ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
 
Tropical Storm Eta Discussion Number   4
NWS National Hurricane Center Miami FL       AL292020
1000 AM EST Sun Nov 01 2020
 
Eta appears to be gradually becoming better organized this morning. 
A small area of persistent, deep convection near and over the center 
has supported the development of a small central dense overcast. 
Meanwhile, a larger convective band with limited curvature is noted 
well northeast and east of the storm center. Objective intensity 
estimates from UW-CIMSS and subjective Dvorak classifications from 
TAFB and SAB support an initial intensity of 35 kt. It should be 
noted that the center was relocated a bit farther south this morning 
based on overnight microwave imagery.  A NOAA Hurricane Hunter 
aircraft is scheduled to investigate Eta this afternoon. 
 
Weak vertical wind shear and high oceanic heat content should 
support steady strengthening over the next couple of days. The SHIPS 
Rapid Intensification Index still indicates the potential for rapid 
strengthening, and the official NHC intensity forecast lies on the 
higher end of the guidance envelope. The current forecast shows Eta 
becoming a hurricane by 36 h, and continued strengthening is 
forecast through landfall. Once inland, Eta should quickly weaken 
over the mountainous terrain of Central America.
 
The tropical storm is moving westward at around 13 kt. A westward or 
west-southwestward motion with a gradual decrease in forward speed 
is expected over the next several days, as Eta is steered by a 
mid-level ridge positioned to its north and northwest. The track 
guidance remains fairly tightly clustered through about 72 h, and 
the only change with this forecast is a slight southward correction 
based on the relocated center position. The official NHC forecast 
now brings Eta inland over Central America by 60 h. There is 
increased uncertainty in the track forecast post-landfall, with a 
range of plausible outcomes. While much of the guidance suggests Eta 
will spin down and weaken over Central America or possibly cross 
into the eastern Pacific, some model solutions indicate the 
potential for Eta or its remnants to re-emerge over the northwestern 
Caribbean Sea at or beyond day 5. For now, the official NHC forecast 
remains close to the previous one and the corrected consensus aid 
HCCA, which keeps the cyclone inland over Central America through 
day 5.
 
 
Key Messages:
 
1. Eta is expected to strengthen to a hurricane before it reaches 
the coast of Central America early Tuesday, and there is a risk of 
storm surge, hurricane-force winds, and heavy rainfall for portions 
of Nicaragua and Honduras, where Hurricane and Tropical Storm 
Warnings have been issued.
 
2. Through Thursday afternoon, heavy rainfall from Eta may lead to 
life-threatening flash flooding and river flooding across portions 
of Jamaica, the Cayman Islands, and Central America, along with 
landslides in areas of higher terrain.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/1500Z 14.8N  77.2W   35 KT  40 MPH
 12H  02/0000Z 14.9N  78.9W   45 KT  50 MPH
 24H  02/1200Z 14.9N  80.6W   55 KT  65 MPH
 36H  03/0000Z 14.5N  81.9W   65 KT  75 MPH
 48H  03/1200Z 14.2N  82.7W   75 KT  85 MPH
 60H  04/0000Z 13.9N  83.6W   70 KT  80 MPH...INLAND
 72H  04/1200Z 13.8N  84.4W   45 KT  50 MPH...INLAND
 96H  05/1200Z 14.1N  86.7W   30 KT  35 MPH...INLAND
120H  06/1200Z 14.6N  88.2W   25 KT  30 MPH...INLAND
 
$$
Forecaster Reinhart/Brown/Berg
 
NNNN