|
Show Area Forecast Discussion - Key West, FL (Florida Keys) Selection: |
| #1180335 (Received by flhurricane at: 7:06 PM 16.May.2024) AFDKEY Area Forecast Discussion National Weather Service Key West FL 303 PM EDT Thu May 16 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 219 PM EDT Thu May 16 2024 We are about two weeks away from the beginning of summer, but the island chain did not get the memo. High temperatures are in the lower to the mid 90s, and combined with dewpoints in the upper 70s, lends to heat indices in the 100s. Skies are sunny and the KBYX radar is echo free. Yesterday at this time there were a few showers on the eastern end of the Lower Keys. It appears the extremely dry lower levels sampled by the 12Z KKEY RAOB, corroborated by the SPC mesoanalysis slices, has put the kibosh on moist congestus. .FORECAST... The month of May is typically brutal, with summer-like heat and slim rain chances to cool off the afternoons. From a climatological perspective, it is not the driest month. It all depends on when rainy season turns on. The mesoscale usually kicks off in June, sometimes earlier, sometimes later (last year). There is a decent signal for later this weekend or early next week to start getting some accumulating rainfall. Synoptically, deep, mean-layer ridging will persist tonight through Sunday. Forecast soundings and time height cross sections suggest low-level moisture will struggle, hence the near nil rain chances through the short term. Near record high temperatures will remain in play Friday through Sunday. By Sunday night or Monday, a mid latitude trough will spill around the eastern flank of the mean layer ridge. The lower heights aloft, confluent lower troposheric southwesterlies, and the tail- end of cyclonic SFC flow will introduce a chance of showers and thunderstorms Sunday night through Monday night/Tuesday. The eventual anticyclonic wave break to our east will result in a closed low and TUTT transition near the Greater Antilles. MOS guidance suggests the northerly fetch Tuesday through Thursday will shave the dewpoints out of the upper 70s. However, we are getting a little late in the season for light northwesterlies to be a source of dry air. && .MARINE... Issued at 219 PM EDT Thu May 16 2024 There are no watches, warnings, or advisories currently in effect for the coastal waters of the Florida Keys. A weak frontal boundary to the north of the Florida Keys interacting with an area of high pressure in the western North Atlantic will result in a chaotic wind forecast through the weekend. Breezes will tend to peak in the evening and overnight hours, and then lull in the afternoon hours. && .AVIATION... (18Z TAFS) Issued at 219 PM EDT Thu May 16 2024 The cloud streamers that were evident this morning have been dissipating this afternoon. However, one main streamer remains present north of the Middle and Upper Keys with this streamer extending into the eastern Lower Keys. However, latest visible satellite imagery shows this starting to drift south towards MTH. Therefore, while VFR conditions are mostly expected, there may be a brief period of MVFR CIGs. Near surface winds are expected to remain southwest to west 10 to 15 knots with occasional gusts to near 20 knots for the next couple hours. Winds will shift to the west to northwest during the late afternoon to early evening hours as the cloud streamer moves through before becoming briefly variable this evening into the overnight hours. Winds will then shift to the southeast to south during the early morning hours Friday. && .CLIMATE... On this day in 1923, a daily record rainfall of 2.89 inches was measured at Key West. May rainfall records for Key West date back to 1871. && .PRELIMINARY POINT TEMPS/POPS... Key West 81 92 82 92 / 0 0 10 10 Marathon 81 92 83 92 / 10 10 10 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ |
| #1180311 (Received by flhurricane at: 3:00 PM 16.May.2024) AFDKEY Area Forecast Discussion National Weather Service Key West FL 1048 AM EDT Thu May 16 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1037 AM EDT Thu May 16 2024 Water vapor imagery highlights a broad belt of westerlies across the Gulf of Mexico and the northern Gulf Coast. The deep, mean- layer ridging centered over Panama is well to the south of its normal position. The low-level ridge axis extends west across Cuba. As such, steering and SFC winds are from the southwest. Satellite derived moisture products place a narrow band of enhanced moisture over the eastern Gulf along a stalled frontal boundary. The Florida Keys