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 

 
 
Search
  • NCHurricane2009

MY 2020 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #17

Updated: May 31

*******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 30 2020 7:13 PM EDT...


Even though the Atlantic hurricane season does not start until June 1...continuing daily birdseye view posts on the Atlantic tropics due two areas of interest for tropical development...see area of interest sections below for additional details. Also see computer model summary section below...new to these birdseye view posts which summarized the computer model data used in making my forecast decisions.


AREA OF INTEREST #1...A fully closed surface low pressure center in the western Atlantic near 30N-58W was confirmed by ASCAT-B and ASCAT-C passes earlier today...but the surface circualtion has not been upgraded to a subtropical cyclone due to the lack of thunderstorm activity as seen in colorized infrared satellite. The surface circulation and its parent upper vortex will head northward around the west side of the northwestern Atlantic deep-layered ridge. This will make thermodynamic conditions less favorable for subtropical development as the surface circulation reaches waters temperatuers in the low 20s of deg C...as the cold core upper vortex at the 200 mb layer only measures 1215 dekameters in height (the upper vortex needs to measure in the low 1200s of dekameters to be cold enough to support thunderstorm activity at those water temperatures). Therefore I have cancelled my subtropical cyclone formation forecast from special update #16A from early this morning...and in the updated outlook below I only have 5% odds of subtropical development in the next 24 hours due to the unfavorable thermodynamic outlook noted above. By 48 hours...development should no longer be possible with even cooler water temperatures...and as the system at the surface and upper levels should become abosrbed by what is now a vigorous upper trough and surface frontal system over eastern north America.

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

IOH 24 Hr Outlook (1800Z May 31)...5% chance of subtropical cyclone formation (western Atlantic near 34N-57.5W)

IOH 48 Hr Outlook (1800Z Jun 1)...0% chance of subtropical cyclone formation (western Atlantic near 39N-56W)


AREA OF INTEREST #2...The thunderstorm activity in the eastern Pacific Ocean...to the south of Guatemala and southeastern Mexico...has quickly spun up into trpoical depression 2-E. This is in response to the upper ridge/outflow in the region expanding in the wake of the south-central United States upper vortex which has recently shifted westward out of the way into northern Mexico while it orbits a longwave upper ridge building over western North America. This upper air pattern has allowed for surface pressures to fall and for thunderstorm activity in the region to increase...and the tropical wave that was passing through this area at 92.5W on May 28 (see birdseye view post #15) may have also contributed to the formation of tropical depression 2-E. Because the upper ridge/outflow has expanded northward from the eastern Pacific and into the southeast Mexico-western Caribbean-Central America region of the Atlantic basin...and because the eastern divergence zone of the northern Mexico upper vortex is situated over the western Gulf of Mexico where widespread showers and thunderstorms are occurring...the upper air pattern is in place to drop surface pressures to the north of tropical depression 2-E over a large area...which should pull the depression northward into Guatemala and potentially allow for tropical cyclone development on the Atlantic side. In the outlook below...I show 0% odds of tropical cyclone development in the western Caribbean region of the Atlantic basin through 48 hours as what is now tropical depression 2-E should dominate the region. The models continue to favor a more westward position of a broad surface low pressure in the Atlantic side...specifically toward the western Gulf of Mexico and Bay of Campeche. This seems to make sense with the ongoing aforementioned dynamics that are already producing widepsread thunderstorms in the western Gulf. It also makes sense to continue to drift the position of this area of interest westward in the outlook below as a strong potentially steering surface ridge develops over eastern North America thru 96 hours in the western convergece zone of what is now the upper trough over central Canada. A northwestward drift in the Bay of Campeche and toward the western Gulf of Mexico is shown in the outlook at 120 hours as the surface ridge potentially weakens while the upper vortex over northern Mexico and its eastern divergence zone drifts back eastward (due to eastward shift of western North America upper ridge). I keep peak odds of development on the low side...only 20%...as the more reliable GFS model continues to completely shunt development on the Atlantic side as it shows the upper vorticity from northern Mexico diving southeastward instead of eastward...which would suppress upper outflow/thunderstorms in the western Gulf of Mexico in the long range. But these odds are higher than my 10% from yesterday as the also reliable ECMWF (Euro) model is now showing possible tropical cyclone formation in the western Gulf of Mexico.

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

IOH 24 Hr Outlook (1800Z May 31)...0% chance of tropical cyclone formation (north coast of Honduras near 16N-87W)

IOH 48 Hr Outlook (1800Z Jun 1)...0% chance of tropical cyclone formation (east coast of Belize near 16.5N-88.5W)

IOH 72 Hr Outlook (1800Z Jun 2)...0% chance of tropical cyclone formation (inland northern Guatemala/Mexico border near 17.5N-90W)

IOH 96 Hr Outlook (1800Z Jun 3)...10% chance of tropical cyclone formation (Mexico Bay of Campeche coast near 18.5N-91.5W)

IOH 120 Hr Outlook (1800Z Jun 4)...20% chance of tropical cyclone formation (Bay of Campech near 20N-92.5W)


...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 #1 shows weak surface low pressure absorbed by incoming frontal low pressure system from eastern North America in 48 hours...For area of interest #2 moves eastern Pacific tropical depression 2-E northward into Guatemala and southeastern Mexico coasts by 36 hours...then has the circulation shifting northward into the Bay of Campeche from southeastern Mexico and develop into an Atlantic-side tropical cyclone in 72 hours...shifts the tropical cyclone northward across the western Gulf of Mexico in the long range.


1200Z ECMWF Model Run...For area of interest #1 shows weak surface low pressure absorbed by incoming frontal low pressure system from eastern North America in 48 hours...For area of interest #2 moves eastern Pacific tropical depression 2-E northward into Guatemala and southeastern Mexico coasts by 36 hours...then shifts the circulation northward into the Bay of Campeche from southeastern Mexico and suggests Atlantic-side tropical cyclone formation in the Bay of Campeche/western Gulf of Mexico at 72+ hours.


1200Z GFS Model Run...For area of interest #1 shows weak surface low pressure absorbed by incoming frontal low pressure system from eastern North America in 48 hours...For area of interest #2 suggests eastern Pacific tropical depression 2-E will dominate from now thorugh 102 hours as it stalls near the southeastern Mexico coast...shows no development on the Atlantic side.


1200Z NAVGEM Model Run...For area of interest #1 shows weak surface low pressure absorbed by incoming frontal low pressure system from eastern North America in 48 hours...For area of interest #2 moves eastern Pacific tropical depression 2-E northward into Guatemala and southeastern Mexico coasts by 48 hours...then shifts broad low pressure area into western Gulf of Mexico with possible tropical cyclone formation here in the longer range.

9 views

©2020 by Info On Hurricanes.

 

Questions? Comments? Send to me on IOHurricanes@outlook.com