Talking the Tropics With Mike: Hurricane Dorian takes aim at the Carolina's... busy Atlantic Basin

Sept. 5, 2019 — The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.  

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DORIAN:

Hurricane Dorian moved to Jacksonville's latitude approximately 100 miles to the east about 2pm Wednesday & will be a major hit on the Carolina coast through early Fri.

Local impacts for Jacksonville/NE Fl./SE Ga. will continue to wane through Thu. & will be relegated to a breezy offshore west wind & slowly improving coastal marine conditions.

Dorian went through a classic rapid intensification (RI) cycle from about mid afternoon Fri. into early Sat. as the central pressure dropped more than 40 mb & winds increased by some 60+ mph followed by yet another rapid intensification cycle Sunday taking the sustained winds to 185 mph making Dorian tied with the 1935 Labor Day hurricane (Fl. Keys) as the most intense Atlantic hurricane on record to make landfall. As of Mon. morning, Dorian had been a Cat. 5 for more than 24 hours - remarkable.  Dorian was the first Cat. 5 hit ever on the Abaco Islands - while the Central & especially Southern Bahamas will fare far better.  A very close call for Nassau, but the most severe part of Dorian will stay north.  Dorian then moved north/northwest about 100 miles east of Jacksonville as a Cat. 2 before re-strengthening into a Cat. 3 (likely helped by the Gulf Stream) Wed. evening about 140 miles northeast of Jacksonville.

According to Dr. Klotzbach, CSU hurricane researcher, this is only the 2nd Cat. 5 hit on any of the Bahamas since 1985 (Andrew, 1992) & is the 27th Cat. 5 in the Atlantic Basin since 1950.  Since 2016, there has been a relative "slew" of Cat. 5's: Matthew in 2016, Irma in 2017, Maria in 2017, Michael last year & now Dorian.  Only Michael made a landfall (Fl. Panhandle) as a Cat. 5.

The positioning AND western edge of a significant upper level ridge of high pressure - Bermuda high - across the Central Atlantic continues has been a key factor in the movement of Dorian.

Dorian has found the alleyway just east of Florida & will now move to a landfall near the South/North Carolina border while turning more northeast very near the N. Carolina coast through the Outer Banks then across the extreme NW Atlantic to near Nova Scotia over the weekend.

For Jacksonville, FL. Dorian was a "nice" compromise between 2016's Matthew which was only offshore Jacksonville's coast by 40-45 miles & 1999's Floyd which was about 150 miles to the east.  It's interesting that Floyd caused one of the greatest mass evacuations in U.S. history while Dorian's evacuation has been far more limited - especially for Fl. & Ga.  This is a true testament to the advances of modern meteorology & tropical forecasting [the cone] (realizing the Dorian forecast has been painful!).

Satellite imagery reveals Dorian ingesting some dry air from the west due to flow off the continental U.S.

The chart below is at 500 mb (~30,000 feet) & shows that ever so critical Bermuda high - its positioning & strength earlier this week.  Hurricanes follow the path of least resistance.

Interesting possible/probable correlation to W. Pacific tropical cyclone "Lingling".  The typhoon is moving almost due north into Korea & China over the next several days.  The positioning of the ridge over the W./Central Pacific teleconnects with the Bermuda high over the Atlantic adding confidence to the forecast of Dorian's northward move to the Carolina's before turning northeast.

Spaghetti model plots for Dorian:

Ensemble (An ensemble weather forecast is a set of forecasts that present the range of future weather possibilities) spaghetti plots: (for an in-depth look on ensemble modeling see * this * [Blake/Brennan, NHC])

Phil Klotzbach - September landfalling hurricanes:

The rest of the Atlantic Basin is active too - Fernandmoved ashore Wed. in Mexico just south of Texas dissipating over mountainous terrain while Gabrielle has developed over the East Atlantic followed by yet another active tropical wave over the far East Atlantic.  The wave moving off Africa has long term potential with the big question mark .... as of right now .... being whether or not the wave develops early on & then turns more northward or remains rather weak which would allow the trade winds to steer a more shallow disturbance more west.  Plenty of time to watch/monitor/track & "cipher".

An examination of dust over the Central & Eastern Atlantic shows generally less dust over the Atlantic Basin vs. past months which is fairly typical for September & the peak of the hurricane season.

2019 names..... "Humberto" is next on the Atlantic list (names are picked at random... repeat every 6 years... historic storms are retired (Florence & Michael last year) & Dorian is almost certain to be next:

East Atlantic:

East Atlantic wave '91-L' has become tropical storm "Gabrielle" & will be no threat to any land areas as the storm turns northward over the Central Atlantic:

Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear of which there is plenty across the Atlantic at the moment:

The Atlantic Basin:

Water vapor imagery (dark blue indicates dry air):

Deep oceanic heat content:

Sea surface temp. anomalies show a warm Gulf of Mexico, Central & Northwest Atlantic while the "Main Development Region" (MDR) remain cooler than avg. along with parts of the Central Caribbean.....

SE U.S. surface map:

Surface analysis centered on the tropical Atlantic:

Surface analysis of the Gulf:

Caribbean:

Cox Media Group