textproduct: Medford

DISCUSSION

High clouds have streamed across the area from the south today, and some more midlevel clouds are just beginning to enter our northern California zones. These illustrate the moisture that is accompanying a shortwave as it enters the region, and will eventually result in instability and convection later this afternoon and evening. This convection will be concentrated along and east of the Cascades, although we cannot rule out an isolated storm or two over the Klamaths and Siskiyous. Moisture is on the low side, so while some precipitation is possible within the cores of any storms today, some could be dry. The latest SPC HREF has a bullseye right over Lake County with a 40 to 50 percent chance of lightning within 20km of a point. Wind shear is about 20 knots out of the south west. Forecast soundings show the typical inverted V soundings in southern Oregon with mixing up 4km above ground level, so gusty outflow winds to 40 knots seem probable in these thunderstorms.

Thunderstorms could continue well into the evening and early overnight hours, although they should start to die around 8Z Monday (shortly after midnight PDT). The upper level low weakens and additional vorticity from that low eventually moves in by Monday. With ample heating and increased moisture, thunderstorms remain in the forecast east of the Cascades on Monday afternoon, and are much more likely to produce precipitation at the surface. Again, probabilities for cloud to ground lightning are around 50 to 70 percent within Lake County, concentrated a bit farther north than today. Convective probabilities drop off significantly farther to the west and south, and will end earlier in the day than Sunday as the impulse pushes off to the northeast by late afternoon.

By Tuesday evening, a 500 mb trough will push into the Pacific Northwest. This will bring some stronger northwest flow to the region, and a marine push into the coastal valleys and the Umpqua Basin. Some data shows a dissipating cold front moving closer to the coast. In any case, temperatures should trend a few degrees cooler on Wednesday with Medford trending 5 degrees cooler based on the latest forecast. With this upper level low pushing inland, isolated showers or thunderstorms can't be ruled out on Tuesday evening. The ECMWF ensemble shows spotty QPF around most of Central Oregon, which could clip northern Lake or Klamath Counties before conditions dry Wednesday. Additionally, we are likely to see enhanced afternoon and evening winds Tuesday and Wednesday as the dying front passes, especially over the East Side.

After rather mundane, typical summer conditions Thursday into Friday, another trough and potential front arrives over the weekend. There is a lot of uncertainty regarding this system, and while it will most likely be dry, we should see another day or two of increased afternoon winds.

AVIATION...05/18Z TAFs

VFR levels are present across most of northern California and southern Oregon late this morning, with LIFR levels persisting at Brookings and gusty winds at the North Bend terminal. Inland areas will stay at VFR through the TAF period, with only high clouds and diurnal breezes in the forecast at area terminals. Marine stratus looks to return to North Bend this afternoon, bringing IFR ceilings and chances for lower visibilities that will continue into Monday morning.

Thunderstorm chances are present in Lake and eastern Klamath counties this afternoon and evening, but guidance keeps activity from the Klamath Falls terminal. There's a nonzero chance of a stray storm nearby, but repeated activity is not expected. -TAD

MARINE...Updated 200 PM PDT Sunday, July 5, 2026

Gusty northerly winds are expected to ease this afternoon and into the week ahead. However, these winds are still strong enough to support very steep seas south of Cape Blanco and beyond 5 nm from shore while steep seas persist in all other area waters through tonight. While winds continue to decrease on Monday, a slight rise in westerly swell will support steep seas continuing in all waters through the day. Steep seas look to be limited to waters south of Cape Blanco for Tuesday through Wednesday morning.

Currently, northerly winds start to increase on Wednesday morning. This may bring additional areas of unsettled seas to area waters into the end of the week. -TAD

FIRE WEATHER...Updated 1200 PM PDT Sunday, July 5, 2026

Warm and dry conditions will continue for the next week, with typical afternoon breezes each day. There will be a few periods of concern: the first this afternoon and again tomorrow east of the Cascades, where abundant lightning is expected, and the second being two dry frontal passages that will bring gusty winds and low RH to portions of the area.

There is a chance of afternoon and evening thunderstorms east of the Cascades, focused mainly over central and southern Lake county and eastern Klamath county. Some isolated storms are possible elsewhere east of the Cascades, and over northern California, including the Klamaths, Siskiyous, and Warners. There is limited moisture today, so while rain is expected within the cores of most of these thunderstorms, a few more high based storms, or those along the periphery of the drier air, could produce very little or no rain at the surface. Along with plenty of lightning, gusty and erratic winds of up to 45 mph will be a concern for any storms that develop (especially the drier ones). Also, there is a possibility that some of these showers and an isolated thunderstorm or two linger on into Sunday night/early Monday morning over Lake county.

Another round of thunderstorms is expected Monday afternoon, this time focused a bit farther north over northern Lake and Klamath counties. More moisture will be available then, so dry thunderstorms are less likely, but still possible. Also, we cannot rule out an isolated storm or two over the rest of the East Side and northern California. Again, lightning and gusty outflow winds will be the primary concerns. A Red Flag Warning has been issued for both afternoons, and details can be found at PDXRFWMFR.

Otherwise, high temperatures remain around 5 to 10 degrees above normal, and afternoon breezes remain typical to slightly enhanced during the next week. This will result in very dry conditions, generally just shy of critical wind and humidity thresholds, especially Tuesday and Wednesday, and potentially again this weekend, as dry cold fronts pass through or just skim by the region.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Red Flag Warning until 9 PM PDT this evening for ORZ624-625.

Red Flag Warning from 2 PM to 8 PM PDT Monday for ORZ624-625.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Monday for PZZ350-356-370.

Hazardous Seas Warning until 2 AM PDT Monday for PZZ356-376.