####018006109#### FXUS66 KSEW 121700 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 1000 AM PDT Sun May 12 2024 .SYNOPSIS...Upper level ridge over the area moving east this afternoon. Weak upper level trough moving through tonight with a weak upper level disturbance following Monday. Upper level ridge building Tuesday and remaining in place through Friday. Upper level trough reaching the area Saturday. && .SHORT TERM /TODAY THROUGH TUESDAY/...Satellite imagery shows weak upper level ridge over the area. Some patchy low stratus has formed along the coast, but will likely dissipate by this afternoon. Temperatures across the area in the mid to upper 50s, up to 60 in Seattle as of 8AM this morning. Upper level ridge moving east today. Light surface gradients this morning turning onshore this afternoon. Marine air moving into the area will drop high temperatures 10 to 15 degrees versus Saturday. Upper level ridge well to the east tonight with low level onshore flow continuing overnight. Weak upper level trough moving across Western Washington. Not much moisture associated with this feature. It will enhance the marine layer over the area. Weak convergence over Snohomish and possibly Northern King County could produce a light shower. Lows in the upper 40s to mid 50s. Upper level ridge building well offshore Monday. Weak shortwave embedded in the northwesterly flow aloft moving through bringing just some cloud cover. This plus the stratus associated with the marine push will make for a mostly cloudy day. Cooling trend continues with highs only in the upper 50s to mid 60s. Upper level ridge offshore building into Western Washington Monday night into Tuesday. Surface gradients going northwesterly Monday night which will limit the amount of stratus Tuesday morning. With the warming temperatures aloft high temperatures will warm back up above normal, in the 60s and lower 70s. Lows Monday night in the 40s. Felton/LH .LONG TERM /WEDNESDAY THROUGH SATURDAY/...Models starting to show more consistency in the extended period with the upper level ridge over the area Wednesday slowly weakening through Friday. Upper level trough dropping down from the north Saturday. Surface gradients remain onshore keeping temperatures from getting very warm. Warmest day with the upper level ridge the strongest Wednesday. Highs in the mid 60s to mid 70s. Highs slowly cooling down to the 60s by Friday. Lows in the 40s. Upper trough bringing more cloud cover and a chance of showers to the Cascades Saturday. Highs remaining near normal, in the 60s. Felton && .AVIATION...Westerly flow aloft will back to southwesterly tonight as an upper ridge gives way to a weak upper trough and associated front that will cross the region late tonight into early Monday. Some patchy MFR stratus developed near the coast this morning but should scatter in the next few hours. However, increasing onshore low-level flow will bring a push of IFR to low MVFR stratus to the coast this evening. Meanwhile, expect ceilings to gradually lower into the MVFR range early Monday morning with gradual lifting to VFR possible later in the day. KSEA...VFR with increasing high level moisture expected late this afternoon into the evening. Ceilings expected to fall to the low end of MVFR by 12Z-15Z Monday. Surface winds increasing northerly through the day, with speeds reaching 6-8 kt this afternoon and evening. Confidence on wind direction becomes lower after 12z, with the most likely scenario being a return to southerly winds. However, if the onshore push through the Strait of Juan de Fuca is stronger, this could create a more variable wind direction or delay this switch. Cullen && .MARINE...Broad surface ridging offshore with lower pressure inland will remain the general synoptic situation through much of the week ahead leading to varying degrees of onshore flow. Meanwhile, seas remain rather choppy with the persistent winds over the coastal waters. A pair of weak systems passing mainly to the north of the area tonight and Monday will enhance the onshore flow for gales later today in the central/east strait and small craft advisory conditions for adjacent waters as well as the coastal waters. Onshore gradients look to temporarily weaken midweek before additional weak systems increase the onshore flow again later in the week. Seas will build a bit with each passing system to 7 to 9 feet, with periods remaining short, around 8 seconds, through the middle of the week. All in all, this looks very much like a typical late spring/early summer type of pattern. 27/12 && .HYDROLOGY...The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated as needed. