Milton evening update (Mon 7 October)

NHC upgraded Milton to Cat 5, and warns it is still intensifying, however, keep in mind it probably can’t maintain that until landfall. Nevertheless, this is still shaping up to be a major disaster for central Florida. The watches in Florida are now warnings, as expected watches are going up for the east coast of Florida as well as coastal Georgia an South Carolina …

The track itself hasn’t really shifted much. The model guidance is still solidly on Central Florida. The forecast impacts went up a bit – current model runs are hovering in the $60 to $80 Billion range, as NHC has the storm center going right over Tampa and the swath of highest winds therefore displaced just south of the I-4 Corridor.

If you’re in the warned areas, especially areas urged to evacuate, you should follow that advice. In Florida, unfortunately given the size of the storm it looks to hit the northern Gulf coast areas in the Big Bend with gusty wind, waves, and rain, perhaps close to tropical storm conditions. I expect wobbles and 50 mile shifts over the next 24 hours, so don’t panic and don’t chase the windshield wipers – concentrate on the watch and warning areas, and the forecast damage swath, which covers the central and northern parts of the Peninsula. The East coast of Florida, especially from the Cape to Jacksonville, should prepare for hurricane conditions – probably Cat 2, but again follow the advice of your local EMAs.

For coastal Georgia, from south to north, the Brunswick area might see close to tropical storm conditions depending on the exact trajectory offshore, and how distorted the wind field gets from the transition to extratropical storm characteristics. Moving north the threat and the wind impacts will decrease. Savannah and inland coastal infrastructure is still fragile from Helene, so even winds 20 mph gusting to 35 mph (both GFS and ECM show about that at the surface, higher out on the water and Islands somewhat) may cause some power outages; inland winds should be less. So on this track and forecast, Thursday morning from before dawn to noon will probably be gusty and rain, but at least it will be daylight for most of the storm.

The one newish twist is that the timing of the tides and onshore winds is such that the high tides Thursday afternoon at 2pm seem likely to exceed the “moderate” flood levels, forecast at 10.2 ft at the Ft. Pulaski gauge (two to three feet above normal, which is about 8ft). That’s well under the Matthew/Irma levels that exceeded 12 feet, but can still cause problems and borderline “major” criteria. So it does look like some shallow coastal flooding is on the way. From the NWS guidance:

At 9.5 ft MLLW, minor coastal flooding occurs. Flooding will begin to impact Shipyard Road to Burnside Island. Parts of Ft Pulaski National Monument will begin to flood, including several trails. Flooding will also begin to impact Tybee Island including Catalina Dr and Lewis Ave. In Bryan County, water could breach docks near Ft McAllister and flooding will impact portions of Mill Hill Rd. In Liberty County, flooding impacts the Halfmoon Landing area and Cattle Hammock Rd near Bermuda Bluff subdivision. At 10.0 ft MLLW, moderate coastal flooding occurs. Shipyard Rd will be impassable, isolating residents on Burnside Island. Water will start to encroach on HW-80 and as the tide gets closer to 10.5 ft MLLW, could begin to cover portions of the roadway. Flooding will expand on Tybee Island and Catalina Dr and Lewis Ave will be impassable. Flooding will also impact Wilmington Island, the Coffee Bluff community, Ossabaw Island, Sapelo Island, and portions of HW-17 south of Darien. At 10.5 ft MLLW, major coastal flooding occurs. Damaging flooding is expected, expanding along the entire southeast Georgia coast. Flooding will likely cause the closure of HW-80, isolating residents on Tybee Island. Several other island communities will also likely become isolated due to flooded and impassable roadways. On Tybee Island, widespread significant flooding is expected with numerous properties impacted.

Brunswick should expect tides to run 3-4 ft above normal, HHI to Hunting Island like Savannah at 2-3 ft. It all depends on how extensive Milton’s wind field is after it crosses Florida. We should have a better handle on all this in the morning, when I’ll do a full post and analysis.