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Tropical Storm Elida Discussion Number   6
NWS National Hurricane Center Miami FL       EP092020
300 AM MDT Mon Aug 10 2020
 
After the earlier burst of deep convection and the development of a 
small 10-nmi-wide low- to mid-level eye noted in passive microwave 
satellite imagery, convection has waned somewhat and the eye feature 
has eroded in the northwestern semicircle due to entrainment of dry 
air, along with some modest northwesterly vertical wind shear. A 
0314Z ASCAT-A overpass revealed peak winds of only 43 kt in the 
northeastern quadrant, along with a radius of maximum winds (RMW) 
of 10-15 nmi. Satellite intensity estimates range from T3.5/55 kt 
from TAFB to T4.0/65 kt from SAB, along with a UW-CIMSS SATCON 
estimate of 53 kt and an ADT estimate of 59 kt. An average of these 
intensity estimates, and allowing for some undersampling by the 
scatterometer instrument due to Elida's small RMW, supports 
maintaining an intensity of 55 kt for this advisory.

The initial motion estimate remains west-northwestward or 300/13 kt. 
Both the forecast track and rationale remain straight-forward and 
basically unchanged from the previous advisory. Elida is expected to 
be steered west-northwestward by a deep layer ridge to the north for 
the next 72 hours or, followed by a westward motion on days 4 and 5 
when Elida will be weakening over much cooler waters and becoming a 
shallower cyclone. The latest NHC track guidance remains tightly 
packed and, thus, the new official forecast is very similar to the 
previous advisory track, and lies near the TVCE and NOAA-HCCA 
consensus track models.
 
The brief intensity hiatus that Elida is experiencing is expected 
to be short-lived due to the cyclone's small RMW and the vertical 
shear forecast to decrease to less than 10 kt in the 12-36 hour 
time frame. This should allow for Elida to strengthen -- possibly 
even rapidly -- during the next 24 hours, followed by a leveling 
off in the intensity due to the cyclone moving over sub-26C 
sea-surface temperatures (SST).  By 48-60 h, SSTs less than 25C and 
modest southwesterly vertical wind shear will combine to induce 
steady weakening. By 96 h or so, Elida is forecast to degenerate 
into a post-tropical cyclone. The new official intensity forecast is 
a little lower than the previous advisory, but is a little above 
the consensus models IVCN and HCCA.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0900Z 18.3N 108.8W   55 KT  65 MPH
 12H  10/1800Z 19.1N 110.8W   65 KT  75 MPH
 24H  11/0600Z 20.0N 113.5W   75 KT  85 MPH
 36H  11/1800Z 20.8N 116.2W   80 KT  90 MPH
 48H  12/0600Z 21.5N 118.6W   65 KT  75 MPH
 60H  12/1800Z 22.2N 120.7W   55 KT  65 MPH
 72H  13/0600Z 22.6N 122.6W   45 KT  50 MPH
 96H  14/0600Z 22.2N 125.7W   35 KT  40 MPH...POST-TROPICAL
120H  15/0600Z 21.4N 128.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Stewart
 
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