Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
635 FXUS62 KKEY 140218 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1018 PM EDT Sun Sep 13 2026 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... - A very moist air mass will linger across the region through tomorrow, supporting near to above normal rain and thunderstorm chances. - Heat index values will range from 100-108 degrees daily, with little relief from the muggy conditions overnight. Know the signs of heat stress, take frequent breaks, and stay hydrated. - Winds are expected to trend upwards over the next several days, likely peaking in the moderate to fresh range around mid week. && .DISCUSSION... Issued at 1016 PM EDT Sun Sep 13 2026 The environment proved much quieter tonight, when compared to yesterday, across the Florida Keys. Showers and thunderstorms were present in the late afternoon to early evening hours. An outflow boundary was able to surge across the Keys waters and bring a burst of stronger winds and breezes to the Lower and Middle Keys. Winds at Harbor Key Bank peaked at 24 knots. That does not mean rain chances have dropped to near normal values, as heavy rainfall can still form over portions of the CWA. The lack of activity prompts the question, what is different compared to yesterday? To start, the low altitude trough that aided showers across the Keys has weakened and moved northwest. Thus, it is not enhancing low level lift across the Keys. Next, the upper altitude environment shifted. Winds aloft are inducing a slight sinking motion over the Keys. However, that does not mean a dry air mass is on its way. The 00Z KKEY sounding sampled a PWAT value over the 90th percentile for the day. The environment is still extremely humid. A slight amount of lift and a lack of shower movement can result in almost 2 inches of rainfall. In light of the outflow boundary, that situation appears less likely. The sounding was released after the outflow boundary passed, and it sampled a very stable environment. It will take time for the atmosphere to destabilize following this round of showers. Overnight, statistical and convective models are pessimistic about showers redeveloping over the Keys. Breezes are on track to remain light to gentle. Anyone in the Keys, enjoy a less eventful night ahead of the work week! && .MARINE... Issued at 1016 PM EDT Sun Sep 13 2026 No watches, warnings, or advisories are in effect for the Florida Keys nearshore or offshore waters. From synopsis: A weak pressure pattern has resulted in light and varying breezes. Breezes will gradually firm up out of the northeast to east over the next few days, as a continental high builds southward towards our area. Low level moisture will remain abundant through tomorrow morning and keep convective potential above normal. Rain chances should fall to near normal early in the week as drier lower levels filter in. The ridge will be reinforced through the first half of the week, resulting in freshening northeast to easterly breezes. && .AVIATION... (00Z TAFS) Issued at 1016 PM EDT Sun Sep 13 2026 VFR conditions will prevail at EYW and MTH for the forecast period. Near surface winds will be variable after an outflow boundary passed across the terminals, but will trend towards east southeasterlies after midnight. Showers are possible but unlikely before sunrise. Expect occasional SHRA after sunrise. && .PRELIMINARY POINT TEMPS/POPS... Key West 81 92 82 92 / 40 30 30 40 Marathon 82 90 82 90 / 30 30 30 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...AJP Aviation/Nowcasts....AJP Data Acquisition.....RG Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest