BIRDSEYE VIEW POSTS

Since 2012 on the Weather Underground (www.wunderground.com) blogs, I have been posting annotated "birdseye view" charts of the Atlantic basin, with a detailed explanation and forecasting that references the chart. From there you may know me as "NCHurricane2009." While I now do these "birdseye view" posts here, I will continue to do comments via Disqus on Weather Underground at www.wunderground.com/cat6. You can see my Disqus feed at this link for my latest comments. Feel free to reply to me with your disqus account or e-mail at IOHurricanes@outlook.com 

 
 
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MY 2020 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #19

*******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.**********


...MONDAY JUNE 1 2020 2:00 PM EDT...

As the official start of the 2020 Atlantic Hurricane Season is today...will now be doing daily birdseye view posts on the Atlantic tropics till the end of the Atlantic Hurricane Season on November 30...with interruptions to daily updates only occurring from personal vacations...etc. See area of interest sections below for all areas of potential tropical development in the Atlantic basin over the next few days.


AREA OF INTEREST #1...A broad low pressure area with widespread thunderstorm activity continues over western Central America...southeastern Mexico...and adjacent Atlantic and Eastern Pacific waters due to the sprawling upper ridge/outflow over the region. Meanwhile yesterday's final advisory from the National Hurricane Center on what was eastern Pacific Tropical Storm Amanda stated that the surface rotation of Amanda dissipated over the mountainous terrain of Guatemala while the mid-level rotation was still in progress. It appears the mid-level rotation fired a circular thunderstorm mass last evening and has reached the surface over the Mexican province of Campeche...and latest satellite animation suggests the surface to mid-level spin is already reaching the Bay of Campeche coast while surrounding clouds and thunderstorms are well organized around this feature. Therefore it appears tropical cyclone formation over the Bay of Campeche waters is imminent in the next 24 hours...so I have begun a tropical cyclone formation forecast as outlined below. Discarding the eastern outlier CMC model run which keeps this system at its current position for the next few days and eventually drifts it northward into the Gulf of Mexico...and going with the short-term ideas presented by GFS...ECMWF...and NAVGEM where this tightening low pressure center orbits westward across the Bay of Campeche around the remainder of the broad low pressure area to the southeast...because of current satellite animation which shows a westward component to the motion of the tightening low pressure. A short-term westward swing is also reasonable considering the eastern North America surface ridge which would also provide a westward push. Longer range forecast (72+ hours) seems uncertain. But based on the unanimous idea in the long range model suite that the remainder of the broad low pressure area will eventually lift northward across the Gulf of Mexico as a possible tropical cyclone...my 72+ hour forecast philosophy is to have the center slide eastward along Mexico's Bay of Campeche coast while merging with remainder of the broad surface low pressure area...I then lift the broad low pressure area northward along the west coast of the Yucatan peninsula by 120 hours. A study of the GFS model upper level winds shows that the upper vortex currently over northern Mexico will eventually slide east into the western Gulf due to the eastward shift of the western North America longwave upper ridge...with the broad low pressure area shifting northward into the Gulf of Mexico as it transitions into a system supported by the eastern divergence of the upper vortex. It seems there are multiple possibilities here...one is that this current tight low pressure dissipates over southeastern Mexico at 72+ hours while the broad low pressure area becomes a second seperate Gulf of Mexico tropical cyclone interacting with the upper vortex. Another idea is that the current tight low pressure...after it becomes a Bay of Campeche tropical cyclone...becomes a remnant low that eventually regenerates as a tropical cyclone in heart of the Gulf of Mexico. Or the third idea which is what I try to convey in my current forecast below is that this becomes one long-lasting...slow-moving tropical cyclone event that eventually shifts from the Bay of Campeche region to the heart of the Gulf of Mexico. Regarding strength...ASCAT passes suggest the winds over the Bay of Campeche are at tropical depression strength...so I show this system strenghthen into a moderate/strong tropical storm over the next 48 hours before it makes landfall in southeastern Mexico as I believe the current organized structure could allow this system to strenghten briskly over its short time over water. Intensity at 72+ hours is kept at a lower tropcial depression strength due to land interaction...and merger with the remainder of the broad low pressure area which would keep the surface pressure gradient between the center and outside of the storm more relaxed.

******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********

0 Hr Position (1200Z Jun 1)...Surface low pressure approaching Mexico's Bay of Campeche coast at 19N-90.5W

IOH 24 Hr Forecast (1200Z Jun 2)...50 mph maximum sustained wind tropical storm centered in the Bay of Capeche at 20N-94W

IOH 48 Hr Forecast (1200Z Jun 3)...60 mph maximum sustained wind tropical storm making landfall on Mexico Bay of Campeche coast at 18.5N-95W

IOH 72 Hr Forecast (1200Z Jun 4)...35 mph maximum susatained wind tropical depression centered along Mexico Bay of Campeche coast at 18.5N-93.5W

IOH 96 Hr Forecast (1200Z Jun 5)...35 mph maximum susateined wind tropical depression centered along Mexico Bay of Campeche coast at 19N-90.5W

IOH 120 Hr Forecast (1200Z Jun 6)...35 mph maximum sustained wind tropical depression centered along the northwestern Yucatan peninsula coast at 21N-90.2W


