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Tropical Storm Hernan Discussion Number   6
NWS National Hurricane Center Miami FL       EP132020
900 AM MDT Thu Aug 27 2020
 
First light visible satellite imagery reveals that Hernan remains a
sheared tropical cyclone with most of the deep convection confined
to the western semicircle. Even though convection has waned a
bit overnight, there appears to be a new cluster developing. 
Therefore the initial intensity is being held at 40 kt, based on 
the earlier morning ASCAT overpass.
 
Hernan should at least maintain its current strength for the next
12-24 h as it remains over very warm waters while battling moderate
easterly shear. This shear is not forecast to abate during the
forecast period. And after 24 h, the cyclone is expected to begin
moving over progressively cooler waters. The combination of these
two factors should induce a weakening trend. By 60 h, simulated
satellite imagery by global models suggest that the cyclone will
become devoid of deep convection. After that time, the remnant low
is expected to be absorbed within the broader circulation of
Hernan to its west. The latest NHC intensity forecast is close to
the IVCN/ICON intensity consensus.
 
Hernan has turned to the north-northwest and is moving at about 4
kt. There is no change to the track forecast reasoning. Hernan is
expected to remain caught within a large-scale, eastern North
Pacific cyclonic gyre during the next few days, which will result in
Hernan moving counter-clockwise around the eastern and northern
periphery of the gyre. The cyclone will continue to parallel the
coast of southwestern Mexico through this evening, followed by a
northwestward then westward turn tonight and Friday. The westward
motion should continue until the system becomes absorbed early next
week.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/1500Z 19.1N 106.2W   40 KT  45 MPH
 12H  28/0000Z 20.1N 107.0W   40 KT  45 MPH
 24H  28/1200Z 21.2N 108.5W   35 KT  40 MPH
 36H  29/0000Z 22.2N 110.2W   30 KT  35 MPH
 48H  29/1200Z 22.8N 112.3W   30 KT  35 MPH
 60H  30/0000Z 22.5N 113.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  30/1200Z...ABSORBED
 
$$
Forecaster Latto
 
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