textproduct: Medford

Updated AVIATION Discussion

AVIATION...08/12Z TAFs

VFR conditions will prevail through the TAF period. The main aviation concern today will be showers and thunderstorms focused along the I-5 corridor south of the Rogue- Umpqua Divide this afternoon and evening, including the Rogue and Shasta Valleys. Both Medford and Klamath Falls TAF sites have at least a 30% chance of a thunderstorm impacting the terminal today. Expect gusty and erratic outflow winds in the vicinity of any thunderstorms today. While conditions should remain VFR, precipitation could temporarily lower conditions to MVFR with any heftier cells.

PREV DISCUSSION

/Issued 305 AM PDT Wed Apr 8 2026/

DISCUSSION...There will be two distinct patterns during the forecast period. The first begins today as low pressure approaches the northern California coast and lingers there through Friday. This is a classic thunderstorm pattern in the warmer months and, with spring well underway, the forecast features daily shower/thunderstorm chances across the area through Friday, mainly during the afternoons and evenings. The pattern transitions Saturday as a stronger, and colder, low pressure drops southward from the Gulf of Alaska. This pattern will lower thunderstorm chances/activity, but maintain showers (likely widespread) across the region through the weekend. Shower activity tapers off early next week, but ensembles are currently in decent agreement on more active weather for the latter half of next week.

Satellite imagery this morning shows low pressure spinning along 40 N, currently west of 130 W. This low pressure will gradually move eastward through the remainder of the week, maintaining southerly flow over the region. Showers and thunderstorms return to the forecast today, persisting through Friday. Models are showing around 500-1000 J/kg of sfc CAPE along with LIs of -2 to -4 during the afternoons/evenings, with some stronger indicies for Thursday afternoon/evening. The focus of thunderstorms will vary each day and of the three days, today looks like the least amount of thunderstorm coverage with the greatest expected on Thursday. Friday could be equally as active as Thursday, but lingering cloud cover could limit instability by the time we get to Friday. The focus for shower/thunderstorm activity today looks to be right along and just west of the I-5 corridor in Siskiyou/Jackson/Josephine Counties, with some isolated activity possible east of the Cascades. The highest chances for lightning today (50-70%) are focused over western Siskiyou County/Shasta Valley region, with lower chances (20- 40%) to the north in Jackson/Josephine Counties. Looking Thursday, the bullseye extends northward, covering much of the area from the western Cascade Foothills and areas westward, including much of Jackson/Josephine/Douglas Counties. In these areas, there is about a 60-80% chance of thunderstorms Thursday afternoon/evening, with around 30-50% chance of thunderstorms for the rest of the forecast area. Chances are lower along the coast, around 15-25%, higher for areas south of Cape Blanco. We aren't expecting severe weather at this time, but any lightning is always dangerous and outflow winds will be gusty, possibly reaching up 30 to 40 mph in stronger cells. While any precipitation is beneficial at this point, there could be some brief heavy downpours right under storm cores.

By Friday, low pressure offshore will be weaker, and instability won't be as potent as what's expected Thursday. There still will be widespread shower/thunderstorm chances, but those chances for lightning lower to 20 to 30% and then there's the question of how much lingering cloud cover will limit daytime instability. Ample cloud cover will keep temperatures lower by around 5 to 10 degrees compared to recent days. This cooling trend will continue into the weekend as the upper level pattern transitions.

Low pressure responsible the late week thunderstorm activity shifts southward on Saturday as low pressure from the north digs southward. There are some differences between models on just how far south this low digs, with the GEFS bringing more into the Bay Area in California and other solutions bringing it more across the CA/OR Border. The more northern solution would favor more widespread shower chances across more of southern Oregon whereas the southern solution would focus shower activity along and south of the OR/CA border. It still looks like the atmosphere will stabilize Saturday compared to Thursday and Friday, with more of a widespread showers/embedded thunderstorms pattern vs a southerly flow thunderstorm pattern. Precip chances remain fairly high (60-90%) for the whole forecast area for Saturday into early Sunday, then diminish later Sunday as the trough moves eastward. The snow level forecast has trended lower, now expected to lower to around 4000 ft Saturday night into Sunday, and snow amounts have trended upward a bit. Current forecast now brings around 4-6 inches of snow in the mountains, but with the recent warm weather and the April sun angle, we don't anticipate much in the way of road accumulations. Temperatures will trend significantly cooler over the weekend, and it will feel pretty cool due to how warm it has been. In fact, afternoon highs are now forecast to be around 5 to 10 degrees below normal through Monday (mid/upper 50s/low 60s West, low 50s/upper 40s East).

A reinforcing shortwave moves into the region Sunday night into Monday, maintaining shower activity into early Monday. Conditions dry out late Monday and a break in the weather is expected through around mid-week next week. Temperatures trend warmer during this time, but remain more near seasonal values instead of a drastic warm up like in recent days. While details are highly variable at this point in time, both GFS and EC ensembles indicate this break will be shortlived and bring the return of active weather for the latter half of next week.

MARINE...Updated 100 AM PDT Wednesday, April 8, 2026...For the remainder of the week, breezy north winds will persist, generally remaining below advisory criteria. Borderline steep seas will linger through around sunrise this morning, transitioning to fresh swell this morning and becoming less steep. Showers and thunderstorms will be possible over the waters during the afternoons and evenings today through Friday. The upper level pattern transitions over the weekend, bringing less thunderstorms and more widespread shower activity into early next week. Overall, conditions look to remain below advisory criteria through the weekend with winds becoming westerly and seas becoming northwest swell dominated.

MFR WATCHES/WARNINGS/ADVISORIES

OR...None.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT early this morning for PZZ350-356-370-376.