NCHurricane2009's Blog

2014 Atlantic Hurricane Season Birdseye Discussion #131A (Speical Update)

By: NCHurricane2009, 12:00 PM GMT on November 07, 2014

...FRIDAY NOVEMBER 7 2014 7:01 AM EDT...
What is left of the frontal boundary disturbance east of the Bahamas and eastern Caribbean is a cut-off upper vortex persisting near Hispaniola (Haiti and the Dominican Republic) and surface trough. The surface convergence of the surface trough and upper divergence on the east side of the upper vortex are producing heavy showers and thunderstorms over and in the vicinity of Puerto Rico this morning. However none of the reliable computer models are predicting tropical development from this disturbance. Therefore expecting this disturbance to gradually shift northeast and weaken over the next 48 to 72 hours as the upper-level wind forecasts show the upper vortex shifting northeast and de-amplifying out ahead of the upper trough currently emerging from eastern North America and out ahead of the next upper trough to follow behind.

And with none of the reliable computer models predicting tropical development in the Atlantic basin over the next few days...expecting a quiet period in the Atlantic tropics. Therefore have stopped doing daily updates on the Atlantic tropics on this blog. Will resume daily updates should the threat of tropical development return to the Atlantic basin.

2014 Atlantic Hurricane Season Birdseye Discussion #131

By: NCHurricane2009, 2:54 AM GMT on November 06, 2014

...WEDNESDAY NOVEMBER 5 2014 9:54 PM EDT...
The surface frontal boundary disturbance east of the Bahamas and eastern Caribbean remains supported by divergence on the east side of a cut-off upper vortex centered over Hispaniola (Haiti and the Dominican Republic). This disturbance has not become better organized and therefore is unlikely to develop. Instead...during the next 48 hours...this disturbance will accelerate northward and merge with the 986 mb frontal cyclone weather system currently moving into eastern North America.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1913Z-released WPC surface analysis.

Features boxed in green...if any...are mentioned in the National Hurricane Center (NHC) traditional 48-hour outlook and or are considered an "Invest" on the Naval Research Laboratory site of the US Navy at the time the chart was generated. I do not box features in green if they are only included in the NHC's longer term 5-day outlook.

In light blue is upper air analysis, with 200 mb wind barbs calculated by GOES satellite imagery showing the upper-level wind direction. Based on the 200 mb wind barbs, blue-dashed lines are locations of upper troughs, blue-zig-zag lines are locations of upper ridges. Blue Ls are locations of upper lows, blue Hs are locations of upper ridges.

In red is surface analysis, with solid lines indicating locations of surface fronts, dashed lines indicating locations of surface troughs, and zig-zag lines indicating surface ridge axes. Ls indicate surface lows, Hs indicate surface highs.

...THERMODYNAMICS BIRDSEYE CHART...

This chart is generated using GOES water vapor satellite imagery. Brown indicates dry air. White, blue, and purple indicates moist air. An increase in moisture indicates slower air parcel lapse rates with elevation and hence an increase toward instability.

Sea-surface temperatures are overlaid with light blue isotherms. The 26 deg C isotherm is highlighted in red. Waters at and south of the 26 deg C isotherm indicate low-level warmth and hence faster environmental lapse rates with elevation (more instability). Waters north of the 26 deg C isotherm indicate slower environmental lapse rates with elevation (less instability).

2014 Atlantic Hurricane Season Birdseye Discussion #130

By: NCHurricane2009, 6:13 PM GMT on November 04, 2014

...TUESDAY NOVEMBER 4 2014 1:14 PM EDT...
The upper trough that was previously over eastern North America in discussion #129 as expected produced a vigorous surface frontal cyclone that has tracked near the coast of North America over the last few days and is currently south of Greenland at 989 mb...and a large portion of this upper trough is now over the western Atlantic. In addition...this frontal cyclone as expected is leaving behind a surface frontal boundary segment east of the Bahamas that has the potential to evolve into a tropical or subtropical disturbance in the next 48 hours in favorable upper winds between a southern fracture of the upper trough to settle over the island of Hispaniola (Haiti and the Dominican Repbulic) and the rest of the upper trough as it moves away. The disturbance is expected to track northwestward from its current location east of the Bahamas to a location midway between the Bahamas and Bermuda in the next 48 hours. Then between 48 and 72 hours this disturbance will accelerate over or just west of Bermuda while transitioning into a non-tropical feature supported by the eastern divergence of the upper trough that is currently moving into central North America...and become absorbed by the 997 mb frontal cyclone currently over central North America not long after 72 hours. Therefore interests in Bermuda should monitor the progress of this system in case subtropical or tropical cyclone formation occurs over the next 48 hours. Waiting to see how well organized this disturbance becomes in the next 24 hours before considering an upgrade to a special feature on this blog.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1200Z and 1325Z-released WPC surface analysis.

Features boxed in green...if any...are mentioned in the National Hurricane Center (NHC) traditional 48-hour outlook and or are considered an "Invest" on the Naval Research Laboratory site of the US Navy at the time the chart was generated. I do not box features in green if they are only included in the NHC's longer term 5-day outlook.

In light blue is upper air analysis, with 200 mb wind barbs calculated by GOES satellite imagery showing the upper-level wind direction. Based on the 200 mb wind barbs, blue-dashed lines are locations of upper troughs, blue-zig-zag lines are locations of upper ridges. Blue Ls are locations of upper lows, blue Hs are locations of upper ridges.

In red is surface analysis, with solid lines indicating locations of surface fronts, dashed lines indicating locations of surface troughs, and zig-zag lines indicating surface ridge axes. Ls indicate surface lows, Hs indicate surface highs.

...THERMODYNAMICS BIRDSEYE CHART...

This chart is generated using GOES water vapor satellite imagery. Brown indicates dry air. White, blue, and purple indicates moist air. An increase in moisture indicates slower air parcel lapse rates with elevation and hence an increase toward instability.

Sea-surface temperatures are overlaid with light blue isotherms. The 26 deg C isotherm is highlighted in red. Waters at and south of the 26 deg C isotherm indicate low-level warmth and hence faster environmental lapse rates with elevation (more instability). Waters north of the 26 deg C isotherm indicate slower environmental lapse rates with elevation (less instability).

2014 Atlantic Hurricane Season Birdseye Discussion #129A (Special Update)

By: NCHurricane2009, 2:15 AM GMT on November 01, 2014

...FRIDAY OCTOBER 31 2014 10:20 PM EDT...
Potential for a tropical disturbance east of the Bahamas in the timeframe that is currently 5 days away remains as outlined in discussion #129. I will be taking a short vacation that will be limiting my internet access and therefore do not plan on releasing any full blog updates until Monday night. In the meantime visit www.nhc.noaa.gov or www.wunderground.com/tropical for up to the minute latest information on the Atlantic tropics.


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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