NCHurricane2009's Blog

2016 Atlantic Hurricane Season Birdseye Discussion #9A (Special Update)

By: NCHurricane2009, 2:42 PM GMT on April 30, 2016

...SATURDAY APRIL 30 2016 10:40 AM EDT...
The surface low southwest of the Azores is now experiencing increasing westerly vertical shear and has lost shower and thunderstorm activity this morning. Subtropical cyclone formation is no longer possible. This is my final blog update until either the official start of the Atlantic Hurricane Season June 1 or if the threat of tropical activity in the Atlantic develops before then.

2016 Atlantic Hurricane Season Birdseye Discussion #9

By: NCHurricane2009, 4:29 AM GMT on April 30, 2016

...SATURDAY APRIL 30 2016 12:30 AM EDT...
Monitoring the surface frontal cyclone southwest of the Azores for subtropical cyclone formation over the next 24 hours. See special feature section below for additional details.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1936Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

...SPECIAL FEATURE...SURFACE FRONTAL CYCLONE...
Current Prognosis...The surface frontal cyclone southwest of the Azores has seen an increase in showers and thunderstorms over the last 48 hours and has become well-organized tonight...with the center passing over 28.5N-34.5W as of 0000Z. This is due the reduced shear as the cold core upper-level vortex of this system has become aligned with the surface circulation...with the cold temps of the upper vortex helping to de-stabilize the atmosphere despite sea-surface temps in the low 20s of deg C. Subtropical cyclone formation may occur in the next 24 hours before conditions become more hostile per the atmospheric outlook below.

Atmospheric Outlook for the Forecast Period...The deep-layered frontal cyclone southwest of the Azores is being steered southwest by the south side of a 1030 mb deep-layered ridge (this ridge is marked in the top-right of the above atmopsheric features chart). The 0000Z position of the surface circulation (per above current prognosis) is further southwest than my previous forecast in discussion #8...and therefore my updated forecast shown below is adjusted southwestward accordingly. The upper-level vortex of the deep-layered frontal cyclone will soon slide eastward while merging with the upper trough to the northeast near Spain (marked by blue-dashed line in the top-right of the above atmopsheric features chart). With the surface circulation expected to continue southwestward...this means the upper-level and surface circulations will decouple which will significantly increase the vertical shear and put an end to any potential tropical activity from the surface circulation after 24 hours.

Thermodynamic Outlook for the Forecast Period...This system is expected to be over sea-surface temps in the low 20s of deg C thru the forecast period. While this is below the threshold of 26 deg C typical of tropical development...this system is also expected to be beneath cold upper vorticity thru the forecast period...with cold upper air temps helping to maintain instability despite the mild waters.

24 Hr Forecast (0000Z May 1)...Sheared remnant low centered southwest of the Azores at 26N-38W

2016 Atlantic Hurricane Season Birdseye Discussion #8B (Special Update)

By: NCHurricane2009, 8:51 PM GMT on April 29, 2016

...FRIDAY APRIL 29 2016 4:50 PM EDT...
The surface frontal cyclone southwest of the Azores has seen an increase in showers and thunderstorms since yesterday...and most markedly over the last few hours this afternoon...while centered at approximately 29.5N-33.5W. This is due the reduced shear as the cold core upper-level vortex of this system has become aligned with the surface circulation...with the cold temps of the upper vortex helping to de-stabilize the atmosphere despite sea-surface temps in the low 20s of deg C. I am considering a full blog update tonight if this situation continues. It is quiet elsewhere in the Atlantic tropics.

2016 Atlantic Hurricane Season Birdseye Discussion #8A (Special Update)

By: NCHurricane2009, 9:50 PM GMT on April 27, 2016

...WEDNESDAY APRIL 27 2016 5:50 PM EDT...
The surface frontal cyclone southwest of the Azores remains in a sheared state as the overhead upper vortex is not aligned with the surface circulation. As a result all shower and thunderstorm activity remains biased to the east of the surface circulation and subtropical cyclone formation is no longer possible. This is my final blog update until either the official start of the Atlantic Hurricane Season June 1 or if the threat of tropical activity in the Atlantic develops before then.

