[Ncep.nhc.nco_contacts] HSU Shift Log -- Technical Edition -- Mon Sep 26, 2016

HSU Shift Log nhc.tsbadmin at noaa.gov
Mon Sep 26 09:38:25 UTC 2016

HSU Shift Log for Mon Sep 26 2016 05:38:18 GMT-0400 (EDT)

Shift: A

Forecaster: SR Stewart

Technical Issues Summary:

ATCF issues: None.

N-AWIPS/AWIPS2 issues: None.

Other Techincal issues: SHIPS intensity model uses TABM model. On 00Z  
output, maximum intensity was 79 kt and 76 kt from DSHIPS and LGEM,  
respectively. However, on 06Z output, the intensities increased sharply to  
107 kt and 90 kt from DSHIPS and LGEM, respectively. Why? Answer: TABM  
created 'self-inflicted' shear of 30 kt and 26 kt at 84 h and 96 h,  
respectively due the center being located at about 16N latitude, which was  
in strong westerly shear caused by the large outflow/ULAC created by the  
GFS model due its significant intensification of Invest 97L when it gets  
into the ecntral Caribbean Sea.In contrast, on the 06Z run, TABM had the  
center of Invest 97L about 4 degrees of latitude/240 nmi south of the 00Z  
positions at 84h and 96 h, which was much closer to the GFS and TVCN  
positions. Also, 00Z SHIPS had no GFS 850 mb vortex (ie, LOST), and the now  
the more equatorward 06Z run does since it is closer to the GFS track.  
SUGGESTION -- once the pre-genesis TVCN forecast track becomes available,  
SHIPS should defer from TABM to TVCN, since TVCN is usually going to be  
pretty close to what we use operationally when issuing advisories. This  
would prevent the large jumps in model intensity output such as what  
occurred between 26/00Z and 26/06Z runs.
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