Tropical Storm Elsa A Long-Range Threat To The Region

000

WTNT35 KNHC 040249

TCPAT5

BULLETIN

Tropical Storm Elsa Advisory Number  15

NWS National Hurricane Center Miami FL       AL052021

1100 PM EDT Sat Jul 03 2021

...RECONNAISSANCE AIRCRAFT FINDS ELSA A LITTLE WEAKER AND MOVING 

SLOWER BETWEEN HAITI AND JAMAICA...

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

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

LOCATION...17.9N 75.3W

ABOUT 175 MI...280 KM ESE OF MONTEGO BAY JAMAICA

ABOUT 205 MI...330 KM SE OF CABO CRUZ

MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H

PRESENT MOVEMENT...WNW OR 295 DEGREES AT 17 MPH...28 KM/H

MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES

WATCHES AND WARNINGS

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

CHANGES WITH THIS ADVISORY:

The Hurricane Warning for the southern portion of Haiti from Port

Au Prince to the southern border with the Dominican Republic has

been replaced with a Tropical Storm Warning.

The Tropical Storm Warning for Haiti north of Port Au Prince has

been discontinued.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...

* Southern portion of Haiti from Port Au Prince to the southern

border with the Dominican Republic

* The Cuban provinces of Camaguey, Granma, Guantanamo, Holguin,

Las Tunas, Santiago de Cuba, Ciego de Avila, Sancti Spiritus, Villa

Clara, and Cienfuegos

* Jamaica

A Hurricane Watch is in effect for...

* The Cuban provinces of Camaguey, Granma, Guantanamo, Holguin,

Las Tunas, and Santiago de Cuba

A Tropical Storm Watch is in effect for...

* Cayman Brac and Little Cayman

* The Cuban provinces of Matanzas, Mayabeque, and Havana

* The Florida Keys from Craig Key westward to the Dry Tortugas

A Tropical Storm Warning means that tropical storm conditions are

expected somewhere within the warning area.

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.

Interests elsewhere in the Cuba, the Cayman Islands, the Florida

peninsula, and the Florida Keys should monitor the progress of Elsa.

Additional watches and warnings will likely be required Sunday

morning.

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 EDT (0300 UTC), the center of Tropical Storm Elsa was 

located by an Air Force Reserve reconnaissance aircraft near 

latitude 17.9 North, longitude 75.3 West. Elsa is moving toward the 

west-northwest near 17 mph (28 km/h). An additional decrease in 

forward speed is expected tonight and on Sunday, followed by a turn 

toward the northwest Sunday night or Monday. On the forecast track, 

Elsa will move near the southwestern peninsula of Haiti over the 

next few hours, and then move near Jamaica and portions of eastern 

Cuba on Sunday.  By Monday, Elsa is expected to move across central 

and western Cuba and head toward the Florida Straits. Elsa is then 

forecast to move move near or over portions of the west coast of 

Florida on Tuesday.

Maximum sustained winds have decreased to near 65 mph (100 km/h) 

with higher gusts.  Little change in strength is forecast tonight, 

with some slight strengthening possible Sunday afternoon as Elsa 

approaches the south-central coast of Cuba.  However, gradual 

weakening is forecast to occur Sunday night and Monday when Elsa 

will be moving over Cuba.

Tropical-storm-force winds extend outward up to 125 miles (205 km)

from the center.

The minimum central pressure recently measured by the aircraft was 

estimated to be 1004 mb (29.65 inches).

HAZARDS AFFECTING LAND

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

Key messages for Elsa can be found in the Tropical Cyclone

Discussion under AWIPS header MIATCDAT5, WMO header WTNT45 KNHC and

on the web at

www.hurricanes.gov/graphics_at5.shtml?key_messages.

WIND: Hurricane conditions are possible in eastern Cuba on Sunday. 

Tropical Storm conditions are expected in the warning area in Haiti 

tonight and on Jamaica and over eastern and central Cuba on Sunday. 

Tropical storm conditions are possible in the watch area in the 

Cayman Islands Sunday and Sunday night and in western Cuba and the 

Florida Keys Sunday night and Monday.

STORM SURGE: A storm surge will raise water levels above normal

tide levels by as much as the following amounts in areas of onshore

flow within the hurricane watch and warning areas...

Southern coast of Cuba...3 to 5 feet

Southern coast of Hispaniola...2 to 4 feet

The combination of a storm surge and the tide will cause normally

dry areas near the coast to be flooded by rising waters moving

inland from the shoreline.  The water could reach the following

heights above ground somewhere in the indicated areas if the peak

surge occurs at the time of high tide...

Craig Key, FL to Dry Tortugas...1-2 ft

Surge-related flooding depends on the relative timing of the surge

and the tidal cycle, and can vary greatly over short distances.  For

information specific to your area, please see products issued by

your local National Weather Service forecast office.

RAINFALL: Across portions of southern Haiti and Jamaica, rainfall

of 4 to 8 inches with isolated maximum amounts of 15 inches is

expected today into Sunday. This rain may lead to scattered flash

flooding and mudslides, some of which may be significant in nature.

Across portions of Cuba Sunday into Monday, rainfall of 5 to 10

inches with isolated maximum amounts of 15 inches is expected. This

will result in significant flash flooding and mudslides.

