#HurricaneIAN is very large, very wet and headed inland. The possibility of strengthening once if it finds itself back over open water is non-zero. It is already being fueled by water/convection from the Atlantic side of Florida.
The eye is 60kms wide at present and it is very slow moving - which is bad news from a landfall winds and flooding perspective. Storm surge impacts and flooding impacts are already extreme.
The capacity of giant storms to maintain strength over land is considerable (#INFA 2021).
Georgia, South Carolina and North Carolina and Eastern Maryland are all squarely inside the severe flooding window.
And forecast rainfall of 10-20 inches over much of Nth Florida is potentially catastrophic (latest NHC warning).
#HurricaneIAN is a remarkable, and hopefully very unsuual phenomena, two distinct weather systems working together - that have appeared to be a single system for several days.
This, the final act, may be the most extraordinary part of this event. But not the most destructive.
This CMISS animation shows what is happening vert clearly. And this explains a lot about #HurricaneIAN:
- its strength
- its super rapid intensification
- the persistent short range model forecast error
- its ability to remain intact over land
This is what I was worried about the interaction between the atmospheric river and #HurricaneIAN.
The Wastern leading edge of the Atmospheric River is now pumping directly into #IAN and it appears to be strengthening over land. The Eyewall is not yet complete.
Earlier threads discussing the interaction phenomena.
What is happening in the Carolinas is not just a hurricane. The catastrophic event ahead is probably more due to the Atmospheric River which #HurricaneIAN has directed onshore. The second image here roughly delinates the two.
Spaghetti guidance is tightly clustered on Charleston landfall. After moving inland a very sharp turn W/SW is expected with some models even predicting a return back to the Carolina coast.
Tropical rain all the way to the Great Lakes is possible/likely given the size of Ian.
Intensity guidance is very clear that the storm is expected to weaken - based on landfall today. This will change rapidly if Ian does not weaken or landfall quickly.
The NHC's forecasting for #HurricaneIAN remains tricky. Inching closer to the North/South Carolina border. And from satellite data, it looks possible that the center of #HurricaneIan is east of the current line.
The specialist HRRR model, which proved more accurate than the main models in predicting the path across Florida is now in agreement with ECMWF, GFS and NAM-CONUS on the location of landfall, but there is a broad range of intensity from 973-984 mb.
There is also a 6 hour range in arrival time among the four models from 1pm to 7pm. Due to the size of the storm, the impacts of #HurricaneIAN on the Carolinas & beyond are already well and truly underway over night local time.
Near live 6hr satellite imagery #IAN beginning its exit of Florida over Cape Canaveral and the Kennedy Space Center. And it looks like it started strengthening significantly before it's center crossed the coast.
This wider angle view helps put the storm into wider perspective, in particular its size, and the importance and significance of the massive convective area to the East of Florida from which #TSIan#HurricaneIAN is being fuelled.
The big question now is how will #HurricaneIAN interact with this atmospheric river as it crosses the Atlantic heading towards the Carolinas, specifically, will this extremely complex moist air field strengthen or inhibit intensification.