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 658 
 WTNT43 KNHC 100244
 TCDAT3
 
 TROPICAL STORM HENRI DISCUSSION NUMBER   5
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082015
 1100 PM AST WED SEP 09 2015
 
 Recently received ASCAT-B scatterometer data showed an area of 35-40
 kt wind vectors in the convection about 75-100 n mi east of the
 center. Based on this, the initial intensity is increased to a
 possibly conservative 35 kt and the cyclone is upgraded to a
 tropical storm. Despite the upgrade, Henri remains a disorganized
 system, with the low-level center remaining exposed to the west of
 the convection due to 15-20 kt of shear.  In addition, microwave
 satellite data and experimental European multispectral satellite
 imagery suggest a tongue of dry air is entraining into the cyclone
 around the west, south, and southeast sides of the circulation.
 
 Henri has started its expected northward track with the initial
 motion of 355/4.  For the next 36-48 hours, the cyclone should move
 generally northward with an increase in forward speed between the
 subtropical ridge to the east and a deep-layer trough moving
 eastward through the eastern United States.  After that time, Henri
 should turn northeastward and eastward as it enters the westerlies.
 The new forecast track is similar to the previous track, but it lies
 a little south of the center of the guidance envelope after 36 hours
 due to a northward shift in the guidance.
 
 The dynamical models suggest that the shear should subside during
 the next 36-48 hours, and that the dry air entrainment should also
 decrease.  This combination should allow Henri to strengthen until
 it reaches colder sea surface temperatures north of the Gulf Stream
 in a little under 48 hours.  After that, the cyclone is expected to
 become extratropical as it merges with a frontal system.  The new
 intensity forecast calls for a peak intensity near 50 kt in 36-48
 hours, followed by gradual weakening.  The first 48 hours are in
 best agreement with the SHIPS model, and the intensities after
 extratropical transition are based on input from the NOAA Ocean
 Prediction Center.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  10/0300Z 31.3N  60.7W   35 KT  40 MPH
  12H  10/1200Z 32.8N  60.9W   40 KT  45 MPH
  24H  11/0000Z 35.3N  60.9W   45 KT  50 MPH
  36H  11/1200Z 38.6N  60.2W   50 KT  60 MPH
  48H  12/0000Z 42.4N  58.0W   50 KT  60 MPH
  72H  13/0000Z 47.5N  48.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
  96H  14/0000Z 47.5N  32.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 120H  15/0000Z 47.0N  17.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 
 $$
 Forecaster Beven
 
 
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