Tropical Storm Isaias at 11 pm

...Disturbance becomes Tropical Storm Isaias (pronounced ees-ah-EE-ahs)...

Having slowed down in its forward motion it has finally had time to consolidate a central circulation.

Here in Nevis we are still experiencing rain bands passing over us. A recent shower band produced some thunder and lightning. The lightning could be seen to the south west/west of the island.

Passed Us By

Potential Tropical Cyclone 9 has passed us by here on Nevis. Never made it to a cyclone in our area as it did not manage to organise a defined circulation. It still had a lot of rain associated with it and fortunately for us the wind field was not to powerful or lasted that long. 

18:00 hours it is still murky and a squally shower has just stated!.

The Latest 5 day Forecast Track From the US National Hurricane Center.

Figures outlining wind strength and rainfall at my location on Nevis.

	High	Low	Average
Wind Speed	20.0 mph	1.0 mph	9.4 mph
Wind Gust	34.0 mph	--	19.7 mph
Wind Direction	--	--	ENE

After the two and a half our rain event in the afternoon (13:00 to 15:30 hours), the total rainfall at my location was measured at 1.90 inches.

WATCHES AND WARNINGS AT 5 pm. 29th July 2020.

--------------------
CHANGES WITH THIS ADVISORY:

The government of Antigua has discontinued the Tropical Storm
Warning for Montserrat, St. Kitts, and Nevis.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Puerto Rico, Vieques, Culebra
* U.S. Virgin Islands
* British Virgin Islands
* Anguilla
* St. Martin and St. Barthelemy
* Saba and St. Eustatius
* St. Maarten
* Dominican Republic entire southern and northern coastlines
* North coast of Haiti from Le Mole St Nicholas eastward to the
northern border with the Dominican Republic
* Turks and Caicos Islands
* Southeastern Bahamas including the Acklins, Crooked Island, Long
Cay, the Inaguas, Mayaguana, and the Ragged Islands

Rain Event

After the initial wind and rain things calmed down until 13:00 hours. We then had rain for about 2 and a half hours. Thankfully this was not accompanied by strong or gusting winds.

The clump of rain weather can be seem on the following Guadeloupe/Martinique Rain Radar picture. St. Kitts and Nevis are circled in red.

Potential Tropical Cyclone 9 Arrives

Squally showers to start the morning off with and some strong gusts of wind. Things are starting to brighten up at about 10:30 hours and the wind reducing in intensity. We still have some more showers around in the area so I expect some squally conditions if they pass our way.

Attached some pictures:

1. A casualty. Had a branch come down on a Cedar Tree.

2. The view first thing this morning. Low cloud and showers. In the twilight zone.

3. Guadeloupe radar at about 09:25 hours, showing St Kitts and Nevis (marked in red) in-between two areas of showers. The one to the east moving towards us.

Wind measurements to give an indication of what we had up in the Nevis Peak foothills so far.

	High	Low	Average
Wind Speed	20.0 mph	4.0 mph	12.3 mph
Wind Gust	34.0 mph	--	24.2 mph
Wind Direction	--	--	ENE

So far at my location the rain measure is 0.45 inches.

Flash Flood Watch including Nevis

FLASH FLOOD WATCH STATEMENT

TAPA
BULLETIN
FLASH FLOOD WATCH
ANTIGUA AND BARBUDA METEOROLOGICAL SERVICES
9:30 PM ECT TUE JUL 28 2020

...Flash Flood Watch in Effect for Antigua, Barbuda, Nevis and Anguilla...

The Antigua and Barbuda Meteorological Service has issued a flash flood watch for flash-flood prone areas of the above-mentioned islands. The flash flood threat level is moderate and there is the potential for significant impacts in the watch area. To be safe, implement you flood plan.

Timing: Wednesday.

Synopsis: Heavy showers associated with Potential Tropical Cyclone Nine are expected to move across the area. Rainfall rates of 50 mm (2 in) per hour or more will produce minor flooding and may produce moderate or worse flash flooding. One to three inches of rain is possible on Wednesday, with isolated higher totals. 

