####018003568#### FXUS66 KSEW 161601 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 901 AM PDT Fri May 16 2025 .SYNOPSIS...Cloudy and showery conditions will continue across the region through the weekend with temperatures remaining below normal. The chance of thunderstorms will increase to around 20 percent across much of the region Saturday afternoon. Showers continue through the start of next week as the pattern remains somewhat active. A shift to somewhat warmer conditions is possible late next week. && .SHORT TERM /TODAY THROUGH SUNDAY/...Previous discussion...Onshore flow continuing across the region with continued rain in the wake of the passing frontal system. Moist, westerly flow aloft will continue through the day today with cloudy and cool conditions continuing. Another disturbance slides across the region Saturday, with another round of showers across the area. Instability increases a bit during the afternoon and evening showers, with around a 20% chance of thunderstorms across portions of the area (generally south and east of Puget sound, extending through the Cascades). Snow levels remain somewhat low into Sunday, around 4000 ft or so, and some light snow may fall in the mountains as a result. However, any accumulations should be light (less than an inch) and short-lived. .LONG TERM /MONDAY THROUGH THURSDAY/...Heights rise a bit by early Monday with an upper ridge moving through the region, bringing a decrease in shower activity. This should also allow for temperatures to trend back up a couple of degrees, mostly in the lower 60s. Another front arrives late Monday or Tuesday for another round of cloudy and showery conditions, along with breezier winds. Ensemble guidance begins to split later in the week, with the forecast continuing to reflect modest onshore flow maintaining clouds and near normal conditions, but the potential for a slightly warmer and perhaps drier pattern to emerge by the late stages of the week. && .AVIATION...Westerly flow aloft will become southwesterly tonight as the next in a series of upper troughs and associated weak fronts approaches Western Washington. The air mass remains quite moist with widespread low MVFR or IFR ceilings. Only marginal improvement is expected late this afternoon with ceilings remaining MVFR areawide with scattered showers. Shower coverage will increase overnight into early Saturday with ceilings dropping back to low MVFR or IFR. KSEA...Low MVFR or occasional IFR with scattered showers and/or drizzle in the vicinity expected to persist into midday. Current thinking leans toward pessimistic approach to any improvement with ceilings only lifting to 020-025 late in the day. Showers will increase late tonight into Saturday with low MVFR or occasional IFR ceilings persisting. Surface winds S/SW generally 5 to 8 knots. 27 && .MARINE...A frontal system will move over the waters today and weaken as it moves inland. Surface high pressure will build over the coastal waters Saturday into Sunday. This will bring increased onshore flow over the coastal waters and Strait of Juan de Fuca. The next frontal system arrives Monday. 27 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Gale Watch from Saturday morning through Saturday evening for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. && $$ ####018006190#### FXUS64 KTSA 161604 AFDTSA Area Forecast Discussion National Weather Service Tulsa OK 1104 AM CDT Fri May 16 2025 ...New SHORT TERM... .KEY MESSAGES... Issued at 255 AM CDT Thu May 15 2025 - Shower and thunderstorm chances for far eastern/southeast OK into northwest AR through mid afternoon today. - An unsettled weather pattern continues through the weekend and into early next week. Severe thunderstorms are expected at times. && .SHORT TERM... (The rest of today ) Issued at 1104 AM CDT Fri May 16 2025 Cold front extended across south central Oklahoma into northeast Oklahoma along a line from Okemah to Nowata and then into southeast Kansas. Ahead/east of this boundary low 70 deg dewpoints were expanding eastward through northwest Arkansas. Cloud cover moving into far northwest Arkansas has continued build over the past hour with radar echoes developing from Sequoyah co to Benton co. This development was moving into an unstable atmosphere with large amounts of surface & elevated instability and deep layer shear. Convection is expected to continue to increase in coverage as this activity quickly moves through far northwest Arkansas over the next couple of