321
FXUS66 KMFR 271205
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
505 AM PDT THU AUG 27 2026
UPDATED AVIATION DISCUSSION
AVIATION...27/12Z TAFS
IFR/LIFR STRATUS AND FOG WILL PERSIST
ALONG THE COAST THROUGH THE MORNING, GRADUALLY BECOMING VFR BY LATE
MORNING/EARLY AFTERNOON. THE MARINE LAYER HAS PUSHED INLAND,
BRINGING LOW END VFR/MVFR CONDITIONS TO THE UMPQUA BASIN. THERE IS
SOME SPILL OVER OCCURRING AND IT'S POSSIBLE (15% CHANCE) FOR SOME
LOW END VFR STRATUS HERE IN THE ROGUE VALLEY AROUND SUNRISE.
OTHER THAN SOME HIGH CIRRUS, VFR WILL PREVAIL FOR THE REST OF THE
AREA THROUGH THIS EVENING. GUSTY WEST TO SOUTHWEST WINDS WILL RETURN
THIS AFTERNOON/EVENING EAST OF THE CASCADES (EAST OF KLAMATH FALLS)
AND IN NE CALIFORNIA WITH PEAK GUSTS IN THE 25-35 KT RANGE.
EXPECT MARINE STRATUS TO RETURN TO THE COAST AND ALSO PORTIONS OF
THE UMPQUA BASIN TONIGHT.
PREV DISCUSSION
/ISSUED 240 AM PDT THU AUG 27 2026/
KEY MESSAGES...
* HEIGHTENED FIRE WEATHER CONCERNS ACROSS THE EAST SIDE THROUGH
THIS EVENING DUE TO GUSTY WINDS AND LOW RH.
* WEAK INSTABILITY JUST CLIPPING FAR SOUTHEAST PORTIONS OF MODOC AND
LAKE COUNTIES FOR A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS LATE IN
THE DAY ON FRIDAY.
* TEMPERATURES TREND COOLER INTO SATURDAY, AND REMAIN NEAR OR BELOW
NORMAL FOR THE NEXT WEEK.
* WEATHER PATTERN LARGELY INFLUENCED BY UPPER LEVEL TROUGHING,
RESULTING IN GUSTY WINDS IN THE AFTERNOONS/EVENINGS, AND NIGHT AND
MORNING COASTAL STRATUS EXTENDING INTO THE UMPQUA VALLEY FOR THE
EARLY MORNING HOURS.
* STRONG TROUGHING TUESDAY THROUGH THURSDAY NEXT WEEK MAINTAINS
BELOW NORMAL TEMPERATURES AND BRINGS RAIN CHANCES, WITH THE
HIGHEST PROBABILITIES ALONG THE COAST AND INTO THE UMPQUA BASIN.
DISCUSSION...MODEL AGREEMENT/CONFIDENCE IN THE FORECAST IS HIGH
THROUGH TUESDAY. SOUTHWEST FLOW CONTINUES OVER THE REGION AS AN
UPPER LEVEL TROUGH CONTINUES PUSHING INLAND OVER THE PACIFIC
NORTHWEST. THIS TROUGH WILL LINGER NEAR THE CANADIAN BORDER
THROUGH SATURDAY. AFTER A BRIEF PERIOD OF RIDGING/SLIGHT WARMING
AND DRYING ON SUNDAY, A STRONGER TROUGH WILL TRACK SOUTHEASTWARD
FROM ALASKA BEGINNING MONDAY AND LINGER THROUGH AT LEAST TUESDAY.
MODEL AGREEMENT ON THE PROGRESSION/DETAILS OF THIS TROUGH FROM
LATE TUESDAY ONWARD VARIES, BUT THERE'S GENERAL AGREEMENT ON A
CONTINUED TROUGH PATTERN THROUGH THE END OF NEXT WEEK.
OVER THESE NEXT SEVERAL DAYS, THE COOLING TREND AND GUSTY AFTERNOON
AND EVENING WINDS WILL CONTINUE. THIS WILL CONTINUE TO BRING
HEIGHTENED FIRE WEATHER CONCERNS TODAY, WITH STRONGER WINDS AND RHS
REMAINING FAIRLY LOW. FIRE WEATHER CONCERNS DIMINISH SOME FRIDAY
ONWARD AS RHS TREND HIGHER, BUT WITH AFTERNOONS REMAINING BREEZY,
AND NO PRECIPITATION EXPECTED (AT LEAST INTO TUESDAY), FIRE DANGER
REMAINS VERY HIGH ACROSS THE REGION. PLEASE REMEMBER TO DO YOUR PART
AND PREVENT A SPARK. ONE LESS SPARK, ONE LESS FIRE.
FOR MOST OF THE FORECAST PERIOD, THE MID-LEVELS WILL BE TOO DRY TO
SUPPORT ANY THUNDERSTORM DEVELOPMENT. THE EXCEPTION WILL BE ON
FRIDAY AS REMNANT TROPICAL MOISTURE GETS SWEPT INTO THE WESTERLIES.
