*******Note that forecasts 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.**********
...SATURDAY MAY 30 2020 1:10 AM EDT...
The following is a special update on the surface trough of low pressure in the open Atlantic located well southeast of Bermuda and supported by a cut-off upper vortex. The low level cloud motion on recent infrared satellite imagery suggests a surface low pressure spin along the surface trough maybe consolidating at 26N-56.5W...close to a clump of organized thunderstorms supported by split flow upper divergence on the northeast quadrant of the upper vortex. A recent ASCAT-A ascending pass seemed to confirm a similar finding...although the circulation of the developing spin is not fully closed in the pass. Therefore I have begun a subtropical cyclone formation forecast as outlined below assuming the divergence maximum of the upper vortex will intensify the spin at 26N-56.5W further. The ASCAT-A pass suggested the system was just below the threshold of subtropical storm strength...with max winds just below 40 mph...therefore the intensity forecast below assumes the surface low pressure spin will intensity to 50 mph before the surface low whirls northwestward beneath the core of the upper vortex where there is less divergence. After 24 hours...I forecast weakening as the surface low and upper vortex move northward in tandem along the west side of the deep-layered ridge in the northwest Atlantic...both due to the lack of divergence directly below of the upper vortex...and due to the northward track taking the system to cooler waters. Just after 48 hours...the frontal system and its upper trough from central Canada should arrive into the northwest Atlantic and absorb the surface circultion and upper vortex...so this is when I end the forecast.
******Infohurricanes.com forecast. Visit hurricanes.gov (hurricanes dot gov) for official forecast***********
0 Hr Position (0000Z May 30)...Surface low pressure centered over the western Atlantic at 29N-56.5W
IOH 24 Hr Forecast (0000Z May 31)...50 mph maximum sustained wind subtropical storm centered in the western Atlantic at 31.5N-57W
IOH 48 Hr Forecast (0000Z Jun 1)...40 mph maximum sustained wind subtropical storm centered in the western Atlantic at 35N-57W...losing identity ahead of apporaching cold front