GeoColor satellite image of Tropical Storm Eta at 10:30 a.m. EST Sunday, November 8, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

A hurricane warning and a storm surge warning are up for the Florida Keys as Tropical Storm Eta gathers strength over the warm waters of the Florida Straits. Eta made landfall in south-central Cuba early Sunday morning with 65 mph winds, and emerged from its traverse of Cuba late on Sunday morning relatively intact, with a solid core of heavy thunderstorms. Eta’s spiral bands were spreading heavy rains over South Florida, the Bahamas, and Cuba. Eta is expected to pass through the Florida Keys on Sunday evening as a strong tropical storm or category 1 hurricane.

Figure 1. Radar image of Tropical Storm Eta at 10 a.m. EST November 8. (Image credit: INSMET)

At 10 a.m. EST Sunday, November 8, Eta was a tropical storm with 65 mph winds and a central pressure of 993 mb, headed north at 14 mph. Tropical storm-force winds from Eta were already affecting the Florida Keys, with sustained winds of 46 mph, gusting to 53 mph, observed at Fowey Rocks. Wind shear was a high 20 – 30 knots over Eta, but the storm was over very warm waters of 29 degrees Celsius (84°F). Some dry air was wrapping toward the center of Eta from the southwest.

Forecast for Eta

The counterclockwise flow of air around a trough of low pressure to its west will steer Eta in a curving arc through the Florida Keys on Sunday, and then into the southeastern Gulf of Mexico on Monday. The southern end of the upper-level trough is detaching from the jet stream and forming a closed low over the southeastern Gulf, and this low is expected to merge with Eta on Monday. During this process, wind shear will fall from the high range to the moderate range, potentially allowing Eta to intensify into a category 1 hurricane as it passes through the Florida Keys on Sunday evening.

It’s more likely though that Eta would reach hurricane strength on Monday. However, there is also dry air associated with the trough, and that dry air will potentially wrap into the core of Eta and put the brakes on any rapid intensification.

Figure 2. Track forecasts out to seven days for Eta from the 6Z (1 a.m. EST) Sunday, November 8, run of the GFS ensemble model (GEFS). The black line is the mean of the 31 ensemble members; individual ensemble member forecasts are the thin lines, color-coded by the central pressure they predict for Eta. After curving west into the Gulf of Mexico, the long-term motion of Eta was highly uncertain. (Image credit: Tropical Tidbits)

Steering currents will be weak once Eta merges with the upper level trough, and it’s not yet clear whether Eta’s long-range path might end up closer to the west coast of Florida, as suggested by the GFS model; more to the north towards the Florida Panhandle, as predicted by the European model; or to the southwest towards Mexico’s Yucatan Peninsula, as predicted by the UKMET model. Eventually – maybe not until late in the week – the approach of a new upper-level trough may push Eta inland over the Florida Gulf Coast.

Figure 3. Observed precipitation for the 24-hour period ending at 7 a.m. EST Sunday, November 8, 2020. (Image credit: NOAA)

The main threats from Eta: Torrential rains and floods

Regardless of the exact track of Eta’s center, the storm will bring heavy rains, strong winds, and storm surge flooding well to the east of its center, resulting in several days of squally weather and locally torrential rain for South Florida and the Bahamas. One-day rainfall amounts of 1-3 inches, with a few areas of 3-5 inches, occurred in the 24 hours ending at 7 a.m. EST Sunday over South Florida (Figure 3). Storm-total rainfall amounts of 6-12″, with some isolated areas of up to 18″, could fall in the coastal cities of South Florida from Fort Myers and Naples to Miami and Fort Lauderdale, where soils are largely saturated from late-October rains. Tornadoes will also be possible in Eta’s rainbands.

Also see: Eta regains tropical storm status, heads for Florida after causing devastation in Central America

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Posted on November 8, 2020(12:55pm EST).

Jeff Masters

Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a...