Potential Impacts: Localised disruption to transportation; interruption of school hours; localised population displacement; erosion; environmental degradation; localised damage to dams, embankment, irrigation and drainage facilities; high sediments transport into reservoir; localised disruption to communication; localised contamination of potable water; localised loss of livestock; financial losses; injuries; temporary stoppage of health services and damage to infrastructure.

Precautionary/preparedness actions: A flash flood watch means that flooding is possible but not imminent in the watch area. Residents in these areas should make preparations to protect life, property and livelihood against flooding and be prepared to move to higher ground, if heavy rains develop.

Stay tuned to updates coming out of the ABMS Met Office via antiguamet.com

FORECASTER
DALE DESTIN

Satellite and Radar Images

Satellite picture showing cloud formation of Potential Tropical Cyclone 9. St. Kitts and Nevis are circled in red. Time at 11:30 pm 28th July 2020.

Radar on Guadeloupe and Martinique outlining distribution of rain across the area. The lighter the display the heavier the rain. St. Kitts and Nevis are circled in red. Time at 11:30 pm 28th July 2020.

Weather Station Summery, 28th July 2020

Pond Hill, Nevis

	High	Low	Average
Temperature	84.1 F	76.4 F	80.0 F
Dew Point	76.0 F	72.0 F	73.6 F
Humidity	90 %	73 %	82 %
Precipitation	0.02 in	--	--

	High	Low	Average
Wind Speed	19.0 mph	1.0 mph	9.5 mph
Wind Gust	29.0 mph	--	20.2 mph
Wind Direction	--	--	East
Pressure	30.06 in	29.98 in	--

Potential Tropical Cyclone 9 - 11 pm Key Message

At 1100 PM AST (0300 UTC), the disturbance was centered near latitude 14.6 North, longitude 59.4 West. The system is moving toward the west-northwest near 25 mph (41 km/h), and this general  motion with some slight reduction in forward speed is expected over the next few days. On the forecast track, the system will move through the Leeward Islands on Wednesday, near or over the Virgin Islands and Puerto Rico Wednesday night, and near or over Hispaniola on Thursday. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.

Some strengthening is expected during the next 48 hours, and the system is forecast to become a tropical storm on Wednesday. Environmental conditions are expected to be conducive for additional

development, and a tropical storm is forecast to form on Wednesday.

* Formation chance through 48 hours...high...90 percent
* Formation chance through 5 days...high...90 percent 

Tropical-storm-force winds extend outward up to 230 miles (370 km) from the center.

The estimated minimum central pressure is 1007 mb (29.74 inches).

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...* Puerto Rico, Vieques, Culebra* U.S. Virgin Islands* British Virgin Islands* Antigua, Barbuda, Montserrat, St. Kitts, Nevis, and Anguilla* Guadeloupe, Martinique, St. Martin, and St. Barthelemy* Saba and St. Eustatius* St. Maarten* Dominica* Dominican Republic from Punta Caucedo eastward to Cabo Engano and then westward along the northern coast to the Dominican Republic/Haiti border

A Tropical Storm Watch is in effect for...* Dominican Republic from the southern Haiti border eastward toPunta Caucedo* Turks and Caicos Islands

Potential Tropical Cyclone 9 - 5 pm Key Message

Monday into Tuesday - Difference

With a Tropical Wave passing through the area Monday was cloudy with some showers and synny spells. Late afternoon gave us low cloud which gave us a gloomy view.

We were also given a break from the ever present Saharan dut (dry air). Total rainfall for the day was about a tenth of an inch.

Tuesday on the other hand was different. Tropical Wave gone and Saharan Dust (dry air) back.
A hazy sunny day and dry. The difference a day makes.

With Potential Tropical Depression 9 on the horizon, Wednesday will no doubt be different again!

