TD31 satellite image
GeoColor satellite image of TD 31 at 1 p.m. EST Friday, November 13. (Image credit: RAMMB/CIRA/Colorado State University)

Tropical Depression 31, which formed in the central Caribbean on Friday morning, is expected to intensify into powerful Hurricane Iota by Sunday. Iota is predicted to bring catastrophic rains of 20-30 inches next week to portions of Central America still recovering from last week’s devasting Hurricane Eta, which hit northern Nicaragua as a category 4 storm with 140 mph winds on November 3.

At 10 a.m. EST Friday, TD 31 was 310 miles south-southeast of Kingston, Jamaica, headed west-southwest at 7 mph. The system had top winds of 35 mph, with a central pressure of 1007 mb. Satellite imagery showed that TD 31’s heavy thunderstorms were confined to the southeast side of the center of circulation, but were steadily becoming more organized. Upper-level winds out of the west were creating a light 5-10 knots of wind shear, keeping TD 31 from forming heavy thunderstorms on the storm’s northwest side.

TD 31 brought flash flooding and heavy rains of three to five inches to Puerto Rico and the Virgin Islands on Wednesday; TD 31 brought up to four inches of rain along the southwestern coast of the Dominican Republic on Thursday.

The first Hurricane Hunter mission into TD 31 is scheduled for Saturday.

Figure 1
Figure 1. Track forecasts out to eight days for TD 31 from the 6Z (1 a.m. EST) Friday, November 13, 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 TD 31, which is expected to move mostly westward and be a significant threat to intensify into a hurricane. (Image credit: Tropical Tidbits)

Track forecast for TD 31

TD 31 is predicted to move west-southwestward through Saturday morning at about 5-10 mph, under the steering influence of a ridge of high pressure to its north. By Saturday afternoon, this ridge will slide to the east, resulting in a more westerly to west-northwesterly motion of TD 31 through Wednesday. On this track, TD 31 will pass about 300 miles south of Jamaica on Saturday, then make landfall near the Nicaragua/Honduras border on Monday, as predicted by the European and UKMET models.

However, in a worst-case scenario for Honduras, Guatemala, and Belize, TD 31 could slide just north of Honduras, moving parallel to and just offshore of the coast, allowing the storm to maintain its strength longer and subjecting the region to much higher rainfall totals. This is the prediction of the HWRF and HMON models and many of the members of the GFS ensemble forecast. At present, there is almost no model support for the idea that TD 31 might move northward into the Gulf of Mexico and threaten the U.S., as so many other storms this year have done.

Figure 2
Figure 2. Predicted seven-day rainfall from the 6Z (1 a.m. EST) Friday, November 13, run of the GFS model, ending at 1 a.m. EST Friday, November 20. The model predicted that TD 31 would dump widespread rainfall amounts in excess of five inches (orange colors) to portions of the Caribbean, with over 20 inches (pink colors) falling in northern Honduras and Belize. (Image credit: NOAA/AOML)

Intensity forecast for TD 31

The intensity forecast from the National Hurricane Center’s first advisory for TD 31 at 10 a.m. EST Friday was an unusually aggressive one, calling for the storm to intensify from 35 mph to 110 mph – to the brink of category 3 status – in just 72 hours. According to an analysis of NHC forecasts by Sam Lillo, this is the fastest rapid intensification ever predicted by NHC for a tropical depression. Senior NHC hurricane specialist Eric Blake commented in a Friday morning Tweet, “You don’t see NHC forecast 75 mph of strengthening in 72 hours from a tropical depression very often (rapid intensification for that time period, and on a first forecast, too). Speaks to the really conducive environment ahead!”

As one might surmise from the NHC forecast, conditions for development will be favorable for development of TD 31 through Tuesday, with the SHIPS model predicting light wind shear less than 10 knots, warm sea surface temperatures of 29 degrees Celsius (84°F), and a moist atmosphere with a mid-level relative humidity of 65-70%. The 12Z Friday SHIPS model gave a 51% chance that TD 31 would follow the NHC intensity forecast, and increase its winds by 75 mph in 72 hours. This probability is 10 times higher than the climatological mean.

These conditions are very similar to what Hurricane Eta experienced in its formative stages in the Caribbean in late October, and TD 31 is a significant threat to intensify into a major hurricane that will affect the same areas of the Caribbean impacted by Hurricane Eta. In particular, Nicaragua and Honduras, which were devastated by Hurricane Eta, appear at great risk of receiving heavy rains from TD 31 beginning on Sunday, with NHC calling for 20-30 inches of rain next week.

