818
FXUS66 KMFR 130923
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
223 AM PDT SAT JUN 13 2026
DISCUSSION
ONCE AGAIN, CLEAR, CLOUDLESS SKIES PREVAIL OVER
SOUTHERN OREGON AND FAR NORTHERN CALIFORNIA THIS MORNING.
THE WARMING CONTINUES, AS OVERNIGHT TEMPERATURES ACROSS THE AREA
ARE TRENDING 5 DEGREES OR MORE ABOVE THIS TIME YESTERDAY, AS OF
THIS WRITING. OF PARTICULAR NOTE, IT IS 79 DEGREES F IN
BROOKINGS, WHERE THE CHETCO EFFECT, NE WINDS CHANNELING DOWN THE
CHETCO RIVER, ARE CONTINUING THE DOWNSLOPE WARMING THROUGH THE
NIGHT.
THE UPPER RIDGE RESPONSIBLE FOR THE WARM UP IS BUILDING OUT
AROUND 130W AND THIS IS INDUCING A SURFACE THERMAL TROUGH ALONG
THE NORCAL COAST, EXTENDING NORTHWARD INTO SW OREGON. WE EXPECT
THE STRONGEST OFFSHORE WINDS WITH THE THERMAL TROUGH OVER THE
SISKIYOU MTNS AND COAST RANGES OF SW OREGON THIS MORNING (HENCE
THE WARM TEMPERATURES IN BROOKINGS). SO, THIS MEANS LITTLE OCEAN
INFLUENCE DOWN THERE AND LESS COOLING THAN RECENT NIGHTS. IT ALSO
MEANS THAT TODAY WILL PROBABLY BE EVEN HOTTER IN BROOKINGS DUE TO
THE LACK OF ONSHORE MARINE INFLUENCE. MODELS HAVE BEEN ABOUT
5-10F TOO LOW WITH TEMPS THERE THE LAST 2 DAYS. SO, IT'LL PROBABLY
END UP IN THE LOW TO MID 90S BASED ON CURRENT MODEL SOUNDINGS
EVEN THOUGH MODELS ONLY GIVE THAT ABOUT A 10% CHANCE OF
OCCURRENCE. A HEAT ADVISORY REMAINS IN EFFECT THERE THROUGH
SATURDAY EVENING.
INLAND, TEMPERATURES WILL RISE BY 3 TO 7 DEGREES OVER THE
PREVIOUS DAY EACH AFTERNOON SAT/SUN. THE UPPER LEVEL RIDGE WILL
WEAKEN SLIGHTLY SATURDAY NIGHT AS A TROUGH INTERRUPTS THE FLOW
BRIEFLY, THEN THE RIDGE REBUILDS QUICKLY AND REMAINS OVERHEAD
THROUGH THE FIRST PART OF NEXT WEEK. EXPECT THE PEAK OF HEAT WAVE
SUN/MON/TUE WITH DAYTIME HIGHS ACROSS THE AREA OF 20 TO 25
DEGREES ABOVE NORMAL FOR EARLY TO MID JUNE. SOME RECORDS WILL BE
CHALLENGED OR BROKEN. WITH NWS HEATRISK SHOWING WIDESPREAD
MODERATE IMPACTS AND SMALLER AREAS OF MAJOR HEAT IMPACTS, WE'VE
ISSUED HEAT ADVISORIES FOR THE REMAINDER OF THE WEST SIDE (ALSO
INCLUDING THE MT. SHASTA REGION). THE DETAILS CAN BE VIEWED AT
PDXNPWMFR. EXPECT HIGHS OF 90-100F IN MANY LOCATIONS WITH SOME
WEST SIDE VALLEYS 100-105F AND UP TO 110F IN WESTERN SISKIYOU
COUNTY. WE HAVEN'T ADDED EAST SIDE AREAS YET, BUT MAY ADD THEM TOO
WITH POTENTIAL ADVISORIES MON/TUE. 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 EXPECTED,
THE REDUCTION IN HEAT HAS DRIFTED OUT ANOTHER DAY OR SO OVER THE
LATEST FEW MODEL CYCLES. TEMPERATURES ARE NOW EXPECTED TO COOL
SLIGHTLY, AS IN AROUND 5 TO 10 DEGREES, DURING THE SECOND HALF OF
THE WEEK, THEN LOWER TOWARDS MORE SEASONABLE, BUT STILL ABOVE
NORMAL TEMPERATURES FOR THE 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 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 FRIDAY AFTERNOON, MAINLY OVER MODOC AND
SISKIYOU COUNTIES AS THAT 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 (~10%) NOW, AND
NOT APPEARING IN THE FORECAST JUST YET, SUSPECT THAT WE WILL SEE
THUNDERSTORM CHANCES INCREASE AND START BEING MENTIONED IN THE
FORECAST OVER THE COMING DAYS. -SPILDE/BPN
AVIATION...13/12Z TAFS
VFR WILL PREVAIL ACROSS THE REGION
THROUGHOUT THE NEXT 24 HOURS, WITH BREEZY AFTERNOON WINDS. THE
POSSIBLE EXCEPTION TO THIS WILL BE THE COAST AND COASTAL VALLEYS
NORTH OF CAPE BLANCO, INCLUDING AT NORTH BEND, WHERE MARINE LAYER
MVFR/IFR CEILINGS MAY DEVELOP EARLY THIS MORNING. ANY LOWER FLIGHT
CONDITIONS SHOULD CLEAR A FEW HOURS AFTER SUNRISE.
