2015 Atlantic Hurricane Season Birdseye Discussion #13

By: NCHurricane2009 , 1:01 AM GMT on June 06, 2015

...FRIDAY JUNE 5 2015 9:01 PM EDT...
The western Caribbean surface low mentioned previously in discussion #11 has seen an increase in showers and thunderstorms over the last 24 hours as the upper divergence maximum associated with the east side of the Gulf of Mexico/eastern US upper trough moves overhead. The heavy weather associated with this disturbance overspreads the western Caribbean region including the Cayman Islands and Cuba...as well as parts of the Bahamas and southern Florida. As seen in the atmospheric features chart below...the southern part of the upper trough has fractured into a southeastern Gulf of Mexico upper vortex (marked as a blue L)...with the remainder of the upper trough (marked as a blue-dashed line) moving offshore from the eastern US and supporting a 1012 mb frontal low. While chasing the ridge weakness associated with the 1012 mb low...the western Caribbean low is expected to accelerate northeastward across Cuba and the Bahamas and into the open western Atlantic in the next 72 hours. There are currently no signs of tropical development...and southwesterly vertical shear on the east side of the upper trough may be too strong for this system to develop into a tropical cyclone. With the usually overly aggressive CMC computer model being the only model that develops this system...not expecting this system to become a tropical cyclone.

As the above-mentioned southeastern Gulf of Mexico upper vortex weakens over the next few days...upper-level winds could become more favorable for development for the tropical wave that is currently in the eastern Caribbean when the wave reaches the western Caribbean and southern Gulf of Mexico region about 5 to 6 days. However the only computer model that has returned to showing development of this wave is the usually over-aggressive CMC model.


This chart is generated based on surface analysis from the National Hurricane Center TAFB at 1800Z and 1931Z-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.


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 temperature isotherms at http://www.nhc.noaa.gov/satellite.php...the site from which the above thermo chart is generated from...are currently outdated. Therfore I have approximated the 26 deg C isotherm in the above chart using the sea-surface temperature maps available at www.wuwnderground.com/tropical. 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.

Reader Comments

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 2 - 1

Page: 1 — Blog Index

2. WunderAlertBot (Admin)
2:02 AM GMT on June 07, 2015
NCHurricane2009 has created a new entry.
1. hatrickp
4:50 AM GMT on June 06, 2015
Far less dry air around this year, so far...
Wonder if that's temporary, or if the Sahara is going to have a more settled summer than usual?
Member Since: December 31, 1969 Posts: Comments:

Viewing: 2 - 1

Page: 1 — Blog Index

Top of Page

NCHurricane2009 doesn't have a bio yet.