top of page
Home: Text


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 

Home: Text
Home: Blog2
  • Writer's pictureNCHurricane2009


*******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.**********

...WEDNESDAY OCTOBER 23 2019 12:07 PM EDT...

See areas of interest section below for an update on the tropical disturbance developing over southeastern Mexico and Bay of Campeche. Elsewhere...the upper trough currently moving into the northeastern Atlantic is amplifying in response to the amplification of the upper ridge extending across the Gulf of Mexico and eastern Canada in the warm sector of the eastern Canada frontal cyclone...which is resulting in the formation of a rapidly developing frontal cyclone west of the Azores. The amplification of the upper trough will send this frontal cyclone initially east-southeastward...followed by a northeastward hook over or just east of the Azores in 72 hours when the upper trough becomes whirled northward by the upper trough energy associated with the eastern Canada frontal cyclone. The frontal cyclone passing by the Azores is not likely to acquire subtropical characteristics while quickly intruded by the cold front extending from the eastern Canada frontal cyclone. In the long range's model runs suggest the intruding cold front could evolve into quiet an impressive second frontal cyclone west of the Azores in response to the upper trough energy from eastern Canada amplifying into a vigorous and large cut-off upper vortex. If indeed this were to occur...would watch for the acquisition of tropical characterstics in the second frontal cyclone due to the cold destabilizing temperatures of the upper vortex that could aid in the generation of thunderstorms. However whether or not this upper vortex forms will depend on how the next frontal system over Canada evolves which the models have not nailed down just yet due to the usual longer-range uncertainty. That frontal system will be key in the genesis of the cut-off upper vortex as its warm sector would control how much downstream upper ridging builds over eastern Canada...with more upper ridging allowing for the formation of the upper vortex.

AREA OF INTEREST #1...The tropical wave that was in the western Caribbean Sea is now moving through Belize...northern Guatemala...and southeastern Mexico. Latest satellite animation suggests the wave is producing maximum spin over the Guatemala/Mexico border...with a general increase in the pockets of thunderstorms in the region...including over the offshore waters of the Bay of Campeche...due to the assistance of outflow from an upper ridge axis settling over the tropical wave and tail end of a surface cold front extending from the large frontal cyclone currently moving into eastern Canada. Over the next 48 hours the aforementioned area of maximum spin should generally progress west-northwest into the Bay of Campeche under the steering influence of the surface ridge building over the southeastern United States. The upper ridge axis with its favorable low shear and supporting outflow should remain in place during the forecast period while persisting in the warm air ahead of another cold front and upper trough to pivot southeastward from the western US and into the Gulf of Mexico and Bay of Campeche on the back side of the eastern Canada frontal cyclonic system...therefore upper-level winds will generally be conducive for tropical development. In 48+ hours...the tail end of the next cold front will likely merge with this disturbance and perhaps help kick up additional thunderstorm activity...with this disturbance potentially taking an atypical southeastward or eastward track back into southeastern Mexico from the Bay of Campeche due to strong surface high pressure building to the west and north behind the cold front. This idea is supported by the latest NAVGEM model run...while the more reliable GFS and Euro well as the CMC model...continue suggesting more entanglement with the next cold front...maybe evolving into a broad low pressure located further north and similar in characteristic to last week's Tropical Storm Nestor where the northern part of the circulation is supported by the divergence zone of the cold front's upper trough. My peak odds of tropical cyclone development are slightly raised to 15% due to the current organization of the spin at the Guatemala/Mexico border and with the NAVGEM model continuing to suggest tropical cyclone formation in a manner similar to the outlook below. This tepid rise in my odds is because the NAVGEM is not typically a reliable model for tropical development...and I will only raise odds further if the current spin later becomes well organized over the Bay of Campeche or if the other models begin showing tropical cyclone formation. My 0% odds at 96 to 120 hours is due to forecast land interaction when this system moves back eastward toward the Yucatan peninsula...but could be raised should a circulation be observed to develop further north over the Gulf of Mexico as the CMC...Euro...and GFS suggest. 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 thunderstorms while meandering erratically over the region.

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

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

IOH 48 Hr Outlook (1200Z Oct 25)...15% chance of tropical cyclone formation (Bay of Campeche offshore of Tabasco and Campeche near 20N-92.5W)

IOH 72 Hr Outlook (1200Z Oct 26)...15% chance of tropical cyclone formation (coast of Campeche near 19N-91W)

IOH 96 Hr Outlook (1200Z Oct 27)...0% chance of tropical cyclone formation (Yucatan peninsula near 19N-89W)

IOH 120 Hr Outlook (1200Z Oct 28)...0% chance of tropical cyclone formation (northeastern Yucatan peninsula near 20.5N-88W)

32 views0 comments


bottom of page