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 957 
 WTPZ45 KNHC 291434
 TCDEP5
 
 Tropical Storm Miriam Discussion Number  14
 NWS National Hurricane Center Miami FL       EP152018
 800 AM PDT Wed Aug 29 2018
 
 Although Miriam remains a sheared tropical cyclone, recent
 geostationary satellite data and a 1002 UTC AMSR2 microwave
 overpass indicates that there has been some improvement in the
 structure of the cyclone.  The microwave data showed an increase in
 banding over the eastern portion of the circulation and less
 separation between the convection and the low-level center.
 Therefore, the initial intensity is increased to 60 kt, which is a
 blend of the most recent subjective Dvorak classifications and
 objective T-numbers from UW/CIMSS.  The northwesterly shear over
 the cyclone appears to have abated slightly, and a further slight
 reduction in shear could allow Miriam to reach hurricane strength
 within the next 24-36 h.  Most of the intensity guidance agrees,
 and the NHC intensity forecast has been increased slightly for the
 first 36 h.  After that time, increasing shear and cooler waters are
 expected to cause Miriam to weaken fairly quickly and the system is
 forecast to become a remnant low by day 4.
 
 Miriam continues to move westward or 275/10 kt. The cyclone is
 approaching the western edge of the subtropical ridge, and the
 global models indicate that Miriam will slow down and turn
 west-northwestward very soon.  By Thursday, a large mid- to
 upper-level trough to the northeast of the Hawaiian Islands is
 expected to cause Miriam to turn northwestward, then northward
 through 72 hours.  At days 3 and beyond, there continues to be
 significant model differences with the ECMWF still taking Miriam
 faster and much farther northward, while the GFS moves a much
 weaker Miriam westward.  Since Miriam is forecast to weaken and
 become a shallow system around that time, the NHC forecast leans
 toward the more westward scenario, but is not as far south and west
 as the GFS. The new NHC track is south of the various consensus aids
 at day 5, and is in best agreement with the GFS ensemble mean
 and UKMET model.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  29/1500Z 14.2N 139.4W   60 KT  70 MPH
  12H  30/0000Z 14.4N 140.6W   65 KT  75 MPH
  24H  30/1200Z 15.1N 141.6W   65 KT  75 MPH
  36H  31/0000Z 16.3N 142.0W   65 KT  75 MPH
  48H  31/1200Z 17.9N 142.1W   60 KT  70 MPH
  72H  01/1200Z 21.0N 142.9W   45 KT  50 MPH
  96H  02/1200Z 23.8N 145.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 120H  03/1200Z 26.7N 149.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Brown
 
 
 
 154 
 WTPZ41 KNHC 291434
 TCDEP1
 
 Tropical Storm Norman Discussion Number   5
 NWS National Hurricane Center Miami FL       EP162018
 800 AM PDT Wed Aug 29 2018
 
 The cloud pattern has continued to improved in organization, and
 SSMIS data at 1400 UTC indicate that an inner core is beginning to
 form. The area of convection is large with a well defined
 cyclonically curved band wrapping around the system, while the
 upper-level outflow is expanding westward.  Based on objective and
 subjective T-numbers, the initial intensity has been set at 55 kt.
 The environment of low shear and warm waters is ideal for Norman to
 intensify, and in fact, the Rapid Intensification (RI) indices are
 quite high. On this basis, the NHC forecast calls for Norman to
 become a hurricane by tonight and a major hurricane in a day or so.
 
 The best estimate of the initial motion is toward the
 west-northwest or 285 degrees at 9 kt. The hurricane is ready to
 start moving more westward or even on a west-southwestward track as
 the nose of the ridge to the north begins to expand westward and
 amplify. Most of the models captured the building of the ridge, and
 unanimously forecast the cyclone to move west-southwestward for the
 next 2 to 4 days. The confidence is the forecast during the first 3
 to 4 days is high since track models are really clustered. The new
 NHC forecast is not too different from the previous one, and it lies
 between the corrected consensus HCCA and the multimodel aids.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  29/1500Z 17.8N 115.7W   55 KT  65 MPH
  12H  30/0000Z 17.9N 116.6W   65 KT  75 MPH
  24H  30/1200Z 18.1N 118.2W   90 KT 105 MPH
  36H  31/0000Z 17.9N 119.8W  105 KT 120 MPH
  48H  31/1200Z 17.5N 121.4W  110 KT 125 MPH
  72H  01/1200Z 16.2N 124.8W  110 KT 125 MPH
  96H  02/1200Z 16.0N 129.0W  100 KT 115 MPH
 120H  03/1200Z 17.5N 134.0W   90 KT 105 MPH
 
 $$
 Forecaster Avila
 
 
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