MY 2019 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #174
*******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.**********
...FRIDAY NOVEMBER 1 2019 12:25 PM EDT...
Subtropical Storm Rebekah loses its thunderstorms and tropical characteristics while passing just north of the western Azores...see remnants of Rebekah section below for details. See area of interest section below for details on the tropical disturbance along the Intertropical Convergence Zone in the eastern tropical Atlantic. Elsewhere...the south part of the elongated upper trough over Rebekah is becoming cut-off by a western Atlantic deep-layered ridge into a seperate vortex to be located northeast and then later north of the Lesser Antilles. Showers and thunderstorms have already increased in the eastern divergence zone of this developing cut-off upper vortex...and computer models agree that this upper divergence zone will produce a broad surface trough of low pressure between the Lesser Antilles and Bermuda in the next few days. Will watch to see if a subtropical or tropical disturbance emerges here.
REMNANTS OF REBEKAH...The circulation of Subtropical Storm Rebekah last evening lost thunderstorms...and as of this early morning was downgraded to a remnant low pressure while skirting eastward just north of the western Azores. The water temperatures and upper-level cold temperatures of the overhead upper trough are the same as before...so the only explanation of the loss of thunderstorms maybe the axis of the overhead upper trough catching up to Rebekah from the west where there is a lack of upper divergence. The upper-level winds will become more hostile to Rebekah by tomorrow as the remnant circulation's eastward speed gets dragged down by the approaching deep-layered ridge from the western Atlantic...causing the remnant circulation to fall behind the eastward accelerating upper trough and enter the western upper convergence zone of the trough. Therefore expecting the remnant circulation to degenerate into a surface trough in the next 24 hours and to be completely dissipated soon thereafter. This is my final statement on Rebekah as it no longer has tropical characteristics.
AREA OF INTEREST #1...The National Hurricane Center in their surface analysis has added a tropical wave to mark the location of the eastern Atlantic disturbance along the Intertropical Convergence Zone (ITCZ). Since their 1200Z discussion that's tied to this anlaysis is not yet available till 2 PM EDT...I am not certain if this is a poorly-defined tropical wave that emerged from Africa a couple of days ago and was not added till now...or if a surface trough of low pressure has formed and it is being treated as a tropical wave. Nonetheless...this disturbance has recently lost its widespread thunderstorm activity. Given that the disturbance remains beneath a supportive low shear and upper outflow environment beneath an upper ridge...I assume this is from the dry saharan air layer to the north. Therefore I have lowered my peak odds of tropical cyclone formation from 15% to 5% in the updated outlook below. My peak odds are not 0% at this time as this disturbance will remain under the aformentioend supportive environment of the upper ridge in the next 48 hours. However I end my updated outlook at 72 hours as this disturbance moves into stronger westerly shear on the east side of a cut-off the upper vortex currently forming and expected to persist near the northern Lesser Antilles. Track of this disturbance during the forecast period is expected to be west-northwest as the western and eastern Atlantic surface ridge cells merge in the wake of Rebekah's remnants and steer this disturbance.
******Infohurricanes.com outlook. Visit hurricanes.gov (hurricanes dot gov) for official outlook***********
IOH 24 Hr Outlook (1200Z Nov 2)...0% chance of tropical cyclone formation (tropical Atlantic near 8N-40W)
IOH 48 Hr Outlook (1200Z Nov 3)...5% chance of tropical cyclone formation (tropical Atlantic near 9.5N-45W)
IOH 72 Hr Outlook (1200Z Nov 4)...0% chance of tropical cyclone formation (tropical Atlantic near 11N-50W)