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WTNT42 KNHC 292033

TCDAT2

 

Tropical Storm Philippe Discussion Number  26

NWS National Hurricane Center Miami FL       AL172023

500 PM AST Fri Sep 29 2023

 

Satellite imagery shows the center of Philippe has become exposed 

again due to 15-20 kt of mid-level westerly shear. Deep convection 

is generally confined to the southeast portion, with a growing band 

to the south of the center. The Air Force Hurricane Hunters 

investigated Philippe this afternoon and found the minimum pressure 

to be 1002 mb and winds to support an intensity of 45 kt. Based on 

the aircraft and ASCAT data, tropical-storm-force winds extend well 

east and southeast of the center.

 

Philippe is moving a little faster this afternoon, but still 

relatively slowly as it continues in a general southwest direction. 

The current track is due to its interaction with Tropical Storm Rina 

several hundred miles to its east.  Since these tropical cyclones 

are expected to continue to interact through the weekend, Philippe 

is forecast to crawl southwestward through Sunday.  After that time, 

Rina is expected to separate from Philippe as a mid-level ridge 

builds over the subtropical central Atlantic. In response, Philippe 

should turn sharply northward early next week. Recent guidance has 

shown an overall shift to the west, with the 12Z ECMWF model about 

60 n mi west of its previous run. The NHC track forecast has also 

been nudged to the west toward the various consensus models.

 

Although Philippe is still being affected by shear, the environment 

over the next couple of days appears to become less hostile. 

Moderate wind shear, upper-level diffluence, increasing mid-level 

humidities around the storm, and very warm SSTs should allow 

Philippe to gradually strengthen through the weekend. Beyond that 

time, the intensity forecast becomes more dependent on the future 

track. If Philippe tracks along the western side of the guidance, it 

will likely weaken due to stronger wind shear. Whereas, if the 

system tracks east of the NHC track, it could strengthen more than 

predicted due to more favorable environmental factors. The NHC 

intensity forecast is a little higher than the previous cycle in the 

short term, but is still on the low end of the guidance.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  29/2100Z 18.0N  55.9W   45 KT  50 MPH

 12H  30/0600Z 17.6N  56.2W   45 KT  50 MPH

 24H  30/1800Z 17.3N  56.5W   50 KT  60 MPH

 36H  01/0600Z 17.2N  57.0W   55 KT  65 MPH

 48H  01/1800Z 17.6N  57.4W   60 KT  70 MPH

 60H  02/0600Z 18.3N  58.0W   60 KT  70 MPH

 72H  02/1800Z 19.5N  58.3W   60 KT  70 MPH

 96H  03/1800Z 22.9N  58.7W   60 KT  70 MPH

120H  04/1800Z 26.9N  57.7W   60 KT  70 MPH

 

$$

Forecaster Cangialosi