For many in the northern mid atlantic / northeast the summer thus far has been rather below to near normal with NYC recording only one 90 degree day , and Boston with none to date.

While most of the heat has been confined to DC/BALT on points south into VA & the carolinas.

This has been the direct result of back door cold fronts with our negative NAO in place since mid june.

With any weather pattern in place the atmosphere goes through a relax or reload pattern and that is exactly what will transpire here.

The polar jet stream in the 500mb pattern will relax in the pacific too allow building 500mb heights up the east coast with the southeast ridge.

The NAO which has been in a rather impressive negative amplitude for the summer is going into a more neutral / transient state for a short time



The MJO forecast makes sense here with it going into a weakening phase 7 , 8 & 1 bordering neutral after a very high amplitude of phase 7.

This MJO forecast does NOT support a sustained heat ridge in the east , but suggests that a transient trough will remain in place over eastern northern america while its in reload mode.


The Ridge building in the east is beginning right now out west as a amplifying Trough moving eastward comes into the pacific northwest from canada , while a secondary trough will dig southwest into the intermountain region.

This secondary trough digging southwest will allow building heights initially in the northern plains to expand eastward.


This will allow building 500mb heights to invade the east as the ULL over eastern north america gets displaced a bit northeast.

While this will NOT be a major east coast heat wave ( unless we had a -PDO & stratospheric cooling) it will be the longest & potentially hottest stretch especially philly on south of weather thus far this summer.

Will Boston hit there first 90 of the year? very possible.

This warm / hot stretch of weather however does not have legs as convection around the date line will eventually become more organized soon and place a trough south of the aleutions & trough in the east.






Questions / Comments SteveGwx on twitter

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