Pacific Hurricane Feed

Tropical Depression Eighteen-E Forecast Discussion

WTPZ43 KNHC 041449

Tropical Depression Eighteen-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP182021
1000 AM CDT Thu Nov 04 2021

The area of low pressure we have been tracking since it formed 
several days ago over the southwestern Caribbean Sea has moved 
over the far eastern Pacific and gradually become better-defined 
over the past couple of days. In addition, the convective 
organization has steadily increased. An ASCAT-C overpass earlier 
this morning showed that the surface low was slightly elongated. 
However, the deep convection has persisted near, or just east of 
that low for several hours since that time. First light visible 
satellite imagery also indicates that the circulation is 
well-defined. Therefore, advisories are being initiated for 
Tropical Depression Eighteen-E. The ASCAT pass also showed peak 
winds of 28 kt associated with the system, and a blend of the latest 
Dvorak intensity estimates from TAFB and SAB suggest an initial 
advisory intensity of 30 kt.  

The initial motion of the depression is 280/7 kt. The cyclone is 
located to the south of a broad mid-tropospheric ridge extending 
across southern Mexico and much of the eastern Pacific basin. This 
feature should steer the depression generally westward for most of 
the forecast period, along with a gradual increase in forward speed. 
By day 5, a turn to the west-northwest may occur, as the cyclone 
becomes situated along the southwestern portion of the ridge. The 
track model guidance is in good agreement on this scenario, and the 
NHC track forecast is near the various multi-model consensus 

The environment surrounding and ahead of the depression appears 
generally favorable for strengthening with ample atmospheric 
moisture and SSTs of 27 to 28 degrees C. The only inhibiting factor 
to strengthening may be the westerly shear vector, which although 
should remain under 10 kt, when combined with the cyclone's 
increasing westerly forward motion may cause convection to 
periodically get stripped to its east of its center. Based on these 
conditions, the model guidance indicates a slow and steady pace of 
strengthening over the next several days, and NHC follows suit with 
an intensity forecast near the IVCN and NOAA-HCCA consensus. 


INIT  04/1500Z  9.4N  90.0W   30 KT  35 MPH
 12H  05/0000Z  9.6N  90.9W   30 KT  35 MPH
 24H  05/1200Z  9.4N  92.0W   35 KT  40 MPH
 36H  06/0000Z  9.2N  93.4W   35 KT  40 MPH
 48H  06/1200Z  9.0N  95.2W   40 KT  45 MPH
 60H  07/0000Z  9.0N  97.3W   40 KT  45 MPH
 72H  07/1200Z  9.0N  99.6W   45 KT  50 MPH
 96H  08/1200Z  9.7N 104.1W   50 KT  60 MPH
120H  09/1200Z 11.1N 108.5W   55 KT  65 MPH

Forecaster Latto

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