*******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.**********
...THURSDAY OCTOBER 3 2019 11:50 PM EDT...
AREA OF INTEREST #1...Around 1800Z earlier this evening...the low level clouds on visible satellite animation suggested to me that the broad northwestern Caribbean low pressure had two swirls...one in the Yucatan Channel between Cuba ans the Yucatan peninsula...and another in the Caribbean east of the Yucatan shore. Thus the 1200Z NHC TAFB surface analysis which had the low pressure analyzed between the swirls appears logical. Although shear is dropping as the Gulf to Western Atlantic upper trough splits in half...the heaviest thunderstorm activity remains east of the lowest surface pressure while over the Cayman Islands and western two thirds of Cuba where outflow between the splitting halves of the upper trough appears maximum. The initial motion of this disturbance should be slow as the steering eastern US surface ridge is dissipating from a developing frontal low over the Great Lakes. But after 24 hours...a surface ridge building behind the departing frontal low should steer this disturbance...likely sending the disturbance northwestward across the southern Gulf of Mexico around its southwest side through 72 hours. By 96+ hours...it appears this disturbance will slow down and drift southwestward as a sharp upper trough currently making landfall in western North America moves across the US/Canada border region...and with its western upper convergence builds another surface ridge emerging from the western US that will provide the southwest drift. I keep the odds of development only at 0% to 10% thru 72 hours given the current poor organization of the disturbance...and as it will encounter unfavorable southwesterly shear from the western split of the current western Atlantic/Gulf upper trough. After that time I climb the odds of development to 30% at 120 hours as the western split upper trough shifts eastward and away. Regardless of tropical development or not...over the next couple of days heavy rains with flash flooding are possible over western Cuba...the Cayman Islands... and possibly the northern Yucatan peninsula of Mexico. My forecast positions below are not of high confidence at this time as the surface low pressure is still broad and could consolidate in a different location...which would change the track forecast.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z Oct 4)...0% chance of tropical cyclone formation (northern Yucatan Peninsula...southeastern Gulf of Mexico...western Cuba)
IOH 48 Hr Outlook (1800Z Oct 5)...10% chance of tropical cyclone formation (southern Gulf of Mexico near 22.5N-90W)
IOH 72 Hr Outlook (1800Z Oct 6)...10% chance of tropical cyclone formation (southern Gulf of Mexico near 23.5N-92.5W)
IOH 96 Hr Outlook (1800Z Oct 7)...15% chance of tropical cyclone formation (southern Gulf of Mexico near 22.5N-94W)
IOH 120 Hr Outlook (1800Z Oct 8)...30% chance of tropical cyclone formation (southwestern Gulf of Mexico offshore of Veracruz near 21N-95.5W)
AREA OF INTEREST #2...The western Atlantic broad surface low pressure located south of Bermuda remains disorganized. Warm air advection ahead of a pair of frontal lows emerging from the NW Atlantic and Great Lakes is amplifying upper ridging over the western Atlantic and over this disturbance...which will reduce the shear imparted by the current western Atlantic upper trough. However development is no longer possible as by 48 hours the disturbance will already be absorbed by the cold front of the frontal low from the Great Lakes. This is my final statement on this disturbance on this blog.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z Oct 4)...0% chance of tropical cyclone formation (western Atlantic near 29N-62W)
AREA OF INTEREST #3...A tropical wave emerging from western Africa has seen a decrease in thunderstorm activity...therefore I have lowered the odds for tropical cyclone development. Upper-level winds are becomimg increasingly favorable for tropical development as the upper trough in the eastern Atlantic drifts northward and away...which is allowing the upper ridge cell (with low shear and upper outflow) over Africa to expand into the tropical Atlantic in its wake. The pair of frontal lows to emerge from the Great Lakes and NW Atlantic will have no effect on this system while passing too far north...but a rather amplifed upper trough associated the western of the two frontal lows will strengthen the Atlantic surface subtropical ridge by 96 hours such that a westward acceleration in track of this tropical disturbance will be possible. I do not raise odds of development above 15% between 96 and 120 hours as lingering central Atlantic upper troughing could begin negatively shearing this disturbance.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1800Z Oct 4)...0% chance of tropical cyclone formation (tropical Atlantic southeast of the Republic of Cabo Verde Islands near 11N-20W)
IOH 48 Hr Outlook (1800Z Oct 5)...5% chance of tropical cyclone formation (tropical Atlantic southwest of the Republic of Cabo Verde Islands near 12N-25W)
IOH 72 Hr Outlook (1800Z Oct 6)...10% chance of tropical cyclone formation (tropical Atlantic near 13N-30W)
IOH 96 Hr Outlook (1800Z Oct 7)...15% chance of tropical cyclone formation (tropical Atlantic near 13.5N-36W)
IOH 120 Hr Outlook (1800Z Oct 8)...15% chance of tropical cyclone formation (tropical Atlantic near 13.5N-42W)