MY 2020 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #85
Updated: Aug 12, 2020
*******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 AUGUST 8 2020 8:53 PM EDT...
See area of interest sections below for tropical waves of low pressure in the central and eastern tropical Atlantic being monitored for development.
Elsewhere...the tropical wave that was in the eastern Caribbean Sea has moved into the central Caribbean and lost thunderstorm activity without affecting Haiti and the Dominican Republic while suppressed by the upper vorticity currently in the westrn Atlantic.
The tropical wave of low pressure currently approaching the Lesser Antilles islands has seen a decrease in the amount and organization of its thunderstorm activity. Even though the wave has no computer model support showing development...will watch for signs of development as the tropical wave will remain in a low shear environment at a distance away from the western Atlantic upper vorticity mentioned in the previous paragraph while crossing the Lesser Antilles and entering the Caribbean Sea.
AREA OF INTEREST #1...The southwest-to-northeast stretched tropical wave of low pressure in the central Atlantic has become less organized while its southwestern lobe has lost thunderstorm activity. Even though this tropical wave is embedded in an otherwise favorable environment of low shear and upper outflow beneath a tropical upper ridge in the region...perhaps it is due to the dry saharan air layer that this wave has not developed. The GFS and NAVGEM model support for this tropical wave has dropped...and the wave has recently been removed from the National Hurricane Center tropical weather outlook. This is also my final statement on this tropical wave unless it later shows signs of redevelopment before potentially encountering less favorable upper winds from upper vorticity currently being cut-off from the northeastern Atlantic and heading southwest around a central Atlantic upper ridge and toward the future path of the tropical wave.
IOH 24 Hr Outlook (1800Z Aug 9)...0% chance of tropical cyclone formation (tropical Atlantic near 10N-42W)
AREA OF INTEREST #2...A tropical wave of low pressure that has recently emerged from western Africa has maintained organized thunderstorm bands that suggest rotation. Currently the rotation appears to be centered at 10N-23W. The 1200Z ECMWF model run from August 6th...the CMC model runs over the last couple of days...and more recently the 1800Z GFS model run from today suggest some possible development from this tropical wave. Combined with the current oragnization of the wave...I am forecasting a moderate 40% chance of tropical cyclone formation in the short term. The 1800Z GFS model run suggested the cut-off upper vorticity from the northeastern Atlantic could get pushed southward toward the tropics (by the current central Atlantic upper ridge) in the vicinity of 40W longitude by 96 and 120 hours...thus I slightly trim odds of development downward by that timeframe.
IOH 24 Hr Outlook (1800Z Aug 9)...40% chance of tropical cyclone formation (tropical Atlantic near 10N-28W)
IOH 48 Hr Outlook (1800Z Aug 10)...40% chance of tropical cyclone formation (tropical Atlantic near 10N-33W)
IOH 72 Hr Outlook (1800Z Aug 11)...40% chance of tropical cyclone formation (tropical Atlantic near 10N-38W)
IOH 96 Hr Outlook (1800Z Aug 12)...35% chance of tropical cyclone formation (tropical Atlantic near 10N-43W)
IOH 120 Hr Outlook (1800Z Aug 13)...35% chance of tropical cyclone formation (tropical Atlantic near 10N-48W)
...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...no tropical cyclone formation shown. For area of interest #2...tropical wave organizes into a tropical low pressure near 12N-30W in 66 hours...opens back into a tropical wave near 47.5W longitude in 162 hours.
1200Z ECMWF Model Run...For areas of interest #1 and #2...no tropical cyclone formation shown.
1800Z GFS Model Run...For area of interest #1...no tropical cyclone formation shown. For area of interest #2...organizes into a tropical low pressure at 10N-22.5W in 12 hours...opens back into a tropical wave near 42W longitude in 108 hours.
1200Z NAVGEM Model Run...For area of interest #1...tropical wave organizes into large and weak tropical low pressure near 14N-39W in 18 hours...opens back into a tropical wave near 45W longitude in 42 hours. For area of interest #2...no tropical cyclone formation shown.