Tropical Storm Ernesto Forms East Of The Lesser Antilles - It Could Pose A Long-Range Threat To Our Region.

106

FXUS61 KCAR 130110

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

910 PM EDT Mon Aug 12 2024

.SYNOPSIS...

An upper level trof will exit across the Maritimes overnight.

A series of surface trofs will then move across the region

Tuesday through Saturday......

.....LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...

By Thursday night, the upper level low will have settled over

the southeast portion of the forecast area, and the majority of

Maine will be under northerly flow on the backside of the low.

This will keep some unsettled weather over the region through

Friday morning, when the upper level ridge begins to move in

from the west. On Friday and Saturday, the ridge will be the

dominating factor and quiet weather will prevail. The pattern

will shift again beginning Saturday night, when the ridge slides

off to the east and a longwave trough approaches from the west.

This will bring increasing chances of rain Saturday through

Monday. However, some uncertainty still exists with the

potential of a tropical system moving off to the east. The

result is a rather broad brushed forecast with showers and

afternoon thunderstorms possible through Monday.....

649 

WTNT35 KNHC 130241

TCPAT5

BULLETIN

Tropical Storm Ernesto Advisory Number   6

NWS National Hurricane Center Miami FL       AL052024

1100 PM AST Mon Aug 12 2024

...ERNESTO APPROACHING THE LEEWARD ISLANDS...

SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION

-----------------------------------------------

LOCATION...16.0N 59.6W

ABOUT 165 MI...265 KM ESE OF ANTIGUA

ABOUT 460 MI...740 KM ESE OF SAN JUAN PUERTO RICO

MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H

PRESENT MOVEMENT...W OR 275 DEGREES AT 25 MPH...41 KM/H

MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...

* St. Kitts, Nevis, Montserrat, Antigua, Barbuda, and Anguilla

* Guadeloupe

* St. Martin and St. Barthelemy

* Sint Maarten

* British Virgin Islands

* U.S. Virgin Islands

* Puerto Rico

* Vieques

* Culebra

A Tropical Storm Warning means that tropical storm conditions are

expected somewhere within the warning area within 36 hours.

Interests elsewhere in the northeastern Caribbean should

monitor the progress of Ernesto.

For storm information specific to your area in the United

States, including possible inland watches and warnings, please

monitor products issued by your local National Weather Service

forecast office. For storm information specific to your area

outside of the United States, please monitor products issued by

your national meteorological service.

DISCUSSION AND OUTLOOK

----------------------

At 1100 PM AST (0300 UTC), the center of Tropical Storm Ernesto was

located near latitude 16.0 North, longitude 59.6 West. Ernesto is

moving toward the west near 25 mph (41 km/h).  A westward to

west-northwestward motion with some decrease in forward speed is

expected during the next day or so.  On the forecast track, Ernesto 

is expected to move across portions of the Leeward Islands by early 

Tuesday and near or over the U.S. and British Virgin Islands and 

Puerto Rico by Tuesday evening.  Ernesto is then forecast to turn 

northward over the western Atlantic.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.

Gradual strengthening is expected during the next few days.

Tropical-storm-force winds extend outward up to 80 miles (130 km)

from the center.

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

HAZARDS AFFECTING LAND

----------------------

Key messages for Ernesto can be found in the Tropical Cyclone

Discussion under AWIPS header MIATCDAT5 and WMO header WTNT45 KNHC

and on the web at hurricanes.gov/text/MIATCDAT5.shtml.

RAINFALL: Tropical Storm Ernesto is expected to produce total rain

accumulations of 4 to 6 inches over portions of the Leeward and

Virgin Islands.  For Puerto Rico, 3 to 6 inches of rainfall, with

maximum amounts of 10 inches, is expected.

For a complete depiction of forecast rainfall associated with

Tropical Storm Ernesto, please see the National Weather Service

Storm Total Rainfall Graphic, available at

hurricanes.gov/graphics_at5.shtml?rainqpf

Elsewhere in the Caribbean, Tropical Storm Ernesto is expected to

produce the following rain accumulations through Friday morning:

Windward Islands... 1 to 4 inches

Eastern Hispaniola... 2 to 4 inches

WIND:  Tropical storm conditions are expected in the warning area 

for the Leeward Islands beginning early Tuesday. Tropical storm 

conditions are expected to begin spreading over the Virgin Islands 

and Puerto Rico by Tuesday evening.