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 2 PM this afternoon to 4 AM PDT Monday for West Entrance U.S. Waters Strait Of Juan De Fuca. Gale Warning from 2 PM this afternoon to 4 AM PDT Monday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory until 3 AM PDT Monday for Northern Inland Waters Including The San Juan Islands. Small Craft Advisory from 5 PM this afternoon to 4 AM PDT Monday for Admiralty Inlet. Small Craft Advisory until 11 PM PDT this evening for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm- Coastal Waters From Cape Flattery To James Island Out 10 Nm- Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm. && $$ ####018005585#### FXUS63 KIND 121702 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 102 PM EDT Sun May 12 2024 .KEY MESSAGES... - Showers and storms expected Monday-Tuesday with 1-2 inches of rain - Near normal temperatures through the week && .FORECAST UPDATE... Issued at 948 AM EDT Sun May 12 2024 Forecast is in great shape this morning. Skies were mostly clear with only a few cirrus and some thin smoke from Canadian wildfires. Some additional cirrus will move in later today but sunshine will remain plentiful. Temperatures look good, so only minor tweaks to hourly forecasts were made based on latest observations. && .SHORT TERM (Today and Tonight)... Issued at 210 AM EDT Sun May 12 2024 Clear skies were present across much of the Ohio Valley early this morning...with just a small area of mid clouds passing through northeast parts of the forecast area currently. This has enabled a much better opportunity for widespread Aurora viewing across the area as the ongoing solar storm continues. 06Z temperatures ranged largely from the upper 40s to the upper 50s. An upper low over the eastern Great Lakes early this morning will move away from the area today...with ridging aloft settling over the Ohio Valley and joining the surface high already present. With low level flow transitioning to southwesterly and warm advection commencing...expect a wonderful finish to the weekend with warm and dry weather for central Indiana. After a cool start this morning as temperatures slide back into the upper 40s and lower 50s...temps will rise quickly with sunny skies and light winds. Winds will increase to closer to 10mph this afternoon as the center of the surface ridge settles to the southeast and return flow develops. Model soundings show another afternoon with deep mixing present up to nearly 9-10kft during peak heating which will also aid in increasing winds a bit. Some cirrus will drift into the region as the day progresses but the overall state of the sky will be for abundant sun into the early evening. A cutoff upper level low will eject out of the Rockies later today and progress into the central Plains by daybreak Monday. The approach of this feature will lead to a subtle increase in mid and high level clouds tonight but the combined tandem of ridging at the surface and aloft will keep plenty of dry air and subsidence across the region. Temps...the deep mixing present below 10kft will maintain lower dewpoints through the afternoon and should enable temperatures to outperform current guidance by a degree or two. Nudged afternoon highs up into the upper 70s and lower 80s for much of the forecast area. Lows tonight will remain in the mid and upper 50s aided by southerly winds at 5-10mph for much of the night. && .LONG TERM (Monday through Saturday)... Issued at 210 AM EDT Sun May 12 2024 Monday and Tuesday Southerly flow will become more robust Monday as a low pressure system exits the Rockies and begins to intensify as it tracks from Kansas into the Ohio Valley. Models have a pretty good handle on both the timing and strength of this low pressure system which helps create a high confidence forecast in a period of moderate to briefly heavy rain Monday evening through the overnight hours with rain amounts around 1-1.5 inches with the heaviest rain falling during the daytime hours on Tuesday. A deformation axis of heavier rain looks to set up on the northwest side of the low but this axis looks to remain northwest of the forecast area with areas near Lafayette on the far periphery of this area of enhanced precipitation. There will be additional precipitation Tuesday night on the backend of the system, but expect that coverage will gradually lessen after midnight going into Wednesday as the better forcing pushes into the East Coast. Wednesday Through Saturday Conditions look much quieter going into the middle of the week as high pressure builds in the aftermath of the early week system. Temperatures will remain near normal with little flow at the surface and aloft to advect warmer air into the area. Another upper level low is expected to take a similar track to the system earlier in the week Thursday night into Friday with another round of sub-severe showers and thunderstorms. The exact track with this system remains much more uncertain with model spread on the axis of heavier rain varying from central Indiana to as far south as Tennessee. There are some ensemble members that keep precipitation as late as Saturday, but those look to be the outlier with the vast majority allowing for a dry forecast for the weekend. && .AVIATION (18Z TAF Issuance)... Issued at 101 PM EDT Sun May 12 2024 Impacts: - No impacts through the forecast period Discussion: Some high clouds will move in this afternoon along with perhaps a few cumulus or mid level clouds. High then mid level clouds will increase tonight into Monday morning, with lower clouds waiting until after 18Z Monday to arrive. Isolated showers may get near the western sites late tonight or Monday morning, but confidence and expected coverage are too low to mention. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...50 SHORT TERM...Ryan LONG TERM...White AVIATION...50