Potential Tropical Depression 9 - Warnings Issued

Watches and Warnings Issued as of 11 am 28th July 2020

A Tropical Storm Warning is in effect for Puerto Rico, including
Vieques, and Culebra, and the U.S. Virgin Islands.

The government of Antigua has issued a Tropical Storm Warning for
Antigua, Barbuda, the British Virgin Islands, Montserrat,
St. Kitts, and Nevis.

The government of France has issued a Tropical Storm Warning for
Guadeloupe, Martinique, and St. Martin.

The government of the Netherlands has issued a Tropical Storm
Warning for Saba and St. Eustatius.

The government of St. Maarten has issued a Tropical Storm Warning 
for St. Maarten.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Puerto Rico, Vieques, Culebra
* U.S. Virgin Islands
* British Virgin Islands
* Antigua, Barbuda, Montserrat, St. Kitts, and Nevis
* Guadeloupe, Martinique, and St. Martin
* Saba and St. Eustatius
* St. Maarten

Atlantic Hurricane Season 2020 - Potential Tropical Depression 9

With weather disturbance AL92 now being classified as a Potential Tropical Depression 9  by the US National Hurricane Hurricane Center (NHC) at 11 am today things are getting busy.

The NHC are forecasting it to be Tropical Storm Isaias (ees-ah-EE-as) within the next 24 hours, it will become the earliest storm to begin with an "I" on record. The previous record was set by what became Hurricane Irene on on 7th August 2005. The 2005 season was the busiest Atlantic hurricane season to date. This would continue the record-breaking pace of the 2020 Atlantic hurricane season. Hurricane Hanna broke the record for earliest storm with an "H" name by 11 days.

NHC Outlook 11 am

At 1100 AM AST (1500 UTC), the disturbance was centered near latitude 13.8 North, longitude 53.7 West. The system is moving toward the west near 23 mph (37 km/h), and this general motion  should continue during the next few days. On the forecast track, the system is forecast to move through the Leeward Islands on Wednesday, and near or over the Virgin Islands and Puerto Rico Wednesday night, and near or over Hispaniola on Thursday. 

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Some strengthening is expected during the next 48 hours, and the system is forecast to become a tropical storm tonight or Wednesday. 

Environmental conditions are expected to be conducive for additional development and a tropical storm tonight or Wednesday.

* Formation chance through 48 hours...high...80 percent
* Formation chance through 5 days...high...90 percent

Tropical-storm-force winds extend outward up to 230 miles (370 km) primarily to the northeast of the center.

The estimated minimum central pressure is 1007 mb (29.74 inches).

AL92L Guessing Game

Disturbance AL92L continues to track towards the North East Caribbean including Nevis. The latest forecast posted by the US National Hurricane Center has decreased the probability of tropical cyclone formation by 10%. This conclusion is probably due to the lack of development overnight.

It continues to promise some wet and windy weather. Problem being how much? If the centre passes to the north then winds will be litter. If it passes to the south then the winds will be stronger. We wait to see what nature has for us.

Latest forecast

"Shower activity associated with a broad area of low pressure located about 1000 miles east of the Windward Islands has changed little in organization since this morning. Environmental conditions are expected to become somewhat more favorable for development during the next few days and a tropical depression or tropical storm is likely to form during that time frame. The system is forecast to move westward to west-northwestward at 15 to 20 mph and it could bring heavy rain to portions of the Leeward Islands by late Wednesday, regardless of development. Interests in the Lesser Antilles should continue to monitor the progress of this system."

* Formation chance through 48 hours...high...70 percent.

* Formation chance through 5 days...high...80 percent.

Forecaster Zelinsky

5 day Forecast.

Tropical Waves and AL92L

Today Monday is another passing tropical wave day. It started fine with some cloud and hazy sunshine, but the cloud has thickened and there have been some light showers. Looking to the east Guadeloupe radar indicates a band of showers will probably effect us this afternoon. As always, predicting is difficult as we are a small island in a big sea.