Figure 3
Figure 3. Rescuers brave floodwaters in Honduras to rescue people trapped by Hurricane Eta’s rains on November 6, 2020. (Image credit: (Image credit: Policia Nacional de Honduras)

Eta and Iota: an unprecedented double catastrophe for Honduras

Hurricane Eta brought catastrophic rains to Honduras last week, triggering flooding that devastated the northwestern portion of the country. According to Jeff Ernst, writing in The Guardian, in the valley surrounding San Pedro Sula in northwestern Honduras, rains of over 20 inches fell, and several rivers and flood canals overflowed so high that tens of thousands were trapped for days on rooftops without food or water. Some families waited more than three days for rescue. San Pedro Sula is the country’s second-largest city and economic engine, and the San Pedro Sula Valley is home to over 2 million people.

The official death toll in Honduras stood at 63 on November 10, but the total number of victims is probably in the hundreds, and will likely never be known. Economic damage has been estimated to between $3 billion and $5 billion, 12-21% of Honduras’ GDP.

In Nicaragua, where Eta initially made landfall, damage is estimated at over $178 million (1-2% of GDP), and two deaths are being blamed on the storm. Nicaragua, in contrast to Honduras, did not have heavily populated areas receive rains in excess of 10 inches.

Figure 4
Figure 4. Flooding in Charlotte, North Carolina, on November 12. Fire fighters performed high-water rescues of 143 people in the city. (Image credit: Charlotte Fire Department)

Eta’s final flood: seven killed in North Carolina before Eta becomes post-tropical

After a lifespan of over 10 days, four landfalls, hundreds of deaths, and billions in damage, Tropical Storm Eta finally became post-tropical on Friday morning over the waters off the North Carolina coast. According to Dr. Phil Klotzbach of Colorado State University, Eta’s 10.25 days as a named storm (not including the time it was a tropical depression) made it the Atlantic’s longest-lived named storm forming in November since the Jamaica Hurricane of 1912, which lasted 10.5 days.

Eta helped trigger heavy rains of up to 8.52 inches that fell in a swatch from South Carolina, through North Carolina, and into southeastern Virginia on Wednesday and Thursday (Figure 4). The resulting floods claimed at least seven lives. The rains were caused by a moist flow of Atlantic air in advance of Eta, which interacted with a frontal boundary – a phenomenon called a predecessor rain event (PRE). Eta also contributed directly to the rains. In addition, Eta is being blamed for one death in Florida, an electrocution in Bradenton. The amount of precipitable water (the total water vapor and liquid water in the atmosphere) on Wednesday morning at Wallops Island, Virginia, was the most ever recorded in November (2.11 inches).

Figure 5
Figure 5. Three-day precipitation amounts in South Carolina and North Carolina, ending at 7 a.m. EST November 13. (Image credit: National Weather Service)

Theta poses little threat to land

There was little change on Friday to Tropical Storm Theta, the record-breaking 29th named storm of the 2020 Atlantic hurricane season. At 10 a.m. EST Friday, Theta was located about 470 miles south-southeast of the Azores Islands, headed east at about 12 mph. Theta had top sustained winds of 60 mph.

Theta will move east through Sunday, taking the storm toward the Canary Islands. High wind shear and cold waters are expected to weaken Theta to a post-tropical cyclone with 35 mph winds by Sunday.

Figure 6
Figure 6. Infrared image of Typhoon Vanmo east of Vietnam at 1710Z Friday, November 13. (Image credit CIMSS/SSEC/University of Wisconsin–Madison).

Typhoon Vamco rapidly strengthens en route to Vietnam

Long-suffering Vietnam – which has already been affected by 10 named storms this year – is now bracing for number 11.

Typhoon Vamco surged from category 1 to category 3 strength in just six hours on Friday, with top winds pegged at 115 mph by the Joint Typhoon Warning Center as of 7 a.m. EST Friday. Located about 330 miles east of Da Nang, Vietnam, Vamco is passing through a zone of unexpectedly favorable upper-air support, with outflow channels on either side favoring the storm’s rapid strengthening.

October 2020 was fourth-warmest October on record, NOAA and NASA report

As Vamco moves toward Vietnam, the upper-level support will weaken and the typhoon will be moving over waters cooler than 26 degrees Celsius (79°F), but it may still reach the coast of northern Vietnam as a minimal category 1-equivalent typhoon on Sunday or Monday local time.

Bob Henson contributed to this post.

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Posted on November 13, 2020(3:22pm EST).

Topics: Weather Extremes
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HadesGodWyvern
HadesGodWyvern
14 days ago

Vamco has 24 hours until landfall, according to JMA track map

Japan Meteorological Agency
Tropical Cyclone Advisory #47 – 15:00 PM JST November 14 2020
TYPHOON VAMCO (T2022)
=============================================
South China Sea

At 6:00 AM UTC, Typhoon Vamco (955 hPa) located at 15.9N 110.3E has 10 minute sustained winds of 85 knots with gusts of 120 knots. The cyclone is reported as moving west at 11 knots.

