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Since 2012 on the now retired Weather Underground 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 at Yale Climate Connections via Disqus where the former Weather Underground community has moved to. Feel free to reply to me there, at my Disqus feed at this link, or via e-mail at 

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Updated: Oct 22, 2019

*******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 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 dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.**********

...MONDAY OCTOBER 21 2019 10:19 AM EDT...

See areas of interest sections below for an update on the remnants of Tropical Storm Nestor and the tropical wave currently heading toward the western Caribbean Sea which may later merge with the tail end of a cold front to produce a slow-moving tropical disturbance over Belize and southeastern Mexico in the coming days.

AREA OF INTEREST #1...The remnant circulation of what was Tropical Storm Nestor this morning is analyzed as a broad non-tropical frontal low currently located just offshore of the Maryland and Delaware coast. The circulation continues to be supported by a broad area of upper divergence between the north side of the upper ridging amplfiying in from the south in the warm sector of the impressive strengthening central US frontal cyclone...and the vast field of upper southwesterlies ahead of the western US upper troughing supporting the central US frontal cyclone. In the updated track in the outlook below is adjusted eastward due to the current position and eastward heading of the circulation...but Nestor should stop moving eastward by 24 hours while running into the western Atlantic surface ridge to the east and a developing surface ridge to the north to be supported by the western convergence zone of a shortwave upper trough ejecting from the main western US upper trough. As the upper ridging from the south amplifies northward over Nestor's remnant circulation...wind shear will reduce...and therefore will watch to see if Nestor can redevelop thunderstorms and some tropical characteristics over the warm Gulf stream waters by 24 hours. However I only have the odds of Nestor re-acquiring tropical characteristics at 5% due to the current lack of thunderstorms near the center and the fact that already by 48 hours Nestor will be pulled northward into cooler waters offshore of Massachusetts and Maine by the intensifying frontal cyclone approaching from the central US. However during that timeframe Nestor could retain strength through the upper divergence zone of the frontal cyclone's upper trough while transitioning into a non-tropical feature along the frontal cyclone's cold front.

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

IOH 24 Hr Outlook (1200Z Oct 22)...5% chance of tropical cyclone formation (south of Cape Cod Massachusetts near 37.5N-70W)

IOH 48 Hr Outlook (1200Z Oct 23)...0% chance of tropical cyclone formation (just northeast of Cape Cod Massachusetts near 41.5N-69.5W)

AREA OF INTEREST #2...The tropical wave currently moving through the central Caribbean Sea is already heading toward the western Caribbean this morning...and therefore my updated forecast points in the outlook below are adjusted southwestward...with the southward component of adjustment having to do with where the most favorable upper winds for thunderstorm activity will setup in the coming days. The tropical wave continues to produce disorganized pockets of thunderstorms...with the rotation east of Nicaragua having more to do with the cut-off upper vortex in the southern Caribbean than the tropical wave itself. The thunderstorm activity continues to be limited due to upper easterlies converging and creating some sinking motion on the north side of the upper vortex and south side of upper ridging to the north amplifying in the warm sector of the intensifying central US frontal cyclone. The frontal cyclone itself will whirl too far north to pull the track northward during the forecast period...therefore the first part of the forecast brings this system steadily west-northwestward into Belize...southeastern Mexico...and the Bay of Campeche. I show a 0% chance of tropical cyclone formation till a cell of the aforementioned upper ridging is forecast to collocate directly over this disturbance...which will maximize upper outflow to produce thunderstorms and keep wind shear low. This upper ridge cell will be due to the warm air ahead of a cold front and upper trough to pivot southeastward toward the Gulf of Mexico and Bay of Campeche on the back side of the central US frontal cyclonic system. In the later part of the forecast period...the tail end of the cold front will likely merge with this disturbance and perhaps help kick up thunderstorm activity...with this disturbance taking an atypical southeastward track back into southeastern Mexico from the Bay of Campeche by 120 hours due to strong surface high pressure building to the west and north behind the cold front. My peak odds of tropical cyclone development are only 5% at this time as the most favorable atmoshperic conditions for tropical development will tend to be over land...with wind shear on the north side of the upper ridge cell and over the Bay of Campeche waters likely being too high for tropical development. Regardless of tropical cyclone development or not...heavy flash flooding rainfall over Belize...the Yucatan peninsula of well as the Mexican provinces of Tabasco and Campeche maybe a concern over the next few days should this disturbance develop plenty of thunderstorsm while meandering erratically over the region.

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

IOH 24 Hr Oulook (1200Z Oct 22)...0% chance of tropical cyclone formation (north of Honduras near 16.5N-85W)

IOH 48 Hr Outlook (1200Z Oct 23)...0% chance of tropical cyclone formation (coast of Belize near 17N-88W)

IOH 72 Hr Outook (1200Z Oct 24)...5% chance of tropical cyclone formation (coast of Campeche near 18.5N-91W)

IOH 96 Hr Outlook (1200Z Oct 25)...5% chance of tropical cyclone formation (Bay of Campeche just offshore of Tabasco and Campeche near 19N-92.5W)

IOH 120 Hr Outlook (1200Z Oct 26)...5% chance of tropical cyclone formation (coast of Campeche near 18.5N-91W)

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