Weekly Synopsis

Forecast Discussion

UPDATED:  26 September 2026 | 7:00 p.m.

Key Messages

·        A weak cold front will influence the weather across the Cayman area tonight into early Sunday.

·        Light southeasterly winds coupled with daytime heating can add to  Sunday afternoon thunderstorms

·        An upper-level trough moves into the area on Sunday, gradually deepening over the area through the week enhancing low level tropical moisture

·        A tropical wave will inch closer to the northwest Caribbean from late Tuesday, increasing the chance of thunderstorms.

·        Heavy showers are expected for Wednesday as the tropical wave drifts over the Cayman area. Moderate winds and seas are expected, with choppy seas in and around these showers.

Nowcast (Tonight)

A weak cold front currently over central Cuba is expected to extend slightly into the Cayman area overnight as it drifts southeastward. The front is forecast to dissipate by late Sunday. Consequently, a few thundershowers are forecast during the latter part of the night into Sunday morning, mainly across the Sister Islands. Winds will shift from east-northeasterly to southeasterly at 5 to 10 knots, becoming variable and light at times.

Short-Term Forecast (Sunday through Tuesday):

For Grand Cayman, daytime heating combined with light southeasterly winds will support isolated showers and possible thunder during Sunday afternoon. An upper-level trough deepening over the area will further enhance this activity. The front is expected to lift northeastward by Sunday night, with a decrease in moisture over the islands.

-Rainfall: Up to 6 mm for the Sister Islands, with less amounts for Grand Cayman.

-Seas: Slight, with wave heights of 1 to 3 feet.

Southeasterly winds will continue, increasing from light to a moderate breeze by Tuesday. A tropical wave approaching the northwest Caribbean will merge with a surge of deep tropical moisture from Central America. Mid to upper levels will remain moist as the upper-level trough persists over the region. Shower activity will increase from sporadic on Monday to scattered on Tuesday, with an increased chance of thunderstorms.

-Rainfall: Up to 15 mm possible over the two-day period, with higher amounts offshore to the south.

Extended Forecast (Wednesday and Thursday)

Atmospheric conditions become more unsettled. Upper-level divergence is expected to produce locally heavy showers Wednesday morning, with most of the heaviest activity remaining offshore to the south.

-Rainfall: Up to 60 mm possible offshore to the south, 15 mm possible for Grand Cayman, and lesser amounts for the Sister Islands.

Showery conditions are expected to continue into Thursday as ample low-level moisture remains in place. Model guidance indicates a possible low-pressure system developing during this time, which could increase winds to 20 to 25 knots.

Marine Forecast:

A gradual deterioration in sea conditions is expected from Tuesday, with wave heights increasing to 3 to 5 feet. A Small Craft Advisory will likely be required by Thursday as seas deteriorate further.

*The Cayman Islands National Weather Service will continue to monitor these conditions and issue updates as necessary.*

Forecaster
Neverson-Jack