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 WTPZ45 KNHC 270243
 Tropical Storm Miriam Discussion Number   4
 NWS National Hurricane Center Miami FL       EP152018
 800 PM PDT Sun Aug 26 2018
 The overall cloud pattern of Miriam has continued to gradually
 improve this evening.  However, light northerly shear of about 10
 kt, as analyzed by UW-CIMSS, seems to be preventing the cyclone from
 strengthening at a more rapid pace.  Earlier ASCAT data and a more
 recent partial AMSR overpass indicated that the low-level center of
 Miriam is slightly displaced to the northwest of most of the deep
 convection, but is still well-embedded within the cirrus canopy.  A
 consensus of objective and subjective satellite intensity estimates
 suggests that Miriam has strengthened a little since the last
 advisory, so the initial intensity has been increased to 45 kt.
 The tropical storm is still moving westward at around 12 kt, and all
 indications are that this motion will continue for the next few
 days.  By day 4, Miriam should turn northward as it reaches a break
 in the subtropical ridge created by an extensive mid- to upper-level
 low located over the central North Pacific.  The track guidance is
 in good agreement on this general scenario, but still differs on the
 exact timing and location of the northward turn.  The NHC forecast
 therefore remains near the middle of the guidance envelope, and is
 essentially a blend of the HCCA and TVCX consensus aids and the
 previous forecast.
 Steady strengthening is still likely for the next day or two. While
 Miriam's structure does not appear to be conducive for rapid
 intensification at the moment, this could change quickly and with
 little warning due to the small size of the cyclone's inner-core.
 The model spread increases from 36 h onward, with the dynamical
 models indicating continued intensification to major hurricane
 strength, while the statistical guidance is much lower. Regardless
 of Miriam's peak intensity, by the end of the forecast, steady
 weakening is likely as Miriam encounters lower SSTs and higher
 shear.  The NHC forecast continues to favor the higher dynamical
 models for the first couple of days, and closely follows the
 intensity consensus after that.
 INIT  27/0300Z 13.8N 127.9W   45 KT  50 MPH
  12H  27/1200Z 13.9N 129.7W   55 KT  65 MPH
  24H  28/0000Z 13.7N 131.9W   65 KT  75 MPH
  36H  28/1200Z 13.8N 134.0W   80 KT  90 MPH
  48H  29/0000Z 13.9N 136.0W   90 KT 105 MPH
  72H  30/0000Z 14.3N 139.5W   90 KT 105 MPH
  96H  31/0000Z 16.8N 141.3W   80 KT  90 MPH
 120H  01/0000Z 21.0N 141.5W   65 KT  75 MPH
 Forecaster Zelinsky
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