Across the Cayman Islands Sunday into Monday, rainfall of 3 to 5

inches is expected. This rain may lead to scattered flash flooding.

Rainfall from Elsa is likely to impact portions of the Florida Keys

and Florida Peninsula early next week. Amounts of 2 to 4 inches with

localized maximum amounts up to 6 inches will be possible, which may

result in isolated flash, urban, and minor river flooding.

SURF: Swells generated by Elsa will spread westward across the

Caribbean Sea through the weekend. 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 EDT.

Next complete advisory at 500 AM EDT.

$$

Forecaster Stewart/Papin

454 

WTNT45 KNHC 040259

TCDAT5

Tropical Storm Elsa Discussion Number  15

NWS National Hurricane Center Miami FL       AL052021

1100 PM EDT Sat Jul 03 2021

Elsa is undergoing a convective bursting pattern the past few 

hours, with some cold overshooting tops of -90 deg C east and 

northeast of the center. However, data from an Air Force Reserve 

reconnaissance aircraft indicate that this convective increase has 

not translated into an intensity increase. To the contrary, 5000-ft 

flight-level and SFMR surface winds have decreased while the central 

pressure has increased to 1004 mb. Based on the latest recon data, 

the intensity has been lowered to 55 kt. The aircraft has now 

climbed to 10,000 ft for safety reasons and will be penetrating the 

area of intense convection to check for stronger winds there.

The initial motion estimate is now 295/15 kt.  Elsa is forecast to 

gradually move around the western periphery of a deep-layer 

subtropical ridge over the next 96 hours, accompanied by an 

additional decrease in forward speed. The latest model guidance has 

continued to converge along the previous advisory track, with the 

corrected-consensus models HCCA and FSSE nearly on top of each 

other. The TCVA simple consensus model is also similar to the HCCA 

and FSSE models. However, out of respect for the slightly more 

westward GFS and GFS-ensemble models, which have performed 

admirably thus far with Elsa, the new official forecast lies a tad 

west of the aforementioned consensus models and lies nearly on top 

of the previous advisory track.

After interacting with the mountainous terrain of southwestern 

Haiti, which could have caused some disruption in the low-level 

field despite the center remaining offshore, little change in 

intensity is expected tonight. However, some slight restrengthening 

could occur by Sunday afternoon as Elsa approaches the south-central 

coast of Cuba where the sea-surface temperatures are quite warm at 

more than 30 deg C and the water is deep. Weakening is expected 

after the cyclone moves across west-central Cuba, followed again by 

some slight restrengthening after Elsa emerges over the warm Gulf 

Stream in the Straits of Florida. Westerly vertical wind shear 

increasing to near 20 kt by 96 hours should prevent any significant 

strengthening from occurring. Elsa should become a very  

asymmetrical tropical cyclone late on day 3 and on day 4 with most 

of the heavy rain and strongest winds displaced along and to the 

east of the forecast track. The initial intensity is similar to the 

previous advisory and closely follows the simple and corrected 

consensus models.

Given the remaining uncertainty in the track forecast and the degree 

of land interaction with Hispaniola and Cuba, users are urged to 

factor in some of this uncertainty.  For reference, average NHC 

track errors at days 3 and 4 are 125 miles and 150 miles, 

respectively.  The average NHC intensity errors are around 15 mph 

for both days 3 and 4.

Key Messages:

1. Widespread heavy rain will move across southern Haiti and Jamaica 

tonight into Sunday where isolated to scattered flash flooding and 

mudslides will be possible. Heavy rain will then impact the Cayman 

Islands and Cuba Sunday into Monday resulting in significant 

flooding and mudslides over Cuba. As Elsa approaches the Florida 

Keys and  Florida Peninsula early next week, isolated flash flooding 

and minor river flooding will be possible.

2. Tropical storm conditions and dangerous storm surge are expected

with hurricane conditions possible in portions of eastern Cuba

beginning early Sunday, with tropical storm conditions possible in

central and western Cuba Sunday night and Monday.

3. There is an increasing risk of tropical storm conditions, storm

surge, and rainfall impacts beginning Monday in the Florida Keys and

the southern Florida Peninsula, and a Tropical Storm Watch is now

in effect for portions of the Florida Keys. This risk will spread

northward along the Florida Peninsula through Wednesday and reach

the coasts of Georgia and the Carolinas Wednesday and Thursday,

however uncertainty in the forecast remains larger than usual due

to Elsa's potential interaction with the islands of Hispaniola and

Cuba. Interests elsewhere in Florida and along the southeast U.S.

coast should monitor Elsa's progress and updates to the forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 17.9N  75.3W   55 KT  65 MPH

 12H  04/1200Z 19.2N  77.3W   55 KT  65 MPH

 24H  05/0000Z 20.9N  79.4W   60 KT  70 MPH

 36H  05/1200Z 22.5N  81.0W   50 KT  60 MPH...INLAND

 48H  06/0000Z 24.1N  82.2W   45 KT  50 MPH...OVER WATER

 60H  06/1200Z 26.0N  82.8W   50 KT  60 MPH

 72H  07/0000Z 28.0N  83.0W   50 KT  60 MPH

 96H  08/0000Z 32.7N  81.0W   45 KT  50 MPH...INLAND

120H  09/0000Z 37.7N  74.9W   35 KT  40 MPH...OVER WATER

$$

Forecaster Stewart/Papin