Good evening everyone!
The remnant of Dorian continues to struggle this evening. Based on a STWO (Special Tropical Weather Outlook) issued by the NHC at 3:35 p.m., reconnaissance aircraft did not find a closed surface circulation. The NHC has lowered the probability of regeneration of this remnant during the next 48 hours to 30%.
Recent satellite loop images and current wind shear map, indicate Dorian’s remnant is undergoing some 20-30 knots of SW shear at the moment, however the shear tendency has been decreasing directly over the system. The shear is evident in satellite loop imagery, as noted by the western edge oft he system being pretty much flattened.
The current upper level winds map does however show a good outflow channel, still west and north of the system, as indicated by the “fanning out” look in satellite imagery. In fact, water vapor imagery indicates two regions aiding in ventilation for the system at the moment.
Based on the most recent wind shear forecast from the GFS, should this remnant survive the current shearing process, and stave off any dry air intrusion, it may have one final chance at regeneration as it approaches the Florida Straits in a few days. The TUTT feature in the upper levels to its west at the moment, is forecast to lift and weaken somewhat slower than originally forecast, then become stronger temporarily, before shear may relax enough for upper level winds to become a little more conducive for regeneration, albeit chances at this time are looking slimmer for survival that far in time.
Since we are lacking a closed surface circulation, based on the current mid layer steering, the remnant should move in a general WNW direction over the next 18 hours or so, before taking on a more westerly heading, based on analysis of the 12Z run of the forecast steering layers maps, valid for 00Z 30 JUL. Current steering indicates a weakness in the ridge just over Florida.
Based on this analysis, I concur with the 18Z Dynamic Model Guidance, however I prefer the northern portion of the suit at this time, and I would expect within the next 2-3 days for the remnant to enter the Florida Straits, just north of the Cuban coast.
Regardless of development, portions of south Florida should see an increase in precipitation in about 3-4 days.
I will continue to monitor the remnant for any significant changes that may occur.
Elsewhere, a small area of convection has exited the west coast of Africa, and will be monitored for any development potential.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)