Weekly Forecast

Forecast Discussion

UPDATED: June-05-2026 7:47pm

Key Messages:

•    Warm conditions continue Saturday with temperatures reaching the lower 90s and heat indices exceeding 100F at times.
•    Isolated shower activity lingers as residual moisture remains north of the Islands.
•    Cloudy to overcast conditions with increased moisture from Sunday through the new week bringing scattered to numerous showers and cooler temperatures as a series of tropical waves interact with a mid-level trough over the central Caribbean.

Nowcast (Tonight):

Relatively warm yet occasionally cloudy conditions have prevailed across the Cayman area throughout the day as moisture lingers north of the Cayman area and the presence of an upper-level jet remains to our west. A few showers sprung up across the region this afternoon as a result, but with decreasing solar radiation, convective activity will slowly diminish after sunset with a slight chance of a shower or two later tonight as diurnal convection advecting from the Cuban archipelago drift near our area and enhance the lingering moisture over the region. Throughout this evening, partly cloudy conditions are expected to continue as bands of higher-level cloud continue to pool into the Cayman area due to Cuban shower activity and influence of the jet. Model guidance through sunrise does show a slight uptick of moisture from Cuba overnight with this expected to drift near the Sister Islands after midnight before slowly subsiding. Any shower activity overnight will be localized to isolated with this more likely across the Sister Islands as with the current easterly wind, advection showers from Jamaica are not expected to impact the Cayman area. Temperatures throughout tonight are not expected to drop below 80F/27C as a gentle onshore breeze with slight amounts of cloud cover may limit any significant radiation cooling with the exception of some sheltered interior regions.
 

Short Term Forecast (Saturday through Monday):

Saturday is expected to remain fairly uneventful as opposed to what will be drifting in during the second half of the weekend as moisture continues to linger north of the Cayman area and with the presence of the weak surface ridging and the upper level jet remaining squarely over or just west of Grand Cayman, deeper levels of convection and thunder chances remain low. Beyond slight perturbations and diurnal convection, the chance of showers will also remain low through Saturday, with a window of afternoon showers possible as was the case earlier today. A tropical wave located southeast in the west-central Caribbean is expected to get caught and slowed as a result of a sharp and developing upper level trough which will induce a mid-level low south of Jamaica through Saturday and with a strong southeast flow behind this wave, an abundance of moisture is expected to get drawn into the region but remaining away and far enough south of the Cayman area to not bring in any weather (for the time). From early-Sunday morning however, this pattern changes as the aforementioned mid-level low begins to migrate slowly westward and with another tropical wave located in the eastern Caribbean expected to continue its westward journey is expected to clash with this feature later in the day, bringing another shot of deeper moisture on its east side as the 700hPa wind field continues to increase, gaining a stronger influence from the equator and South America. As a result of this slow migrating low, model guidance has been in agreement on the rough timing of this to begin impacting the Cayman area, with Sunday morning expected to begin seeing an influx of low level cloud and with higher precipitable water content expected to increase from ~1.9" to around 2.2-2.3" by midday Sunday, with relatively high humidity in the low-levels. As a result, conditions are likely to be mostly cloudy and with some bands of mid-level cloud expected to drift in with this, some periods of lighter rain are likely. As reflected well by ensemble guidance, QPF values begin to slightly increase from 1/10 of an inch Saturday to around 1/4 of an inch Sunday. Due to the presence of the upper-level jet remaining near Grand Cayman and with stronger areas of subsidence, the chance of thunderstorms remains low, but with a trough axis located across Cuba this may create a diffluent pattern to our east and with the aid of cold air advection thus maintaining a higher chance of thunder for the Sister Islands meaning they may see the highest quantities of rainfall Sunday with deterministic model isolated maximums reaching 3/4 of an inch in any heavier showers. Relatively similar conditions are expected through early-Monday with the models beginning to slightly disagree here on how the eventual development and final approach of this low plays out as our 3rd and final tropical wave eventually clashes with this system by Monday morning, bringing an even stronger shot of moisture into the central Caribbean. The American GFS model remains to be on the higher end of moisture and organisation on Monday as it shows the mid-level low bringing an east to southeast moisture flow with a weaker trough and jet at 700hPa over the Cayman Islands. However, due to natural bias' in the GFS when it remains close to the Panamanian low, weight on this outcome is lower with the European model showing a broader low with the main trough axis located at an ENE orientation far southeast of Jamaica, keeping the highest areas of precipitable water south of Jamaica. Throughout Monday however, overcast conditions with periods of rain and some scattered showers are expected to linger over the Cayman area and with the axis of the upper-level low expected to be slowly drifting over the Cayman area in the morning, the upper-levels remain low for thunderstorm activity until later in the day. Winds will increase substantially from Sunday as they begin to veer more southeast and with a strengthening pressure gradient over the region, fresh to locally strong winds are expected. QPF values throughout the period differ by model, but ensemble guidance has remained fairly on point with keeping the totals around 1 - 1/4 of an inch through Monday with isolated maxima of 2 inches possible in heavy showers. These values remain below warning thresholds for the time but will continue to monitor for any significant uptick in these values through the weekend.

