Major Hurricane Idalia hit Florida last week

From NHC discussion:


There's a notable risk of rapid intensification while the system moves across the record warm eastern and northeastern Gulf of Mexico, which is highlighted by the recent HAFS and HWRF guidance. The new NHC
forecast is raised from the previous one, near or above the model consensus, and could be too low. I'm reluctant to make any big changes to the forecast until we get more in-situ data, but the upward overnight model trend certainly bears watching. Users are reminded to continue monitoring forecasts for any changes to the system's expected intensity as it approaches Florida.

Never seen language like this before in a discussion. Mike of MWP talks about recent history of similar storms shows that West Central Florida still at substantial risk

Two hurricane hunters out now. More data in 11 or 5 update

 

Mike is live now on YouTube. Worth a listen. Also this page

Central Florida Hurricane Center 2023 - 28 Years Tracking Storms

 

From Central Florida Hurricane


AM 27-Aug EDT
7:30AM EDT 27 August 2023 Update
Idalia-to-be (TD TEN) and Hurricane Franklin are being aggressively flown by recon today, and this invaluable data will be fed into the models, forecast models which have been especially struggling a bit with TEN, and forecasters too.

By the end of the day we should be able to have greater confidence in the forecasts, but this is not to say that impacts won't be felt. There is already high confidence that a then-hurricane Idalia will make landfall somewhere along the west coast of Florida, and that a then-Major Hurricane Franklin will be within striking distance of Bermuda.

 

Will some of you scientific types interpret this from the 11am NHC discussion? I have a good idea from context, but more translation would be welcome. Three terms I need to look up, bolded with an article


Although this feature could produce some moderate
southwesterly vertical wind shear over the system, positive
vorticity advection and diffluent upper-level flow to the east of the trough will likely be conducive for strengthening.


From the NWS

Vorticity is any twisting motion in the troposphere. Positive vorticity can be broken down into three components, which are positive shear vorticity, positive curvature vorticity and earth vorticity. A counterclockwise spin in the Northern Hemisphere will produce positive vorticity.

Webster’s


What is called advection?


ad·vec·tion ad-ˈvek-shən. : the usually horizontal movement of a mass of fluid (such as air or an ocean current) also : transport (as of pollutants or plankton) by such movement.

NWS again
Difluence
(or diffluence) - A pattern of wind flow in which air moves outward (in a "fan-out" pattern) away from a central axis that is oriented parallel to the general direction of the flow. It is the opposite of confluence.

Difluence in an upper level wind field is considered a favorable condition for severe thunderstorm development (if other parameters are also favorable). But difluence is not the same as divergence. In a difluent flow, winds normally decelerate as they move through the region of difluence, resulting in speed convergence which offsets the apparent diverging effect of the difluent flow.

 

Mike is live on YouTube