36 replies on “Tropical Storm Eta strengthens on approach to Florida Keys”

  1. Good afternoon to you all, just did my latest birdseye view post and chart of the Atlantic tropics which can be found at this link.

    The upper air pattern we are seeing in the Atlantic has less wind shear than I am used to seeing for November. Below is a snippet of upper-level winds today versus a year ago from my birdseye view charts. Note that a year ago we had westerly shear in the western part of the basin, but today we see a lot less shear with a Caribbean upper ridge cell that has been persisting and also an upper vortex that is currently stacked with Eta. We also have unusually low shear in the central Atlantic today with our amplified trough in that location as well, which is allowing for Invest 97L to develop tropical characteristics (wouldn’t be surprised if that gets upgraded to Subtropical Storm Theta later today).

    I think the reduced shear is from La Nina, but also from the meandering weaker jet stream which is allowing for all kinds of amplified upper troughs and ridges (and also cut-off upper vortices) instead of a more straightforward jet stream with low amplitude troughs and ridges that produces more wind shear like we usually see in November. This kind of weaker and meandering jet stream is something that we should see in a warming climate as the jet stream loses its strength from the lower temp difference between the warm equator and the less cold poles of the earth.

  2. Friday right off Tampa bay..Saturday up and inland FLA gulf coast..per navy model//https://www.tropicaltidbits.com/analysis/models/navgem/2020110906/navgem_mslp_pcpn_watl_17.png

  3. RSMC Reunion
    Tropical Cyclone Outlook – 16:00 PM RET November 9 2020
    ============================================

    Under the impulse of a strong wave activity ahead of a positive Madden-Jullian oscillation currently approaching the African continent, a favorable context for cyclogenesis is being set up on the East of the basin. In particular, the arrival of an Equatorial Rossby wave should allow the entry of a still weak but closed clockwise circulation on the east of the basin by the middle of the week.

    From Thursday onwards, this weak system should find rather conducive environmental conditions for its development: a good poleward low-level convergence, high mid-level humidities and low wind shear. Indeed, the westward shift of the surface circulation center should compensate for the presence of a slight eastward constraint aloft.

    Consequently, the available deterministic and ensemble guidance give more and more credit to a cyclogenesis scenario over the next weekend.

    From Saturday, the risk of a developing moderate tropical storm south of Chagos archipelago is MODERATE.

  4. Japan Meteorological Agency
    Tropical Cyclone Advisory #13 – 21:00 PM JST November 9 2020
    TROPICAL STORM ETAU (T2021)
    =============================================
    South China Sea

    At 12:00 PM UTC, Tropical Storm Etau (996 hPa) located at 12.1N 111.6E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The cyclone is reported as moving west southwest at 12 knots.

    Gale Force Winds
    =================
    180 nm from the center in northwestern quadrant
    90 nm from the center in southeastern quadrant

    Dvorak Intensity: T2.5

    Forecast and Intensity
    =========================
    12 HRS: 12.4N 109.9E – 40 knots (CAT 1/Tropical Storm) South China Sea
    24 HRS: 12.8N 107.4E – Tropical Depression over land Cambodia

    ——————————————————————————————-

    Tropical Cyclone Advisory #9 – 21:00 PM JST November 9 2020
    TROPICAL STORM VAMCO (T2022)
    =============================================
    Sea East of the Philippines

    At 12:00 PM UTC, Tropical Storm Vamco (1004 hPa) located at 12.0N 130.5E has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving west northwest slowly.

    Gale Force Winds
    =================
    210 nm from the center

    Dvorak Intensity: T2.0

    Forecast and Intensity
    =========================
    24 HRS: 14.5N 127.7E – 50 knots (CAT 2/Severe Tropical Storm) Sea East of the Philippines
    48 HRS: 14.7N 123.6E – 80 knots (CAT 3/Strong Typhoon) Sea East of the Philippines
    72 HRS: 14.9N 118.7E – 65 knots (CAT 3/Strong Typhoon) South China Sea

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