Long Term Forecast (Tuesday and Wednesday):

From Tuesday, the models begin to realign better with the outcome in the long term as both GFS and Euro show the highest content of moisture will sweep into the northwest Caribbean with these values reaching borderline excessive amounts (greater than 2.5"/63mm). This uptick is due to the fact the previously mentioned mid-level low becomes absorbed by a broader feature across Nicaragua with model guidance suggesting a broad Central American Gyre will develop early-Tuesday, keeping the northwest Caribbean in a strong southeast wind flow as the moisture becomes drawn into Central America. Our upper-level low is also expected to begin dissipating on Tuesday and with it, weakening shear and lighter upper-level winds, which will bring an increase in thunderstorm activity, although due a convergent pattern remaining aloft, these will be more isolated in nature. Conditions are expected to be worst on Tuesday and Wednesday with overcast conditions and numerous showers or rain expected. Ensemble guidance has kept rain totals low (1/2 an inch per day), with deterministic models being notably higher (1 1/2 inch per day). Regardless of amounts, some embedded shower activity is likely to be prolonged with heavier aspects meaning isolated totals of 2 inches per day are not unlikely, however these remain below current warning thresholds. Any messaging regarding this will likely be issued on Monday with urban flooding remaining a possibility during these days. Through Wednesday no significant changes are expected as until the late afternoon/evening but even this is just the sparsity of rain will likely shift more west, with the Sister Islands likely to see diminishing amounts. Winds and seas also remain elevated during this time with winds remaining fresh to strong and even reaching gusts near 30 knots at times. As a result of the overabundance of clouds and rain, temperatures will be below average with current forecasts showing 85F/29C both days and minimums expected to bottom out at the mid-70s during heavier showers.

Marine Forecast:

Generally fair conditions for the start of the weekend, with slightly increasing seas becoming more moderate further into Saturday as the winds in the open seas increase slightly. A more significant deterioration in conditions are expected thereafter, with the pressure gradient slowly pinching over the western Caribbean and a longer fetch from the central Caribbean, seas will increase more rough with periods of 7 feet likely at times later Sunday with this rising further into the start of the new week. A Small Craft Advisory will be in effect on Sunday and will be upgraded Monday into an Alert as seas of wide swaths of 6 - 7 foot seas are expected. Further roughness remains possible and shows on some guidance with even 8 foot in some peaks, being the bottom line of a Marine Watch, however, this is not being considered for issuance at this time but may likely be upgraded Tuesday if conditions continue to deteriorate. Risk of showers remaining confined Saturday with localized to isolated patches nearshore with a low chance of thunderstorms. Sunday beyond high to very high risk of showers and scattered bouts of heavy showers with reduced visibility due to mist and choppy sea conditions. Risk of thunderstorms lower for GCM and increasing chance on Tuesday with scattered cumulonimbus possible creating a further risk of lightning.

Forecaster: Harding