360 FXUS66 KMFR 062156 AFDMFR Area Forecast Discussion National Weather Service Medford OR 256 PM PDT Wed Oct 6 2021 .DISCUSSION...A frontal boundary is pushing out of our area this afternoon with some post frontal clouds remaining over portions of southern Oregon and northern California. The big thing to note is that the moisture profiles are largely dry at this point, so showers are not really expected in wide swaths today. That being said, we have struggling to reach anywhere near forecasted highs with the 2:30 pm temperature at the Medford Airport only at 58 degrees (our high was supposed to be near 67). This is somewhat worrisome as dewpoint temperatures are around 36 which would be prime for some frost formation. However, clouds cover or fog development, both very possible tonight with the marine push could preclude any fog. Therefore, if you are in a West Side Valley, it would be beneficial to make arrangements for a season ending frost, especially if you live outside of a city/town. That being said, the confidence in this is relatively low, so am not issuing a frost advisory at this time. Southern Oregon and northern California will move into more of a split flow pattern with our main trough rising northeastward while a low splits off to our southeast. Overall, we will remain mostly dry, if not cooler with periods of fog and stratus at night with additional frosts east of the Cascades. A secondary very weak front could bring some light drizzle to the coast on Friday. Things will gradually warm up this weekend under a weak ridging regime. Then, our next system will arrive sometime Monday into Tuesday. Ensembles are tightly clustered and show some decent rainfall (much like we saw with the last system), particularly for the coast and areas west of the Cascades. Snow levels will be significantly lower this time around since the warm up will be modest at best, and snow levels could reach the higher passes, and possibly even Siskiyou Summit along I-5. Still, snow amounts are expected to be extremely light, and with a relatively high sun angle in early to mid October, I expect any snow to melt relatively quickly with limited impacts. Additionally, this rainfall will likely not be a definitive end to fire season; but it will help the season fizzle out as it has been for the last couple of weeks. More likely is that ensembles are hinting at a freeze for many of the West Side Valleys on Friday night, particularly south of the Umpqua Divide. Although our forecast finally shows mid 30s in the Rogue Valley, the National Blend of Models is forecasting a 45 percent chance of reaching freezing temperatures early Tuesday morning, and then once again early Wednesday morning. Heavy frosts stand at over a 90 percent chance for those mornings. Stay tuned to the forecast as we begin to decider the potential impacts of the forecast. -Schaaf && .AVIATION...06/18Z TAFs...Over the coastal waters, along the coast, and in the coastal valleys...VFR conditions will prevail initially, but areas of IFR cigs/vsbys in low clouds and fog will develop tonight. The lower conditions will clear to the coast by Thursday afternoon, but will persist offshore through at least Thursday. Over inland areas from the Cascades west...Local MVFR cigs in low clouds over the valleys will clear to VFR by Wednesday afternoon, then remain VFR through Thursday. East of the Cascades...Areas of MVFR cigs and low clouds will clear to VFR Wednesday afternoon, then remain VFR through Thursday. && .MARINE...Updated 200 PM PDT Wednesday 6 October 2021...Northwest swell is building into the waters. The current forecast keeps steep seas in the outer waters this morning, then spreads them to all areas as swell peaks this afternoon. A thermal trough will develop today then strengthen Thursday, producing gusty north winds and steep wind driven seas tonight into Thursday evening, with very steep seas likely south of Cape Blanco, and have upgraded the hazardous Seas Watch to a warning. The thermal trough will weaken Thursday night into Friday. A weak front will move onshore Friday night into Saturday, followed by another front Sunday. Northwest swell then increases early next week. && .FIRE WEATHER...Updated 200 PM PDT Wednesday 6 October 2021...Cool and unsettled weather will persist through Saturday, but precipitation will be spotty and light. Another front may bring slightly heavier and more widespread precipitation to the area Sunday, mostly from the Cascades west and Siskiyous north. && .MFR WATCHES/WARNINGS/ADVISORIES... OR... CA...None. Pacific Coastal Waters... Small Craft Advisory until 2 AM PDT Friday for PZZ350-356-370-376. Hazardous Seas Warning from 11 AM Thursday to 2 AM PDT Friday for PZZ356-376. $$