" third lowest pressure gradient"
But now the pressure is back up over 900mb...(at 915mb).
Note: I have absolutely no idea what a millibar is.
The pressure is back up and that is indicative of the weakening in winds caused by the EWRCC. This storm is still a day or more from landfall. She's going to complete her EWRC. The water she's been churning has to go somewhere. She's about to push into shallower water. The water she is pushing will interact with that shelf and not in a good way.
And really, when it's the difference between a Cat 5 25 ft storm surge or a Cat 4 15-20 ft storm surge.. who's counting?
1 bar = 14.5 psi.
915 millibar = 13.2 psi
1/1000th of a bar
A bar is the measure of atmospheric pressure at sealevel. A millibar is 1/1000 of a bar. Meteorologists measure pressure in millibars and it gets converted to inches for the general public. Standard atmospheric pressure is 1,013 millibars so, 900 millibars is REALLY, REALLY low. Wind is the movement of air from high to low pressure. The bigger the difference between the high and low pressure systems next to each other, the higher the winds.
A smaller bar than that which you get in your high-priced room at the better hotels. Also called a minibar.
(Better answers are given elsewhere on the thread)