2016 Atlantic Hurricane Season Birdseye Discussion #8

By: NCHurricane2009, 2:11 AM GMT on April 27, 2016

...TUESDAY APRIL 26 2016 10:12 PM EDT...
Subtropical cyclone formation is possible southwest of the Azores over the next 48 hours. Not expecting this system to strike the Azores...but instead expecting this system to stay south of the Azores. See special feature section below for additional details on this situation.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1930Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

...SPECIAL FEATURE...SURFACE FRONTAL CYCLONE...
Current Prognosis...Under supportive upper divergence on the southeast side of an upper trough extending from eastern Canada...the 1004 mb surface frontal low in the open central Atlantic has deepened to a 996 mb frontal cyclone over the last 24 hours. Meanwhile far to the west...a frontal cyclone has recently traveled from the central US and into the northeast US (labeled at 1002 mb in the atmospheric features chart above). Warm air adveciton ahead of the frontal cyclone has recently split the cold core upper trough extending from eastern Canada into two cold core upper vortices...one over eastern Canada and the other directly overhead of our 996 mb frontal cyclone. As a result as of this afternoon...our frontal cyclone is now a deep-layered circulation. The low-shear nature of the deep-layered flow was allowing some shower and thunderstorm activity to organize around the surface center...but over the last couple of hours the overhead upper vortex has outpaced our surface center a bit...placing the surface center under some westerly shear on the south side of the upper vortex. This has very recently caused whatever shower activity that was near the surface center to be sheared eastward and away. As of 0000Z the surface center passed over 31N-44W. This is 2W longitude further west than the previous forecast...and therefore my updated forecast track is adjusted accordingly.

Atmospheric Outlook for the Forecast Period...Continued warm air advection ahead of the 1002 mb NE US frontal cyclone (mentioned in the above current prognosis) will build up a deep-layered ridge that will spread across the north Atlantic. However initially our deep-layered frontal cyclone will be pulled east-northeast toward the Azores by the 1003 mb deep-layered low to the northeast ...followed by a turn to the southwest and west by 72 to 96 hours while steered by the south side of the deep-layered ridge. I have lowered the intensity forecast in the later part of the forecast period due to a less favorable upper wind forecast shown by the GFS computer model tonight...which shows the upper layer of the 1003 mb low to the northeast merging with the upper vortex overhead of our system...with the merger creating an east-west upper trough to the south of the deep-layered ridge (the lastest forecast track is aligned with the south side of the forecast upper trough where highly unfavorable westerly shear will be present).

Thermodynamic Outlook for the Forecast Period...This system is expected to be over sea-surface temps in the low 20s of deg C thru the forecast period. While this is below the threshold of 26 deg C typical of tropical development...this system is also expected to be beneath cold upper vorticity thru the forecast period...with cold upper air temps helping to maintain instability despite the mild waters.

24 Hr Forecast (0000Z Apr 28)...50 mph maximum sustained wind subtropical storm centered southwest of the Azores at 32N-37W

48 Hr Forecast (0000Z Apr 29)...60 mph maximum sustained wind subtropical storm centered south of the Azores at 31N-32W

72 Hr Forecast (0000Z Apr 30)...45 mph maximum sustained wind subtropical storm weakening under westerly shear...centered south of the Azores at 29N-33W

96 Hr Forecast (0000Z May 1)...Sheared remnant low centered southwest of the Azores at 29N-37W

2016 Atlantic Hurricane Season Birdseye Discussion #7

By: NCHurricane2009, 2:35 AM GMT on April 26, 2016

...MONDAY APRIL 25 2016 10:40 PM EDT...
The potential remains for a subtropical or tropical system to develop southwest of the Azores over the next few days. Currently not expecting this system to strike the Azores...but instead expecting this system to stay south of the Azores. See special feature section below for additional details on this developing situation.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1925Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

...SPECIAL FEATURE...SURFACE FRONTAL LOW...
Current Prognosis...The extensive area of showers and thunderstorms that was previously northeast of Puerto Rico 24 hours ago has raced east-northeastward into the open Atlantic waters and remains supported by the south end of an upper trough/surface cold front that extends from eastern Canada. Recently a 1004 mb surface low pressure center was declared with this activity...and satellite imagery as of 0000Z reveals that the broad circulation is centered at approximately 29.5N-50W with the extensive thunderstorm activity lopsided to the east of the center. This is exactly on par with my previous forecast and therefore I am making only minor changes to my forecast tonight.