AREA OF INTEREST #2...An elongated surface frontal low pressure area in the northeastern Atlantic to the east of the Azores persists with the support beneath the eastern divergence zone of a southern fracture of the northeastern Atlantic upper trough...with the fracture evolving into an elongated cut-off upper vortex and in turn explaining the elongated nature of the surface low. Computer models remain in agreement that the the upper vortex will become more circular while becoming tucked on the southeast side of the expanding north Atlantic deep-layered ridge. This should result in a circular consolidated surface frontal low pressure area...which later will whirl westward toward the center of the upper vortex. The surface frontal low will be over water temps in the 18 to 20 deg C range during the forecast period...but because the forecast cut-off upper vortex is rather cold...measuring 1190 dekameters in height at 200 mb...I think there is potential for thundestorm activity and acquisition of subtropical characteristics with the surface frontal low. Forecast track in the outlook below is based on the GFS model presentation of the upper vortex...with the surface frontal low whirling around the north side of the upper vortex thru 48 hours as the upper vortex itself drifts southeastward. During this time the frontal low will make its closest pass to the eastern Azores just before 48 hours. At 72+ hours...the forecast track of the surface frontal low is to have it drifting eastward with the upper vortex...with the east drift of the upper vortex caused by the northern remaining piece of the northeastern Atlantic upper trough diving southeastward around the north Atlantic upper ridge and finally catching the upper vortex. Albeit in the latest GFS model run...the upper vortex is shown to move slower to the east as the northern upper trough fragement stays further from the upper vortex and struggles to catch it...thus my long term track forecast is adjusted accordingly. I have dropped odds of development to 0% for June 2 to give more time for the elongated surface frontal low to become more circular/consolidated. My peak odds of development...pegged at 30%...are on the low side due to the general rarity of tropical development at these water temps. I begin dropping odds of development at 96+ hours as the surface frontal low will eventually weaken while settling beneath the core of the upper vortex...an environment that lacks supportive upper divergence.

******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********

IOH 24 Hr Outlook (1200Z Jun 2)...0% chance of subtropical cyclone formation (just east of the Azores near 37N-21W)

IOH 48 Hr Outlook (1200Z Jun 3)...30% chance of subtropical cyclone formation (just southeast of the Azores near 35N-23.5W)

IOH 72 Hr Outlook (1800Z Jun 4)...30% chance of subtropical cyclone formation (southeast of the Azores near 35N-21W)

IOH 96 Hr Outlook (1800Z Jun 5)...20% chance of subtropical cyclone formation (southeast of the Azores near 35N-21W)

IOH 120 Hr Outlook (1800Z Jun 6)...0% chance of subtropical cyclone formation (just north of the Canary Islands at 35N-17.5W)


...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 #1...consolidates broad surface low pressure area on west coast of Yucatan peninsula and suggests gradual tropical cyclone formation at 36+ hours...with tropical cyclone intensifying will shifting slowly northward across the Gulf of Mexico in the long range. For area of interest #2...shows frontal low pressure intensified into frontal cyclone east of the Azores in 24 to 54 hours...then has frontal cyclone drift southeastward and loses its identity over the Canary Islands at 132 hours.


0000Z ECMWF Model Run...For area of interest #1...consolidates broad surface low pressure area over Bay of Campeche just after 24 hours as a tropical cyclone...with cyclone slowly orbiting west-southwestward around the remainder of the broad low pressure area into southeastern Mexico by 96 hours (suggest possible compact and strong tropical cyclone just before landfall at 72 hours). In longer range...suggests remainder of broad low pressure area lifting northward across western Gulf of Mexico...and consolidates it into another tropical cyclone during this time. For area of interest #2...shows frontal low pressure intensified into frontal cyclone east of the Azores in 24 hours...cycloncially looping southwest and staying just east of the Azores by 48 hours...then has frontal cyclone drift southeastward and lose its identity over the Canary Islands just after 120 hours.

0600Z GFS Model Run...For area of Interest #1...shows northern lobe of broad surface low pressure area drifting westward across Bay of Campeche in 36 hours and making landfall in southeastern Mexico by 48 hours without explicitly showing tropical cyclone formation. In longer range...suggests broad low pressure area eventually lifts northward into the western Gulf of Mexico while consolidating into tropical cyclone. For area of interest #2...shows frontal low pressure intensified into frontal cyclone east of the Azores in 24 hours...cycloncially looping southwest and passing just east of the Azores by 36 hours...then has frontal cyclone drift southeastward as it gradually weakens...losing its identity over the Canary Islands at 132 hours.


0600Z NAVGEM Model Run...For area of interest #1...consolidates of broad surface low pressure area over the Bay of Campeche as a tropical cyclone...with this feature drifting eastward to the west Yucatan peninsula coast by 72 hours where it merges with remainder of the broad low pressure area. In long range...shifts tropical cyclone northward from west coast of the Yucatan and across the Gulf of Mexico. For area of interest #2...shows frontal low pressure intensified into frontal cyclone east of the Azores in 18 hours...cycloncially looping southwest very close to eastern Azores by 42 hours...then has frontal cyclone drift southeastward as it gradually weakens...eventually losing its identity just east of the Canary Islands in 132 hours.

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