Marine Weather and Tide Forecast for Big Pine Key, FL

DISCUSSION
Issued at 1036 AM EDT Thu May 22 2025 According to GOES-19 satellite imagery, if you're out on the water it seems like a sunny day... on land, a majority of the island chain is under partly cloudy skies. Temperatures across the island chain are in the mid 80s with dewpoints in the mid to upper 70s making for a muggy day outside. Along the Reef, winds have remained light and variable. Light showers have been detected on KBYX north of the island chain for a majority of the morning.
In the last hour or so, a cloudline has begun to develop just north of the Lower Keys, producing light showers currently over Stock Island. This cloudline along with the light winds and moisture down in the lower levels make for a favorable waterspout environment. Our in-house waterspout index from KKEY 12Z balloon this morning was 28%, which is well above climatology for this time of year. While none have been reported as of now, our waterspout index means there's a 28% chance of observing at least one today. Winds are expected to stay light and generally variable through the rest of the day. The majority of any shower development along the island chain will be in the cloudline but apart from that mostly dry conditions are expected through tonight.

FORECAST
Issued at 349 AM EDT Thu May 22 2025 It's another quiet, dull, but sultry early morning for the Florida Keys. Temperatures as of 3 AM are in the lower 80s with dew points in the mid to upper 70s (yuck). After a brief surge from the north in the late evening, winds have quickly settled down and becoming variable. As alluded to, the KBYX radar remains rain free this morning. Meanwhile, a weak frontal boundary currently draped across the Panhandle of Florida is slowly trudging southward this morning.

Said front will continue to slowly move southward today, only reaching south central Florida by this evening. In the meantime, as it approaches the region, it will help to maintain the col already in place due to a lack of any synoptic features. As such, we can expect another light and variable day along with daytime temperatures in the mid to upper 80s and dew points in the mid 70s. There is a chance we may see some relief from the heat today. Given the light and nebulous flow that will sit across the Keys, we could see a brief reverse cloud line attempt to develop in the late morning and afternoon. Looking at last evening's sounding, there remains an inversion around 750 mb, but there was still decent MLCAPE present in the layer. If we can overcome this inversion, we could see embedded showers and isolated thunderstorms within the cloud line. Unfortunately, given that it will be a reverse cloud line, it means that Key West may miss out on this one.

The aforementioned frontal boundary will stall just north of our area and gradually dissipate overnight into Friday. This will mean one more day of light and variable winds. As the next low level ridge settles in across the Southeast U.S. and slinks into the southwestern North Atlantic, breezes will decidedly clock around from the east. This will usher in better moisture and rain chances will return closer to, if not slightly above our climatological norm. The ridge looks to hold in place well into the new work week and we can expect a little more active weather pattern next week.

MARINE
Issued at 1036 AM EDT Thu May 22 2025 No watches, warnings, or advisories are in effect for the Florida Keys, although, waterspouts are possible through this afternoon for the Lower Keys. From synopsis, winds across the Florida Keys coastal waters will remain light and generally variable through Friday. Rain and thunder chances will gradually increase by Saturday, along with freshening east to southeast breezes. These conditions will then last through early next week.

KEY WATCHES/WARNINGS/ADVISORIES
FL...None.
GM...None.