Atmospheric Outlook for the Forecast Period...The 999 mb frontal cyclone currently over the central US will accelerate northeastward across eastern Canada over the next few days while getting supported by the northern half of the upper trough over eastern Canada/western Atlantic. Warm air advection ahead of this frontal cyclone will build up a deep-layered ridge that will spread across the north Atlantic...and in turn this deep-layered ridge will cut-off the southern part of the eastern Canada/western Atlantic upper trough into an upper vortex directly over our 1004 mb surface low...resulting in the formation of a deep-layered low in the next 24 hours. Initially this deep-layered low will be pulled east-northeast toward the Azores by the 995 mb deep-layered low to the northeast while potentially evolving into a subtropical storm. The latest GFS computer model no longer merges the upper-layers of both deep-layered lows into a shearing upper trough and therefore I have upped the intensity in the later part of my forecast. By 96 to 120 hours the potential subtropical storm will be moving southward and then westward away from the Azores due to steering on the south side of the aforementioned deep-layered ridge that is expected to form. I have edged the late part of my forecast track a little more northwards to be in alignment with the latest GFS computer model run.

Thermodynamic Outlook for the Forecast Period...This system is expected to be over sea-surface temps in the low 20s of deg C thru the forecast period. While this is below the threshold of 26 deg C typical of tropical development...this system is also expected to be beneath cold upper vorticity thru the forecast period...with cold upper air temps helping to maintain instability despite the mild waters.

24 Hr Forecast (0000Z Apr 27)...Strengthening surface low centered at 32N-42W

48 Hr Forecast (0000Z Apr 28)...50 mph maximum sustained wind subtropical storm centered southwest of the Azores at 32N-35W

72 Hr Forecast (0000Z Apr 29)...60 mph maximum sustained wind subtropical storm centered south of the Azores at 31N-30W

96 Hr Forecast (0000Z Apr 30)...60 mph maximum sustained wind subtropical storm centered south of the Azores at 29N-30W

120 Hr Forecast (0000Z May 1)...60 mph maximum sustained wind subtropical strom centered southwest of the Azores at 29N-35W

2016 Atlantic Hurricane Season Birdseye Discussion #6

By: NCHurricane2009, 2:01 AM GMT on April 25, 2016

...SUNDAY APRIL 24 2016 10:01 PM EDT...
Potential for a subtropical or tropical system to develop southwest of the Azores over the next few days. Currently not expecting this system to strike the Azores...but instead expecting this system to stay south of the Azores. See special feature section below for additional details.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1925Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

...SPECIAL FEATURE...SURFACE COLD FRONT...
Current Prognosis...Showers and thunderstorms have rapidly flared up northeast of Puerto Rico over the last 24 hours under the support of surface convergence from a cold front crossing the western Atlantic and upper divergence on the east side of an upper trough associated with the cold front. Additional surface convergence from a decaying cold front tied to a 989 mb deep-layered low pressure center to the northeast may have also aided in this flare up of activity.

Atmospheric Outlook for the Forecast Period...The 994 mb frontal cyclone currently over the central US will accelerate northeastward across eastern Canada over the next few days while getting supported by the upper trough stalling over the central US and northern half of the upper trough over eastern Canada/western Atlantic. Warm air advection ahead of this frontal cyclone will build up a deep-layered ridge that will spread across the north Atlantic...and in turn this deep-layered ridge will cut-off the southern part of the eastern Canada/western Atlantic upper trough/surface cold front into a deep-layered low in the next 48 hours. Initially this deep-layered low will be pulled east-northeast toward the Azores by the 989 mb deep-layered low to the northeast while potentially evolving into a subtropical storm. By 96 hours the upper-layers of both deep-layered lows will have merged into an upper trough inducing light northerly shear over the potential subtropical storm...and by 120 hours the potential subtropical storm will be moving southward and away from the Azores due to steering on the southeast side of the aforementioned deep-layered ridge that is expected to form. Just beyond the forecast period a portion of the upper trough over the potential subtropical storm could re-cut-off into an upper vortex directly overhead and favorably reduce the northerly shear over this system.

Thermodynamic Outlook for the Forecast Period...This system is expected to be over sea-surface temps in the low 20s of deg C thru the forecast period. While this is below the threshold of 26 deg C typical of tropical development...this system is also expected to be beneath cold upper vorticity thru the forecast period...with cold upper air temps helping to maintain instability despite the mild waters.

