2016 Atlantic Hurricane Season Birdseye Discussion #163

By: NCHurricane2009 , 2:05 AM GMT on November 08, 2016

...MONDAY NOVEMBER 7 2016 9:05 PM EDT...
A pattern supporting a series of frontal disturbances that could acquire tropical characteristics to persist in the western Atlantic over the next several days...resuming daily updates on the Atlantic tropics on this blog...

The following statement concerns area of interest #1 marked over the western Atlantic just north of Bermuda in the atmospheric features chart below. Over the last 48 hours...a surface frontal depression and its associated shortwave upper trough from eastern Canada has dived southeastward into the longwave western Atlantic upper trough regime that has persisted over the last several days. The shortwave upper trough has amplified into a cut-off upper vortex during this process...with stronger upper divergence on the east side of the amplifying upper feature causing the surface frontal depression to rapidly strengthen into a 1002 mb frontal cyclone located just north of Bermuda. Even though the frontal cyclone is currently just northeast of warm 26 deg C waters typically supportive of tropical development...increasingly organizing showers and thunderstorms have fired around and close to the center due to de-stabilizing cold temperatures of the overhead cut-off upper vortex. Although I will watch for the development of subtropical characteristics from this frontal cyclone in the next 24 hours...by 48 hours it will be accelerated northeastward into even cooler waters southeast of Atlantic Canada by the upper trough and surface frontal system approaching from central North America...and so subtropical cyclone formation does not appear likely at the moment.

The following statement concerns area of interest #2 marked over the central United States in the atmospheric features chart below. A shortwave upper trough currently over central North America is supporting a lengthy surface frontal system...and in 72 hours the portion of this weather system currently over the central United States could amplify into a cut-off frontal cyclonic system while diving into the western Atlantic longwave upper trough regime that has persisted over the last several days. At this time it appears such a frontal cyclone would form over sufficiently warm waters over or near Bermuda to potentially acquire subtropical characteristics. Therefore will also monitor the progress of this frontal system over the next few days.

...ATMOSPHERIC FEATURES BIRDSEYE CHART...

This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1918Z-released WPC analysis.

Areas of Interest maybe first introduced circled by a yellow-dashed line. If the area of interest becomes introduced in the 5-day National Hurricane Center (NHC) Atlantic tropical weather outlook then it gets upgraded with a green-dashed line encircling it. If the area of interest gets upgraded to an Invest or is mentioned in the 48-hour NHC Atlantic tropical weather outlook then it gets upgraded with a green-solid polygon encircling it.

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 (also called an upper vortex or upper cyclone), blue Hs are locations of upper ridges (also called upper anticyclones).

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 (cyclones), Hs indicate surface highs (ridges/anticyclones).

...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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2:58 AM GMT on November 09, 2016
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