textproduct: Medford

Updated AVIATION Discussion

AVIATION...02/12Z TAFs

Aside from MVFR/IFR ceilings along the coast and in the Umpqua Basin, VFR conditions prevail across the region and will do so through the TAF period. Isolated showers with some occasional lightning continue west of the I-5 corridor north of Grants Pass. Expect shower/thunderstorm coverage to increase later this afternoon as the atmosphere destabilizes again. The highest chances (50-70%) for lightning are focused along the Cascades north of Crater Lake, across the Modoc/Warners east of the Cascades and in the Kalmiopsis region. Chances are fairly low for thunderstorms at the TAF locations, but there is about a 10-20% chance of a thunderstorm impacting Medford and/or Klamath Falls this afternoon. Expect gusty and erratic outflows in the vicinity of thunderstorms today. Additionally, gusty south to south to southeast winds are expected this afternoon/evening.

PREV DISCUSSION

/Issued 256 AM PDT Sat May 2 2026/

DISCUSSION...Upper level low pressure lingers offshore this morning, maintaining southerly flow and bringing a blanket of mid to high level clouds to the region. Meanwhile, marine stratus has returned to the marine waters, coastal locations and has pushed inland into the Umpqua Basin and portions of the Illinois Valley. Shower and thunderstorm activity from yesterday has mostly come to an end, though there are some radar returns indicating showers in portions of Douglas/Coos Counties west of the I-5 corridor, moving northward. Satellite derived lightning data indicates some in cloud lightning activity with these showers, but ground systems have only recorded one cloud to ground strike so far. Models maintain this corridor of elevated instability persisting into the early morning hours, with some increased shower activity around sunrise.

Low pressure offshore will start to cut off today and gradually drift southwestward into Sunday. Meanwhile, high pressure to the west of that low, amplifies, then also closes off to the north of the low pressure for a brief time Sunday. Low pressure to the south gradually moves inland into central California on Monday, then eastward into the Desert Southwest by Tuesday. As this low pressure cuts off today and drifts southwestward, southerly flow will continue to bring moist, unstable air to the region, maintaining daily shower/thunderstorm chances during the afternoon and evenings today through Monday.

Friday afternoon's (yesterday) activity was fairly minimal with two main cells producing the bulk of the ~70 cloud to ground strikes yesterday...one that moved through western Jackson County and the other north of Chemult in northern Klamath County. We expect more activity today with more instability (-3 to -5 LI, 1000-1500 J/kg CAPE) in the region compared to yesterday. The highest chances for lighting (50-70%) are focused across portions of Modoc/eastern Siskiyou Counties, along the Cascades from Crater Lake northward and over western Josephine/eastern Douglas in the Kalmiopsis region. We don't expect any severe weather today, but there could be a few stronger cells at times. The main threats will be gusty outflow winds, lightning, and brief downpours directly under storm cores. Storms today will generally move from south to north, becoming more southeast to northwest this evening as the low continues moving southwestward. Shower/thunderstorm activity diminishes after sunset with the loss of daytime heating.

Sunday into Monday, the low is forecast to elongate and shift eastward -- moving onshore into California just south of SF Bay during this time. The focus for showers and storms will be directed into NorCal, but also still into portions of southern Oregon. We'll probably start off sunny Sunday and it will remain quite warm/even humid. There should be enough moisture, instability and forcing for more widespread showers and thunderstorms during the afternoon/evening. Highest PoPs and thunder chances will be across NorCal and up the Cascades with lower chances in NW sections (northwest of Roseburg). Storm motion on Sunday is expected to start out from the southeast, backing to easterly as the pattern evolves.

By Monday, we'll be decidedly on the northern periphery of the low with upper ridging to the north and mid-level flow around the low from the ENE. Most areas will be at least slightly cooler, but especially NorCal where clouds/showers will be most persistent. There's still a chance of thunderstorms, but the best chances shift to east of the Cascades. Rain amounts with this entire system will likely vary quite a bit due to the showery nature of the precipitation (and also the potential for thunderstorms). Some places could end up with nothing at all, while those that get under more persistent showers could have 0.25-0.50 of an inch (most likely in Siskiyou County of NorCal) with up to an inch in areas that manage to get beneath a thunderstorm core for a while.

Tuesday into Wednesday, the upper ridge to the north will win out as the closed low settles into the Great Basin and Desert Southwest. This will keep shower/thunder chances mostly to our south and east, and bring another period of above normal temperatures. Afternoon highs will peak about 10 to 15 degrees above normal (mid 80s West/upper 70s-low 80s East), feeling more like late June than early May. Subtle cooling is possible Friday with long range guidance hinting at the potential for a weak trough to arrive late next week. The vast majority of ensemble guidance maintains dry conditions with this trough.

MARINE...Updated 130 AM PDT Saturday, May 2, 2026....A thermal trough pattern will bring gusty north winds with steep to very steep and hazardous seas through this evening. The strongest winds and very steep seas are expected south of Gold Beach today, with steep seas elsewhere. Conditions improve some this afternoon as winds begin to weaken, with only steep seas expected for all areas from Coos Bay southward. Winds diminish moreso late tonight while a longer period northwest swell builds, then becomes dominant later Sunday into Monday along with a fresh north swell. Relatively quiet conditions are expected for much of next week.

BEACH HAZARDS...Updated 115 AM PDT Saturday May 2, 2026...A short period northwest swell and a building long period northwest swell may combine their energy to produce unpredictable waves washing up on area beaches this weekend. The risk will be highest around sunrise on Sunday morning.

Sneaker waves can run up significantly farther on beaches than normal, including over rocks and jetties. These waves can suddenly knock people off of their feet and sweep them into the ocean. The waves can also move logs or other objects which could crush or trap anyone caught underneath. Never turn away from the ocean!

MFR WATCHES/WARNINGS/ADVISORIES

OR...Beach Hazards Statement from this evening through Sunday morning for ORZ021-022.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this evening for PZZ350-356-370-376.

Hazardous Seas Warning until 11 AM PDT this morning for PZZ376.