Weekly Synopsis

Forecast Discussion

UPDATED:  08 August 2026 8:50 p.m.

KEY MESSAGES:

•    Moisture advection coupled with an upper-level low can produce showers and isolated thunder through Sunday morning.
•    A Tropical wave is expected to traverse the area Monday evening area bringing a renewed chance of showers into the new week
•    Temperatures are forecast to be 90 °F-93 °F with possible heat index of 109 °F into the new week. 

Nowcast (Tonight):

An influx of low-level moisture streaming in off of Cuba across the western Caribbean will continue to favor some showers with a possibility of isolated thunder overnight. A broad upper-level low positioned near the Greater Antilles with the center over Jamaica, combined with weak troughing at the lower levels will provide additional support for convective development. The pressure gradient produced by the Atlantic high and the Panamanian Low is maintaining gentle to moderate winds and slight to moderate seas. 

Short Term Forecast (Sunday through Tuesday):

Sunday starts of cloudy with a possibility of morning showers and a rumble of thunder as the upper-level support continues to favor some instability before it steers to the northwest of Cayman area and as it moves away, it drags the associated moisture along with it and thus making way for partly cloudy skies for the later part of the day. Winds begin to pick up as well through the period as the pressure gradient force strengthens, as the Atlantic ridge interacts with the Panamanian low. By Monday, a tropical wave analyzed by NHC near 57W from 09N to 19N, is expected to approach the western Caribbean. Upper-level support remains profound with Cayman being on a divergent side and this will offer lift sufficient to generate some showers and thunderstorms, introducing a wet start to the week. By Tuesday, lingering moisture behind the wave in tandem with daytime heating and a surface trough, might pave way for showers through the day. Model confidence remains modest as both ECMWF and GFS both depict precipitation signals for the mentioned day. For the sister islands however, DUEX dust values for the sister islands are mild, and therefore hazy skies should be expected. 

Extended Forecast (Wednesday and Thursday):

The Atlantic ridge is expected to be the dominant feature across the region from Wednesday, resulting in a gradual decrease in moisture and a more stable atmospheric environment. Mid-levels are expected to remain dry while mild Saharan intrusion may favor hazy skies and further limiting any further convective activity. By Thursday, moisture is expected to begin funneling through the windward channel, providing a renewed source of moisture influx across the Cayman islands .Upper level low may provide additional support for enhanced convective activity and consequently some showers are possible for the morning into the afternoon before conditions become stable through the day.

Marine Forecast:

Slight to moderate seas- 2ft to 4ft are expected through Monday, before increasing to generally moderate -3ft to 5ft on Tuesday and Wednesday as the pressure gradient tightens across the western Caribbean.  It should be noted that sea conditions can become choppy in heavy showers and thunderstorms and mariners are advised to exercise caution during these times.

Forecasters
Ebanks/Karanja