Tropical Storm Franklin A Potential Long-Range Threat Update Two

000

WTNT33 KNHC 240252

TCPAT3

BULLETIN

Tropical Storm Franklin Advisory Number  14

NWS National Hurricane Center Miami FL       AL082023

1100 PM EDT Wed Aug 23 2023

...FRANKLIN STRENGTHENING AS IT MOVES AWAY FROM THE DOMINICAN 

REPUBLIC...

...FLASH FLOODING THREAT CONTINUES OVERNIGHT...

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

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

LOCATION...21.2N 70.4W

ABOUT 50 MI...80 KM ESE OF GRAND TURK ISLAND

MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H

PRESENT MOVEMENT...NNE OR 15 DEGREES AT 13 MPH...20 KM/H

MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

WATCHES AND WARNINGS

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

CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...

* Dominican Republic south coast from Punta Palenque eastward

to Cabo Engano

* Dominican Republic entire north coast from Haiti border eastward

to Cabo Engano

* Turks and Caicos Islands

A Tropical Storm Warning means that tropical storm conditions are

expected somewhere within the warning area.

For storm information specific to your area, please monitor

products issued by your national meteorological service.

DISCUSSION AND OUTLOOK

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

At 1100 PM EDT (0300 UTC), the center of Tropical Storm Franklin was

located by an Air Force Reserve Hurricane Hunter aircraft near 

latitude 21.2 North, longitude 70.4 West. Franklin is moving toward 

the north-northeast near 13 mph (20 km/h). A turn to the northeast 

and then east-northeast with a decrease in forward speed is 

forecast on Thursday and Friday.  On the forecast track, the center 

of Franklin will continue to move farther away from the Dominican 

Republic and then move over the southwestern Atlantic into the 

weekend.

Maximum sustained winds have increased to near 45 mph (75 km/h)

with higher gusts. Gradual strengthening is forecast during the next

several days, and Franklin could be near hurricane strength over the

southwestern Atlantic by Saturday.

Tropical-storm-force winds extend outward up to 90 miles (150 km), 

primarily east of the center.

The estimated minimum central pressure from dropsonde data is 1002 

mb (29.59 inches).

HAZARDS AFFECTING LAND

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

Key messages for Franklin can be found in the Tropical Cyclone

Discussion under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC

and on the web at hurricanes.gov/text/MIATCDAT3.shtml.

RAINFALL:  Franklin is forecast to produce the following rainfall

totals through Thursday:

Hispaniola: Additional 1-3 inches.

Turks and Caicos: 1 to 3 inches, mainly across the eastern islands.

Puerto Rico: Up to an inch in western portions.

WIND:  Tropical storm conditions, primarily in gusts, are 

expected to occur in portions of the Dominican Republic and Turks 

and Caicos Islands overnight.

NEXT ADVISORY

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

Next intermediate advisory at 200 AM EDT.

Next complete advisory at 500 AM EDT.

$$

Forecaster Blake

000

WTNT43 KNHC 240253

TCDAT3

Tropical Storm Franklin Discussion Number  14

NWS National Hurricane Center Miami FL       AL082023

1100 PM EDT Wed Aug 23 2023

Franklin is showing signs of intensification on the latest satellite 

imagery with increasing deep convection near and southeast of the 

center.  This trend is confirmed by an Air Force Reserve Hurricane 

Hunter aircraft mission that has been flying through the storm 

during the past few hours with maximum flight-level winds of 46 kt, 

believable SFMR winds of at least 40 kt, and the central pressure 

falling to 1002 mb.  The initial wind speed is set to 40 kt as a 

blend of the data.

The storm continues heading north-northeastward or 015/11 kt, 

steered by a ridge over the eastern Caribbean.  Franklin should move 

around the northern periphery of the ridge, turning 

east-northeastward tomorrow and slowing down by Friday.  As the 

remnants of Emily exit the central Atlantic, mid-level ridging 

should build back northeast of Franklin, turning the cyclone 

north-northwestward and northward this weekend.  For such an unusual 

August track, the model guidance is in reasonably good agreement, 

and little change was made to the last NHC track forecast.

Moderate westerly shear is forecast to limit the strengthening rate 

of Franklin during the next couple of days, though very warm waters 

should allow for gradual intensification.  In 2 or 3 days, an 

upper-level trough should cutoff to the southwest of Franklin, 

creating a lower shear and very diffluent flow pattern near the 

storm.  This environmental change will likely promote significant 

strengthening by late this weekend, and Franklin is forecast to 

become a powerful hurricane southwest of Bermuda.  The new intensity 

forecast is raised from the previous one at most time periods, and 

the stronger regional hurricane models showing major hurricane 

strength at long range are certainly reasonable possibilities.

KEY MESSAGES:

1. Localized heavy rainfall from the outer bands of Franklin could

cause further isolated flash flooding through Thursday in vulnerable

areas of the Dominican Republic that already received torrential

rainfall.

2. Franklin is expected to continue to bring tropical storm 

conditions to portions of the Dominican Republic and the Turks and 

Caicos Islands overnight.

FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 21.2N  70.4W   40 KT  45 MPH

 12H  24/1200Z 22.3N  69.6W   45 KT  50 MPH

 24H  25/0000Z 23.0N  68.1W   50 KT  60 MPH

 36H  25/1200Z 23.3N  66.8W   55 KT  65 MPH

 48H  26/0000Z 23.7N  65.8W   55 KT  65 MPH

 60H  26/1200Z 24.4N  65.4W   60 KT  70 MPH

 72H  27/0000Z 25.8N  65.9W   70 KT  80 MPH

 96H  28/0000Z 29.2N  67.5W   90 KT 105 MPH

120H  29/0000Z 33.0N  67.4W   95 KT 110 MPH

$$

Forecaster Blake

000

FXUS61 KCAR 240201

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

1001 PM EDT Wed Aug 23 2023

.SYNOPSIS...

High pressure builds in through tonight, then slides to the

east on Thursday. A complex low pressure system approaches

Thursday night and Friday. A cold front crosses the area Saturday,

as a coastal low tracks across the Gulf of Maine. High pressure

builds towards the area Sunday and crests over the area Monday.....

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/......

.....Uncertainty increases towards the middle of next week, but

ensembles agree that a large upper level trough will approach

the area Tuesday night into Wednesday. With surface high

pressure to the east, southerly return flow will bring moisture

northward and chances of rain increase. This is an opportunity

to pull in potential tropical moisture from the Gulf of Mexico

or western Atlantic, especially with weaker tropical systems.

Tropical Storm Franklin is expected to strengthen as it moves

northward and due to its strength will be influenced by

persistent southwest winds around 200 to 250mb, most likely

keeping the system well off to the east as shown by the vast

majority of ensemble members. The pattern is somewhat concerning

for a predecessor heavy rain similar to what is described in

Galarneau et. al. 2010, so even with the system recurving well

to the east, a heavy rainfall threat may still exist depending

how the timing of Franklin, the upper level trough, and another

potential plume of tropical moisture moving northward from the

Gulf of Mexico interact........