are within a plume of drier air, nicely noted by SPC`s 850 mb analysis. The forecast calls for high temperatures in the lower 90s this afternoon, well above normal (upper 80s) for this time of year. Dewpoints are a shade below yesterday`s values, but still in the upper 70s. Heat indices will peak in the high 100s, so plan accordingly if working or playing outside. Per rain chances, the reverse cloud line bubbled a few showers along and in the lee of the eastern-most Lower Keys yesterday. We will hold onto 10% rain chances to account for a similar scenario today. The forecast is on track. && .MARINE... Issued at 1037 AM EDT Thu May 16 2024 A weak frontal boundary to the north of the Florida Keys interacting with an area of high pressure in the western Atlantic will result in a somewhat chaotic wind forecast through the weekend. Breezes will tend to peak in the evening and overnight hours, and then lull in the afternoon hours. Rain and thunder chances will remain low through early next week. && .AVIATION... (15Z TAFS) Issued at 1037 AM EDT Thu May 16 2024 Cloud streamers are evident on GOES 16 Visible satellite data this morning oriented southwest to northeast. These cloud streamers may occasionally result in brief periods of MVFR conditions for CIGs around 020-025. Near surface winds are expected to remain southwest to west near 10 knots with occasional gusts to near 15 knots through the early to mid afternoon. Winds will shift sometime during the mid to afternoon to the west to northwest before becoming briefly variable during the evening and then southeast to south overnight. && .CLIMATE... On this day in 1923, a daily record rainfall of 2.89 inches was measured at Key West. May rainfall records for Key West date back to 1871. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 81 90 82 / 10 10 10 10 Marathon 91 82 91 83 / 10 10 10 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ |
| #1180278 (Received by flhurricane at: 9:03 AM 16.May.2024) AFDKEY Area Forecast Discussion National Weather Service Key West FL 454 AM EDT Thu May 16 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 450 AM EDT Thu May 16 2024 It`s a muggy, pseudo wet season start along the island chain this morning. Current temperatures are in the lower 80s with disgusting dewpoints in the upper 70s. We found some relief in our nightly wind surge with moderate to fresh south to southwest breezes observed along our Reef observation stations. However, these breezes are already starting to simmer down and, similar to yesterday, really slacken after sunrise. KBYX radar is clear of any showers in our CWA, but does note a cluster of thunderstorms way off to our northwest in the Gulf of Mexico. These storms are sending billows of cirrus cloud debris over South Florida. In addition to these high clouds, a few streams of shallow cumulus have crossed the island chain from the south with little fanfare. Another warm day is on tap for the Keys today. South to southwesterly breezes will be moderate early turning towards the northwest and slackening throughout today influenced by a surface low off the coast of New England and mainland Florida heating. A stalled out front over central Florida will house the better environment for convection tomorrow, but zonal flow aloft will likely keep most activity north of our area. That being said, even with our drier profile, a stray air parcel pushed through our capping inversion could access a great deal of CAPE (ML from yesterday`s 00z is over 2000 J/kg!) and possibly develop into showers or even a stray thunderstorm. Heat index values will rise into the 100s once again during the hottest part of the afternoon with highs in the lower 90s and dewpoints in the upper 70s. Low temperatures will once again be in the lower 80s. Moving into this weekend, ridging and its associated surface high nosing in from the western North Atlantic will guide our winds for the early part of this weekend. The deep layer moisture from the stalled out front over mainland Florida will remain north of our CWA as the rest of the mid latitude system spirals out into the Atlantic. A warm dome of air will persist aloft with guidance suggesting another few warm and dry days Friday and Saturday. The pattern starts to shift on the other half of the weekend as the next trough progresses east across the midwest Saturday afternoon. This system along with a developing low along Florida`s east coast will draw moisture into our area from the south and provide a decent environment for convective development at the beginning of the