Weekly Synopsis

Forecast Discussion

UPDATED:  16 August 2026 6:30 p.m.

KEY MESSAGES:

•    Dry atmospheric conditions with Saharan dust present on Sunday and late Tuesday through Thursday. 
•    Moderate to fresh winds and occasionally rough marine conditions through Tuesday afternoon as the          pressure gradient remains tight over the region with a Small Craft Advisory in effect.
•    A tropical wave is expected to drift over the Cayman from early Monday with the chance of thunderstorms possible through Tuesday afternoon.

Nowcast (Tonight):

The chance of morning showers is expected as moisture associated with a tropical wave off Cuba exists, but they should be light and short-lived. The upper-level conditions are not conducive for deep vertical movement; thus, an isolated thunderstorm can be expected. A weak plume of Saharan dust is pushing across the area and can give slightly hazy skies and hinder sustained precipitation.

Short-Term Forecast  (Monday through Wednesday):

According to model guidance, a tight pressure gradient should exist across the western Caribbean, leading to moderate to fresh winds through Tuesday.  A tropical wave (formerly AL92) should begin to increase the moisture in the atmosphere of western Caribbean from tonight. The Cayman area may experience a minimal increase in moisture as the area may lie on the fringe of the dominant moisture plume. An upper-level low centered near the Yucatan, can provide upper diffluence can support isolated thunder from just after midnight and occasionally during the day over the Cayman area. The south-westerly upper-level wind can also bring high level cloud into the area from the convective activity occurring to the south. 
Rainfall accumulation expected on Monday can range between 10 to 20 mm.  By Tuesday, the moisture associated with the tropical wave would gradually decrease as it pushes further westward. This would then signal the return of another mild plume into the Cayman area late Tuesday.

Extended Forecast  (Thursday and Friday):

The wind speeds are expected to decrease, becoming light to moderate, from Wednesday morning as the pressure gradient slackens over the region. Though the atmosphere may be generally drier during this time, resulting in fair to partly cloudy skies with slight haze, the overnight or early morning showers with thunder will be reduced as the atmosphere is not conducive to sustained precipitation.

Marine Forecast:

A Small Craft Advisory is in effect and is expected to persist through near midday on Monday as model guidance shows moderate to rough sea condition resulting from the moderate to fresh winds of a Caribbean low-level jet caused by a tight pressure gradient. As the pressure gradient slackens, the sea conditions should become moderate by Monday afternoon (when the Small Craft Advisory is expected to be discontinued) and further becoming slight by late Tuesday through Thursday.  

Small craft operators are advised to continue to exercise caution in open seas during heavy showers and thunderstorms as these may produce strong, gusty winds with lightning and lowered visibility.

Forecaster
Miller