MY 2021 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #164
*******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.**********
...TUESDAY NOVEMBER 16 2021 12:33 AM EDT...
Satellite image as of 0500Z. 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 0000Z:
GFS Model Upper-Level Winds 1800Z (Nov 15):
See area of interest #1 section below for an update on the surface low pressure system south of the Azores.
Elsewhere… another deep-layered ridge is forecast to develop in the western Atlantic in the days ahead with the aid of the warm sector of another strong frontal system to cross North America. However the latest model runs have trended with a less amplified ridge… which reduces the chances for the current eastern North America upper trough becoming a southern-located cut-off upper vortex when that trough later moves across the Atlantic. Therefore at this time it appears less likely that this trough will be able to reach far south enough to re-energize the remnants of area of interest #1 with its eastern divergence zone… and the potential for subtropical development by next week from the remnants of area of interest #1 or any surface cyclone to be generated by the upper trough is low. However should model trends flip back to a more amplified upper trough… an area of interest for subtropical development will be declared as needed in future updates.
AREA OF INTEREST #1...The eastern Atlantic surface frontal low pressure once generated by the divergence zone of the east side of the cut-off upper vortex in the region is currently located well south of the Azores islands… and is migrating southwest into the west side of the upper vortex while pushed by the surface layer of the deep-layered ridge passing to the north. Meanwhile the upper vortex is not moving southwest with the surface low as the upper layer of the ridge is located more to the west. Conditions beneath the west side of the upper vortex are not favorable for subtropical development from a one-two punch of northerly wind shear and upper convergence… and the time has ran out for subtropical development of the surface low. Therefore this my planned final statement on this surface low on this blog.
Also note that the probability of this surface low’s remnants later becoming re-energized by the current eastern North America upper trough… once the trough moves out across the Atlantic… has reduced. See the intro section of this post for more information.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Nov 17)… 0% chance of subtropical cyclone formation (eastern Atlantic near 28N-35W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Nov 15)… CMC Model Run...
**For Area of Interest #1... frontal low shifts southwest to 24.5N-35.5W through 54 hours while weakening to a remnant trough.
1200Z (Nov 15) ECMWF Model Run...
**For Area of Interest #1... frontal low shifts southwest to 25N-34W through 72 hours while weakening to a remnant trough.
1800Z (Nov 15) GFS Model Run...
**For Area of Interest #1... frontal low shifts southwest to 24.5N-37W through 66 hours while weakening to a remnant trough.
1800Z (Nov 15) NAVGEM Model Run...
**For Area of Interest #1... frontal low shifts southwest to 25N-34W through 102 hours while weakening to a remnant trough.