Tropical Storm Philippe Forecast Discussion Number 4

By | September 24, 2023

WTNT42 KNHC 240837

Tropical Storm Philippe Discussion Number   4
NWS National Hurricane Center Miami FL       AL172023
500 AM AST Sun Sep 24 2023

Philippe is still trying to become better organized this morning. 
There continues to be burst within the convection with very cold 
cloud tops to -80 degrees Celsius. However, the convection remains 
displaced to the northeast of the estimated low-level center. An 
ASCAT pass that arrived just after the previous advisory revealed 
winds on the northeast side of the system were near 40 kt. 
Subjective satellite Dvorak estimates for this cycle from TAFB and 
SAB were T3.0/T2.5, respectively. Using a blend of these estimates 
and the scatterometer satellite-derived winds, the intensity for 
this advisory is raised to 40 kt. 

The system is moving westward at an estimated motion of 280/8 kt. 
Philippe should continue westward fro the next couple of days, 
steered along the southern side of a mid-level ridge. In about 2 to 
3 days, a weakness in the ridge will develop and the tropical storm 
should gradually turn west-northwest and then northwest. Models 
have continued to slow the forward motion of Philippe towards the 
end of the forecast period, and the NHC track forecast was adjusted 
accordingly. The NHC track forecast lies near the corrected 
consensus aids throughout the period, with a slight nudge to the 
left of the previous track.

Models depict that Philippe will take some time to get organized due 
to mid-level vertical wind shear and some drier mid-level RH values. 
This will lead to only slow strengthening the next few days. In 
about 3 days, as Philippe approaches a mid-upper level trough, 
deep-layer vertical wind shear is forecast to increase but 
upper-level divergence should increase over the system as well. The 
guidance continues to favor some additional strengthen through the 
end of the forecast period. The NHC intensity forecast is similar to 
the previous advisory.


INIT  24/0900Z 15.6N  41.4W   40 KT  45 MPH
 12H  24/1800Z 15.9N  43.1W   40 KT  45 MPH
 24H  25/0600Z 16.3N  45.3W   45 KT  50 MPH
 36H  25/1800Z 16.7N  47.5W   45 KT  50 MPH
 48H  26/0600Z 17.3N  49.2W   45 KT  50 MPH
 60H  26/1800Z 18.1N  50.9W   50 KT  60 MPH
 72H  27/0600Z 19.2N  52.4W   50 KT  60 MPH
 96H  28/0600Z 22.4N  54.4W   55 KT  65 MPH
120H  29/0600Z 24.2N  55.4W   60 KT  70 MPH

Forecaster Kelly

Leave a Reply