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WTPZ44 KNHC 311444

TCDEP4

 

Tropical Storm Pilar Discussion Number  12

NWS National Hurricane Center Miami FL       EP192023

1000 AM CDT Tue Oct 31 2023

 

Pilar's structure has changed little since last night.  GOES-16

one-minute visible satellite imagery shows that the center is

exposed to the southeast of the main convective mass, with some

banding noted over the far northeastern portion of the circulation.

Subjective Dvorak satellite estimates from both TAFB and SAB were

T3.0 or 45 kt at 1200 UTC, and the initial intensity remains at

that value for this advisory.

 

Pilar is still moving slowly eastward or 090/3 kt.  The storm is 

forecast to stall later today as the steering current over the far 

eastern Pacific collapse.  On Wednesday, a narrow mid-level

ridge is forecast to build to the north and northeast of Pilar

which should cause the storm to begin moving west-southwestward. A

west-southwestward to westward motion is then expected into the 

weekend as the ridge builds westward to the north of the storm.  The

latest NHC track forecast is similar to the previous advisory and

is a blend of the the ECMWF, GFS, and the latest consensus aids.

The Tropical Storm Watch for portions of Central America remains in

effect, but given the latest model trends it could be discontinued

later today or this evening.  Although the threat of tropical-storm- 

force winds appears to be diminishing, the risk of heavy rain and 

flash flooding is expected to continue over portions of Central 

America during the next couple of days.

 

Some slight strengthening is possible during the next day or so

as the storm is located within moderate vertical wind shear and

over warm sea surface temperatures. However, the latest NHC

forecast calls for a little less intensification during this time

than before.  As Pilar moves westward the shear could relax, but

intrusions of dry air from a gap wind event are likely to hold the

intensity in check.  Very late in the period, the intensity guidance

suggests that environmental conditions could become a little more

conducive to support some strengthening during the weekend, and the

NHC wind speed forecast has been adjusted accordingly.

 

Key Messages:

 

1. Heavy rains 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 

Wednesday.



2. Tropical storm conditions are possible along portions of the

Pacific coast of El Salvador, Honduras, and Nicaragua, where a

Tropical Storm Watch remains in effect.

 

3. Swells generated by Pilar will continue to affect the Pacific

coast of Central America during the next few days.  These swells are

likely to cause life-threatening surf and rip current conditions.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  31/1500Z 11.2N  89.9W   45 KT  50 MPH

 12H  01/0000Z 11.5N  89.8W   50 KT  60 MPH

 24H  01/1200Z 11.7N  90.2W   50 KT  60 MPH

 36H  02/0000Z 11.5N  91.4W   50 KT  60 MPH

 48H  02/1200Z 11.1N  93.4W   45 KT  50 MPH

 60H  03/0000Z 10.5N  95.8W   45 KT  50 MPH

 72H  03/1200Z  9.9N  98.5W   45 KT  50 MPH

 96H  04/1200Z  9.4N 103.8W   45 KT  50 MPH

120H  05/1200Z  9.8N 108.7W   50 KT  60 MPH

 

$$

Forecaster Brown