WTNT44 KNHC 292059

Hurricane Ian Discussion Number 29
NWS National Hurricane Center Miami FL AL092022
500 PM EDT Thu Sep 29 2022

Ian remains a hybrid tropical cyclone with characteristics of an extratropical low, including a comma-pattern on satellite images and some frontal features in the outer circulation. The cyclone continues to have a warm core, however, and all indications are that it will re-develop strong convection over the center overnight. Based on Melbourne Doppler radar velocity data of persistent 70-80- kt winds from 5-10 thousand feet, and earlier sustained winds of about 60 kt near that band from an observation in New Smyrna Beach, the initial wind speed is raised to 65 kt. This makes Ian a hurricane again. An Air Force Reserve Hurricane Hunter aircraft is scheduled to fly through Ian this evening and will provide a better intensity estimate.

Ian finally appears to be making more of a turn to the north- northeast this afternoon. The hurricane should turn to the north overnight due to the incoming trough diving southward over the southern United States and then north-northwestward on Saturday with an increase in forward speed. While the overall synoptic pattern is similar in all of the models, Ian has been uncooperative and remains right of the previous track. Thus, the new forecast is adjusted to the east, and lies east of the model consensus. Assuming Ian re-develops thunderstorms near the core overnight, it should take the expected north-northwest turn, but this shouldn't be considered a confident forecast yet. Because of the uncertainty, the Hurricane Warning has been extended eastward into North Carolina to Cape Fear.

The hurricane is moving over the Gulf Stream for the next day or so, where it has some time for further re-intensification. Additionally, the trough interaction should provide a baroclinic energy kick. These factors point to some strengthening before landfall tomorrow. The new forecast is close to the GFS and regional hurricane models and is a bit stronger than before. It should be emphasized that while we don't expect Ian to be a classic hurricane at landfall, this does not diminish the danger it poses. Strong winds and storm surge will also extend far from the center and will begin well before the center arrives.

Key Messages:

1. There is a danger of life-threatening storm surge through Friday along the coasts of northeast Florida, Georgia, and South Carolina. Residents in these areas should follow any advice given by local officials.

2. Hurricane-force winds are expected across coasts of South Carolina and southeastern North Carolina beginning early Friday, where a Hurricane Warning is in effect. Hurricane conditions are possible by tonight along the coasts of northeastern Florida, Georgia, and North Carolina where a Hurricane Watch is in effect. Preparations should be rushed to completion since tropical-storm-force winds will begin well before the center approaches the coast.

3. Ongoing major-to-record river flooding will continue across portions of central Florida, with considerable flooding in northern Florida. Considerable flash and urban flooding is expected across coastal portions of northeast Florida through Friday. Local significant flooding in southeastern Georgia and eastern South Carolina is expected through the end of the week.


INIT 29/2100Z 29.3N 79.9W 65 KT 75 MPH 12H 30/0600Z 30.5N 79.4W 70 KT 80 MPH 24H 30/1800Z 32.8N 79.6W 70 KT 80 MPH 36H 01/0600Z 35.0N 80.4W 30 KT 35 MPH...POST-TROP/EXTRATROP 48H 01/1800Z 36.5N 81.0W 15 KT 15 MPH...POST-TROP/EXTRATROP 60H 02/0600Z...DISSIPATED

$$ Forecaster Blake