MY 2022 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #19
Updated: Jun 3
*******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.**********
…WEDNESDAY JUNE 1 2022 11:55 PM EDT...
A broad tropical low pressure system spanning southeastern Mexico and the western Caribbean Sea is expected to lift northeast. There is a high chance of this system bringing tropical storm conditions to the northeastern Yucatan peninsula… western Cuba… south Florida… and the western Bahamas late this week and into the weekend. Tropical storm conditions are possible for Bermuda early next week if this system can remain intact under the forecast heightened levels of wind shear. See area of Interest #4 section below for more details.
Elsewhere… the surface trough currently northeast of the western Bahamas will only have a narrow window of time to develop in a pocket of low wind shear in about 24 hours as it moves eastward into open waters… see area of Interest #5 section below for 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 two areas of interest in this blog post are designated #4 and #5 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… Satellite image of southeast Mexico-to-western Caribbean broad low pressure taken at 2251Z just before sunset. Yellow plus marks the eastern low-level vorticity center of this system… and red plus marks the western low-level vorticity center. Arrows show the expected motion of both centers over the next several hours:
A broad tropical low pressure system over southeastern Mexico and western Caribbean continues to have two mid-level spins… most notably detected on the CIMSS 850 mb vorticity product (http://tropic.ssec.wisc.edu/real-time/windmain.php?basin=atlantic&sat=wg8&prod=vor&zoom=&time=). The western (spin) center over southeastern Mexico and Bay of Campeche… most associated with what is left of eastern Pacific Hurricane Agatha… has struggled due to high levels of shear and outflow suppression induced by an axis of upper vorticity to the north. The eastern center located over the western edge of the Caribbean has flourished in a better environment of lower shear and anticyclonic outflow in association with an upper ridge in the region. The outflow supported a strong complex of thunderstorms in the morning hours whose latent heat only re-enforced the warm core upper ridge and outflow… with the outflow helping to strengthen the eastern mid-level low pressure. In fact NHC TAFB surface analysis shows the eastern mid-level low pressure is now defined at the surface as well. Therefore this eastern center has become the prime focus for potential tropical cyclone formation in the days ahead.
Whatever develops is expected to track northeast while following the surface ridge weakness associated with the current Canada frontal system… as the frontal system and its supporting upper trough shift east with time. The axis of upper vorticity mentioned in the previous paragraph will also aid in generating a northeastward push. As noted on the home page bulletins of this site… earlier today I was watching for the struggling western mid-level low pressure to dissipate which would allow the eastern mid-level low pressure to slip east-northeastward… resulting in a more south track than I previously forecasted (also more south than models have been showing). Meanwhile the models today agreed that the eastern center would be initially tugged by the western center while absorbing it… resulting in the two orbiting each other after which time a northeastward track at a more north location would commence. The orbiting motion of both centers is illustrated in the above satellite picture… and was confirmed just before sunset in satellite animation which showed the eastern center whirling westward toward the Yucatan peninsula. Therefore no southward adjustment is needed in the forecast track… and my updated one in the outlook below continues to generally follow the GFS which remains on the southern side of the model consensus. I have not selected the more northern forecast tracks seen in the other models as it will be harder for development further north due to higher levels of shear in association with the aforementioned upper vorticity axis.
Regarding the probability of tropical cyclone formation over the next five days… I have raised peak odds to 50% as this system has demonstrated progress in organizing around the eastern mid-level center… and as the more reliable GFS and ECMWF insist on eventual tropical cyclone formation. I have slightly lower 40% odds for the short-term to allow time for the eastern center to absorb the western and become the dominant needed for development. However my odds of development remain below the NHC’s 80% (as of this writing) as I remain skeptical of the shear levels to be induced by the axis of upper vorticity. As this system begins to accelerate northeast while chasing the surface ridge weakness mentioned in the previous paragraph… that might help reduce the shear as the direction of travel would be aligned with the direction of the shearing upper winds. Even if this is the case… this system may still suffer from an elongated structure that would technically not count it as a tropical cyclone as cyclones by scientific definition require a circular structure with a well-defined center. In fact today’s 12Z cycle of the NAVGEM and CMC showed this idea. The elongation is possible as the supportive upper divergence region of the upper vorticity axis will also be elongated.