Storm Force Winds
===================
60 nm from the center

Gale Force Winds
=================
180 nm from the center in northeastern quadrant
150 nm from the center in southwestern quadrant

Dvorak Intensity: T5.5

Forecast and Intensity
=========================
12 HRS: 16.7N 108.5E – 65 knots (CAT 3/Strong Typhoon) South China Sea
24 HRS: 17.4N 106.6E – 50 knots (CAT 2/Severe Tropical Storm) Over land Vietnam
48 HRS: 17.7N 102.7E – Tropical Depression over land Thailand

HadesGodWyvern
HadesGodWyvern
14 days ago

Alicia continues to intensify

Mauritius Meteorological Services
Tropical Cyclone Advisory #8 – 10:00 AM RET November 14 2020
FORTE TEMPETE TROPICALE ALICIA (01-20202021)
================================================
East of Diego Garcia

At 6:00 AM UTC, Severe Tropical Storm Alicia (992 hPa) located at 8.6S 78.6E has 10 minute sustained winds of 50 knots with gusts of 70 knots. The cyclone is reported as moving west southwest at 9 knots.

Storm Force Winds
===================
Extending up to 35 nm in the eastern semi-circle

Gale Force Winds
==================
35 nm radius from the centre, extending up to 65 nm in the southern semi-circle and the northeastern quadrant

Near Gale Force Winds
======================
85 nm radius from the centre, extending up to 90 nm in the southwestern quadrant, up to 105 nm in the northeastern quadrant and up to 130 nm in the southeastern quadrant

Dvorak Intensity: T3.5/3.5/D1.0/24 HRS

Forecast and Intensity
===========================
12 HRS: 10.4S 76.2E – 60 knots (Forte Tempête Tropicale)
24 HRS: 12.7S 74.4E – 70 knots (Cyclone Tropical)
48 HRS: 16.9S 73.3E – 70 knots (Cyclone Tropical)
72 HRS: 19.1S 72.8E – 40 knots (Tempête Tropicale Modérée)

Additional Information
===========================
Alicia continues to show signs of organization. In classical imagery, the well defined curved band pattern of this morning is evolving into a central dense overcast pattern after a burst of deep convection has occurred near the center since 0300z. The morning microwave imagery reveal a further consolidation of the low levels structure. The final intensity is estimated at 50 kts in the high range of the last available Dvorak estimates (40-50 kts in 10-min winds) but in good agreement with an ADT at 45-50 kt (10-min winds) and winds over 45 kts measured in the northeast quadrant by this morning’s ASCAT.

Alicia has slowed down these last 6 hours but should resume a fairly fast southwestward movement guided by the guiding flow generated by the subtropical ridge. Under the impulse of the dynamics further south, the ridge is gradually shifting eastwards and will leave a northerly guiding flow from Sunday onwards. The numerical models are in good agreement on this global trajectory. At the end of the deadline, the uncertainty becomes important in relation to the weak guiding flow and the existence of two possible scenarios: the persistence of a southward or southeasterly shift or the resumption of the residual minimum in the trade wind flow.

On this track, the environmental conditions are very favorable up to Monday morning. With the help of strengthening equatorial westerly winds, a very good divergence, little shear and a very strong oceanic potential, Alicia is likely to reach tropical cyclone intensity in the next 24/48h. At the beginning of next week, conditions are expected to deteriorate significantly with insufficient oceanic potential south of 17.0S, and increasing shear associated gradually with dry mid-tropospheric air intrusions.

Dirk
Dirk
14 days ago

Thank you Dr. Jeff, this season is far from over it seems.

Last edited 14 days ago by Dirk
ChanceShowerLA
ChanceShowerLA
14 days ago

comment image

ChanceShowerLA
ChanceShowerLA
14 days ago

comment image?hash=3686

Michael Paul
Michael Paul
14 days ago

Thank you for the update Dr. Masters.

cyclonemelissa
cyclonemelissa
14 days ago

Thank you, Dr. Masters and Bob Henson! Very informative post. We received over 3″ of rain here in NC, just SW of Raleigh. I am worried about Honduras and Nicaragua with Iota. Crazy year in the Atlantic Basin, and it’s not over yet, I’m afraid.

HadesGodWyvern
HadesGodWyvern
14 days ago

Japan Meteorological Agency
Tropical Cyclone Advisory #45 – 9:00 AM JST November 14 2020
TYPHOON VAMCO (T2022)
=============================================
South China Sea

At 0:00 AM UTC, Typhoon Vamco (950 hPa) located at 15.7N 111.4E has 10 minute sustained winds of 85 knots with gusts of 120 knots. The cyclone is reported as moving west at 10 knots.

