textproduct: Medford

KEY MESSAGES

*Moderate to major heat wave in SW Oregon and NorCal through Tuesday.

-High temps from upper 90s to 100+ expected inland west side valleys and in the upper 80s to mid 90s over the east side. -Even some unusual warmth reaching coastal locations (90s, maybe even 100F this afternoon in Brookings; highs in the 80s to near 90F Coos Bay/North Bend Sunday).

-Cooling expected along immediate coast south of Cape Blanco (including Brookings) Sunday due to southerly wind surge, onshore and possibly nearby stratus.

*Some cooling expected mid-late next week, but temps still remaining above normal levels. *Rain chances are low through Wednesday, however, moisture and instability increase in the afternoons/evenings Thursday and especially Friday. This introduces a slight chance of thunderstorms late next week.

DISCUSSION

The Chetco effect is in full force early this afternoon with readings around Brookings ranging from 90-95F (as of noon PDT). Even the agrimet site closer to the ocean was reading 89F. Expect some inland areas up river to be in the 100s this afternoon and 100F is even a possibility for some areas around the mouth of the Chetco where the enhanced NE winds are keeping the typical ocean influence at bay. A heat advisory remains in place there through this evening.

The thermal trough responsible for this bout of heat is analyzed in NW California and extending northward into SW Oregon. Meanwhile, a strong upper ridge is positioned offshore with a weakness in the ridge settling southward into northern California. This will disrupt the thermal trough pattern a bit tonight into Sunday. As such, we'll see a surge of southerly wind (not too strong) up the coast of NorCal tonight (can see the stratus on satellite near Cape Mendocino now) and this will be nature's air conditioning for the Brookings area on Sunday. Temps still could be in the 70s/80s early on, but we do expect onshore flow to provide cooling during the day. The strongest offshore flow will shift to the north on Sunday and this will allow coastal areas near Coos Bay/North Bend to get much warmer than usual. We are expecting highs largely in the 80s, but possibly even around 90F if the afternoon northerlies stay more NNE. A heat advisory remains in place there for Sunday as well. Areas inland just a few miles will have highs well into the 90s.

Heat advisories are also up for all inland areas west of the Cascades (but also including the Mt. Shasta region - CAZ082), where high temps of 95-105F will be common through Tuesday. Even a few locations in the lower Klamath river valley will get close to 110F. We added heat advisories for Mon/Tue for the Klamath Basin and also the rest of norCal east of Mt. Shasta City where highs of low to mid 90s are expected with moderate heat risk. Those who are sensitive to heat or lack cooling/hydration resources could be affected by heat-related illnesses.

Recent trends in the guidance suggest that there will be some cooling from the NW Tuesday as the thermal trough shifts farther inland. As such, the advisories for Coos and Douglas counties end a bit sooner than the rest.

The ridge is expected to flatten a bit at midweek as a strong upper jet becomes directed across southern British Columbia into northern ID/MT. As such, the reduction in heat has been muted a bit over the latest few model cycles. Temperatures are now expected to cool only slightly Wed/Thu, as in around 5 to 10 degrees, then lower towards more seasonable, but still above normal temperatures Fri into next weekend as an upper level trough digs in from the northwest. As mentioned over the past few days, we tend to see an increased risk for thunderstorms on the back side of heat waves. Models are still keeping the area mostly dry at the end of this one, but models are showing increasing signs of instability in some runs as early as Wednesday afternoon, but moreso Thursday and especially Friday afternoon, mainly over Modoc and Siskiyou counties as the trough moves into the area. Moisture values in the model runs are increasing, now with PWATs approaching 1 inch, and the trough itself is likely to act as a sufficient trigger. So while chances are very low/low (~10-15%) for Wed/Thu, we have added thunderstorm chances to Friday over portions of the East Side. -Spilde/BPN

AVIATION...13/18Z TAFs

VFR will prevail across the region throughout the next 24 hours, with breezy afternoon winds. A southerly wind surge up the NorCal coast could reach the southern Oregon waters near Brookings overnight into Sunday morning. Winds won't be strong, but this could result in IFR/LIFR ceilings/visibility in fog/stratus just off the beaches. This area could reach south of Cape Blanco during Sunday, but confidence is low at this time. -Spilde

MARINE...Updated 100 PM PDT Saturday, June 13, 2026

The thermal trough will continue this afternoon with gusty north winds, steep wind-driven seas north of Cape Blanco, and gales and very steep seas to the south. The thermal trough will push inland Sunday, allowing winds to weaken temporarily. Although winds diminish, seas will remain steep for all areas, potentially very steep south of Gold Beach, though latest guidance shows seas easing from around 6-7 feet down to 4-5 feet during the afternoon at Buoy 46027 (Pt. St. George). Also, a wind reversal is likely south of Gold Beach and within 20 nm of shore, where a southerly wind surge could produce reduced visibilities in fog.

The thermal trough quickly reforms Monday and Tuesday, bringing the return of strong north winds and steep to very steep wind driven seas through much of next week. -Spilde/BPN

FIRE WEATHER...Updated 100 PM PDT Saturday, June 13, 2026

Rapid warming and drying continues this weekend. This will result in an early season heat wave that will last into early next week. Temperatures will peak Sunday to Tuesday with daytime highs about 20- 25 degrees above normal. This will likely result in some triple digit readings for the valleys west of the Cascades, but especially western Siskiyou County, where it could get to around 110F. Minimum relative humidities will also trend lower (bottoming out in the 10- 20% range for most areas) -- though RHs could even drop into single digits at times, especially over the East Side deserts and also the West Side valleys. Meanwhile, broad north through east flow will produce moderate to poor RH recoveries over upper slopes/ridges each night, especially over the Klamath mountains, Siskiyous, and Cascades. While the stronger NE winds have been focused in the SW Oregon coast ranges the last couple of nights, guidance is showing the breezy east winds tonight (20-30 mph) more focused on the Cascades. Poor ridge RH recoveries are most likely tonight, but again Sunday night. Expect another round of enhanced northerlies to channel through the Goose Basin near Lakeview tonight-Sunday morning.

Elsewhere, expect fairly typical diurnal afternoon N-E winds that could become breezy at times during the afternoons/evenings through Tuesday. This will make for elevated fire weather concerns into early next week and localized conditions could get extremely close to Red Flag criteria, especially considering the low teens and potential single digit minimum humidities during the peak of the heat wave along with the afternoon breezes. Undoubtedly, this period of hot, dry, breezy weather will continue to move the needle toward higher fire danger as we head into next week.

We continue to see a signal in the extended forecast as the heat begins to ease mid next week that moisture/instability will increase. As such, lightning potential will increase. Right now, models are showing focus areas mainly to our south through Thursday. However, there is a low possibility (10-15% chance) that something pops up in some of our southern and eastern mountains (Mt Shasta region/Warners) Thursday afternoon/evening. But, by Friday afternoon/evening, there is enough of a signal to introduce a slight chance of thunderstorms in those same general areas (SE sections of the forecast area). We'll continue to monitor and adjust the forecast as necessary. -Spilde/BPN

MFR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory until 11 PM PDT Tuesday for ORZ021>026-029.

CA...Heat Advisory until 11 PM PDT Tuesday for CAZ080>085.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Monday for PZZ356-376.

Small Craft Advisory until 11 AM PDT Monday for PZZ350-370.

Gale Warning until 11 PM PDT this evening for PZZ356-376.