Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
522 FXUS62 KKEY 190238 AFDKEY Area Forecast Discussion National Weather Service Key West FL 1038 PM EDT Wed Sep 18 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1038 PM EDT Wed Sep 18 2024 Tonight has been very similar to last night in terms of shower coverage around this time...not much happening within our forecast area. Convection developed early this morning, followed by coverage waning by mid-morning. Thereafter, the environment was thoroughly worked over and showers had a very hard time developing for the most part. The only notable activity was a few clusters of thunderstorms that moved off of South Florida and brought rainfall to island communities in the Upper Keys, and the failed attempt at the development of a reverse cloud line near Big Pine. While tonight definitely has some similarities to last night, there are a few notable differences. The sounding revealed less lower-level dry air which indicates that the atmosphere has recovered some, there is more drier air aloft, and there is more convection across the region. This convection could be a trigger for shower development tonight, which is what we have been lacking the past few days. Over the past couple of days, temperatures aloft have cooled some thanks to the presence of a deep upper trough currently stretched across the Southeast that is providing some upper-level support. Winds remain light and generally variable across the Florida Keys coastal waters. Lastly, due to the combination of light winds and mostly clear skies, some radiational cooling can be seen on the protected areas of the larger islands, with the Big Pine Key RAWS recording a temperature of 78F. For tonight, not much of an environment change is expected and mesoscale processes will continue to dominate. Since the atmosphere is showing signs of recharging and the larger extent of coverage of convection around outside of our forecast area, it is hard to drop PoPs tonight. PW values are well above normal, and CAPE is ample, so all we really need is the lifting mechanism. Winds will remain light overnight outside of any convection that develops. The forecast remains on track and no changes were needed. && .MARINE... Issued at 1038 PM EDT Wed Sep 18 2024 Light and often variable breezes will continue through the remainder of the week due to persistent troughing near the Atlantic Coast. Expect higher winds and seas in and around thunderstorms. The troughing will meander southeast to southward this weekend and into early next week and deepen while ridging builds in across the southeast. Confidence in the extended forecast is very low due to uncertainties with this evolution, as well as expected formation of a low in the northwestern Caribbean Sea. A Coastal Flood Advisory remains in effect for the Upper Keys, and a Coastal Flood Statement remains in effect for the Middle and Lower Keys. Boaters can expect less clearance under fixed bridges. && .AVIATION... (00Z TAFS) Issued at 1038 PM EDT Wed Sep 18 2024 VFR conditions will prevail through the TAF period, but multiple rounds of convection are not out of the question over the next 24 hours. There is some uncertainty in the timing of shower development overnight, so have left out mention of showers until tomorrow morning. This will likely need to be amended during the next TAF cycle when confidence increase. VCSH was included at both terminals by mid-morning tomorrow. Winds, while generally variable for most of the day, look to become southwesterly so the development of a reverse cloud is a good possibility. && .CLIMATE... In 1926, "the Great Miami Hurricane" made landfall in Miami at category 4 intensity, bringing Hurricane force winds to the Upper Keys. In Key West, the minimum pressure was 29.48" and the maximum sustained wind was 52 mph. && .PRELIMINARY POINT TEMPS/POPS... Key West 81 90 80 90 / 50 50 50 40 Marathon 81 90 81 90 / 50 50 50 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 5 PM EDT Thursday for FLZ076. GM...None. && $$ Public/Marine/Fire...NB Aviation/Nowcasts....NB Data Acquisition.....MJV Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest