Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
750 FXUS62 KKEY 100950 AFDKEY Area Forecast Discussion National Weather Service Key West FL 450 AM EST Fri Jan 10 2025 ...New DISCUSSION, MARINE, AVIATION... .DISCUSSION... Issued at 450 AM EST Fri Jan 10 2025 Another cool but quiet overnight for the Florida Keys. KBYX radar shows no signs of precipitation anywhere within 150 nm of the radar. Looking at nighttime microphysics satellite imagery we can clearly see a convergence zone in the eastern half of our waters. To the west of this boundary we have north to northeast winds and to the east we have winds becoming more easterly. This feature is thanks to a high pressure centered along the spine of the Appalachians, which is sliding east in response to a surface low in the northwestern Gulf of Mexico. Temperatures this morning are similar to yesterday with current readings in the mid to upper 50s. Dew points are quickly recovering and already have lower 50s across all of the island chain. .FORECAST... Let me start this discussion with saying that the forecast is going to be messy beyond day 3. Before we get there though, let`s talk near to short term first. In the near term, the aforementioned surface high will continues to slide east in response to the low pressure in the Gulf of Mexico. As a result, winds will quickly clock around from the northeast early this morning to the east and southeast by late morning/early afternoon. This also means that convergence zone noted on satellite this morning will also be shifting westward. Even though the low levels will moisten up we will still be parked under a relatively deep mean layer ridge and this will suppress rain chances today. As we go east to southeast, temperatures will rebound from the recent cool snap. This warm up will last into the first half of the weekend as temperatures return closer to and slightly above normal. However, that low pressure in the Gulf this morning, will push through a cold front late Saturday. We could see a decaying line of showers along a pre-frontal trough in the afternoon on Saturday. There is growing consensus of this scenario and have nudged PoPs up slightly. Behind this front will be a brief surge in winds, though not expecting breezy conditions. In addition, we will see another cool down but again, not to the same extent as the previous front. Now we get to the messy part. Although GFS and ECMWF agree on certain things on Sunday, their differences actually start Saturday night. Let`s explain. The GFS has the next front stalling just to our north. As it stalls it will set up a baroclinic zone across the Gulf of Mexico. This would allow for a somewhat active weather pattern as the Keys would be just south or close enough to have moisture pool along this boundary. Thankfully there looks to be no upper level support with this solution and therefore any showers would likely be shallow and relatively light in nature. The ECMWF on the other hand as the front clearing through the Keys Saturday night with the baroclinic zone setting up further to the west. As a result, moisture would not get trapped along the boundary and therefore the Keys will be mostly rain free. By early next week the models try to converge on a similar solution with a weak area of lower pressure developing along the baroclinic zone though the position and strength remains in question. The similarities in model solutions will continue into Tuesday but quickly diverge again. They both agree on eventually another frontal passage sometime Tuesday into Wednesday with some timing differences and strengths. Wednesday and beyond there is high uncertainty in the forecast. The GFS keeps the next high pressure that would trail the front further north across the CONUS. At the same time, a similar situation would unfold with a baroclinic zone once again somewhere in the vicinity of the Florida Keys. Meanwhile, the ECMWF has the high charging south well into the Gulf of Mexico and taking with it the baroclinic zone. How these features move will determine if the next upper level trough dipping into the Central Plains will successfully interact with the baroclinic zone or not. For now have tried to maintain a middle of the road approach while heavily favoring the previous forecast cycle in the long term. But note, that there will likely be a change to the second half of the forecast period and residents and those with interests in the Keys should monitor for future updates. && .MARINE... Issued at 450 AM EST Fri Jan 10 2025 High pressure centered near the Carolina coast will continue to shift east in response to a developing low pressure system across the northern Gulf of Mexico. This will allow for winds to clock around from northerlies this morning towards the east and southeast by this afternoon. Further veering will occur through Saturday as the low pressure system treks eastward and a cold front approaches from the northwest. Frontal passage is expected late Saturday afternoon or early evening with northerly breezes returning. Another cold front looks to arrive Tuesday with a more noticeable northerly surge in its wake. && .AVIATION... (06Z TAFS) Issued at 450 AM EST Fri Jan 10 2025 VFR conditions will prevail at EYW and MTH through the TAF period. Near surface northeast winds will become easterly late this morning remaining at near 10 knots. && .CLIMATE... On this day in 2010, the daily record cold high temperature of 50F was recorded in Marathon. This is also the coldest high temperature ever recorded during the month of January for Marathon. Temperature records for Marathon date back to 1950. && .PRELIMINARY POINT TEMPS/POPS... Key West 73 70 76 66 / 0 10 30 10 Marathon 72 69 77 65 / 0 10 20 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...LIW 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