Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
638 FXUS62 KKEY 191905 AFDKEY Area Forecast Discussion National Weather Service Key West FL 305 PM EDT Thu Sep 19 2024 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 300 PM EDT Thu Sep 19 2024 Currently - Weak mostly northwesterly breezes prevail across the Keys this afternoon. This is due to a weak pressure field brought about by weak troughing along the Atlantic Coast and day time heating sitting between a high over the southeastern United States and a bubble high east of the Bahamas. Amplifying troughing remains aligned along the Atlantic Coast and into the Gulf of Mexico. This along with continued copious lower to mid level moisture is keeping a wetter than normal weather pattern in place across our broader area. Activity along the Keys has been somewhat muted this afternoon. This is not to say there has been no activity, and portions of our forecast area has and continue to be affected by healthy clusters of showers and thunderstorms. Considerable cloud cover from mid and upper decks arriving from gulf convection has kept temperatures muted for much of the day. However, it is early and a number of observation have been able to climb high into the upper 80s to near 90. Dew points remain broadly in the mid 70s. Forecast - The deep layered troughing over the Atlantic Coast will continue to amplify over the next couple of days. However, much of the trough will pivot out to the northeast as robust ridging builds northeastward through the heartland. In response, surface ridging centered over the Mississippi Valley will strengthen and expand while the mid to upper trough near our area breaks off and eventually balls up near the Yucatan. As a result, after another night and day of faint and variable breezes, a light broadly easterly flow will begin to take shape. The still present trough will remain a player through this period. However, lower level moisture is expected dip some. Above normal rain chances tonight will slip back to near normal by tomorrow night. Expect near normal temperatures and dew points through this period. Forecast uncertainty ramps up for early to mid next week. All guidance has been very consistent with the development of a low pressure system that gets its start in the Northwestern Caribbean Sea. Meanwhile, the previously mentioned surface high will have expanded, strengthened, and built eastward through the Atlantic states. This combination should result in an inexorable tightening of the local pressure gradient and accompanying freshening east to southeasterly breezes. In addition, all sensible weather elements will be highly dependent on how not just the low, but the overall pattern, unfolds. Stay tuned. && .MARINE... Issued at 300 PM EDT Thu Sep 19 2024 A nebulous pressure field across the Keys will maintain a light and variable wind regime through tomorrow. High pressure will gradually take hold of the southeast heading into this weekend resulting in winds becoming a prevailing broadly easterly flow. Uncertainty ramps up early next week due to the expected development of a low starting out in the northwestern Caribbean Sea. Expect east to southeasterly breezes to freshen considerably early to mid next week. Stay tuned. && .AVIATION... (18Z TAFS) Issued at 300 PM EDT Thu Sep 19 2024 Shower and thunderstorm activity has diminished for the time being at both terminals leaving VFR conditions prevailing. VCSH is reintroduced tonight as shower activity may return but confidence is not very high and it is possible will not see any further impacts tonight. Near surface winds will be light and mostly variable. && .CLIMATE... On this day in 1917, the daily record cold high temperature of 79F was recorded in Key West. Temperature records for Key West date back to 1872. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory for FLZ076. GM...None. && $$ Public/Marine/Fire...11 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