*******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.*********
...UPDATE...FRIDAY APRIL 26 2024 12:30 PM EDT...
For tropical area of interest #1 in the eastern Atlantic... the surface low pressure swirl is in the process of dissipating near 20N-40W and tropical cyclone formation is not expected.
For the north-central Atlantic... the frontal system currently in the northwest Atlantic is still forecast to evolve into a deep-layer cut-off low pressure system by early next week. However the more reliable GFS/ECMWF model consensus is for the surface layer of this system to be parked over cooler waters southeast of Newfoundland unfavorable for the development of tropical characteristics. Therefore not upgrading this system to a tropical area of interest at this time... regardless of tropical or not tropical status the northwestern periphery of this system will bring gusty winds and coastal surf to Newfoundland and Nova Scotia by early next week.
Will resume regularly scheduled posts on the Atlantic tropics at the start of hurricane season on June 1st... or if a new tropical area of interest emerges in the Atlantic basin beforehand.
...THURSDAY APRIL 25 2024 12:25 AM EDT...
Even though the 2024 Atlantic Hurricane Season does not officially start until June 1... continuing daily birdseye view posts on the Atlantic tropics while currently monitoring a low pressure swirl in the eastern Atlantic for signs of acquiring tropical characteristics. See area of interest #1 section below for more information.
Elsewhere... the current frontal system over the western Atlantic and trailing frontal system now emerging into the western Atlantic from eastern North America are in the process of merging. Long-range computer model runs suggest the merged system has a high likelihood of evolving into a cut-off deep-layer low pressure over the central or north-central Atlantic in approximately 5 to 7 days... where sea-surface temperatures are currently 18 to 20 deg C. However upper air temperatures of the deep-layer low are forecast to be rather cold which may still allow for instability at these water temperatures. Not declaring another tropical area of interest for this situation at this time as models are not currently consistent on whether or not the surface layer of this system will have a well-defined center needed for tropical development... and the models are not in agreement on the forecast position of this system with some runs showing this system at a further north location where water temps are even cooler.
AREA OF INTEREST #1... Satellite imagery of eastern Atlantic as of 1640Z April 24 showing eastern Atlantic low pressure swirl of interest (red arrow)... left pane is true-color visible and right pane is colorized infrared:
Over the last 24 hours the deep-layer low pressure system in the eastern Atlantic has continued southwest while steered by the deep-layer ridge to the northwest. The surface steering is stronger than in the upper-levels... as a result the surface layer of this system has been angling toward the southwest side of the parent upper vortex. Despite heading away from the de-stabilizing colder core of the upper vortex... the surface swirl has maintained a round of showers and thunderstorms located just east of center that has finally earned this system mention into the NHC official tropical weather outlook. The maintenance of activity is likely due to the surface swirl reaching warmer 24 deg C waters that has offset the effect of moving away from the cold core of the upper vortex... and a careful look at the current position of the surface swirl in upper-level maps has shown the swirl has not yet arrived into the suppressing upper convergence on the southwest side of the upper vortex. However this system will be moving into the upper convergence shortly... and combined with westerly shear on the south side of the upper vortex (which has kept the latest activity lopsided east of center) transition of the surface swirl into a subtropical or tropical cyclone is becoming unlikely. In fact the intensity of the activity on the east side of this system has decreased in recent hours on colorized infrared satellite imagery.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (0000Z Apr 26)... 0% chance of subtropical cyclone formation (eastern Atlantic near 21N-39W)
*****National Hurricane Center (hurricanes.gov) official outlook as of 4:14 PM EDT***************************
Formation chance through 48 hours... 10%
Formation chance through 7 days... 10%
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields(http://moe.met.fsu.edu/tcgengifs/).
1200Z (Apr 24) CMC Model Run...
**For area of interest #1... surface low continues southwest while gradually weakening and dissipates near 20N-40W at 42 hours
1200Z (Apr 24) ECMWF Model Run...
**For area of interest #1... surface low continues southwest while gradually weakening and dissipates near 19N-40.5W at 54 hours
1800Z (Apr 24) GFS Model Run...
**For area of interest #1... surface low continues southwest while gradually weakening and dissipates near 19N-41W at 45 hours
1800Z (Apr 24) NAVGEM Model Run...
**For area of interest #1... surface low continues southwest while gradually weakening and dissipates near 20.5N-39W at 30 hours
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