Show Area Forecast Discussion - Key West, FL (Florida Keys) Selection: |
#1173202 (Received by flhurricane at: 5:12 AM 19.Mar.2024) AFDKEY Area Forecast Discussion National Weather Service Key West FL 453 AM EDT Tue Mar 19 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 450 AM EDT Tue Mar 19 2024 We`re off to a surprisingly wet and thundery start this Tuesday morning across the Florida Keys. Yesterday evening, a broken line of Cuban thunderstorms meandered into the Straits of Florida towards the island chain. While most convection dissipated before reaching land, a lone shower swept through the western Lower Keys before falling apart. After midnight, northwesterly breezes started to filter over the island chain and promoted moisture convergence fueling convective development as originally forecast. However, instead of being confined to the Straits, showers and thunderstorms erupted along the Lower and Middle Keys breaking through the dry air in the middle layers sampled from yesterday evening`s sounding. In fact, this line developed so quickly that it`s reminiscent of a cloud line on a summer day. Temperatures across the island chain have fallen into the lower to mid 70s in response to the rainfall. Wind observations along the Reef are generally contaminated by storm outflow, but show a trend of veering breezes to the northwest as a cold front approaches from the Gulf. The cold front on our doorstep will sweep through our area this morning. Northerly breezes along the island chain, as well as a southerly shift of the convergence boundary already hint at this motion. By sunrise, most of the convection will have shifted off land into the Straits, but another round is pushing through from the Gulf waters. This line does not look nearly as robust as this morning`s activity with CAMs generally suggesting it will fall apart before arriving to the island chain. That being said, slight chance PoPs are held for the rest of today as the air mass transitions from moist to dry. Fresh to strong northerly breezes are imminent across our waters and are expected to persist into this afternoon before continuing to shift to the northeast and gradually slackening through tonight. Cooler and drier weather will follow into the end of the week when a period of unsettled weather is expected. A trough sliding through the Great Plains towards the Gulf coast will parent a surface low in the Gulf of Mexico sometime Thursday evening. As this low approaches Florida, breezes will freshen out of the east to southeast Thursday night into Friday over our CWA. While the exact position of the low will be the final determining factor for intensity, Small Craft Advisories may be required for this time period. The low will also pull in a large amount of moisture resulting in enhanced PoPs from Thursday night through Saturday. Guidance continues to favor Friday for the highest chances but due to this event being still a few days away with the major feature yet to develop will hold at 60% for now. Another round of drier and cooler weather will be on tap after Saturday night as the low is expected to drive another cold front through the area for the start of next week. && .MARINE... Issued at 450 AM EDT Tue Mar 19 2024 A Small Craft Advisory is in effect for all Florida Keys coastal waters. From synopsis, fresh to strong northerly breezes will kick off today behind this morning`s frontal passage through the coastal waters of the Florida Keys. Breezes will turn easterly and diminish Today through Wednesday. Unsettled weather at the end of the week will result in fresh to strong breezes Thursday night and Friday, followed by breezes shifting to the southwest then northwest at the tail-end of the unsettled weather. && .AVIATION... (06Z TAFS) Issued at 450 AM EDT Tue Mar 19 2024 Showers and thunderstorms will shift south of the EYW and MTH terminals before sunrise as a cold front moves through the area, but periods of MVFR ceilings will remain possible through the morning hours. VFR conditions should return this afternoon. Gusty north winds of 12 to 15 knots with frequent gusts over 20 knots will prevail through midday, then winds will shift to the NE and decrease to around 10 knots during the afternoon. && .CLIMATE... On this day in Keys weather history in 2019, the daily record rainfall of 1.60" was recorded at Key West International Airport. Preliminary readings from the airport this morning have already broken this record with 2.25" reported. Precipitation records date back to 1871. && .PRELIMINARY POINT TEMPS/POPS... Key West 76 69 79 73 / 10 10 10 10 Marathon 78 70 80 72 / 10 10 0 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory until 11 AM EDT this morning for GMZ031>035- 042>044-052>055-072>075. && $$ |