*******Note that forecasts and outlooks in this post are NOT the official forecast from the National Hurricane Center (NHC). They are my own detailed views on the Atlantic tropics based on current observations and latest computer model runs. As such do not make decisions based on my posts...consult news media...watches and warnings from your local weather office...and any evacuation orders issued by local governments to make the most informed and best decisions. Visit the NHC website hurricanes.gov (hurricanes dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.**********
...THURSDAY NOVEMBER 18 2021 10:10 PM EDT...
Satellite image as of 2350Z. Areas of interest circled in yellow are not mentioned in the NHC tropical weather outlook. Areas circled in a green dashed line are in the NHC 5-day tropical weather outlook. Areas circled in a solid green are in the NHC 2-day tropical weather outlook:
NHC TAFB Surface Analysis 1200Z:
GFS Model Upper-Level Winds 1200Z:
A warm deep-layered ridge is developing in the western Atlantic with the aid of the warm sector of the current central Canada frontal cyclone. The ridge is forecast to cut-off a large portion of the upper trough currently in the North Atlantic into an upper vortex located just west of the Azores…with the divergence zone of the vortex in turn generating a surface cyclone in the days ahead. Models still vary on the shape and amplitude of the western Atlantic ridge… which results in some solutions that have an elongated upper vortex with a broad upper divergence zone which in turn causes the forecast surface cyclone to be elongated with possible multiple centers instead of a singular circular center needed for subtropical development. As a result I have not declared an area of interest for the forecast surface cyclone. However it should be noted that regardless of subtropical development… the surface cyclone is expected to generate a period of gusty winds and coastal sea swells for the Azores in 3 to 5 days. The surface cyclone will likely be a long-duration feature while becoming re-invigorated by the divergence zone of amplified upper vorticity to be deposited by the current central Canada upper trough… once that trough moves later moves into the Atlantic in the longer range.
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z CMC Model Run...
**Current North Atlantic cold front develops a surface low west of the Azores at 30 hours with the support of an upper vortex to be left behind by the current North Atlantic upper trough… frontal low intensifies into an elongated frontal cyclone through 102 hours while cyclonically whirling beneath the upper vortex… through 138 hours the surface cyclone whirls west-northwest toward upper vorticity to be left behind by the current upper trough over central Canada (once that trough later moves into the Atlantic) while becoming less organized/more elongated
1200Z ECMWF Model Run...
**Current North Atlantic cold front develops a surface low west of the Azores at 24 hours with the support of an upper vortex to be left behind by the current North Atlantic upper trough…frontal low intensifies into a frontal cyclone with circular possible tropical core through 72 hours while cyclonically whirling beneath the upper vortex…through 120 hours the surface cyclone whirls west-northwest toward upper vorticity to be left behind by the current upper trough over central Canada (once that trough later moves into the Atlantic) while becoming less organized/more elongated
1800Z GFS Model Run...
**Current North Atlantic cold front develops a surface low west of the Azores at 24 hours with the support of an upper vortex to be left behind by the current North Atlantic upper trough…frontal low intensifies into an elongated frontal cyclone through 102 hours while cyclonically whirling beneath the upper vortex…through 144 hours the surface cyclone whirls west-northwest toward upper vorticity to be left behind by the current upper trough over central Canada (once that trough later moves into the Atlantic) while becoming less organized/more elongated
1800Z NAVGEM Model Run...
**Current North Atlantic cold front develops a surface low west of the Azores at 18 hours with the support of an upper vortex to be left behind by the current North Atlantic upper trough…frontal low intensifies into a frontal cyclone with circular possible tropical core through 102 hours while cyclonically whirling beneath the upper vortex at a location south of the Azores… afterwards the current upper trough over central Canada deposits upper vorticity in the region and the surface cyclone performs a second cyclonic loop south of the Azores through 168 hours while becoming less organized/more elongated