


Area Forecast Discussion
Issued by NWS Medford, OR
Issued by NWS Medford, OR
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558 FXUS66 KMFR 162143 AFDMFR Area Forecast Discussion National Weather Service Medford OR 243 PM PDT Wed Jul 16 2025 .DISCUSSION (Today through Tuesday)... Overview: The general theme going forward is hot, dry, and breezy. Main impact continues to be the heat as our heat related hazards continue through this afternoon. That said, we are fortunately going to see a trend of slightly cooler temperatures starting tomorrow, and we will likely be back "down" to near normal highs by this weekend. Today is the hottest day in the forecast for many westside areas (100-105), and while temperatures are expected to cool off tomorrow, we will still see highs around the upper 90s through Friday. Otherwise, we are going to see haze/smoke impacts for the next few days as nearby wildfires continue. Lastly, while its a low end chance (10%-20%), we will see a potential for thunderstorms the next couple afternoons (today through Friday). Smoke will likely add to inhibit these storm chances, so we will need to monitor smoke/haze trends through these next few afternoons. Further Details: Generally speaking, we have a northwesterly flow pattern aloft over the PacNW with slight high pressure to the south of us. Model agreement has a 500mb low strengthening over the Pacific around 37N and 135W tonight. This will cause some disruption to the general NW flow and may introduce some upper level dynamics over the forecast area the next few afternoons. As we hit convective temperatures each afternoon (today through Friday), we will have a very small chance for thunderstorms each afternoon. This will be primarily for northern California and areas east of the Cascades. These weak forcing events are tough to forecast, but the smoke and haze in the area does further confidence that thunderstorms are generally going to struggle to mature. Most likely is we have towering cumulus that struggle to develop into a thunderstorm. However, one cannot rule out an isolated storm or two, with the best chance tomorrow afternoon through this stretch. By better, this is only a 10-20 percent chance, so its a low end chance scenario. Tomorrow will have the better instability (~300-500 J/kg), and better upper level dynamics as the aforementioned H5 low brings PVA over the forecast area, albeit weak forcing. Not expecting severe weather but lightning and gusty winds will be possible with any thunderstorm that develops. The northwesterly flow pattern will essentially be unchanged through the next several days. The airmass today will be the warmest, and a generally decrease in temperatures are expected slightly each day through Saturday. By Sunday, we will likely be close to normal temperatures. For example, Medford is normally around the low/mid 90s this time of year, and we are forecasting 92 which is 1 degree below normal. By Monday, there is a chance for westside valleys to be below 90 with Medford currently forecast to be 89. These cooler temperatures might be a nice welcoming for some folks after this stretch of warm weather we have had. While wind speeds are expected to be breezy (sustained 15-25 mph) for some areas and in very typical diurnal fashion, we are not seeing any days where wind speeds are expected to be strong. -Guerrero && .AVIATION (18Z TAFs)... The coastal stratus has cleared out this morning and the main aviation hazard is now smoke from active wildfires around the region. Northwest flow should help scape out some of the smoke for locations west of the Cascades by this evening. However, some thicker smoke could settle into areas east of the Cascades with visibilities down to 2 miles near KLMT. Conditions are anticipated to improve by Thursday with visibilities. There is also a very low chance of some cloud ground lightning in the forecast area. -Smith && .FIRE WEATHER...Updated 230 PM PDT Wednesday, July 16, 2025... We don`t have any thunderstorms in the official forecast, although there is a 5-10% chance of cloud to ground lightning in western Siskiyou County based on the latest forecast this afternoon. Aside from thunderstorms, the west coast thermal trough dissipates according to the inverted MSLP and 850mb charts as we see deeper westerly flow this afternoon and evening. This cooler onshore flow really shows up on temperature trends west of the Cascades. Highs drop 5 to 10 degrees, especially around the Umpqua basin. A short wave trough will move in and bring another chance of thunderstorms which is covered in the discussion above. Winds and relative humidities will bring some concerns in the eastern portions of our forecast area. our local MOS guidance is suggesting some wind gusts up to 30 mph over the exposed RAWS sites east of the Cascades with near single digit minimum humidities. This will remain headlined in our fire weather forecast discussion. Friday is another day to watch out for as pressure gradients tighten. High pressure in the Pacific and generally lower pressure farther to the east should allow for some gusty winds east of the Cascades. There is very little change in humidities, so concerns remain elevated for fire weather conditions in south central Oregon. There should be gradual improvement in fire weather conditions Saturday and Sunday with a bigger improvement by Monday as minimum humidities about 5 percent higher compared to what we`ve been observing. The hot dry windy index also shows this trend with fire weather conditions improving into the extended period. -Smith && .MARINE...Updated 130 PM PDT Wednesday, July 16, 2025...Steep seas persist across all waters through tonight. However, as wind waves transition to fresh swell through early tomorrow morning, there may be a brief period of improved conditions starting tomorrow and going through at least Friday. That said, a weak thermal trough could return over weekend. Though winds are expected to be weaker than the previous event, steeps seas and advisory level winds could return south of Cape Blanco over the weekend. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Heat Advisory until 8 PM PDT this evening for ORZ023>026. CA...Heat Advisory until 8 PM PDT this evening for CAZ080-081. PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Thursday for PZZ350-356-370-376. && $$