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Hurricane Dora Discussion Number  38
NWS Central Pacific Hurricane Center Honolulu HI   EP052023
1100 AM HST Wed Aug 09 2023
 
Dora continues to track westward across the central North Pacific, 
unscathed by shear and sustained by marginally warm ocean water. 
Satellite presentation includes a clearly-defined eye and a 
symmetrical central structure. While the periphery is a bit ragged 
in appearance, there is little or no evidence of shear effects. 
Surrounding dry air has not been entrained sufficiently to erode 
the core. Dora is very slowly gaining latitude but will pass far 
south of Johnston Island later today. All three fix agencies have 
derived subjective Dvorak intensity estimates of 6.0, corresponding 
to 115 kt. Latest UW-CIMSS ADT intensity is also 115 kt. Given the 
overall unchanged appearance of Dora over the past six hours, the 
obvious move is to assign her an initial intensity of 115 kt. 
 
Initial motion with this advisory is 275/19 kt, unchanged from the 
last advisory. Track guidance remains remarkably tight through tau 
72, with spread only becoming significant at tau 96 and tau 120, 
long after this system has passed out of the basin into the western 
North Pacific. Strong ridging north of Dora, and the westward 
migration of this ridging, accounts for this system's prolonged 
westward movement. However, the slow and rather recent increase in 
latitude indicates that Dora is reaching the southwest periphery of 
this ridging and is poised to begin a track to the west northwest. 
This track swing will continue as Dora is forecast to assume a 
northwest motion Thursday and Friday. The forecast track, closely 
following the previous track and TVCN model consensus, continues to 
become more northerly after Dora passes west of the date line.  

Warm water, with temperatures of 28 degrees C or above, lies along 
the entire forecast track and shear will be minimal through tau 72. 
With 18Z ECMWF SHIPS showing almost no Dora intensity drop through 
tau 36, this advisory will only slowly weaken this system through 
tau 60, with more pronounced weakening introduced afterwards as 
Dora gains latitude and shear increases. The 18Z GFS SHIPS shows a 
similar slow weakening trend, but through tau 24. Both SHIPS 
versions keep Dora stronger at all tau than most intensity model 
guidance, but Dora's demonstrated resilience increases confidence 
that a slower weakening trend, at least initially, is reasonable. 
Dora will eventually weaken to a post-tropical/remnant low, but 
just after tau 120.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/2100Z 11.6N 166.0W  115 KT 130 MPH
 12H  10/0600Z 12.0N 168.9W  115 KT 130 MPH
 24H  10/1800Z 12.8N 172.5W  110 KT 125 MPH
 36H  11/0600Z 13.7N 175.7W  110 KT 125 MPH
 48H  11/1800Z 14.8N 178.7W  105 KT 120 MPH
 60H  12/0600Z 15.7N 178.5E  100 KT 115 MPH
 72H  12/1800Z 16.5N 175.9E   90 KT 105 MPH
 96H  13/1800Z 17.7N 171.1E   65 KT  75 MPH
120H  14/1800Z 19.1N 167.1E   50 KT  60 MPH
 
$$
Forecaster Powell
 
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