low 90s for some.  Chance of strong thunderstorms.  Particularly south of the Mass Pike.  Some storms could produce damaging winds and hail.

Tomorrow Night: Storms end and cold front moves offshore.  Lows in the upper 60s to around 70.

Thursday through Saturday: Beautiful.  Highs around 80.  No complaints here.

Sunday: Chance of a late day thunderstorm.  Highs in the low 80s.

Monday:  Chance of a shower or storm.  Highs in the mid 80s.

-Chris


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