*******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.**********
...SATURDAY MAY 21 2022 11:29 PM EDT...
Current north Atlantic surface frontal cyclone expected to become a cut-off deep-layered low pressure system in the open central Atlantic by Monday. Will monitor this system for acquisition of tropical characteristics as it does so... therefore continuing daily birdseye view posts on the Atlantic tropics even though hurricane season does not start until June 1st. See area of interest #2 section below for more information.
New to this site this year... I will be sequentially numbering up areas of interest for possible Atlantic tropical development. In this scheme... will reset back to #1 at the start of next year (January 2023). The current area of interest is designated #2 as I designated the first one of this year earlier this month (in birdseye view posts #1 to #9 on the home page). This scheme is to reduce confusion as Atlantic tropical activity increases during the peak of the hurricane season... when multiple simultaneous areas of interest begin and end which previously required shuffling around the area of interest numbers from update to update.
AREA OF INTEREST #2... As annotated in the above birdseye view chart... a warm core deep-layer ridge across the western Atlantic remains supported by an ongoing fetch of northward warm air transport across eastern North America. The current north Atlantic frontal cyclone and its supporting upper trough will evolve into a cut-off deep-layered low pressure that will take a southward excursion into the open central Atlantic through Monday... thanks to the deep-layer ridge’s steering influence. This will allow the deep-layered low pressure to reach 20.5 deg C water. Although this is below the typical 26+ deg C associated with tropical development... upper air temps may be cold enough for instability and thunderstorm generation (for Monday and Tuesday... the GFS model is currently forecasting a 200 mb height of 1190 to 1192 dekameters in association with the cold core upper vortex to be tied to this deep-layer low pressure system). Models are also in agreement that the surface structure of the low pressure will maintain a broad circular shape with a well-defined center through Tuesday... also needed for subtropical cyclone development.
The updated forecast track in the outlook below is in the short-term nudged north as the 18Z position of the surface frontal cyclone (42N-48W) was a little northwest of the previous forecast. The 48 and 72 hour forecast track points are nudged east as the latest 18Z GFS model data suggests the upper vortex of the deep-layered low pressure will be a little further to the east. This adjustment places the deep-layered low pressure over slightly cooler water and so I have lowered my peaks odds of subtropical cyclone development to 10%. Odds at 96 hours are lowered to 0% as the deep-layer low pressure is forecast to move northeast to even cooler water. The northeast track in the longer range is anticipated as the current upper trough energy over the northwestern US is expected to break through the deep-layered ridge and grab the deep-layered low pressure system.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z May 22)...0% chance of subtropical cyclone formation (north Atlantic near 38N-47.5W)
IOH 48 Hr Outlook (1800Z May 23)...10% chance of subtropical cyclone formation (central Atlantic near 35N-47.5W)
IOH 72 Hr Outlook (1800Z May 24)...10% chance of subtropical cyclone formation (central Atlantic near 35N-47.5W)
IOH 96 Hr Outlook (1800Z May 25)...0% chance of subtropical cyclone formation (north Atlantic near 37.5N-46W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z CMC Model Run...
**For area of interest #2...Current North Atlantic surface frontal cyclone begins to turn south at 18 hours and reaches 34N-49W at 66 hours... moves northeast and reaches 44N-40W by 120 hours while weakening
1200Z ECMWF Model Run...
**For area of interest #2... Current North Atlantic surface frontal cyclone begins to turn south at 24 hours and reaches 34.5N-49.5W at 72 hours... accelerates northeast and reaches 44N-38W by 120 hours while weakening
1800Z GFS Model Run...
**For area of interest #2... Current North Atlantic surface frontal cyclone begins to turn south at 18 hours and reaches 35N-48.5W at 48 hours... remains generally stationary in this region through 72 hours... accelerates northeast and reaches 47.5N-40W by 120 hours while weakening and then re-strengthening as an elongated less tropical system
1200Z NAVGEM Model Run...
**For area of interest #2... Current North Atlantic surface frontal cyclone begins to turn south at 24 hours and reaches 34.5N-47.5W at 60 hours... accelerates northeast and reaches 38.5N-39W at 108 hours where it loses identity to another developing frontal low to the north.