Monday morning view

A shower falling around Nevis Peak

Meanwhile further to the east out in the Atlantic weather disturbance AL92L continues on its track towards us. The strength of this disturbance regarding wind speeds and rainfall have proven difficult to forecast. It became a little disorganised overnight so slowed down the predicted development. Whether this is an "active" tropical wave or becomes a Tropical Storm it will mean wind and rain. The problem is how much?

as always plan for the worst and hope for the best.

The "alert" issued by Antigua Met Services earlier this morning:

The latest 08:00 hours forecast from the US National Hurricane Center:

"Shower activity associated with a broad area of low pressure located a little more than 1000 miles east of the Windward Islands has become a little less organized since last night. However, environmental conditions are still expected to become more favorable for development in a day or two and a tropical depression or tropical storm will likely form within the next couple of days. The system is forecast to move westward to west-northwestward at 15 to 20 mph and could begin to affect portions of the Lesser Antilles on Wednesday or Wednesday night. Interests on those islands should continue to monitor the progress of this system."

* Formation chance through 48 hours...high...80 percent.

* Formation chance through 5 days...high...90 percent.

Eyes Back on Looking to the East

Tropical Storm Gonzalo has run its course and is no more. A small storm thankfully that never escaped its low latitude track.

For Nevis Friday evening dark clouds came in from the East and we had some showers overnight. This gave us just over a tenth of an inch in rain up in the Nevis Peak foothills.

Meanwhile our eyes now turn to the East as we look at another disturbance AL92L that looks as if it will form into the next Tropical Cyclone. As of Saturday evening this has been estimated by the US National Hurricane Center to have a 50% chance of forming a cyclone within 48 hours and n 80% chance  within 5 days. The forecast track has consistently pointed towards the Leeward Islands. It is a fair way out so things can change, but as they say prepare for the worst and hope for the best.

 NHC Forecast at 8 pm

"A broad area of low pressure associated with a tropical wave located several hundred miles west-southwest of the Cabo Verde Islands is producing a large area of cloudiness and disorganized showers and thunderstorms. Environmental conditions appear conducive for development, and a tropical depression is likely to form early next week while the wave moves westward at around 15 mph across the tropical Atlantic."

* Formation chance through 48 hours...medium...50 percent.

* Formation chance through 5 days...high...80 percent.

A further developing disturbance may follow from West Africa ready to cross the Atlantic.

Things are Warming Up!

Tropical Storm Gonzalo's progress is causing some problems with forecasts. Predicting the strength of the system as it approaches the Windward Islands has been difficult. This is mainly due to the small size of the storm. Therefore the question remains will it become a hurricane or remain a Tropical Storm. At the moment the forecast is for the system to pass the islands on Saturday.

800 PM AST Thu Jul 23 2020

SUMMARY OF WATCHES AND WARNING IN EFFECT...

A Hurricane Watch is in effect for...
* Barbados
* St. Vincent and the Grenadines

A Tropical Storm Watch is in effect for...
* Tobago
* Grenada

A Hurricane Watch means that hurricane conditions are possible
within the watch area.  A watch is typically issued 48 hours before
the anticipated first occurrence of tropical-storm-force winds,
conditions that make outside preparations difficult or dangerous.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

As we look back over the Atlantic towards Africa the US National Hurricane Center is monitoring another disturbance just leaving the coast. Development would seem to be some way off so nothing is a definite as yet. It will be interesting to see how this forecast develops over the coming days.

 

TD7 to Tropical Storm Gonzalo

Tropical Depression 7 upgraded to named storm Tropical Storm Gonzalo at 11:00 hours (AST) by the US National Hurricane Center. A fairly small storm in physical size it is forecast to develop into a hurricane on Thursday, but drop back to a Tropical Storm before reaching the Windward Islands. As with most storms of this size they have a tendency to fluctuate in strength, therefore close monitoring is required.

This is thought to be the earliest recorded date for a 7th named storm. The prior record was Gert (a Tropical Storm) on 24th July 2005. Ominously 2005 recorded the most number of storms at 28! 

