*******Note that forecast 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 AUGUST 20 2024 11:09 PM EDT...
See Ernesto section below for a final update on the north Atlantic hurricane which has transitioned into a remnant non-tropical frontal cyclone.
For the tropical latitudes of the Atlantic... tropical activity has been limited by dry Saharan air. Within the last day satellite animation across Africa (https://tropic.ssec.wisc.edu/real-time/europe/movies/m7irn/m7irn_loop.html) shows that a northern tropical wave of low pressure emerged from the coast of Mauritania and into the eastern tropical Atlantic... however the wave lacks thunderstorms as its northward position allowed it into easily ingest dry air from the north Africa Sahara desert. Satellite animation also shows a second tropical wave of low pressure featuring a large area of rotating thunderstorm bands... located further south... has raced westward across western Africa from central Africa. It appears the two waves have high potential to merge into a broad tropical low pressure system over the eastern Atlantic within the next couple of days... however tropical development of the merged system appears unlikely as the aforementioned northern of the two waves from the merger will help mix in dry Saharan air.
For the mid-latitudes of the Atlantic... the current upper trough and surface frontal system slowly departing eastern North America is depositing the tail end of a surface cold front across the Gulf of Mexico and western Atlantic. The western Atlantic portion of the surface front is not expected to undergo tropical development as southwesterly shear levels remain elevated as the upper trough pushes offshore. For the Gulf of Mexico... over the six days... the shortwave upper trough that recently passed over the Dakotas (a piece of energy that recently separated from the large-scale western North America upper trough) is forecast to make an anticyclonic revolution around the periphery of the steering central North America upper ridge... taking the shortwave energy south across the eastern United States through day 3 then west across the Gulf of Mexico and into the Texas/Mexico border region through day 6 as an upper vortex. In the days ahead will watch to see if divergence between the periphery of the forecast upper vortex and surrounding upper flow results in a tropical disturbance along the decaying Gulf of Mexico portion of the surface front.
REMNANTS OF ERNESTO... After the northwest part of Hurricane Ernesto's circulation swiped southeastern Newfoundland late Monday... Ernesto has proceeded very rapidly east across the north Atlantic while caught in the jet stream along the north side of the regional upper ridge. After losing its core of thunderstorms Ernesto was downgraded by the NHC to a remnant non-tropical frontal cyclone at 11 AM EDT earlier today. Ex-Ernesto is currently supported by upper divergence on the northeast side of the regional upper ridge as marked in the above birdseye view chart. The north side of the lengthy upper trough emerging from eastern North America is tilted toward ex-Ernesto with its divergence zone producing a developing frontal low to the north of ex-Ernesto. Within the next 36 hours the larger frontal low is forecast to absorb ex-Ernesto as ex-Ernesto moves into the British Isles... with the southeast side of the absorbing frontal low producing gusty winds and coastal surf across the British Isles... the North Sea region of Europe... and Scandinavia (the northwest side of the absorbing frontal low will produce similar conditions across Iceland). Because Ernesto is no longer a tropical system... this is my final statement on it on this blog.
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/).
1200Z (Aug 20) CMC Model Run...
**No tropical development shown in Atlantic basin through 7 days (168 hours)
1200Z (Aug 20) ECMWF Model Run...
**No tropical development shown in Atlantic basin through 7 days (168 hours)
1200Z (Aug 20) GFS Model Run...
***No tropical development shown in Atlantic basin through 7 days (168 hours)
0600Z (Aug 20) NAVGEM Model Run...
**No tropical development shown in Atlantic basin through 7 days (168 hours)
Comments