STORM SURGE: A storm surge will raise water levels by as much as 1

to 3 feet above ground level for the eastern coast of Puerto Rico

from San Juan to Guayama, including the islands of Culebra and

Vieques and in the U.S. Virgin Islands, including St. Thomas, St.

John, and St. Croix.

A storm surge will raise water levels by as much as 1 to 3 feet

above normal tide levels in the British Virgin Islands. Near the

coast, the surge will be accompanied by large and destructive waves.

SURF:  Swells generated by Ernesto will likely begin to affect

portions of the Leeward Islands beginning late tonight.  These

swells are likely to cause life-threatening surf and rip current

conditions. Please consult products from your local weather office.

NEXT ADVISORY

-------------

Next intermediate advisory at 200 AM AST.

Next complete advisory at 500 AM AST.

$$

Forecaster Pasch

000

WTNT45 KNHC 130242

TCDAT5

Tropical Storm Ernesto Discussion Number   6

NWS National Hurricane Center Miami FL       AL052024

1100 PM AST Mon Aug 12 2024

Ernesto remains a rather broad tropical cyclone, and satellite and 

radar data shows that deep convection has yet to 

consolidate/concentrate near its center. Tonight's NOAA P-3 TDR data 

in Ernesto also suggests the broad center currently lacks much 

vertical alignment.  However, there are a number of convective 

banding features around the circulation and the overall organization 

of the cloud pattern has been increasing since earlier today.  

Satellite imagery shows that the upper-level anticyclonic outflow 

pattern is well defined over the western semicircle of the 

circulation.  The intensity is held at 35 kt for this advisory based 

on observations from Air Force and NOAA reconnaissance aircraft and 

Dvorak satellite estimates.

Since the system is still in the formative stage, there is some 

scatter in the center position estimates, making the initial motion 

estimate somewhat uncertain.  My best motion estimate is generally 

westward at a slightly slower speed, around 275/22 kt.  During the 

next day or so, a mid-level ridge to the north of Ernesto should 

maintain a westward to west-northwestward motion at a gradually 

decreasing forward speed.  This should take the center of the 

tropical cyclone over portions of the Leeward Islands very soon, 

across the extreme northeastern Caribbean Sea on Tuesday, and near 

or over portions of Puerto Rico Tuesday evening or Tuesday night.  

After that, the flow on the eastern side  a deep-layer trough moving 

off the U.S. east coast should cause Ernesto turn northward to 

north-northeastward.  Later in the forecast period, the first trough 

that steers the system northward from the Greater Antilles leaves 

Ernesto behind, and the tropical cyclone may have to wait for a 

second trough to steer it farther into the mid-latitudes.  The 

official track forecast is near the left edge of the guidance suite 

during the first 24-36 hours and close to the simple model consensus 

from 2-5 days.  

Assuming that deep convection will increase near the center of 

Ernesto, the high-level outflow and otherwise conducive oceanic and 

atmospheric environment favors strengthening during the next few 

days.  Although the intensification is expected to be gradual during 

the early part of the period, a more rapid rate of strengthening is 

likely after the system moves north of the Greater Antilles.  The 

official intensity forecast is about the same as the previous one 

and close to the multi-model consensus.

Key Messages:

1. Ernesto is expected to bring tropical storm conditions to

portions of the Leeward Islands beginning early Tuesday and to the

Virgin Islands and Puerto Rico by late Tuesday. Tropical Storm

Warnings are in effect for this entire area.

2. Heavy rainfall may result in locally considerable flash flooding

and mudslides in areas of the Leeward and Virgin Islands through

Wednesday, and over Puerto Rico late Tuesday into Thursday.

3. It is too soon to know what impacts Ernesto could bring to

Bermuda late this week, and interests there should monitor the

progress of this system.

FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 16.0N  59.6W   35 KT  40 MPH

 12H  13/1200Z 16.4N  62.0W   40 KT  45 MPH

 24H  14/0000Z 17.7N  64.6W   50 KT  60 MPH

 36H  14/1200Z 19.5N  66.5W   60 KT  70 MPH

 48H  15/0000Z 21.7N  67.8W   70 KT  80 MPH

 60H  15/1200Z 24.0N  68.3W   80 KT  90 MPH

 72H  16/0000Z 26.1N  67.7W   90 KT 105 MPH

 96H  17/0000Z 29.9N  65.3W   95 KT 110 MPH

120H  18/0000Z 32.7N  64.2W   95 KT 110 MPH

$$

Forecaster Pasch

000

WTNT35 KNHC 122045

TCPAT5

BULLETIN

Tropical Storm Ernesto Advisory Number   5

NWS National Hurricane Center Miami FL       AL052024

500 PM AST Mon Aug 12 2024

...DISTURBANCE BECOMES TROPICAL STORM ERNESTO...

...EXPECTED TO BRING TROPICAL STORM FORCE WINDS AND HEAVY RAINS TO

PORTIONS OF THE LEEWARD ISLANDS BEGINNING LATE TONIGHT...

SUMMARY OF 500 PM AST...2100 UTC...INFORMATION

----------------------------------------------

LOCATION...16.0N 57.5W

ABOUT 295 MI...475 KM ESE OF ANTIGUA

ABOUT 590 MI...950 KM ESE OF SAN JUAN PUERTO RICO

MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H

PRESENT MOVEMENT...WNW OR 285 DEGREES AT 28 MPH...44 KM/H

MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY:

None

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...

* St. Kitts, Nevis, Montserrat, Antigua, Barbuda, and Anguilla

* Guadeloupe

* St. Martin and St. Barthelemy

* Sint Maarten

* British Virgin Islands

* U.S. Virgin Islands

* Puerto Rico

* Vieques

* Culebra

A Tropical Storm Warning means that tropical storm conditions are

expected somewhere within the warning area within 36 hours.

Interests elsewhere in the northeastern Caribbean should 

monitor the progress of Ernesto.

For storm information specific to your area in the United

States, including possible inland watches and warnings, please

monitor products issued by your local National Weather Service

forecast office. For storm information specific to your area

outside of the United States, please monitor products issued by

your national meteorological service.

DISCUSSION AND OUTLOOK

----------------------

At 500 PM AST (2100 UTC), the center of Tropical Storm Ernesto was

located near latitude 16.0 North, longitude 57.5 West. Ernesto is

moving toward the west-northwest near 28 mph (44 km/h). A westward 

to west-northwestward motion with some decrease in forward speed is 

expected during the next couple of days. On the forecast track, 

Ernesto is expected to move across portions of the Leeward Islands 

late tonight or Tuesday and near or over the U.S. and British 

Virgin Islands and Puerto Rico by Tuesday evening.  Ernesto is then 

forecast to turn northward over the western Atlantic.

Maximum sustained winds have increased to near 40 mph (65 km/h) 

with higher gusts.  Gradual strengthening is expected during the 

next few days.

Tropical-storm-force winds extend outward up to 60 miles (95 km)

from the center.

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

HAZARDS AFFECTING LAND

----------------------

Key messages for Ernesto can be found in the Tropical Cyclone 

Discussion under AWIPS header MIATCDAT5 and WMO header WTNT45 KNHC 

and on the web at hurricanes.gov/text/MIATCDAT5.shtml.

RAINFALL: Tropical Storm Ernesto is expected to produce total rain 

accumulations of 4 to 6 inches over portions of the Leeward and 

Virgin Islands. For Puerto Rico, 3 to 6 inches of rainfall, with 

maximum amounts of 10 inches, is expected.

For a complete depiction of forecast rainfall associated with 

Tropical Storm Ernesto, please see the National Weather Service 

Storm Total Rainfall Graphic, available at 

hurricanes.gov/graphics_at5.shtml?rainqpf

Elsewhere in the Caribbean, Tropical Storm Ernesto is expected to 

produce the following rain accumulations through Friday morning:

Windward Islands… 1 to 4 inches

Eastern Hispaniola… 2 to 4 inches

WIND:  Tropical storm conditions are expected in the warning area

for the Leeward Islands beginning late tonight or early Tuesday.

