400 
 WTNT41 KNHC 020836
 TCDAT1
 
 TROPICAL STORM FRED DISCUSSION NUMBER  14
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062015
 500 AM AST WED SEP 02 2015
 
 Fred has been devoid of significant deep convection near the
 center for almost 6 hours. The pronounced upper-level circulation
 and associated convection is displaced at least 150 n mi to the
 east of the now fully exposed low-level circulation due to strong
 westerly vertical wind shear. The initial intensity of 40 kt is
 based on a gradual spin down of the 45-kt ASCAT-B vortex mentioned
 in the previous discussion, and a blend of 35-kt and 45-kt Dvorak
 satellite intensity estimates from SAB and TAFB, respectively.
 
 Now that the upper-level circulation has decoupled from the low- and
 mid-level circulations, it is unlikely that Fred will restrengthen
 since the cyclone will be moving over cooler SSTs of about 26 deg C,
 into even stronger shear in excess of 30 kt, and also into a much
 drier airmass. Cloud top temperatures in the radius of maximum
 winds are only in the -10 to -20 deg C range, which suggests that
 Fred's circulation now likely only extends no higher than the 400-mb
 level, if that. As a result, Fred should continue to slowly spin
 down and become a depression within the next 18-24 hours, and
 degenerate into a remnant low within 36 hours, if not sooner. The
 NHC intensity forecast follows a blend of the SHIPS, LGEM, and HWRF
 models, which steadily weaken Fred, and is lower than the IVCN model
 due to the GFDL model re-strengthening Fred into a 75-kt hurricane
 again, which has created a high bias in the consensus.
 
 The initial motion estimate is 295/09.  There remains no significant
 change to the previous track forecast or reasoning. Fred is
 expected to continue moving west-northwestward for the next 72 hours
 or so while it remains embedded within the trade wind flow south of
 the Bermuda-Azores subtropical high. After that time, the models
 continue to forecast a mid-latitude trough to dig southward over
 the central Atlantic and erode the western portion of the ridge,
 allowing Fred to turn slowly northwestward by 96 hours and
 northward by 120 hours. The new forecast track is a tad south of
 the previous advisory track, mainly due to the more southerly
 initial position. The track forecast also lies along the southern
 edge of the guidance envelope and is left of the TVCA consensus
 model due to the more northerly track created by the much stronger
 and vertically deeper GFDL model, which has strongly biased the
 consensus model with a more northward and eastward track.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  02/0900Z 19.5N  30.1W   40 KT  45 MPH
  12H  02/1800Z 20.0N  31.4W   35 KT  40 MPH
  24H  03/0600Z 20.7N  32.9W   30 KT  35 MPH
  36H  03/1800Z 21.2N  34.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
  48H  04/0600Z 21.6N  35.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
  72H  05/0600Z 22.3N  39.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
  96H  06/0600Z 23.5N  41.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
 120H  07/0600Z 25.6N  43.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Stewart