Weekly Synopsis

Forecast Discussion

UPDATED:  05 September 2026 | 7:00 p.m.

KEY MESSAGES:

·  Showers and isolated thunder remain possible tonight, with a decreased chance for showers from tomorrow morning.

·  Slight increase in seas is expected from Tuesday as the pressure gradient tightens across the western Caribbean.

·  An increased chance of showers is expected by Thursday as a surface trough influences the Cayman area.

Nowcast (Tonight): 

Moderate precipitable water along with an area of upper-level diffluence over the Cayman area today supporting some showers along with thunder is expected through the evening. These conditions are expected to discontinue by early tomorrow morning as the low-level moisture drifts northwest and the upper-level diffluence pattern over the Cayman area weakens. Light northeasterly winds, becoming variable at times, are expected tonight along with slight seas.  

Short-Term Forecast  (Saturday through Monday):

A decrease in precipitable water is expected for Sunday compared to today, with only a slight temporary increase during the afternoon followed by low to moderate precipitable water available through Tuesday. Slight drying of the mid-levels is expected from Sunday morning limiting the chance of deep convection for Sunday. A weak mid-level trough drifts over the Cayman area from early Sunday morning, along with a low-level trough by Sunday afternoon. Along with light southeasterly winds, a slight chance of isolated afternoon showers is expected. Further drying of the mid-levels is expected from Monday morning through the evening, further limiting the chance of deep convection for Monday. Coupled with an area of upper-level confluence along a cyclone centered south of Jamaica over the Cayman area, mostly partly cloudy skies are expected for Monday. Winds will turn northeast by Monday afternoon. An increase in mid-level moisture is expected by Tuesday. Moderate to high low-level moisture coupled with a weak area of upper-level diffluence along the cyclone centered southwest of Jamaica and a weak surface trough, can support some afternoon showers with possible thunder. Additionally, moisture over Cuba is expected to drift over the Cayman area during Tuesday night, bringing the chance of overnight showers. The pressure gradient over the Cayman area temporarily tightens with winds becoming moderate and easterly, with slight to moderate seas for Tuesday. Rainfall accumulation is expected to be about 5mm for Sunday, less than 5mm for Monday and about 5-10mm for Tuesday. 

Extended Forecast  (Tuesday and Wednesday):

An increase in precipitable water over the Cayman area is expected from Wednesday morning with further increase into the evening. Additionally, from Wednesday morning, another plume of dry air drifts into the mid-levels and lingers through the evening limiting deep convection. A slight chance of afternoon showers is expected. Light northeasterly winds for Wednesday. An increase in precipitable water and mid-level moisture for Thursday, along with a weak trough drifting over our area during the morning and a second trough developing off the coast of Jamaica and drifting over the Cayman area from the late afternoon and lingering through the evening, will support the chance of isolated showers for Thursday. Light southeasterly winds will become light and variable into the evening with the passage of the second trough on Thursday Slight to moderate seas are expected for the period. Rainfall accumulation is expected to be about 5mm on Wednesday and 5-10mm for Thursday.   

Marine Forecast:

Light winds and slight seas are expected through Monday. Winds should gradually increase and the seas begin to respond as well, building slight to moderate from Tuesday. 

Forecaster
Forbes