892 FXUS66 KMFR 231008 AFDMFRArea Forecast Discussion National Weather Service Medford OR 308 AM PDT Tue Sep 23 2025
.DISCUSSION...
Overview:
Overall, weather hazards/impacts continue to be limited. The main concern is around hot temperatures today and Wednesday with near record conditions for some locations, mainly west of the Cascades. High temperatures are expected to be around 15 degrees above normal across inland areas. Humidities will also trend drier today and Wednesday with poor overnight RH recoveries along with breezy winds. This will lead to elevated fire weather concerns. Please see the Fire Weather discussion below for more details.
Details:
A high pressure ridge is over the region with a low over the Rockies moving into the Plains today. Meanwhile a cutoff low will remain well south of the area over and west of southern California. This is setting up and omega block over the region with stagnant high pressure remaining in place through the week. Further north, the upper level westerly jet stream will remain positioned across Canada.
Today and Wednesday, the ridge will be centered over the area. This will result in unseasonably warm temperatures (with high temperatures about 15 degrees above normal) and dry conditions across inland areas. Near record afternoon high temperatures are expected today and Wednesday for some locations west of the Cascades. In particular, the record for Medford is 100 today and 99 on Wednesday, and we are forecasting a high of 97 both days.
At the surface, a thermal trough is located along the coast. This is bringing breezy gusty northeast to east winds and low humidities to the mountains this morning, especially from the Cascades west. Winds trend slightly lower tonight but expected another night with low humidities and easterly breezes over the ridges.
The warm and dry pattern continues through the end of the week. The cutoff low to the south will drift slightly north- northeastward late Wednesday and Thursday. Meanwhile, well to the north, a weak trough will move over the ridge. However, expect little change in the weather across the area, other than temperatures trending slightly less hot on Thursday and Friday. Additionally, we will continue to monitor the low to the south and its track as it drifts northward Wednesday night and Thursday. However, current ensembles continue to indicate that moisture around this low and any thunderstorms that develop will stay south of the area.
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.AVIATION...23/06Z TAFs...Widespread VFR late this evening will persist the next 24 hours beneath high pressure, offshore low- level flow and a strengthening subsidence inversion. Patchy IFR/LIFR fog could develop very near the coast or just offshore north of Cape Blanco in a very shallow marine layer (500 ft or lower). We think most of this will stay to the west of North Bend due to low-level N-NE winds, but can`t rule out some shallow 2-5 NM mist overnight or first thing Tuesday before VFR prevails again. -Spilde
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.MARINE...Gusty north winds and steep hazardous seas will persist across most the waters this morning, then across the outer waters this afternoon through tonight. Winds may increase Wednesday afternoon through Friday, resulting in steep to very steep seas, highest across the waters south of Cape Blanco.
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.FIRE WEATHER...Updated 200 AM PDT Tuesday, September 23, 2025...Upper ridging will remain in place over the area today through Wednesday with warming and drying as a thermal trough persists along the northern California and Oregon coast. The thermal trough will result in breezy to gusty east to northeast winds near and at the ridges, especially in Fire zones 619, 621, 623, and 280, along with moderate to poor overnight recoveries this morning. Winds trend slightly lower tonight and Wednesday morning, but expect continued easterly breezes and some poor recoveries over the ridges. These conditions may result in near or brief critical fire weather conditions in the zones mentioned above. During the afternoons, today and Wednesday, expect low to very low humidities across inland areas with a mix of easterly to northeasterly/northerly breezes.
We are continuing a headline at the top of the Fire Weather Planning Forecast for the locally gusty east winds and poor RH recoveries this morning and again tonight/Wednesday morning. High temperatures both Tuesday and Wednesday will be in the mid to upper 90s west of the Cascades, and in the 80s over the East Side (about 10-15 F above normal). So, those out on the landscape should plan for the expected hot weather/unusual warmth. Take breaks during the peak of the heat in the afternoons and stay hydrated. The good news is that with the longer nights, temperatures in the valleys will cool down shortly after sunset.
The upper ridge is expected to persist across the area as a closed upper low drifts north to northeast into central California on Thursday. Models keep the thunder risk to the SE of the area with probabilities generally 10% or less across northern California zones. Slight cooling is expected Thursday into Friday. It won`t be quite as hot as today and Wednesday, but still above normal. This warm and dry pattern continues into the weekend.
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.MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT early this morning for PZZ350-356-370-376.
Hazardous Seas Warning until 5 AM PDT early this morning for PZZ376.
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NWS MFR Office Area Forecast Discussion