24 Hr Forecast (0000Z Apr 26)...Surface low forming at 29.5N-50W with extensive amounts of thunderstorm activity east of the center

48 Hr Forecast (0000Z Apr 27)...Strengthening surface low centered at 32N-42W

72 Hr Forecast (0000Z Apr 28)...50 mph maximum sustained wind subtropical storm centered southwest of the Azores at 32N-35W

96 Hr Forecast (0000Z Apr 29)...45 mph maximum sustained wind subtropical storm slightly weakening under light northerly shear centered south of the Azores at 31N-30W

120 Hr Forecast (0000Z Apr 30)...45 mph maximum sustained wind subtropical storm under light northerly shear centered south of the Azores at 27N-30W

2016 Atlantic Hurricane Season Birdseye Discussion #5A (Special Update)

By: NCHurricane2009, 8:25 PM GMT on April 24, 2016

...SUNDAY APRIL 24 2016 4:20 PM EDT...
Showers and thunderstorms have significantly increased north-northeast of Puerto Rico in association with the southern part of a surface cold front and upper trough that will evolve into a cut-off deep-layered low to the northeast of the Lesser Antilles in the next 48 hours. With this much thunderstorm activity and continued indications from computer models that this low pressure will have some strength...I believe chances are increasing that a subtropcial or tropcial system could emerge within this deep-layered low over the next few days. Therefore I will be upgrading this system to a special feature with a full forecast and discussion on my next blog udpate tonight.

It remains quiet elsewhere in the Atlantic tropics.

2016 Atlantic Hurricane Season Birdseye Discussion #5

By: NCHurricane2009, 11:51 PM GMT on April 23, 2016

...SATURDAY APRIL 23 2016 7:55 PM EDT...
The latest computer model runs continue to indicate the the southern part of the surface cold front/trough and associated upper trough currently entering the Atlantic from the United States will evolve into a cut-off deep-layered low pressure system in three days while moving into the open waters midway between the Lesser Antilles and Azores. During this time there is some opportunity for this low pressure system to acquire some subtropical characteristics.

It is quiet elsewhere in the Atlantic tropics.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1935Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

2016 Atlantic Hurricane Season Birdseye Discussion #4

By: NCHurricane2009, 11:50 PM GMT on April 22, 2016

...FRIDAY APRIL 22 2016 7:55 PM EDT...
The latest computer model runs indicate the the southern part of the cold front and associated upper trough currently over the eastern United States will evolve into a cut-off deep-layered low pressure system while moving into the open Atlantic waters southwest of the Azores over the next four days. During this time there is some opportunity for this low pressure system to acquire some subtropical characteristics. Therefore have resumed daily updates on this blog.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1200Z and 1330Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

2016 Atlantic Hurricane Season Birdseye Discussion #3

By: NCHurricane2009, 2:07 AM GMT on April 19, 2016

...MONDAY APRIL 18 2016 10:07 PM EDT...
The deep-layered low pressure center northeast of Bermuda has been moving eastward and away. The associated showers and thunderstorms have weakend and tropical development is not expected as it will become absorbed by a developing gale currently developing in the northwest Atlantic in the next 24 hours.

This is my final blog update until the threat of tropical cyclone activity returns to the Atlantic basin.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1929Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).

2016 Atlantic Hurricane Season Birdseye Discussion #2

By: NCHurricane2009, 7:06 PM GMT on April 17, 2016

...SUNDAY APRIL 17 2016 3:07 PM EDT...
Watching for the development of tropical characteristics within a deep-layered vortex centered just northeast of Bermuda. A deep-layered vortex with a 1004 mb surface low pressure center is showing some signs of organization but weak amounts of shower and thunderstorm activity on satellite imagery this afternoon. This system has only 48 hours to acquire tropical characteristics before an upper trough over eastern Canada (marked by blue-dashed line in the atmospheric features chart) digs southward and triggers the formation of a surface gale in the northwest Atlantic that will absorb this system. Regardless of tropical development or not...this system will generally drift southeastward and then eastward away from Bermuda as it gets absorbed.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1200Z and 1607Z-released WPC 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. Surface troughs labeled with TW indicates the trough is a tropical wave whose origin is from the mid-level African Easterly Jet. 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).


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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