week. Thus have included a chance of showers with a slight chance of thunderstorms Sunday night and Monday. Following this, the freshly formed low may help the approaching front pivot through the Keys dropping dewpoints into the lower 70s. While this is a nice relief possibly on the horizon, we`ll have to see how consistent this solution is in the next few runs before promising a dip in oppressive moisture. && .MARINE... Issued at 450 AM EDT Thu May 16 2024 Small Craft Should Exercise Caution until winds decrease in all Florida Keys waters this morning. This overnight surge has been ongoing for a while, but will back off as we near sunrise. From synopsis, a weak frontal boundary to the north of the Florida Keys interacting with an area of high pressure in the western Atlantic will result in a somewhat chaotic wind forecast through the weekend. Breezes will tend to peak in the evening and overnight hours, and then lull in the afternoon hours. Rain and thunder chances will remain low through early next week. && .AVIATION... (00Z TAFS) Issued at 450 AM EDT Thu May 16 2024 Near-surface winds accelerated before sunrise to near 20 knot crosswinds across EYW and MTH, but the winds are expected to collapse after sunrise. Streams of BKN CIGs are passing across the terminals in the early morning, and TEMPOs may be necessary if IFR CIGs manage to develop. Periods of MVFR CIGs will be short-lived, but cloud cover will persist below FL020 through the pre-dawn hours. High altitude debris cloud from a thunderstorm cluster in the Gulf of Mexico will continue to move across Florida Keys waters as well. && .CLIMATE... On this day in 1923, a daily record rainfall of 2.89 inches was measured at Key West. May rainfall records for Key West date back to 1871. && .PRELIMINARY POINT TEMPS/POPS... Key West 91 81 90 82 / 10 10 10 10 Marathon 91 82 91 83 / 10 10 10 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ |
| #1180243 (Received by flhurricane at: 2:42 AM 16.May.2024) AFDKEY Area Forecast Discussion National Weather Service Key West FL 1029 PM EDT Wed May 15 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 1030 PM EDT Wed May 15 2024 Currently - A deep layered trough is riding eastward through the eastern United States this evening. This is resulting in an associated surface low near the New England coast with a trough extending southwestward through the southeastern United States. This low has nudged the Atlantic ridge southward across Cuba. The combination of the above has resulted in a nebulous wind field across the Keys. Meanwhile, modest confluence has setup across our broader area, but is maximized across Central Florida and well north our area. While a few showers were able to percolate in the eastern Lower Keys earlier this afternoon, all more recent activity has been located along the confluent zone far to the north. More recently, this activity has been trending downwards but is still sagging slowly southwards. Short Term Update - The previously mentioned low will meander of the coast while the attached surface trough pivots slightly eastward off the southeast coast. As a result, the surface ridge will remain across Cuba. As day time effects wear off, expect winds to firm up modestly out of the south to southwest. The best low level confluence is expected to remain to our north. The Keys will remain within the southern fringes of this confluent flow, but also not far away from the lower level ridge axis. Forecast soundings suggest some low level inhibition will persist. Taken together, along with the current activity in the southeast gulf, a slight chance for showers and thunderstorms is justified. The increasing flow will forestall any notion of appreciable radiational cooling and overnight lows should still be well up in the lower 80s. Dew points will also high in the upper 70s. && .MARINE... Issued at 1030 PM EDT Wed May 15 2024 The combination of mainland day time heating, troughing over the eastern United States, and a ridge across Florida has resulted in light and variable winds across Keys waters this evening. As the mainland cools and day time effects wear off, expect winds to firm up modestly out of the south to southwest. Have only refreshed first period wind wording in the evening marine update. && .AVIATION... (00Z TAFS) Issued at 1030 PM EDT Wed May 15 2024 VFR conditions will prevail at the island terminals overnight. Surface winds will start out light and variable, but will gradually firm up out of the south to southwest late. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ |
