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BIRDSEYE VIEW POSTS

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 IOHurricanes@outlook.com 

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MY 2023 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #21

*******Note that forecast 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 media...watches 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.gov (hurricanes dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.**********


...FRIDAY JUNE 2 2023 2:05 AM EDT...

The surface low pressure area in the northeastern Gulf of Mexico becomes the second cyclone of the 2023 Atlantic Hurricane Season... see tropical depression two section below for more information. Meanwhile the upper trough that generated the depression has potential to bring additonal rounds of heavy rainfall to Cuba... the Bahamas... and Haiti over the next few days.


Note the first cyclone of the season... an unnamed subtropical storm... formed in mid-January in the northwestern Atlantic. More information on the northwestern Atlantic storm system is provided at the following link:


For the northeastern Atlantic Ocean... over the next five days the current northwestern Atlantic upper vortex will be pushed into the northeastern Atlantic by a warm core upper ridge that develops to its west (this upper ridge will be manifested in the warm sector of a forecast northwest Atlantic frontal cyclone to be gradually generated by divergence zone of the merger between the current upper troughs approaching from the Gulf of Mexico and east coast of Canada). As the upper vortex shifts east toward the northeast Atlantic... the current north-central Atlantic frontal cyclone it has been supporting will become stacked with and weaken below the core of the upper vortex where there is a lack of divergence... while the southeastern divergence zone of the upper vortex goes on to generate a new frontal cyclone midway between the Azores and the Canary Islands. Recent runs of the GFS and ECMWF models suggest the new cyclone could be strong enough with a well-defined (instead of elongated) center to support subtropical development. However water temps in the region are currently at 19 deg C and the 200 mb height of the upper vortex core is forecast to be 1188 dekameters. Would prefer to see more forecast instability thru colder upper air temps (lower 200 mb heights) for these water temps before issuing outlooks on possible subtropical development... therefore I have not done so at this time. Regardless of its eventual structure (non-tropical... subtropical etc)... the forecast cyclone will likely be large enough to bring coastal surf and gusty winds to the Azores and Canary Islands by early next week.


TROPICAL DEPRESSION TWO... Satellite image of the surface low pressure in the northeastern Gulf of Mexico evolving into tropical depression two (1306Z Thursday June 1):

The eastern divergence zone of an upper trough traversing across the Gulf of Mexico over the last couple of days has triggered the second cyclone of the 2023 Atlantic Hurricane Season. The cyclone... located in the northeastern Gulf of Mexico... is not particularly impressive while a cloud swirl tropical depression with the thunderstorm activity displaced to the northeast thanks to shear imparted by the upper trough. The upper trough itself has recently merged with upper vorticity that has been trapped over the eastern US over the last few days... and will also soon merge with the upper trough currently diving southeastward from its current east Canada coast position... with the merged upper trough sliding eastward over the tropical depression. This will expose the tropical depression to upper northwesterly flow on the back side of the upper trough that will shove the depression south-southeastward while also weakening it with upper convergence and shear (by shear... meaning the upper winds keep any thunderstorm activity displaced from the swirl center). Given the latest satellite frames show the depression beginning to move southward... and that thunderstorm activity has been weakening while also becoming displaced well to the northeast... this process appears to have already begun. As such I forecast the depression to become a remnant low within the next 24 hours... a lower intensity forecast than the NHC as of this writing which suggests some possible short-term strengthening followed by a more gradual decay (note that as of this blog post... I have begun to list the NHC official forecast for active tropical cyclones next to my forecast. Only the highlights of the NHC forecast are included such as forecast peak strength... for all points of the NHC offical forecast defer to the NHC official site at hurricanes.gov). Regarding forecast track points... I have nudged my points slightly northwestward due to the current position of the depression relative to my previous blog post's forecast for this system.


Note the eastern divergence zone of the upper trough mentioned in the prior paragraph has been producing thunderstorms with pockets of heavy rainfall across south Florida... the Bahamas... Cuba and Haiti within the last several hours. Note this rainfall is NOT associated with tropical depression two. The potential for additional heavy rainfall will reduce for south Florida within the next 24 hours as the upper trough edges eastward... however for the Bahamas... Cuba and Haiti additional heavy rainfall is possible for a few more days as the upper trough will be slow to shift east. The divergence zone of the upper trough may also trigger a surface trough in this region. The upper trough will be taking on a southwest-northeast tilt while dragged in its merger with the high-latitude upper trough from the east Canada coast... this tilt direction will create hostile westerly shear over the surface trough such that no tropical development is anticipated with it.

******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********

0 Hr Position (0000Z Jun 2)... 35 mph maximum sustained wind tropical depression centered in the northeastern Gulf of Mexico at 27.5N-86.5W

IOH 24 Hr Forecast (0000Z Jun 3)... Remnant low centered in the eastern Gulf of Mexico at 25.5N-85W

******National Hurricane Center (hurricanes.gov) official forecast as of 11 PM EDT***************************

Peak Strength (1200Z Jun 2)... 40 mph maximum sustained wind tropical storm centered in the northeastern Gulf of Mexico at 26.8N-86.5W

Loss of Tropical Cyclone Status (0000Z Jun 4)... 30 mph maximum sustained wind remnant low centered just offshore of northwestern Cuba at 22.9N-85.1W


...COMPUTER MODEL SUMMARY...

Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)


1200Z (Jun 1) CMC Model Run...

**For Tropical Depression Two... circulation weakens while drifting south to 24.5N-86.5W through 30 hours... while moving south-southeast toward the northwest coast of Cuba the circulation loses its identity within a larger-scale surface trough becoming established in the region.


1200Z (Jun 1) ECMWF Model Run...

**For Tropical Depression Two... circulation moves south-southeast toward the Yucatan channel (between the west tip of Cuba and Yucatan peninsula) while weakening and loses identity by 54 hours within a larger-scale surface trough becoming established in the region.


1800Z (Jun 1) GFS Model Run...

**For Tropical Depression Two... circulation moves south-southeast toward the Yucatan channel (between the west tip of Cuba and Yucatan peninsula) while weakening and loses identity by 51 hours within a larger-scale surface trough becoming established in the region.


1800Z (Jun 1) NAVGEM Model Run...

**For Tropical Depression Two... circulation moves south-southeast toward the Yucatan channel (between the west tip of Cuba and Yucatan peninsula) while weakening and loses identity by 48 hours within a larger-scale surface trough becoming established in the region.

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