hours. Severe potentials have also increased over this area and it likely will not take much for storms to become strong/severe with large hail and damaging winds the main threats. Storm motions, like yesterday should be rather quick to the northeast with much of this convective development exiting the forecast area early afternoon as the frontal boundary continues its east southeast movement. Behind the cold front, dewpoints in the 50s to around 60 deg were reported with mostly clear skies. This clearing line should continue to move east southeast with the front as well and be located over southeast Oklahoma into west central Arkansas mid afternoon. Mostly clear conditions combined with westerly winds will help afternoon temps warm into the 80s for most locations. With the front across far southeast Oklahoma mid to late afternoon interacting with ample moisture and an unstable atmosphere, additional convection is forecast to develop. Current thinking is for storm initiation near the Red River into west central Arkansas. Much of this development looks to be near and just east of the CWA from Choctaw co to Franklin co. These storms should quickly move out of CWA and into southwest/central Arkansas by late afternoon/early evening. Again, increasing severe potentials will aid in large hail and damaging winds to be the primary threat. A very low tornado threat will also exist with the greater potential outside of the CWA. For the morning update, have adjusted PoPs and sky grids based on the mentioned above and also tweaked dewpoints to maintain the low 70 deg dewpoints ahead of the front. The rest of the forecast is trending well at this time. && .LONG TERM... (Tonight through Thursday) Issued at 255 AM CDT Fri May 16 2025 Drier air will push into the area for tonight into Saturday morning, with a lull in any thunderstorm activity through the morning hours on Saturday. This will be short lived however as moisture once again lifts back north in response to Lee cyclogenesis ahead of the main upper level storm system digging into the Desert Southwest. This will begin a period of increasing thunderstorm chances from Saturday afternoon through Monday and possibly into Tuesday. While the specific details are still to be determined and will be highly depended on previous days activity, expect periods of thunderstorms through the weekend as modest southwest flow aloft overspreads a seasonally moist and unstable airmass. Severe thunderstorms will be possible each day, with all hazards in play depending on timing and location of relevant features. As it stands now, thunderstorm chances will increase across eastern Oklahoma Saturday afternoon and evening as the warm front lifts northward. Another round of storms is expected into Sunday afternoon and evening as storms develop off a dryline over western/central Oklahoma. The main storm system begins to move into the Plains on Monday ,providing what is likely the most likely day to see more widespread severe thunderstorms across the region. Storms could linger into Tuesday as the slow moving trough axis slides through the area before departing to the east and pushing a rather strong cold front through the area. Cooler and drier air will filter in behind the frontal boundary with noticeably cooler temperatures progged for the rest of the work week. Lows could even dip into the 40s a couple of nights next week with highs mainly in the 70s. Low shower/storm chances enter the forecast again by the end of the week and into next weekend as northwest flow aloft strengthens over the Plains. Bowlan && .AVIATION... (12Z TAFS) Issued at 532 AM CDT Fri May 16 2025 No major changes made from 06Z forecast. Still some potential for MVFR cigs from SE OK up into NW AR this morning. CAMs remain very consistent run-to-run, so will continue with TEMPO tsra mention at the NW AR sites 15 to 18Z. VFR conditions will prevail this afternoon, with storm chances too low to mention at KFSM. Skies will clear out by evening. Sfc winds will get gusty out of the SW to W and will trend toward NW and subside this afternoon. Lacy && .PRELIMINARY POINT TEMPS/POPS... TUL 87 57 83 64 / 0 0 10 40 FSM 89 63 88 68 / 20 0 10 50 MLC 88 61 87 66 / 10 0 30 40 BVO 85 51 81 60 / 0 0 0 50 FYV 85 57 85 63 / 40 0 10 60 BYV 84 57 84 61 / 50 0 10 60 MKO 86 57 84 64 / 10 0 20 40 MIO 83 53 80 61 / 10 0 10 60 F10 87 58 84 64 / 10 0 20 40 HHW 87 64 86 67 / 30 10 40 60 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...20 LONG TERM....04 AVIATION...30