Whether or not this system becomes elongated or circular… it has potential to strengthen due to the aforementioned upper divergence of the upper vorticity axis and anticyclonic outflow of the upper ridge to be located ahead of the upper vorticity. In an elongated state… note that this system may bring tropical storm conditions and be classified by the NHC as a potential tropical cyclone (PTC) in order to issue tropical storm warnings. Whether we have PTC or tropical storm status… the following is the expected timing for possible gusty winds… heavy rain… and coastal sea swells in the days ahead:
(1) For tomorrow through Saturday: Western Cuba… south Florida and the Florida Keys. This is a little sooner than mentioned yesterday as the consolidation of this system toward the eastern center already brings it closer to these areas
(2) For Sunday: the western Bahamas
(3) The northeastern Yucatan may see tropical storm conditions by tomorrow should the eastern center strengthen more quickly.
(4) This system could approach the vicinity of Bermuda after this weekend. Tropical storm conditions are possible if this system remains intact under the wind shear
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z Jun 2)… 40% chance of tropical cyclone formation (northeast coast of the Yucatan peninsula near 20N-87.5W)
IOH 48 Hr Outlook (1800Z Jun 3)… 50% chance of tropical cyclone formation (north coast of Cuba’s west tip near 22.5N-84W)
IOH 72 Hr Outlook (1800Z Jun 4)… 50% chance of tropical cyclone formation (just offshore of southeast Florida near 25N-80W)
IOH 96 Hr Outlook (1800Z Jun 5)… 50% chance of tropical cyclone formation (northeast of the western Bahamas near 27N-76W)
IOH 120 Hr Outlook (1800Z Jun 6)…50% chance of tropical cyclone formation (western Atlantic near 29N-70W)
AREA OF INTEREST 5… The eastern divergence zone of upper vorticity now near the western Bahamas continues to sustain a surface trough of low pressure. Shear induced by the upper vorticity is weakening as the vorticity itself weakens while remaining cut-off from high-latitude cold air… as a result the shower and thunderstorm activity has moved closer to the surface trough and become a little better organized. The NHC has introduced this system into their tropical weather outlook… also with low 10% odds of tropical cyclone formation as I projected in the previous blog post. Low odds appear sensible as the window of low shear will be brief… wind shear ramping back up just after 24 hours as upper westerly flow increases with the eventual approach of the major upper trough currently over central North America. By 48 hours the westerly flow ahead of the upper trough will have carried this system east-northeast toward water temps below 26 deg C… and so I drop development odds to 0%
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z Jun 2)…10% chance of tropical cyclone formation (western Atlantic near 29N-74.5W)
IOH 48 Hr Outlook (1800Z Jun 3)…0% chance of tropical cyclone formation (west-southwest of Bermuda near 30N-68.5W)
...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 #4... Over next 30 hours the southeastern Mexico and western Caribbean circulations merge over the Yucatan peninsula… through 60 hours the circulation becomes elongated SW-NE spanning from the east coast of the Yucatan to the southeast Gulf of Mexico… northeast end of the elongated circulation continues across the central Florida peninsula through 72 hours while the southwest end does not develop… through 120 hours the circulation that passed through Florida continues northeast and reaches the waters west of Bermuda while itself becoming elongated
**For area of interest #5... no development shown
1200Z ECMWF Model Run...
**For area of interest #4... Over next 48 hours the western Caribbean circulation shifts north to the northeast corner of the Yucatan peninsula while absorbing the southeastern Mexico circulation and becomes a large tropical depression in the process… makes landfall in southwest Florida peninsula
as a tropical storm just after 72 hours… tropical storm passes north of the western Bahamas at 96 hours… strengthens midway between North Carolina and Bermuda by 120 hours
**For area of interest #5... surface trough becomes a small/weak surface low near 29N-75.5W at 24 hours… surface low weakens back to a trough near 31N-71W at 48 hours
1200Z GFS Model Run...
**For area of interest #4… Over next 30 hours the western Caribbean circulation shifts north to the Yucatan channel (between the west tip of Cuba and Yucatan peninsula) while absorbing the southeastern Mexico circulation and becomes a compact tropical cyclone in the process… tropical cyclone passes over Key West Florida at 60 hours and passes over the south end of the Florida peninsula at 78 hours…. passes over the western Bahamas at 90 hours… tropical cyclone reaches 30N-70W at 120 hours
**For area of interest #5… no development shown
1200Z NAVGEM Model Run...
** For area of interest #4… Over next 30 hours the southeastern Mexico and western Caribbean circulations merge over the Yucatan peninsula…through 78 hours the circulation becomes elongated SW-NE spanning from the northeast coast of the Yucatan to the northern Florida peninsula… elongated circulation shifts northeast into waters offshore of SE US by 120 hours
**For area of interest #5... surface trough becomes a surface low near 29.5N-73W at 30 hours… passes through Bermuda at 72 hours… through 120 rapidly accelerates northeast across the North Atlantic where it loses identity to a sprawling frontal system located to the north.