MARINE...UPDATED 0100 AM PDT SATURDAY, JUNE 13, 2026
THE THERMAL
TROUGH WILL CONTINUE TODAY 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. 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.
FIRE WEATHER...UPDATED 100 AM PDT SATURDAY, JUNE 13, 2026
RAPID WARMING AND DRYING IS EXPECTED TO CONTINUE INTO 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 OR EVEN IN 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
MTNS, SISKIYOUS, AND CASCADES. A PERIOD OF GUSTY OFFSHORE E-NE WINDS
IS EXPECTED THIS MORNING OVER THE SISKIYOU MTNS AND COAST RANGES
WITH PEAK GUSTS IN THE 25-35 MPH (40 MPH?) RANGE. THIS COULD REPEAT
AGAIN TONIGHT, BUT LOOKS LIKE IT WILL BE MORE OVER THE INLAND
MOUNTAINS SINCE THE THERMAL TROUGH WILL GRADUALLY SHIFT INLAND. POOR
RIDGE RH RECOVERIES ARE MOST LIKELY SATURDAY NIGHT. ALSO SOME
STRONGER NORTHERLIES COULD CHANNEL THROUGH THE GOOSE BASIN NEAR
LAKEVIEW TONIGHT-SUNDAY MORNING.
THE TYPICAL DIURNAL AFTERNOON N-E BREEZES COULD AGAIN BECOME
GUSTY AT TIMES SATURDAY. WHILE CRITICAL CONDITIONS ARE NOT EXPECTED
WITHIN THE CURRENT FORECAST, LOCALIZED CONDITIONS COULD GET
EXTREMELY CLOSE, ESPECIALLY CONSIDERING THE LOW TEENS AND POTENTIAL
SINGLE DIGIT MINIMUM HUMIDITIES DURING THE PEAK OF THE HEAT WAVE AND
THE AFTERNOON BREEZES. UNDOUBTEDLY, THIS PERIOD OF HOT AND DRY
WEATHER WILL CONTINUE TO MOVE THE NEEDLE TOWARD HIGHER FIRE DANGER
AS WE HEAD INTO NEXT WEEK.
ALSO OF NOTE, ONCE THE HEAT BEGINS TO EASE MIDWEEK, WE WILL NEED
TO KEEP AN EYE OUT FOR POSSIBLE THUNDERSTORMS. MODEL GUIDANCE IS
NOT CURRENTLY SHOWING ANY SIGNIFICANT CONVECTION CHANCES THROUGH
WEDNESDAY. BUT, THERE CONTINUE TO BE HINTS IN THE VARIOUS MODEL
SUITES, AND THUNDERSTORMS DO TYPICALLY ACCOMPANY THE BREAKDOWN OF
A HEAT WAVE IN THIS AREA. THERE IS AT LEAST A VERY SLIGHT
POTENTIAL (~10% CHANCE) WITH SOME GUIDANCE SHOWING CONVECTION
NEAR THE SIERRA, WHICH COULD AFFECT SE SECTIONS OF OUR FORECAST
AREA TOWARD THU/FRI NEXT WEEK. BEST CHANCE FOCUSED ON FAR
NORTHERN CALIFORNIA AND THE EAST SIDE. CONFIDENCE REMAINS LOW
RIGHT NOW, BUT WE WILL UPDATE THE FORECAST AS NECESSARY OVER THE
COMING DAYS. -SPILDE/BPN
MFR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT TUESDAY FOR
ORZ021>026.
CA...HEAT ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT TUESDAY FOR
CAZ080>082.
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.
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