In 2005 there were also Tropical Depression 19, an unnamed Sub-Tropical Storm (Azores) and Sub-Tropical Depression 22.

 

AL99L becomes Tropical Depression 7

From 5:00 pm 21st July 2020 weather disturbance AL99 has been designated Tropical Depression 7 (TD7) by the US National Hurricane Center.

Public Advisory:

At 500 PM AST (2100 UTC), the center of Tropical Depression Seven as located near latitude 9.8 North, longitude 40.4 West. The depression is moving toward the west-northwest near 8 mph (13 km/h). A turn toward the west with an increase in forward speed is expected tonight and Wednesday, and that motion should continue through Friday.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.

Strengthening is forecast during the next couple of days, and the depression is expected to become a tropical storm tonight or Wednesday.

The estimated minimum central pressure is 1009 mb (29.80 inches).

It is still tracking towards the Windward Islands and is expected to develop into a Tropical Storm later today. 

Invest 99L - Development Continues

This disturbance continues to develop quickly. It is still at a low latitude and is near the Intertropical Convergence Zone (ITCZ). This area is known as the doldrums or the calms because of its monotonous, windless weather. It is where the northeast and southeast trade winds converge. It encircles Earth near the thermal equator, though its specific position varies seasonally.

US National Hurricane update at 2:00 (EDT) Tuesday 21st July 2020.

"Showers and thunderstorms associated with the low pressure area located about midway between the west coast of Africa and the Lesser Antilles continue to get better organized, and a tropical depression appears to be forming. If current trends continue, advisories could be initiated on this system this afternoon. Regardless of development during the next couple of days, less favorable conditions should limit additional development of the system by the weekend."

* Formation chance through 48 hours...high...90 percent.

* Formation chance through 5 days...high...90 percent.

Invest 99L - Quick Developer

This one seems to be a fast developer. At the moment it has been updated to an 80% chance of development into a tropical system.

US National Hurricane Center update: 11:05 (EDT) Tuesday 21st July 2020.

"Updated: Satellite imagery and recent satellite wind data indicate that the low pressure system located about midway between the west coast of Africa and the Lesser Antilles continues to get better organized. If current trends continue, advisories could be initiated on this system as a tropical depression later today.

Regardless of development during the next couple of days, less favorable conditions should limit additional development by the weekend."

* Formation chance through 48 hours...high...80 percent.

* Formation chance through 5 days...high...80 percent.

Invest 99L One to Watch!

So far six named storms have occurred that have been brief in nature and to the north of the Caribbean. The US National Hurricane Center have highlighted a tropical wave with an associated low pressure as having a medium chance of developing into a tropical system.

This had a 20% chance of development late Monday 20th July 2020. It has also slowed in speed from 15 mph to 10 mph as it crosses the Atlantic.

NHC update 8:00 (EDT) Tuesday 21st July 2020 

"Showers and thunderstorms have become better organized in association with a low pressure system located about midway between the west coast of Africa and the Lesser Antilles. Environmental conditions are expected to be somewhat conducive for development, and a tropical depression could form during the next day or two while the low moves westward at around 10 mph over the tropical Atlantic. By the weekend, however, less favorable conditions should limit additional development."

* Formation chance through 48 hours ...medium ...60 percent. 

* Formation chance through 5 days ...medium ...60 percent.

2020 Atlantic Hurricane Season

These are the names of the 2020 Atlantic storms, established by an international committee of the World Meteorological Organization:

1.     Arthur

2.     Bertha

3.     Cristobal

4.     Dolly

5.     Edouard

6.     Fay

7.     Gonzalo

8.     Hanna

9.     Isaias

10. Josephine

11. Kyle

12. Laura

13. Marco

14. Nana

15. Omar

16. Paulette

17. Rene

18. Sally

19. Teddy

20. Vicky

21. Wilfred

The National Oceanic and Atmospheric Administration (NOAA) calls for six to 10 hurricanes, of which three to six could achieve major hurricane strength — Category 3 or higher.