IFEX daily log
Wednesday, September 28, 2005
Whereas the Caribbean system looked promising yesterday, today it looks very
disorganized. Infrared imagery (Fig. 208) indicates that the system has returned to a
more linear state. The system has been following a pattern where concentrated
convection develops during the daytime hours and then dissipates during the overnight
hours. This is opposite from the normal diurnal cycle of convective maximum during the
overnight hours and convective minimum during the daytime hours. One of the factors
that may be playing an inhibiting role in the organization of convection is an upper-level
cyclonic circulation located over Florida and extending into western Cuba (Fig. 209).
This may be imparting some westerly shear on the northern part of the system that is
preventing convection from developing and organizing. If it does become a depression,
however, track guidance (Fig. 210) generally brings it close to the Yucatan within 2 days.
Because of the lack of organization of the system, no research flights are planned for
tomorrow. The last window of opportunity for flying is Friday. If the system does
become a tropical depression by tomorrow a mission may be tasked for Friday. That will
be dependent on how close the system is to land, however.
Figure 208. GOES-East infrared image valid 1245 UTC September 28.
Figure 209. CIMSS-derived cloud motion vectors for 100-500 hPa layer (barbs, kt) valid
03 UTC September 28.
Figure 210. Track guidance for Caribbean system valid 12 UTC September 28.
Rob Rogers
HRD Field Program director
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