####018003111####
WTNT42 KNHC 300237

TCDAT2

 

Tropical Storm Philippe Discussion Number  27

NWS National Hurricane Center Miami FL       AL172023

1100 PM AST Fri Sep 29 2023



Deep convection continues to pulse over the southeastern portion of 

Philippe's circulation this evening.  The center is located near 

the northwestern edge of the deep convection due to moderate 

westerly shear.  The intensity is held at 45 kt, and is based on 

the earlier reconnaissance aircraft data and a T3.0 (45 kt) 

subjective Dvorak classification from TAFB.  Another Air Force 

Reserve reconnaissance mission is scheduled overnight, and this 

mission should provide a full assessment of Philippe's structure 

and intensity. 



The earlier aircraft center fixes and more recent satellite 

position estimates indicate that Philippe is moving slowly 

southwestward. This motion is being influenced by Philippe's 

interaction with Tropical Storm Rina located to Philippe's 

east-northeast.  As the two tropical cyclone's continue to 

interact, Philippe is expected to move slowly west-southwestward

to westward during the next 24 to 36 hours.  After that time, the 

distance between the tropical cyclones should increase, and 

Philippe is forecast to turn northwestward when a mid-level ridge 

builds over the central Atlantic.  After 72 hours, Philippe is 

expected to turn northward between the aforementioned ridge and a 

mid- to upper-level trough over the southwestern Atlantic.  

Although the models are in general agreement on this scenario, 

there is significant spread on the longitude of the northward turn, 

and on how fast Philippe moves later in the period.  The updated 

NHC track forecast is near the various consensus aids, and very 

close to the previous advisory. 



The moderate shear that has been affecting Philippe the past few 

days could lessen during the next day or two.  This should allow 

for some gradual strengthening over the weekend.  After that time, 

there is a bifurcation in the intensity guidance with the 

GFS-based SHIPS model, the HMON, the HWRF, and even the GFS showing 

a more favorable upper-air environment and more significant 

deepening with a track farther east.  Meanwhile, the ECMWF-based 

SHIPS guidance, and the HAFS-A and HAFS-B which show a more westward 

track keeps stronger southwesterly vertical wind shear over the 

storm and therefore less strengthening.  The NHC intensity foreast 

is near the middle of these two scenarios, but is a bit more 

conservative than the lastest intensity consensus models. 



 

FORECAST POSITIONS AND MAX WINDS

 

INIT  30/0300Z 17.6N  55.8W   45 KT  50 MPH

 12H  30/1200Z 17.3N  56.0W   45 KT  50 MPH

 24H  01/0000Z 17.2N  56.4W   50 KT  60 MPH

 36H  01/1200Z 17.3N  56.9W   55 KT  65 MPH

 48H  02/0000Z 17.8N  57.5W   60 KT  70 MPH

 60H  02/1200Z 18.7N  58.2W   60 KT  70 MPH

 72H  03/0000Z 20.2N  58.7W   60 KT  70 MPH

 96H  04/0000Z 23.4N  58.9W   60 KT  70 MPH

120H  05/0000Z 27.3N  57.5W   60 KT  70 MPH

 

$$

Forecaster Brown