textproduct: Medford

DISCUSSION

There will be two distinct patterns during the forecast period. The first is underway with low pressure near the northern California coast where it will linger 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 with lower snow levels. 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.

Shower activity has greatly diminished compared to yesterday afternoon, though some isolated showers continue along the coast and east of the Cascades. Any lightning in the region is south of the forecast area, along the Sierras east of Redding. Showers and thunderstorms in the region yesterday brought some beneficial precipitation to the area. Outside of the heavier/more persistent showers, rainfall amounts ranged from a few hundreths up to a tenth of an inch. Under the heavier showers, however, amounts of 0.25"- 0.40" were observed, largely over western Siskiyou County. Meanwhile, a more persistent area of showers in southeast Jackson County near Ashland and southward delivered 0.50"-0.75". With the recent precipitation, and some stabilization in the valleys this morning, patchy areas of fog and low clouds have developed in the Scott/Klamath River and Illinois Valleys.

There were 285 lightning strikes yesterday afternoon, focused over the mountains of western Siskiyou County with lesser amounts in Josephine and northwestern Modoc Counties. By the end of today, lightning strike counts will likely be higher than what occurred yesterday. The peak of thunderstorm coverage is expected today as low pressure moves farther eastward. Models continue to show around 500-1000 J/kg of sfc CAPE along with LIs of -2 to -4 during the afternoons/evenings through Friday, with some stronger indicies focused over western Jackson and into Josephine County today. There are more widespread chances of thunderstorms today, even reaching into Douglas County this afternoon/evening. There's generally a 60- 70% chance of lightning from Bly/Adin and areas westward to the Coastal Mountains, with a bullseye of 80% chance across Jackson/Josephine/souther Douglas Counties today. While we aren't expecting much in the way of severe weather today, there is a low chance for damaging winds due to steep low to mid level lapse rates. The Storm Prediction Center has placed western Siskiyou and portions of Joesphine County south of Grants Pass in a Marginal Risk (5-14% chance) of severe thunderstorms that could produce damaging winds (>58 mph) today. Any lightning is always dangerous and gusty outflow winds are expected with any thunderstorms today, with gusts of 20 to 30 most common, possibly up to 40 mph with stronger cells. While any precipitation is beneficial at this point, there could be some brief heavy downpours right under storm cores.

Friday looks to be equally active as today, but low pressure offshore will be weaker, and instability won't be as potent as what's expected today. There still will be widespread shower/thunderstorm chances, but those chances for lightning lower to 20 to 40%. Ample cloud cover will keep temperatures lower by around 5 to 10 degrees compared to recent days and this cooling trend will continue into the weekend as the upper level pattern transitions.

Low pressure responsible this thunderstorm activity continues to weaken and shift eastward on Saturday as low pressure from the north digs southward. Guidance is coming into better agreement on where this low moves inland, with the center expected to move onshore around Cape Mendocino. This will maintain widepsread shower activity across the region, but more focused near the OR/CA border and southward. It still looks like the atmosphere will stabilize Saturday compared to today 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. Snow levels are still expected to lower to around 5000 ft on Saturday, then down to 4000 ft Saturday night into Sunday. The latest forecast maintains 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 show another round of active weather for the latter half of next week.

AVIATION...09/06Z TAFs

VFR conditions are forecast through this cycle. Another round of showers and thunderstorms are expected towards the end of this cycle with similar timing as today's showers and thunderstorms. However, coverage may expand and impact all 4 terminals. Given the isolated nature of thunderstorms, confidence was not high enough to include this quite yet and instead went with vicinity. This may change in subsequent TAFs as confidence in coverage increases.

-Guerrero

MARINE...Updated 130 AM PDT Thursday, April 9, 2026

For the remainder of the week, breezy north winds will persist, generally remaining below advisory criteria. Showers and thunderstorms will be possible over the waters during the afternoons and evenings through Friday. The upper level pattern transitions over the weekend, bringing less thunderstorms and more widespread shower activity into early next week. Seas are likely to remain below advisory criteria early next week while breezy winds become westerly and seas transition to northwest swell dominated.

MFR WATCHES/WARNINGS/ADVISORIES

OR...None.

CA...None.

PACIFIC COASTAL WATERS...None.