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WTPZ44 KNHC 312035

TCDEP4

 

Tropical Storm Pilar Discussion Number  13

NWS National Hurricane Center Miami FL       EP192023

400 PM CDT Tue Oct 31 2023

 

Satellite imagery shows that Pilar's center remains exposed on the 

southeast side of the main convective plume. Earlier AMSR2 and 

SSMI/S microwave imagery depicts some partial banding features 

within the northern semi-circle. Scatterometer ASCAT-B and -C passes 

this afternoon shows satellite derived winds are around 40 to 45 

knots. These values are in good agreement with the latest Dvorak 

satellite intensity estimates from both TAFB and SAB, T/3.0 or 45 

knots. Therefore, given the combination of data this the 

initial intensity remains at 45 kt for this advisory.

 

Pilar is moving slowly east-northeastward or 060/3 kt. The storm is 

forecast to move very little tonight as the steering currents over 

the far eastern Pacific collapse. A mid-level ridge is then forecast 

to build to the north and northeast of Pilar, which should cause the 

storm to begin moving west-southwestward. As the mid-level ridge 

continues to build westward, Pilar will be steered on a 

west-southwestward to westward motion along the southern side of the 

ridge. The latest NHC track forecast is similar to the previous 

advisory and lies near the latest consensus aids. The threat of 

tropical-storm-force winds should begin to diminish as Pilar starts 

moving westward, but the risk of heavy rain and flash-flooding is 

expected to continue over portions of Central America over the next 

couple of days.

 

Some slight strengthening is possible during the next day or so as 

the storm is located over warm sea surface temperatures and moderate 

vertical wind shear. In about 2 to 3 days vertical wind shear is 

forecast to weaken, but dry air from a gap wind event from the Gulf 

of Tehuantepec may limit intensification.  Towards the end of the 

period, the environmental conditions may become a little more 

conducive and the official forecast depicts strengthening once 

again. The NHC intensity forecast lies near the corrected HCCA 

consensus aids.

 

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  31/2100Z 11.4N  89.5W   45 KT  50 MPH

 12H  01/0600Z 11.5N  89.7W   50 KT  60 MPH

 24H  01/1800Z 11.5N  90.5W   50 KT  60 MPH

 36H  02/0600Z 11.2N  92.2W   50 KT  60 MPH

 48H  02/1800Z 10.7N  94.5W   45 KT  50 MPH

 60H  03/0600Z 10.1N  97.2W   45 KT  50 MPH

 72H  03/1800Z  9.6N 100.0W   45 KT  50 MPH

 96H  04/1800Z  9.5N 105.3W   45 KT  50 MPH

120H  05/1800Z 10.1N 109.3W   50 KT  60 MPH

 

$$

Forecaster Kelly