Storm Force Winds
===================
60 nm from the center

Gale Force Winds
=================
210 nm from the center in northeastern quadrant
150 nm from the center in southwestern quadrant

Dvorak Intensity: T5.5-

Forecast and Intensity
=========================
12 HRS: 16.2N 109.6E – 75 knots (CAT 3/Strong Typhoon) South China Sea
24 HRS: 17.1N 107.5E – 60 knots (CAT 2/Severe Tropical Storm) Gulf of Tonkin
48 HRS: 17.3N 104.2E – Tropical Depression over land Thailand

HadesGodWyvern
HadesGodWyvern
14 days ago

Mauritius Meteorological Services
Tropical Cyclone Advisory #7 – 4:00 AM RET November 14 2020
TEMPETE TROPICALE MODEREE ALICIA (01-20202021)
==============================================
East of Diego Garcia

At 0:00 AM UTC, Moderate Tropical Storm Alicia (995 hPa) located at 8.0S 79.2E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The cyclone is reported as moving southwest at 19 knots.

Gale Force Winds
==================
50 nm radius from the center, extending up to 130 nm in the southeastern quadrant

Near Gale Force Winds
======================
70 nm radius from the center, extending up to 120 nm in the southwestern quadrant and up to 200 nm in the southeastern quadrant

Dvorak Intensity: T3.0/3.0/D1.0/12 HRS

Forecast and Intensity
===========================
12 HRS: 10.2S 76.9E – 50 knots (Forte Tempête Tropicale)
24 HRS: 12.5S 74.8E – 60 knots (Forte Tempête Tropicale)
48 HRS: 16.2S 73.2E – 80 knots (Cyclone Tropical)
72 HRS: 18.5S 72.7E – 50 knots (Forte Tempête Tropicale)

Additional Information
===========================
Over the last six hours, convective activity got better organized around Alicia center. 2027z AMRS2 and 2223z SSMI show that even the inner is still elongated, it features increasing signs of curvature. On the latest images, a persistent warm spot can be seen on the infrared imagery, probably related to the broad structure of the inner core.

Alicia continues to move rapidly southwestwards guided by the steering flow generated by the subtropical ridge. The system should soon accelerate its southwestward movement. Under the impulse of the dynamics further south, the ridge is gradually shifting eastward and will leave a northward directed steering flow from Sunday onwards. The numerical models are in good agreement on this global track. From Monday onwards, the uncertainty becomes important in relation to the weak steering flow and the existence of two possible scenarios: continuation of a south/southeastward movement or takeover of the trade wind in the steering flow. The first one seems still more likely.

On this track, the environmental conditions are very favorable up to Monday morning. With the help of strengthening equatorial westerly winds, a very good divergence, little shear and a very strong oceanic potential, Alicia is likely to reach tropical cyclone intensity in the next 24-48 hours. At the beginning of next week, conditions are expected to deteriorate significantly with insufficient oceanic potential south of 17.0S, and increasing shear associated gradually with dry mid-tropospheric air intrusions.

Last edited 14 days ago by HadesGodWyvern
jiiski
jiiski
14 days ago

Sad and informative post, Dr. Masters. Thank you so much for writing.

jason weed
14 days ago

comment image?w=800&h=742

Amature Met
Amature Met
14 days ago

I just moved this from the last blog.

elioe
 3 hours ago

Didn’t Delta or Zeta do any damage in Yucatan worth mentioning?

Amature Met
Amature Met
14 days ago

Wow, another update. Thank you Dr. Masters.

“Eta and Iota: an unprecedented double catastrophe for Honduras”
I think that about covers that,

I had very minimal impacts from the TS. I imagine the image with the lawn chair blown over. Now blow the plastic table over also.

HadesGodWyvern
HadesGodWyvern
14 days ago

“severe typhoon”

Japan Meteorological Agency
Tropical Cyclone Advisory #44 – 6:00 AM JST November 14 2020
TYPHOON VAMCO (T2022)
====================================
South China Sea

At 21:00 PM UTC, Typhoon Vamco (950 hPa) located at 15.7N 111.9E has 10 minute sustained winds of 85 knots with gusts of 120 knots. The cyclone is reported as moving west at 10 knots.

Storm Force Winds
===================
60 nm from the center

Gale Force Winds
=================
210 nm from the center in northeastern quadrant
150 nm from the center in southwestern quadrant

Last edited 14 days ago by HadesGodWyvern
NCHurricane2009
14 days ago

Thank you Dr. Masters for this post. TD 31 (soon to be Iota) is devastating news, my prayers for Nicaragua and Honduras.

My latest birdseye view post and chart highlighting TD 31 and TS Theta at this link.