Talking the Tropics With Mike: Eta moves across North Florida then into the Atlantic

Caribbean disturbance likely to develop

Talking the Tropics With Mike: Eta moves across North Florida then into the Atlantic

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*** The first round of impacts from Eta occurred across South Florida last weekend. Round 2 hit the west coast of Fl. centered on Tampa Wed. followed by relatively minor impacts across North Fl. & SE Ga. into Thursday ***

FOR JACKSONVILLE/NE FL./SE GA:

** I do not expect significant damage or any long term interruptions of our general infrastructure resulting from Eta. Any power outages should be sporadic & temporary... tree damage mostly minor... & any flooding mostly of the nuisance type, if at all. Businesses should be able to remain open & day to day activities should be able to easily resume after Eta moves away.

** gusty winds Thursday. Winds sustained 15-25 mph with gusts of 30-40 mph during the morning through early afternoon. Isolated gusts to 50+ mph in a few of the rain bands then diminish through the afternoon into the evening.

** dangerous rip currents at area beaches with rough seas/surf ... winds will go offshore (from the west/northwest) Thu. afternoon through Friday.

** on-&-off rain bands will move from south to north across the area Thursday morning ending from west to east by noon. These bands will produce brief stronger winds some moderate to heavy rain. Rainfall through Thursday will average less than an inch for most areas.

** some minor flooding, especially at high tide with higher than avg. tides also along the St. Johns River & some of its tributaries + an approaching new moon phase. Tide times * here *. Some might remember the severe flooding with Irma in 2017 when the storm was in a similar location to where Eta will be. THIS IS A COMPLETELY DIFFERENT SITUATION. The flooding will *not* be near as severe since Eta will be much weaker than Irma was 3 year ago.... while coming in more from the west vs. Irma’s approach from the south & southwest. Still... there will likely be at least some - mainly short term - nuisance ponding of water in some of the same locations as during Irma in ’17 (downtown Jacksonville, near the St. Johns River & its tributaries... a rise on Black Creek but not a major flooding situation with most if not all streams & rivers staying within their banks).

** virtually *no* storm surge due to Eta’s angle of approach + weakening trend. There will be some “piling” up of the water d’town in the Riverside area Thu. morning while there’s along fetch of winds out of the south.

Tropical depression #29 was upgraded Sat. afternoon, Oct. 31st & to tropical storm Eta Sat. evening then to a hurricane (12th of the Atlantic season) early Mon., Nov. 2nd - a high end Cat. 4 Mon. afternoon/evening followed by a Cat. 4 landfall on the northeast coast of Nicaragua Tue. afternoon. So Eta becomes the record-tying storm - 28th - for most in a single season. According to Dr. Klotzbach, Eta is also only the 5th Cat. 4 Nov. hurricane in the Atlantic Basin (Cuba Hurricane, 1932; Lenny, 1999; Michelle, 2001; Paloma, 2008). Conditions (shear, water temps., moisture) were all favorable for steady & rapid strengthening interrupted only by an eyewall replacement cycle Mon. night. The combination of the change in structure + proximity to land took Eta a bit off its peak while on a very slow journey inland. Eta re-emerged over the far Western Caribbean Thu. night... moving northeast across the Caribbean with a landfall on Central Cuba early Sunday, Nov. 8 as a strong tropical storm the the upper Fl. Keys Sunday night near 11pm EST. This is a record 12th U.S. landfall this year with at least one U.S. landfalling named storm in every month since May! Eta has been over the Gulf of Mexico since Sunday night moving north/northeast becoming a hurricane again Wed. morning - the latest Gulf hurricane since “Kate” in 1985. Eta weakened back to a tropical storm Wed. afternoon with gradual weakening right up to landfall at Key West about 4am EST. There will be mostly minor Florida & South Ga. impacts through midday Thu. after the 2nd Eta Fl. landfall & 4th overall (Nicaragua, Cuba, Keys, W. Fl. coast).

The ultimate outcome of where Eta goes came down to a high pressure ridge to the east of Fl. & an incoming mid latitude trough over the U.S.

MODELS:

The models significantly shifted east & increased the forward speed the last couple days & finally solved the enigma we know as “Eta”.

