Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
199 FXUS62 KKEY 170759 AFDKEY Area Forecast Discussion National Weather Service Key West FL 359 AM EDT Mon Jun 17 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 359 AM EDT Mon Jun 17 2024 It has been rather quiet across the Florida Keys and surrounding coastal waters, at least in terms of precipitation. Winds are another story and we`ll get to that in a minute. First, last night`s sounding showed a subsidence inversion along with dry air above the boundary layer, leading to a shutdown in precipitation. KBYX does show this morning that there are plenty of ghost boundaries out across mainly the Straits of Florida waters. Now onto the winds. A large area of disturbed weather is located over Central America, the Yucatan Peninsula of Mexico, and the adjacent waters of the northwestern Caribbean Sea and southern Gulf of Mexico. This coupled with a broad surface high located along the Eastern Seaboard, has led to a tightened pressure gradient across the region, especially our western waters. This is creating fresh easterly breezes to the west and moderate breezes across the eastern half of the CWA. .FORECAST... Unfortunately confidence remains below average for the upcoming week. There are a lot of moving parts that will interact with each other leading to a complicated and complex dance of sorts. First let`s talk about the elephant in the room, i.e, that large area of disturbance. This feature will generally move northwest into the Bay of Campeche. From there it remains unclear where it will ultimately go but it`s safe to say that it will continue a west to northwest trek and be a rain maker for Mexico and south Texas. Meanwhile, the surface high along the Eastern Seaboard will get reinforced as an upper level ridge sharpens across the same general area. This will maintain our easterly winds and will provide at times breezy conditions through at least Tuesday. By Wednesday it when things start to go off the rails. The act of the ridge sharpening will in turn deepen an upper level trough just to the east and eventually become cut off. This will interact with an inverted trough moving through the easterlies and a weak surface reflection is beginning to take shape. This feature whatever it ultimately becomes, will slide almost due west into the Florida/Georgia region. Meanwhile, the cut off upper level low will slide westward through the end of the week. Here models diverge on where the center will develop and ultimately where to the west it goes. GFS has it maintaining its cut off status as it slides west southwest across the Gulf of Mexico. The ECMWF has it as a less defined cut off low that meanders west into the Lower Mississippi Valley and eventually becomes reabsorbed into the main flow. Again how all of these pieces interact with one another is going to drive our rain chances and wind speeds through the forecast period. For now, what is certain is that we will maintain generally an easterly steering flow which will be moisture rich. The question will be whether or not we have something to act upon it other than our typical mesoscale forcing. Therefore, will keep as close to a middle of the road approach with rain chances this week (generally 30-40 percent). There is a chance that PoPs may need to be raised as we get a better picture of what is going to happen with the upper level pattern. In addition, will leave breezy conditions in place through at least Tuesday. Thereafter winds may briefly slacken before freshening again late in the week. && .MARINE... Issued at 359 AM EDT Mon Jun 17 2024 Small Craft Advisories are in effect for all of the Florida Keys coastal waters for freshening 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 is expected to result in moderate to fresh breezes today through mid week. An area of low pressure may develop mid week a few hundred miles north of the central Bahamas towards mid week and move towards the north to central Florida coastline. This may result in a brief slackening of breezes before high pressure takes control again resulting in freshening east to southeasterly breezes late week. && .AVIATION... (06Z TAFS) Issued at 359 AM EDT Mon Jun 17 2024 VFR conditions will prevail at both EYW and MTH through the TAF period. Showers and possible isolated thunderstorms may develop towards the afternoon and linger into the evening, however, confidence is not high enough at this time to include mentions of either. Near surface winds will be northeast to east at near 15 knots with frequent gusts of around 25 knots. && .PRELIMINARY POINT TEMPS/POPS... Key West 89 83 89 82 / 20 30 40 30 Marathon 90 82 90 82 / 30 30 30 30 && .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....AP Data Acquisition.....AP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest