*******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 NOVEMBER 18 2022 11:36 PM EDT...
Wind shear over the Caribbean remains low... with an increased upper outflow environment... as an upper ridge remains parked over the region. Their appear to be two rounds of possible tropical development in this environment over the course of the next week:
(1) For the short-term... the tail end of a surface cold front that has entered the northwestern Caribbean from the Gulf of Mexico has been downgraded to a surface trough of low pressure with the loss of airmass contrasts on either side of it. The surface trough is generating showers and thunderstorms in the northwestern Caribbean... while an additional tropical low near Panama (generated earlier by the outflow of the Caribbean upper ridge) is producing some activity in the southern Caribbean Sea. The GFS model continues to project potential short-term development in this activity over the next 48 hours... however their are currently no signs of development.
(2) Over the next seven days... the southwest portion of the current North American upper trough is forecast to become cut-off from the mid-latitude westerlies by the current northeast Pacific/western Canada blocking upper ridge. Eventually the cut-off upper trough is forecast to shift across the Gulf of Mexico and drive the tail end of the current northwestern Caribbean surface trough deeper into the central Caribbean Sea. In addition to the arrival of the surface trough from the northwest... the current central Atlantic upper vorticity is forecast to approach the central Caribbean from the northeast while retrograding around the current Caribbean-to-Atlantic upper ridge... with possible split flow upper divergence between the upper vorticity and upper ridge further supporting low surface pressures in the central Caribbean. Models are currently in general agreement in forecasting a sprawling area of central Caribbean surface low pressure by day 7... this area therefore may require monitoring for tropical development around that time.
...COMPUTER MODEL SUMMARY...
Source...Florida State University Experimental Forecast Tropical Cyclone Genesis Potential Fields (http://moe.met.fsu.edu/tcgengifs/)
1200Z (Nov 18) CMC Model Run...
**Broad tropical low becomes defined in the central Caribbean Sea near 12.5N-79W at 144 hours... reaches 12N-81.5W at 168 hours.
1200Z (Nov 18) ECMWF Model Run...
**No tropical development shown in the Atlantic basin for the next 168 hours (7 days)
1200Z (Nov 18) GFS Model Run...
**Compact tropical low becomes defined just east of the Nicaragua/Costa Rica border at 48 hours... drifts northwest into southeastern Nicaragua where it dissipates at 66 hours.
1200Z (Nov 18) NAVGEM Model Run...
**Broad tropical low becomes defined just east of Nicaragua at 168 hours.