Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
835 FXUS62 KKEY 190804 AFDKEY Area Forecast Discussion National Weather Service Key West FL 404 AM EDT Wed Jun 19 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 400 AM EDT Wed Jun 19 2024 We are currently reaching a maximum in nocturnal shower activity across the Florida Keys and surrounding coastal waters. Shortly after midnight, we saw showers explode and flourish as they moved northwest across the area. Given a moisture rich boundary layer, these showers have been able to drop between a quarter and a third of an inch of rainfall despite a forward speed of near 20 knots. Where rain has fallen, temperature have cooled down. Currently seeing some locations (as of 3 AM) near or just below 80 degrees. Dew points however, remain stubbornly in the lower to mid 70s. As alluded to breezy conditions continue across the entire CWA this morning. .FORECAST... The forecast thought remains a little murky in the short term and surprisingly more clear in the long term. This is because there are still uncertainties with how differing features will interact with one another over the next 24 to 72 hours. Let`s examine it. First the large disorganized area of low pressure currently classified as Potential Tropical Cyclone 1 (PTC 1) continues to swirl in the Bay of Campeche and is slowly moving westward. As it pulls further west and away from our general area, winds will gradually slacken. This means that we will be losing our speed convergence that has been aiding in shower development that last couple of nights. At the same time, a mid level cut off low will transit southwest across the Florida Peninsula today. However, we will be on the western side of this feature, which doesn`t lend itself to a lot of upper level support. On the other side of the coin, we will still have ample moisture in the boundary layer being fed in across the region. This should at least allow us to maintain above normal rain chances for today, though thunder chances will continue to be limited to a combination of ridging in the low levels and dry air in the low to mid levels. By Thursday an easterly undulation currently north of Hispaniola will move west northwest and pivot up into the Southeast U.S. This may allow for better convergence coupled with an already saturated air mass. In addition, the Keys will be on the more favorable side of the aforementioned cut off low. The combination of all this looks to allow for probably our best chances this week for both showers and thunderstorms. This is all dependent however, on all the players working together and as such, will stay with middle of the road PoPs for now. As we go into the long term, the undulation will move inland and dissipate as it becomes absorbed into the main flow. This will allow for ridging to return across the western North Atlantic. This will maintain a moist easterly flow over the region with above normal rain chances. There are signs of another CAG developing over the weekend with yet another area of low pressure developing in the Bay of Campeche but this looks to be further removed to the west and a little bit faster. As a result, influences from this feature will be minimal if at all. && .MARINE... Issued at 400 AM EDT Wed Jun 19 2024 Small Craft Advisories remain in effect across all of the Florida Keys coastal waters due to fresh easterly breezes. Strong surface high pressure centered off the New England coast working in tandem with falling pressures over the Yucatan Peninsula and the Bay of Campeche will result in moderate to fresh breezes today through late week. A disorganized area of low pressure will begin to develop later today a few hundred miles north of the central Bahamas and move towards the Southeast U.S. coast. This will eventually lead to slackening breezes beyond Friday. && .AVIATION... (06Z TAFS) Issued at 400 AM EDT Wed Jun 19 2024 TEMPO MVFR CIGS, IFR VIS, and occasional showers will prevail at the EYW and MTH terminals through 10 to 12z. East to southeast winds will gust to 30 knots within the most potent showers. As South Florida and Cuba heat up, the coverage of showers across the Florida Keys should decrease. && .CLIMATE... June 19th, on this day in 1999, Marathon`s high temperature only reached 82 degrees and the rain gauge recorded 1.40 inches of rainfall, both records for the date. Temperature and rainfall records for Marathon date back to 1950. && .PRELIMINARY POINT TEMPS/POPS... Key West 89 82 89 81 / 40 40 50 40 Marathon 89 82 89 82 / 40 40 50 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075. && $$ Public/Marine/Fire...LIW Aviation/Nowcasts....CLR Data Acquisition.....CLR Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest