Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
813 FXUS62 KKEY 031412 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1012 AM EDT Wed Jun 3 2026 ...New DISCUSSION, AVIATION... .KEY MESSAGES... - Light and variable breezes are on track to freshen to gentle to moderate easterlies tonight. The wind forecast is unusually uncertain for the next few days. Large swings both up and down will be possible. - Rain and thunder chances will continue the trend upwards, peaking tonight and Thursday. - A marginal (1 of 4) risk of excessive rainfall is in effect over the Florida Keys this afternoon and tonight. - Increased cloud cover and convective coverage will help to trend temperatures down to near normal over the next few days. && .DISCUSSION... Issued at 1010 AM EDT Wed Jun 3 2026 GOES satellite observations this morning highlight nearly overcast skies across the Florida Keys. The combination of an upper level trough over the Gulf, a mid latitude trough over the southeastern United States, and a weak surface frontal boundary over Southern Florida will act in concert to create a favorable environment for heavy rainfall this morning through the rest of the work week. In the short term, showers have been less active across the Keys. Most of the returns on KBYX radar before sunrise were high altitude clouds instead of bursts of morning showers. However, isolated thunderstorms over the Straits and Florida Bay have been able to form after sunrise. The morning KKEY sounding highlights why showers have been struggling to develop. Despite a PWAT value near the daily record, dry layers were present in the from the surface to 13,000 feet. Dew point depressions in the bottom 10,000 feet were as high as 10 F, which is surprising for this amount of moisture. However, this amount of dry air meant estimated CAPE values rose above 2500 J/kg. Enough instability, moisture, and the nearby presence of a front and upper altitude trough as a source of lift was sufficient for WPC to place the Florida Keys in a marginal risk (1/4) of excessive rainfall. For this afternoon, keep a close eye on the radar. && .PREV DISCUSSION... Issued at 430 AM EDT Wed Jun 3 2026 A fairly complicated evolution of our weather is expected over the next few days. The mid latitude trough will continue to swing off of the Atlantic Coast and the associated surface low will deepen as it migrates northeastward just off the Atlantic Coast. At the same time the eastern United States surface high will build southward reaching into the Keys and steadily push a weak surface frontal boundary through South Florida and eventually the Keys. Adding to this mess, a southern stream upper trough over the Gulf will result in the formation of a central Gulf low that will slowly lumber its way northward as it deepens. The band of increased moisture will remain across our area and CAPE will remain at least modest. Altogether, this points to a several day period of much higher than normal rain and thunder chances, as well as the threat of bouts of moderate to fresh northeasterlies to easterlies. There is considerable uncertainty regarding wind speeds through the remainder of the week. The incoming freshening northeasterlies, along with increased cloud cover and convective activity will help to stymie the recent hot weather. Expect highs and lows to trend back towards normal over the next couple of days, remaining there through the remainder of the week. Dew points will likely remain in the lower to mid 70s, with some slight lowering later in the week as drier air moves in around the surface high. Towards and through the weekend, strong mid to upper level ridging will build northeastward across the Gulf of America. This will result in mid level warming, reducing CAPE significantly. However, lower level moisture will remain quite high and inhibition will generally be limited. The old eastern United States surface high will steadily migrate southeastward off the Carolina Coast on Friday and eastward out into the Atlantic through the weekend. Expect broadly easterly breezes to trend downwards and rain chances fall back to normal climatology at a slight to low chance. With this temperatures will rebound to slightly above normal with dew points returning to the mid 70s. && .MARINE... Issued at 430 AM EDT Wed Jun 3 2026 A robust surface high blanketing the eastern United States will build southward across our area today. Meanwhile, a low pressure system in the Gulf of America will gradually take shape and deepen over the next few. In addition, shower and thunderstorm activity is expected to ramp up, peaking tonight or Thursday. The combination of the above will result in light breezes this morning increasing to at least gentle to moderate this afternoon. There is the potential for periods of stronger breezes. However uncertainty is unusually high, and will be dependent on how far south the high builds, the strength and position of the Gulf low, and the extent and nature of showers and thunderstorm activity. Heading into late week and this weekend, the high will swing southeast and eastward into the Atlantic and the Gulf low will lift into the central Gulf Coast. In response, breezes will gradually trend downwards, as will rain chances. && .AVIATION... (12Z TAFS) Issued at 1010 AM EDT Wed Jun 3 2026 Showers and occasional thunderstorms will develop in waves across the Florida Keys. While VFR conditions will prevail, there is high confidence bouts of IFR to MVFR CIGs and VIS will occur at EYW and MTH. Timing of these periods are very uncertain. Near surface winds, outside of showers, will gradually become northeast to easterly breezes. && .PRELIMINARY POINT TEMPS/POPS... Key West 90 78 88 78 / 60 80 80 70 Marathon 87 77 85 78 / 70 70 80 70 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...AJP Aviation/Nowcasts....AJP Data Acquisition.....AJP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest