*******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 JUNE 4 2022 8:00 PM EDT...
A broad tropical low pressure system has recently crossed through western Cuba… south Florida… and the western Bahamas. This system is expected to cross Bermuda late Monday and into Tuesday possibly as a tropical storm transitioning into a non-tropical frontal cyclone. Even if it doesn’t become a tropical storm… this system is still strong enough to bring tropical storm conditions to the island upon arrival. See area of Interest #4 section below for more details.
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 in this blog post is designated #4 as I designated the first three of this year earlier this month (in previous birdseye view posts 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 4 (POTENTIAL TROPICAL CYCLONE ONE)…The broad tropical low pressure system that was previously over the southeastern Gulf of Mexico has accelerated northeastward across south Florida and already in the process of emerging into the western Atlantic waters offshore of the Florida east coast. The heaviest weather of this system has already passed through south Florida… western Cuba… and the western Bahamas as southwesterly shearing upper winds generated by nearby low-latitude upper vorticity continue to displace the strongest weather east of the axis of lowest surface pressure. Because of the elongated axis of low surface pressure lacking a well-defined center… the NHC continues designating this system as a potential tropical cyclone instead of a tropical cyclone (tropical depression or storm). The potential tropical cyclone designation allows for issuance of tropical storm warnings as this system is currently and will for some time remain capable of producing heavy rains… choppy seas… and gusty winds.
A couple of features continue steering this tropical system northeast… (1) In the high-latitudes the current northwest Atlantic frontal low is creating a surface ridge weakness helping to attract this tropical system northeastward… (2) in the low-latitudes the nearby upper vorticity to the west is creating a northeast push in the upper layers of the atmosphere. By 48 to 72 hours the shortwave upper trough currently entering the central US from New Mexico and Colorado will arrive near this tropical system and re-enforce the low-latitude upper vorticity. At 72+ hours there are two possible long-range tracks for this system…. (1) the current central Canadian upper vortex will spawn a fresh surface frontal cyclone whose warm sector will build an upper ridge over the northwest Atlantic. In turn the amplifying northwest Atlantic upper ridge will amplify the nearby low-latitude upper vorticity… with the east side of the amplifying upper vorticity hooking the track of this tropical system more northward…. or (2) this system will be located east enough to escape the influence of the northwest Atlantic upper ridge and amplifying upper vorticity… instead continuing east-northeast while chasing the aforementioned surface ridge weakness. Because this system’s most organized portion is located just northeast of my previous forecast… my updated one in the outlook below is adjusted in that direction and therefore for the long-range leans toward the scenario of an ongoing east-northeastward escape.
The probability of this system consolidating into a tropical storm hinges upon the nearby low-latitude upper vorticity to the west. The batch of upper vorticity that this tropical system has been interacting with has been weakening while remaining cut-off from high-latitude cold air. What will remain of it in the next 24 hours will create a focal point of upper divergence offshore of the southeastern US that will potentially induce a concentrated surface low pressure spin needed for tropical storm status. Given the most organized northeast portion of the disturbance is poised to align with the forecast focal point of upper divergence… I have raised short-term odds of tropical cyclone formation back to 90%. After 24 hours the shortwave upper trough to approach from the central US will arrive and re-enforce the upper vorticity… again resulting in an elongated area of upper vorticity and associated upper divergence region. The result is this system could become elongated if tropical cyclone formation is not achieved beforehand… therefore I lowered 48-hour odds of tropical cyclone formation to 60%. As this system passes over or near Bermuda by day 3… it will be over water temps below 26 deg C and thus my tropical development odds are lowered to 0% for that timeframe. The cooler waters and ongoing upper divergence support from the upper vorticity will likely transition this system to non-tropical around this timeframe… but still capable of producing gusty winds and sea swells.
The following is the expected timing for gusty winds… heavy rain… and coastal sea swells:
(1) Weather conditions in the western Bahamas will continue to improve as this system moves northeast and away.
(2) For late Monday and Tuesday… Bermuda. The island is currently under a tropical storm watch… prepare now.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z Jun 5)... 90% chance of tropical cyclone formation (western Atlantic near 29N-75W)
IOH 48 Hr Outlook (1800Z Jun 6)... 60% chance of tropical cyclone formation (western Atlantic near 31N-69.5W)
IOH 72 Hr Outlook (1800Z Jun 7)… 0% chance of tropical cyclone formation (northeast of Bermuda near 33N-62.5W)
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
0000Z CMC Model Run...
**For area of interest #4... broad low pressure becomes a tropical storm just offshore of the east coast of Florida at 28N-79W at 30 hours… system becomes more elongated and less tropical as it reaches Bermuda at 84 hours… weakening remnant low drifts to a location just southeast of Bermuda by 120 hours.
0000Z ECMWF Model Run...
**For area of interest #4... broad low pressure becomes a tropical storm just offshore of the east coast of Florida at 27.5N-79W at 24 hours… while gaining strength and size passes just north of Bermuda at 72 hours… as a remnant non-tropical frontal cyclone continues east-northeast into the open central Atlantic and reaches 37N-52.5W at 120 hours
1200Z GFS Model Run...
**For area of interest #4… over next 30 hours broad low pressure departs Florida and into waters offshore of the southeast US in an elongated state with multiple centers… elongated circulation passes just north of Bermuda at 60 hours… by 75 hours elongated circulation transitions into a cold front in the central Atlantic featuring a frontal low near 37.5N-52.5W
0600Z NAVGEM Model Run...
** For area of interest #4… broad low pressure becomes a tropical storm after departing Florida at 24 hours while located at 29N-78W… turns more east in track passes just north of Bermuda at 66 hours… as a remnant frontal low reaches the open central Atlantic at 35N-54W at 120 hours