*******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.**********
...FRIDAY MAY 20 2022 11:38 PM EDT...
Current northwest Atlantic surface frontal cyclone offshore of Nova Scotia 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 have once again resumed daily birdseye view posts on the Atlantic tropics before the official start of the hurricane season (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 and southeastern Canada is gaining steam due to northward warm air transport ahead of a strong frontal system entrenched over eastern Canada (this frontal system is the same one producing severe thunderstorms over northern Michigan and parts of southeastern Canada over the last several hours). Over the last couple of days... models have come into better agreement that the current northwest 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 21 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 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.
I currently forecast a peak 20% odds of subtropical development over the five day forecast period with water temps along the forecast track in the low-20 deg C range. Will raise odds of development further if the current computer model agreement holds... and pending future observations in regards to the state of the deep-layered low pressure. Odds at 96 and 120 hours are lowered from the 20% peak as the deep-layer low pressure is forecast to move northeast to cooler water. The northeast track in the longer range is anticipated as the current upper trough energy over western North America 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 21)...0% chance of subtropical cyclone formation (north Atlantic near 41.5N-46.5W)
IOH 48 Hr Outlook (1800Z May 22)...0% chance of subtropical cyclone formation (north Atlantic near 37.5N-47.5W)
IOH 72 Hr Outlook (1800Z May 23)...20% chance of subtropical cyclone formation (central Atlantic near 35N-49W)
IOH 96 Hr Outlook (1800Z May 24)...10% chance of subtropical cyclone formation (central Atlantic near 36N-48W)
IOH 120 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 NW Atlantic surface frontal cyclone begins to turn south at 48 hours and reaches 34N-50W at 78 hours... moves northeast and reaches 36.5N-46W by 120 hours while weakening
1200Z ECMWF Model Run...
**For area of interest #2... Current NW Atlantic surface frontal cyclone begins to turn south at 48 hours and reaches 35N-50W at 72 hours... accelerates northeast and reaches 40N-35W by 120 hours where it loses definition to another developing frontal low to the north.
1800Z GFS Model Run...
**For area of interest #2... Current NW Atlantic surface frontal cyclone begins to turn south at 42 hours and reaches 35N-49W at 75 hours... accelerates northeast and reaches 37.5N-47.5W by 120 hours while weakening
1200Z NAVGEM Model Run...
**For area of interest #2... Current NW Atlantic surface frontal cyclone begins to turn south at 48 hours and reaches 31.5N-47.5W at 96 hours... accelerates northeast and reaches 35N-42W by 120 hours