Area Forecast Discussion
Issued by NWS Key West, FL

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000 FXUS62 KKEY 181848 AFDKEY Area Forecast Discussion National Weather Service Key West FL 248 PM EDT Sun Apr 18 2021 .DISCUSSION... Satellite imagery indicates generally mostly sunny to partly cloudy skies across the island chain. This has allowed temperatures to easily climb into the mid to upper 80s. Interestingly, despite increased lower-level moisture as well as ample land heating, cloud streamers have had a tough time firing north of the island chain today. This may be the result of the winds collapsing a little quicker today compared to yesterday as well as a slight backing of winds to southeast to south (instead of yesterday`s southwesterlies). Expecting no rain for the balance of this afternoon and evening for the island chain. A frontal boundary is draped across Central Florida. This feature will remain stalled for the next couple of days before slowly creeping across Florida Tuesday and Wednesday. The general pattern of mainly southerly winds peaking overnight into the morning hours is expected to continue through Tuesday. With the aforementioned increased moisture, there is a chance for a few showers overnight tonight with the diurnal wind surge. A weak mid- level pouch of vorticity will move east along the frontal boundary Monday night, providing a large-scale source for ascent. With another south to southwest wind surge, any convection that fires over Cuba Monday afternoon may survive the trek to the island chain. In addition, the available longer-range CAM model guidance indicates some in- situ convective development south of the island chain. Forecast soundings indicate moderate instability, so have kept a mention of thunder during this period. The front will finally push through the Florida Keys Wednesday afternoon and evening. Although upper-level support will be relatively benign, have kept PoPs at 30 percent for Wednesday and Wednesday evening as the front pushes through (with the mention of possible thunder). Thereafter, high pressure will build over the Florida Peninsula for the rest of the work week. Temperatures will tick down a few degrees, with the most noticeable difference being a reduction in humidity. Dewpoints will likely bottom out in the mid to upper 60s for Thursday and Friday. This may be one of the last times we get to advertise that for some time. && .MARINE... A weak area of high pressure centered east of the Bahamas will result in generally southerly flow through Tuesday. Breezes will peak during the overnight and mornings, with noticeable lulls in the afternoon and evenings. A frontal boundary will remain stalled over the Florida Peninsula through Tuesday. The front will finally slide southward through South Florida Tuesday night and Wednesday, passing through the Keys coastal waters late Wednesday afternoon and evening. In the wake of the front, gentle to moderate northerly breezes on Thursday will veer toward the northeast to east and freshen Thursday night through at least Friday night. && .AVIATION... VFR conditions with brief bouts of MVFR ceilings are expected for the island terminals through 18z/19th. Isolated showers activity may form near both EYW and MTH late this evening and during the overnight, however confidence in timing and coverage is low. Will leave it out at this time, but short-term amendments and TEMPOs may be needed. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT Aviation/Nowcasts....Williams Data Acquisition.....DR Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest

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