####018003416####
WTNT42 KNHC 020839

TCDAT2

 

Tropical Storm Philippe Discussion Number  36

NWS National Hurricane Center Miami FL       AL172023

500 AM AST Mon Oct 02 2023

 

The overall structure of Philippe has changed very little during the 

past day or so.  Deep convection remains confined to the 

southeastern portion of the circulation due to moderate to strong 

northwesterly vertical wind shear.  There is no significant banding 

features, but the cloud tops within the main convective mass are 

quite cold.  Radar imagery from Barbados shows very heavy rainfall 

is occurring just east of the Lesser Antilles.  The initial 

intensity is held at 45 kt in deference to the earlier aircraft 

data, and the latest subjective Dvorak intensity estimates which are 

unchanged from before.  The next Air Force Reserve reconnaissance 

aircraft mission is scheduled to investigate Philippe later this 

morning.

 

Center fixes during the past 6-12 hours indicate that Philippe has 

turned northwestward (315 degrees) and is moving a little faster, 

around 6 kt.  Philippe is forecast to move around the southwestern 

portion of a mid-level ridge over the subtropical Atlantic during 

the next couple of days.  After that time, Philippe should turn 

northward between the aforementioned ridge and a mid- to upper-level 

trough over the southwestern Atlantic.  Around day 5, there is 

increasing uncertainty as to whether Philippe will turn 

east-northeastward or continue on a more northerly trajectory ahead 

of a large trough moving into the eastern United States. Little 

change was made to the previous forecast through 72 hours, but after 

that time the track was adjusted northwestward closer to the GFS 

ensemble mean.  The new track is not as far west as the latest ECMWF 

or the multi-model consensus aids.

 

Strong westerly vertical wind shear is expected to prevent 

significant strengthening for about another 12-24 hours.  After that 

time, Philippe is expected to encounter a more favorable upper-level 

wind pattern as it moves northward over the Atlantic. This should 

allow for steady strengthening, and much of the guidance predicts 

that Philippe will become a hurricane in 3 to 4 days.  The NHC 

intensity forecast follows suit, and is a blend of the HFIP 

corrected consensus model and the multi-model (ICVN) intensity aid.

 

 

KEY MESSAGES:

 

1. Tropical storm conditions are possible across portions of the

northern Leeward Islands through tonight while Philippe passes near

or just northeast of the area, and a Tropical Storm Watch is in

effect for Antigua and Barbuda.  Interests elsewhere in the northern

Leeward Islands should continue to monitor this system.

 

2. Heavy rainfall from Philippe could produce isolated to scattered

flash flooding, particularly across Barbuda and Antigua, through

Tuesday.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  02/0900Z 17.1N  60.0W   45 KT  50 MPH

 12H  02/1800Z 17.7N  60.7W   45 KT  50 MPH

 24H  03/0600Z 18.6N  61.4W   45 KT  50 MPH

 36H  03/1800Z 19.8N  61.8W   50 KT  60 MPH

 48H  04/0600Z 21.2N  62.2W   50 KT  60 MPH

 60H  04/1800Z 22.7N  62.3W   55 KT  65 MPH

 72H  05/0600Z 24.6N  62.2W   60 KT  70 MPH

 96H  06/0600Z 28.3N  60.8W   70 KT  80 MPH

120H  07/0600Z 31.7N  58.9W   75 KT  85 MPH

 

$$

Forecaster Brown