Tropical storm conditions are expected to begin spreading over the

Virgin Islands and Puerto Rico by Tuesday evening.

STORM SURGE: A storm surge will raise water levels by as much as 1

to 3 feet above ground level for the eastern coast of Puerto Rico

from San Juan to Guayama, including the islands of Culebra and

Vieques and in the U.S. Virgin Islands, including St. Thomas, St.

John, and St. Croix.

A storm surge will raise water levels by as much as 1 to 3 feet

above normal tide levels in the British Virgin Islands. Near the

coast, the surge will be accompanied by large and destructive waves.

SURF:  Swells generated by Ernesto will likely begin to affect

portions of the Leeward Islands beginning late tonight.  These

swells are likely to cause life-threatening surf and rip current

conditions. Please consult products from your local weather office.

NEXT ADVISORY

-------------

Next intermediate advisory at 800 PM AST.

Next complete advisory at 1100 PM AST.

$$

Forecaster Cangialosi

000

WTNT45 KNHC 122045

TCDAT5

Tropical Storm Ernesto Discussion Number   5

NWS National Hurricane Center Miami FL       AL052024

500 PM AST Mon Aug 12 2024

Satellite images and data from the Air Force Hurricane Hunters 

indicate that a center of circulation has now formed, and deep 

convection is gradually organizing in bands around that feature.  A 

combination of flight-level wind and SFMR data from the aircraft 

support increasing the winds to 35 kt.  Since the system meets the 

definition of a tropical cyclone and has winds of tropical storm 

force, it is now designated Tropical Storm Ernesto.

Based on the latest satellite images and aircraft data, the center 

has formed about 30 n mi north of the previous track.  This makes 

the initial motion uncertain, but our best estimate is 285/24 kt. 

This fast forward speed is due to a strong low- to mid-level ridge 

situated just north of the system over the subtropical Atlantic.  A 

fast west-northwestward motion is expected to continue, taking the 

storm across the northern Leeward Islands overnight and near or over 

the Virgin Islands and Puerto Rico Tuesday afternoon or Tuesday 

night.  After that time, a significant slowdown and a turn to the 

north over the Atlantic is expected as a deep-layer trough pushes 

off the U.S. east coast, causing the ridge to shift eastward. The 

NHC track forecast is a little to the right of the previous one in 

the short term and lies on the left edge of the guidance through 

Ernesto's track across the Caribbean.  This forecast is closer to 

the middle of the guidance envelope while it is over the western and 

central Atlantic.

Since Ernesto now has a center and a slightly improved circulation, 

strengthening seems likely.  However, the rate of intensification 

will likely be slow during the next day or two due to the system's 

broad structure and ragged convective pattern.  More significant 

strengthening is forecast after Ernesto exits the Caribbean, when 

nearly all of the environmental conditions appear conducive.  The 

NHC intensity forecast is a little higher than the previous one in 

the short term, trending toward the latest consensus aids.

Key Messages:

1. Ernesto is expected to bring tropical storm conditions to

portions of the Leeward Islands late tonight and Tuesday and to the 

Virgin Islands and Puerto Rico by late Tuesday. Tropical Storm 

Warnings are in effect for this entire area.

2. Heavy rainfall may result in locally considerable flash flooding 

and mudslides in areas of the Leeward and Virgin Islands through  

Wednesday, and over Puerto Rico late Tuesday into Thursday.

3. It is too soon to know what impacts Ernesto could bring to 

Bermuda late this week, and interests there should monitor the 

progress of this system.

FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 16.0N  57.5W   35 KT  40 MPH

 12H  13/0600Z 16.2N  60.3W   40 KT  45 MPH

 24H  13/1800Z 16.9N  63.4W   45 KT  50 MPH

 36H  14/0600Z 18.5N  65.6W   50 KT  60 MPH

 48H  14/1800Z 20.9N  67.1W   60 KT  70 MPH

 60H  15/0600Z 22.9N  67.8W   70 KT  80 MPH

 72H  15/1800Z 25.0N  68.0W   80 KT  90 MPH

 96H  16/1800Z 29.4N  66.0W   95 KT 110 MPH

120H  17/1800Z 32.5N  64.3W   95 KT 110 MPH

$$

Forecaster Cangialosi