537 FXUS66 KMFR 122135 AFDMFRArea Forecast Discussion National Weather Service Medford OR 235 PM PDT Fri Sep 12 2025
.DISCUSSION...An upper ridge will move over the area today and on Saturday, bringing temperatures to just above seasonal levels. Under this ridge, the weekend will get off to a quiet start.
The progressive pattern continues with a weak trough approaching late Saturday and passing over the area on Sunday. Showers look likely for the Oregon coast and into Josephine and Douglas counties. The Cascades and elevated east side terrain are also expected to see some rainfall. Jackson, Siskiyou, and Modoc counties will generally see a few hundredths of an inch or less of rainfall. This front will help to bring another day of below seasonal temperatures.
Another ridge follows on Monday, bringing more stable conditions and warm temperatures. Daytime highs in west side valleys could be in the high 80s to low 90s, while east side areas are forecast to see temperatures in the high 70s to low 80s on Tuesday and Wednesday. While there are fire weather concerns addressed in the discussion below, this ridge will also be overall uneventful.
Deterministic imagery for both the GFS and ECMWF models show another upper trough following the ridge, preventing additional warming. NBM probabilistic data shows a decrease to ~20% chance for 90 degree days for Medford beyond Tuesday while yesterday`s discussion had these chances at ~50%. While this trough will help to flatten the ridge and keep temperatures closer to seasonal levels, for Thursday and beyond, there`s uncertainty for more specific details going into the end of next week. Deterministic imagery starts to diverge into Friday, while both meteogram guidance and NBM temperature ranges also reflect significant uncertainty. Long-term clusters generally reflect some version of upper troughing, but with noticeable differences between the exact shape. This seems lean towards seasonable to cool conditions with chances of showers for next weekend, but this is offered with slight to moderate confidence at best. -TAD
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.AVIATION...12/18Z TAFs...Along the coast and into the Umpqua Valley, MVFR ceilings will gradually clear between 18-21z. Then, expect areas of IFR/LIFR to develop late this evening and overnight along the coast and into the Coquille Valley. Models and guidance indicate mainly VFR continuing through Saturday morning in the Umpqua Valley. However there is a chance (25%) for IFR/MVFR ceilings early Saturday morning, including at Roseburg. Elsewhere, inland expect mainly VFR. However, there is a potential for a brief period of localized IFR/LIFR in valley fog for areas east of the Cascades early Saturday morning.
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.MARINE...Updated 200 PM PDT Friday, September 12, 2025...Breezy northerly winds are expected south of Cape Blanco through this afternoon, but conditions should remain below advisory levels. Northwest swell continues to build into the region and will persist through the weekend. Total seas look to remain below advisory levels until Sunday, when an approaching front could bring showers and increased northwest swell. A thermal trough may support wind-driven steep seas Sunday afternoon and into early next week.
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.FIRE WEATHER...Updated 200 PM PDT Friday, September 12, 2025...A low pressure will move into the area Saturday night and Sunday bringing rain showers and chances for isolated thunderstorms. Wetting rain is likely along the coast (60-80% chance) Saturday night into Sunday, with lower chances (10-50%) inland across southwest Oregon. Northern California zones are expected to see lower chances for any precipitation and wetting rain (5-25%.
Fire weather concerns include a slight chance of thunderstorms along the coast Saturday night and early Sunday morning, and from the Southern Oregon Cascades east Sunday morning and afternoon. Additionally, a moderate to strong warming and drying trend is expected Monday morning and Tuesday. Moderate east winds are expected across the coastal ranges early Monday morning with moderate ridgetop recoveries. Then, on Tuesday, winds decrease but moderate to locally poor ridge top are expected. Moderate ridgetop recoveries are expected again on Wednesday morning. A weak and dry front is expected to move into the area Wednesday. This may result in some enhanced afternoon breezes for inland area. Otherwise, expect temperatures to trend less warm Wednesday into Thursday.
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.MFR WATCHES/WARNINGS/ADVISORIES... OR...None.
CA...None.
PACIFIC COASTAL WATERS...None.
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TAD/MNF/CC
NWS MFR Office Area Forecast Discussion