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 WTPA43 PHFO 300858
 Hurricane Miriam Discussion Number  17
 NWS Central Pacific Hurricane Center Honolulu HI   EP152018
 1100 PM HST Wed Aug 29 2018
 The satellite presentation of Miriam has improved slightly since
 the previous advisory, with deep convection remaining over the
 difficult to locate low level circulation center. The latest
 subjective Dvorak intensity estimates from PHFO, SAB and JTWC ranged
 from 4.0 (65 knots) to 4.5 (77 knots) while the Advanced Dvorak
 Technique from UW-CIMSS came in at 3.5 (55 knots). Since the
 satellite presentation has improved slightly since the previous
 advisory, the initial intensity will be increased to 70 knots with
 this advisory, which correlates well with a blend of the intensity
 estimates. The initial motion is set at 300/07 knots.
 Miriam is being steered by a large subtropical ridge to the 
 northeast of the system and a deep mid-upper level trough to the 
 north-northwest. Miriam is expected to track off to the northwest 
 tonight then make a turn toward the north Thursday through Friday 
 night. The increasing west-southwesterly shear should result in a 
 decoupling of the system by early Saturday, and this is expected to 
 result in a turn toward the northwest and eventually west Saturday 
 through Monday as Miriam becomes influenced primarily by the low 
 level trade wind flow. The official forecast for this advisory is 
 nearly identical to the previous advisory and closely follows the 
 consensus guidance.
 The environment will be conducive for additional intensification of 
 Miriam over the next 24 hours, with shear values remaining low, sea 
 surface temperatures holding around 28C, while the system moves
 over a region of higher Ocean Heat Content. As a result the
 official forecast calls for slight intensification over the next 24
 hours, followed by slow and steady weakening between 24 and 36
 hours as Miriam begins to feel the effects of strengthening west-
 southwesterly shear. Beyond 36 hours the intensity forecast will 
 show fairly rapid weakening as shear values increase into the 30 to 
 45 knot range, while the system moves over marginal sea surface 
 temperatures of 26C or below.
 INIT  30/0900Z 14.7N 141.1W   70 KT  80 MPH
  12H  30/1800Z 15.4N 141.6W   75 KT  85 MPH
  24H  31/0600Z 16.8N 141.6W   80 KT  90 MPH
  36H  31/1800Z 18.4N 141.5W   70 KT  80 MPH
  48H  01/0600Z 19.9N 141.9W   55 KT  65 MPH
  72H  02/0600Z 23.0N 144.0W   40 KT  45 MPH
  96H  03/0600Z 25.5N 147.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 120H  04/0600Z 27.0N 152.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 Forecaster Jelsema
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