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Tropical Storm Pilar Discussion Number  18
NWS National Hurricane Center Miami FL       EP192023
1000 PM CDT Wed Nov 01 2023

Deep convection near the center of Pilar has diminished 
significantly this evening.  Cloud tops associated with the cyclone 
are now generally warmer than -50 deg C.  This degradation in the 
cloud structure could be at least partially be caused by the 
system's passage over upwelled ocean waters near the coast.  Another 
factor could be some disruption due to the influence of a nearby 
Tehuantepec gap wind event.  Given the decrease in convection, it is 
assumed that some weakening has occurred and the current intensity 
is set at 40 kt for this advisory.  This is close to the mean of 
final T-numbers and CI numbers from TAFB and SAB. 

Center fixes indicate that the westward track is continuing with a 
motion estimate of 270/10 kt.  A prominent mid-level subtropical 
ridge is expected to remain north of Pilar, and strengthen further, 
during the next few days.  This should force a westward to 
west-southwestward motion with some increase in forward speed.  The 
official track forecast is again a little faster than the previous 
one and is a blend of the simple and corrected dynamical model 
consensus predictions.

The gap wind event and easterly vertical wind shear could cause 
some additional weakening during the next day or so.  Later in the 
forecast period, moderate shear and marginal thermodynamic 
conditions are likely to inhibit strengthening.  The NHC forecast 
shows very slow weakening through the period.  However, there is a 
possibility that the system will degenerate into a remnant low or a 
trough within the next 5 days.

 
Key Messages:
 
1. The combination of previous heavy rainfall and any additional 
rainfall from Pilar may produce flash and urban flooding, along with 
mudslides in areas of higher terrain of the Pacific coast from El 
Salvador into southern Guatemala overnight.
 
2. Swells generated by Pilar and strong winds near the Gulf of
Tehuantepec are expected to continue affecting the Pacific coast of 
Central America during the next day or two.  These swells are 
likely to cause life-threatening surf and rip current conditions.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0300Z 12.4N  92.6W   40 KT  45 MPH
 12H  02/1200Z 11.7N  94.8W   40 KT  45 MPH
 24H  03/0000Z 10.8N  97.8W   40 KT  45 MPH
 36H  03/1200Z  9.9N 101.0W   35 KT  40 MPH
 48H  04/0000Z  9.4N 104.1W   35 KT  40 MPH
 60H  04/1200Z  9.5N 106.8W   35 KT  40 MPH
 72H  05/0000Z  9.7N 109.2W   35 KT  40 MPH
 96H  06/0000Z 10.5N 113.1W   30 KT  35 MPH
120H  07/0000Z 11.3N 116.0W   30 KT  35 MPH
 
$$
Forecaster Pasch
 
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