Tuesday, August 22, 2023

Tropical Storm Franklin A Potential Long-Range Threat Update One


































000
WTNT33 KNHC 230244
TCPAT3

BULLETIN
Tropical Storm Franklin Advisory Number  10
NWS National Hurricane Center Miami FL       AL082023
1100 PM EDT Tue Aug 22 2023

...HEAVY RAINFALL AND POTENTIALLY LIFE-THREATENING FLASH FLOODING 
LIKELY ON HISPANIOLA THROUGH WEDNESDAY...

SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.4N 71.4W
ABOUT 175 MI...280 KM SW OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 9 MPH...15 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 entire south coast from Haiti border eastward
to Cabo Engano
* Dominican Republic entire north coast from Haiti border eastward
to Cabo Engano
* Haiti entire south coast from Anse d'Hainault eastward to the
Dominican Republic border

A Tropical Storm Watch is in effect for...
* Turks and Caicos Islands

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

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

Interests elsewhere in Haiti should monitor the progress of this
system.

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 near latitude 16.4 North, longitude 71.4 West. Franklin is
moving toward the north near 9 mph (15 km/h), and this motion is
expected to continue the next day or so, followed by a turn toward 
the northeast by Thursday.  On the forecast track, the center of
Franklin is expected to approach the southern coast of Hispaniola
tonight, cross the island on Wednesday, and then emerge over the
southwestern Atlantic waters late Wednesday.

Maximum sustained winds remain near 40 mph (65 km/h) with higher 
gusts. Little change in strength is forecast during the next couple 
of days while Franklin moves near and across Hispaniola.  Some 
strengthening is possible Friday as Franklin moves farther 
northeast over the southwestern Atlantic waters.

Tropical-storm-force winds extend outward up to 105 miles (165 km)
from the center.

The estimated minimum central pressure 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 expected to produce rainfall totals of 5 to 
10 inches, with higher amounts around 15 inches mainly across 
central portions of Hispaniola through Wednesday. Rainfall totals of 
1 to 3 inches, with storm total maxima of 4 inches, are expected 
across Puerto Rico through Wednesday.

WIND:  Tropical storm conditions are expected to begin within the
warning area tonight and continue through Wednesday. Tropical storm
conditions are possible in the Turks and Caicos Islands Wednesday
night.

STORM SURGE: Minor coastal flooding is possible along the coast of
Hispaniola in areas of onshore winds.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.

$$
Forecaster Kelly/Blake


110 
WTNT43 KNHC 230245
TCDAT3

Tropical Storm Franklin Discussion Number  10
NWS National Hurricane Center Miami FL       AL082023
1100 PM EDT Tue Aug 22 2023

The satellite presentation of Franklin has improved since the last 
advisory.  Recent Proxy Vis imagery suggest that the low-level 
circulation has become better defined, although there is still some 
question exactly where the center is.  The overall cloud pattern 
suggests the low-level center is closer to a recent burst of deep 
convection, closer to the mid-level circulation found by the last 
NOAA reconnaissance mission.  A blend of subjective and objective 
satellite estimates remain near 35 kt for this advisory, which is 
in agreement with what NOAA hurricane hunter aircraft found 
earlier. Therefore, the intensity will remain 35 kt for this 
advisory.

The system looks to have finally started a northward motion towards 
the island of Hispaniola, moving at 8 kt. The track guidance 
continues to be in fairly good agreement with a northward motion 
through tomorrow and then a northeastward course near the end of 
the work week due to broad troughing located over the western 
Atlantic.  By days 4 and 5, a stronger mid-level ridge develops over 
the central Atlantic, with Franklin expected to turn back to the 
north by the end of the forecast period.  Given the uncertainty in 
the center position, the current NHC forecast track lies near the 
previous forecast, which is also near the HCCA corrected consensus 
aid.

The new intensity forecast is fairly similar to the previous 
advisory. Little change in strength is forecast during the next day 
or so due to land interaction with Hispaniola and moderate wind 
shear. Gradual strengthening is anticipated after Franklin emerges 
north of Hispaniola due to warm waters but still notable shear. 
For days 4 and 5, when Franklin is still over the very warm western 
Atlantic waters, wind shear should decrease slightly, and  
strengthening is forecast, with the system becoming a hurricane by 
the end of the period. The NHC intensity forecast after day 3 is 
slightly higher than the previous advisory, but lower than the 
stronger HCCA and IVCN consensus aids.  

KEY MESSAGES:

1. Heavy rainfall from Franklin is expected across much of 
Hispaniola into Thursday. The heavy rainfall is expected to produce 
significant and potentially life-threatening flash and urban 
flooding as well as mudslides, particularly over central Hispaniola 
through Wednesday.

2. Franklin is expected to bring tropical storm conditions to
portions of the Dominican Republic and Haiti, where Tropical Storm
Warnings are in effect, beginning later tonight and continuing
through Wednesday.

FORECAST POSITIONS AND MAX WINDS

INIT  23/0300Z 16.4N  71.4W   35 KT  40 MPH
 12H  23/1200Z 17.6N  71.2W   40 KT  45 MPH
 24H  24/0000Z 20.0N  70.6W   35 KT  40 MPH
 36H  24/1200Z 21.5N  69.9W   35 KT  40 MPH
 48H  25/0000Z 22.3N  68.9W   40 KT  45 MPH
 60H  25/1200Z 22.6N  67.9W   45 KT  50 MPH
 72H  26/0000Z 23.1N  67.0W   50 KT  60 MPH
 96H  27/0000Z 24.9N  66.7W   65 KT  75 MPH
120H  28/0000Z 28.7N  68.0W   80 KT  90 MPH

$$
Forecaster Kelly/Blake

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