The National Hurricane Center has identified an area of low pressure (invest 94L) about 700miles east of Bermuda that could transition into a sub-tropical storm as it heads westwards – towards Bermuda. Currently, it is in a favorable environment to make this transition:
The upper level low is aligned with the surface low pressure allowing for wind shear to be very low. Meanwhile, the cold air aloft generated by the upper level low is increasing instability and allowing convection to build around the surface low. In theory, as this convection builds, it releases latent heat into the atmosphere through condensation in clouds and warms the upper level low. As the upper level low warms, it weakens and can reverse its circulation and become an upper level high or anticyclone which is associated with a tropical cyclone. During this process, the surface low warms in all sectors and so it loses all frontal characteristics – a key characteristic of extra-tropical cyclones.
As of 2pm Eastern time, the National Hurricane center has given the low pressure area a high (60%) chance for developing into a sub-tropical or tropical cyclone in the next 48 hours. Bermuda and Atlantic Canada should monitor the progress of this system – although forecast models aren’t too impressed right now.
Meanwhile near tropical storm conditions continue in the Azores where tropical storm warnings are in effect courtesy of Tropical Storm Nadine – the storm that doesn’t want to die over the cold Northeastern Atlantic. Forecasts have the storm heading southeastwards towards Madeira and quickly transitioning to a post-tropical cyclone; but we will see what she does, interests there, in North Africa and the Iberian Peninsula need to monitor Nadine closely. See Portuguese Institute of Meteorology.