The GFS has been emphatic that Eta would make a comeback over the Caribbean then to near Fl. by last Sunday while peeling back to the west to the Gulf before turning north & northeast again & so has been reasonably good with Eta. The GFS has generally been faster & a little more north which is playing out. The model had been flip-flopping on whether or not the trough “catches” Eta but trended “catch” & taking a weakening Eta ashore on the northwest coast of Fl. then continuing northeast across N. Fl. then out to sea again east/northeast of Jacksonville while accelerating & becoming post-tropical.

The European model is pretty close to the GFS solution now though a bit slower & farther north. The combination of increasing shear + land interaction not to mention cooler ocean water & some dry mid & upper level air has lead to weakening since the storm’s latest peak midday Wed.

So.... we should be able to get Eta out of the area & east of the entire U.S. by Thu. night while moving northeast over the Western Atlantic.

RECAP:

As a whole forecast models have been struggling with “all the low pressure” (there will again be some tropical development soon over the Caribbean) at low latitudes - the tropics & subtropics - not to mention the typical autumn-related fast-to-change meridional flow (troughs of low pressure & ridges of high pressure) over the higher latitudes. So we saw a lot of changes & fluctuations in the forecast models. Special (4 times a day) weather balloon launches across Fl. & much of the Southeast U.S. along with NOAA research aircraft sampling the atmosphere over & near Eta combined to seemingly add some stability to model forecast but not until late Tue./early Wed. Admittedly... Eta was a pain to forecast with many sharp turns & very poor model output though my initial call/thoughts of little damage from the latest landfall will turn out accurate.

Eta’s sinusoidal track has been tied to the upper level flow which has returned to what we’ve seen most of the hurricane season: a trough over/near the Central U.S. with increased ridging near Fl. & to the east. How this all evolved was critical in steering Eta. As the western portion of the ridge broke down enough & shifted east, Eta moved inland across North Florida & followed the alleyway between the ridge to the east & the trough to the west.

Courtesy S. Fl. Water Management District:

Moderate shear helped to weaken Eta upon approach to land in addition to cooler water temps.

Lots of dry air lurking just west of Eta:

The steering “players”: After moving steadily west/southwest & even a little south, Eta turned around & is moved north/northeast. . As upper level high pressure to the east “softens” on its western edge while upper level troughing increases over the Central U.S., Eta made a sharper turn northeast. So Eta took the “red arrow” path. Complicated & interesting, maybe a little frustrating - to say the least - to forecast!

More spaghetti:

Eta technically developed on Oct. 31st but the map below will suffice & shows the Caribbean is a relative “hot bed” for late season/first 10 days of Nov. tropical cyclones:

And Theta formed over the East Atlantic - the record 29th storm of the season which beat the record of 28 in the infamous year of 2005. Theta will stay over the Eastern Atlantic & is no threat to the U.S. or any land areas.

Atlantic Basin wave forecast for 24, 48 & 72 hours respectively:

Elsewhere... Another tropical wave, 98-L - over the Caribbean - has longer range potential for gradual development. It appears this system would stay over/near the Caribbean (vs. turning north) as the disturbance moves toward the west & bends a little southwest potentially becoming a hurricane(!) before moving into Central America.



Saharan dust, dry air:

2020 names..... “Wilfred” was the last name on the Atlantic list (names are picked at random by the World Meteorological Organization... repeat every 6 years... historic storms are retired (Florence & Michael in ’18 & Dorian is certain to be retired from the ’19 list). Interesting side note: the last six of the names on the ’20 list had never been used. So it’s on to the Greek alphabet. "Iota” is next... the first time the Greek alphabet has been used since 2005 (total of 28 named storms using 6 Greek letter names in ’05 [there was one unnamed storm). Theta broke the record for the most Atlantic storms in a single season on record at 29.

East Atlantic:

Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear:

Water vapor imagery (dark blue indicates dry air):

Deep oceanic heat content:

Sea surface temp. anomalies:

SE U.S. surface map:

Surface analysis centered on the tropical Atlantic:

Surface analysis of the Gulf:

Caribbean:

Global tropical activity:

The West Pacific remains active with “Vamco” now west of the Philippines & eventually moving into/near Northern Vietnam while weakening but would be the 7th tropical cyclone for Vietnam over the last couple of months causing yet more flooding: