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 780 
 WTPA43 PHFO 011448
 TCDCP3
  
 Hurricane Miriam Discussion Number  26
 NWS Central Pacific Hurricane Center Honolulu HI   EP152018
 500 AM HST Sat Sep 01 2018
  
 Shear continues to profoundly affect the core of Miriam this 
 morning, with the low level circulation center (LLCC) now mostly 
 exposed along the southwest flank of diminishing deep convection.
 UW-CIMSS reports 41 kt of vertical wind shear across this system,
 up from 34 kt last evening. Good outflow exists only to the north 
 through north-northeast, consistent with the shear direction. 
 Subjective Dvorak current intensity estimates decreased to 4.0/65
 kt from PHFO and SAB, and to 3.5/55 kt from JTWC. ADT from UW-CIMSS
 was 65 kt. Initial intensity for this advisory is set at 65 kt
 which, like last time, represents weakening but may still be a bit
 too high given the rapidly deteriorating satellite presentation.
 
 Initial motion is 355/10 kt as Miriam continues northward between
 an upper trough to the northwest and a deep ridge to the northeast. 
 Track guidance continues to depict a turn toward the
 north-northwest through Sunday and toward the northwest on Monday.
 The guidance envelope is rather tight through 48 hours, with HWRF
 depicting a sharper turn toward the left as it forecasts rapid
 dissipation of this system and a greater role for low level steering
 in the near term. In contrast, ECMWF lies along the right side of
 the guidance envelope. The forecast track closely follows the
 previous one, neatly following TCVE consensus, but adjusted slightly
 to the right through 24 hours to account for initial motion.
 
 Miriam will continue to weaken in the face of increasing shear and 
 sub-26 degree C SSTs through the forecast period, with this system 
 forecast to dissipate at 72 hours. We expect Miriam will weaken to
 a tropical storm later today before becoming a post tropical
 remnant low early Monday. Some guidance dissipate Miriam earlier,
 with DSHIP and LGME calling for this at 36 and 48 hours,
 respectively. Our intensity curve follows HMNI through 12 hours,
 then along HWRF through dissipation.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  01/1500Z 22.2N 141.3W   65 KT  75 MPH
  12H  02/0000Z 23.6N 141.9W   55 KT  65 MPH
  24H  02/1200Z 25.4N 143.4W   40 KT  45 MPH
  36H  03/0000Z 27.1N 145.2W   30 KT  35 MPH
  48H  03/1200Z 28.7N 147.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
  72H  04/1200Z...DISSIPATED
  
 $$
 Forecaster Powell
  
 
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