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Tropical Storm Pilar Discussion Number  17
NWS National Hurricane Center Miami FL       EP192023
400 PM CDT Wed Nov 01 2023
 
Convection over and near Pilar's low-level circulation continues to
flare periodically.  A recent burst of convection has obscured the
center on visible satellite imagery.  Satellite intensity estimates
have trended downward this cycle, with 45 kt from TAFB and SAB
and a range of 33-49 kt from various objective estimates.  The
initial intensity has been lowered to 45 kt based on these values.
 
Pilar is accelerating westward with an estimated motion of 270/9
kt.  This general motion with an increase in forward speed is
forecast for the next few days as the storm is steered along the
south side of a mid-level ridge.  The model guidance has
accelerated again from the previous advisory.  The latest forecast
track is a blend of the prior prediction and the latest simple and
corrected consensus aids.
 
Moderate deep-layer vertical wind shear is expected to persist for
at least another 24 hours.  While the shear decreases beyond a day,
Pilar will likely encounter a drier, more stable airmass associated
with a Gulf of Tehuantepec gap wind event.  These environmental
conditions, along with cooler, upwelled ocean waters should result
in a gradual weaken trend as indicated by the majority of the
dynamical intensity guidance.  The official intensity forecast
reflects this scenario and is closest to the simple model consensus. 
There remains the possibility that Pilar could weaken sooner and 
become a post-tropical cyclone or open into a trough.  However, the 
official forecast conservatively maintains a 5-day forecast for now.
 
 
Key Messages:
 
1. Additional heavy rainfall from Pilar will produce flash and urban
flooding, along with mudslides in areas of higher terrain of the
Pacific coast of Central America from southern El Salvador, across
southern Honduras, western Nicaragua into northern Costa Rica
through today.
 
2. Swells generated by Pilar will continue to affect 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  01/2100Z 12.4N  91.7W   45 KT  50 MPH
 12H  02/0600Z 12.0N  93.4W   45 KT  50 MPH
 24H  02/1800Z 11.1N  96.2W   40 KT  45 MPH
 36H  03/0600Z 10.2N  99.4W   40 KT  45 MPH
 48H  03/1800Z  9.5N 102.4W   35 KT  40 MPH
 60H  04/0600Z  9.3N 105.1W   35 KT  40 MPH
 72H  04/1800Z  9.4N 107.8W   35 KT  40 MPH
 96H  05/1800Z 10.0N 111.7W   30 KT  35 MPH
120H  06/1800Z 10.9N 115.0W   30 KT  35 MPH
 
$$
Forecaster Bucci
 
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