Official Discussion issued by the National Hurricane Center

Philippe (AL172023) DATA RELEASED: 9/26/2023 3:00:00 PM UTC

Copy of official data

Tropical Storm Philippe Discussion Number  13
NWS National Hurricane Center Miami FL       AL172023
1100 AM AST Tue Sep 26 2023

Philippe continues to struggle due to strong west-southwesterly 
shear associated with a mid- to upper-level low to its northwest. 
The low-level center is completely exposed and deep convection 
remains well removed to the east of the center.  The latest 
satellite intensity estimates range from 30 to 42 kt, and based on 
that data, the initial wind speed is nudged downward to 40 kt.

The strong shear is not expected to let up over the next several 
days, which should keep the storm asymmetric and weak.  A 
combination of the shear and dry air entrainment should lead to a 
gradual decay, and simulated satellite images from the GFS and ECMWF 
models suggest that Philippe will likely degenerate into a remnant 
low in 3 or 4 days. The NHC intensity forecast lies near the middle 
of the guidance envelope and now shows the system becoming a 
remnant low by day 4.

Philippe continues to move westward, and it has not gained much 
latitude over the past 24 hours due to its sheared structure.  
Based on the previous track, the expected asymmetric structure, and 
the new model guidance, the NHC track forecast is again shifted to 
the left as Philippe is expected to continue to move in the low- to 
mid-level flow.  This forecast lies on the southern side of the 
guidance envelope, in best agreement with the ECMWF model.


INIT  26/1500Z 17.3N  50.3W   40 KT  45 MPH
12H  27/0000Z 17.9N  51.6W   40 KT  45 MPH
24H  27/1200Z 18.9N  53.4W   40 KT  45 MPH
36H  28/0000Z 19.8N  55.0W   40 KT  45 MPH
48H  28/1200Z 20.7N  56.5W   35 KT  40 MPH
60H  29/0000Z 21.2N  58.0W   35 KT  40 MPH
72H  29/1200Z 21.2N  59.8W   30 KT  35 MPH
96H  30/1200Z 21.2N  62.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  01/1200Z 21.3N  65.1W   25 KT  30 MPH...POST-TROP/REMNT LOW

Forecaster Cangialosi