GUIDANCE REMAINS STEADFAST WITH THE TRAJECTORY OF THIS MOISTURE,
BRINGING IT INTO CENTRAL CA/NORTHWESTERN NEVADA. THIS WILL CLIP THE
SOUTHEASTERN PORTIONS OF LAKE AND MODOC COUNTIES, BRINGING SOME
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FRIDAY
AFTERNOON/EVENING.
A MORE ELONGATED TROUGH WILL APPROACH THE COAST FROM THE NORTHWEST
ON MONDAY, MOVING INLAND ON TUESDAY. THIS WILL LIKELY BE ANOTHER
WIND MAKER FOR THE REGION, ESPECIALLY EAST OF THE CASCADES, BUT IT
WILL ALSO START A PERIOD OF INCREASED PRECIPITATION CHANCES,
PRIMARILY ALONG THE COAST AND NORTH OF THE ROGUE-UMPQUA DIVIDE.
WE'LL NEED TO MONITOR THE POTENTIAL FOR HEIGHTENED FIRE WEATHER
CONCERNS ON MONDAY DUE TO GUSTY WINDS, BUT RHS MAY BE HIGH ENOUGH TO
LIMIT THIS.
DESPITE THE DIFFERENCES IN THE GUIDANCE ON THE PROGRESSION OF THIS
TROUGH, THERE IS FAIRLY GOOD AGREEMENT (FOR THIS TIME FRAME IN THE
FORECAST) THAT AN OVERALL DEEPER TROUGH WILL BE OVER/IN THE VICINITY
OF THE PACIFIC NORTHWEST LATE TUESDAY THROUGH AT LEAST FRIDAY. THE
VAST MAJORITY OF ENSEMBLE MEMBERS BRING MEASURABLE PRECIPITATION TO
THE COAST DURING THIS TIME, WITH A SIZABLE MAJORITY OF THE MEMBERS
SHOWING MEASURABLE PRECIPITATION EVEN FOR MEDFORD (THE 00Z/27 EC
SUITE IS MORE BULLISH WITH THIS COMPARED TO THE GEFS SUITE). GIVEN
THE TIME OF YEAR, ONE TENDS TO BE SKEPTICAL OF THIS COMING TO
FRUITION, ESPECIALLY SINCE OFTEN TIMES, WE SEE THESE PRECIP CHANCES
LOWER AS THE TIME GETS CLOSER, OR GET PUSHED LATER IN TIME OVER
FUTURE MODEL RUNS. BUT, ENSEMBLES HAVE STEADILY BEEN SHOWING THIS
POTENTIAL FOR PRECIPITATION IN THE REGION. STILL, CONFIDENCE IS LOW
ON THE INLAND EXTENT FOR RAINFALL, AND ANY RAINFALL LOOKS TO BE
GENERALLY LIGHT WITH THE HIGHER PRECIPITATION CHANCES EXPECTED NORTH
OF THE FORECAST AREA. CONFIDENCE IS HIGHER, HOWEVER, FOR CONTINUED
COOLER TEMPERATURES NEXT WEEK, WITH HIGH TEMPERATURES CURRENTLY
FORECAST TO BE 5 TO 10 DEGREES BELOW NORMAL.
MARINE...UPDATED 1200 AM PDT THURSDAY, AUGUST 26, 2026...RELATIVELY
CALM CONDITIONS WITH LIGHT WINDS AND LOW SEAS ARE EXPECTED INTO
FRIDAY MORNING. SOUTHERLY WINDS WILL PERSIST THROUGH THIS MORNING,
THEN TURN NORTHERLY BY THIS AFTERNOON. NORTH WINDS INCREASE ON
FRIDAY WITH STEEP SEAS DEVELOPING SOUTH OF CAPE BLANCO IN THE
AFTERNOON, THEN PERSISTING THROUGH THE WEEKEND. WINDS WILL BE
STRONGEST SATURDAY AND SUNDAY DURING THE AFTERNOON AND EVENING
HOURS. CONDITIONS ARE LIKELY TO IMPROVE MONDAY INTO TUESDAY.
FIRE WEATHER...UPDATED 200 AM PDT THURSDAY, AUGUST 27,
2026...CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE ACROSS THE
EAST SIDE TODAY AS AN UPPER LEVEL TROUGH CONTINUES MOVING INLAND.
GUSTY WINDS WILL TREND A BIT STRONGER TODAY (GUSTS 30-35 MPH,
POSSIBLY UP TO 40 MPH IN THE WINDIEST SPOTS) AND DAYTIME HUMIDITIES
WILL REMAIN LOW (SINGLE DIGITS TO LOW TEENS). A RED FLAG WARNING
REMAINS IN EFFECT FOR THE SOUTHERN PORTIONS OF FIRE WEATHER ZONES
(FWZS) 624/625 AND MOST OF 285.
ASIDE FROM A BRIEF PERIOD OF RIDGING/SLIGHT WARMING AND DRYING ON
SUNDAY, UPPER LEVEL TROUGHING WILL DOMINATE THE WEATHER THROUGH THE
FORECAST PERIOD. THIS WILL MAINTAIN GUSTY AFTERNOON/EVENING WINDS,
THOUGH GENERALLY WEAKER THAN TODAY/RECENT DAYS. ADDITIONALLY, RHS
WILL TREND HIGHER AS TEMPERATURES CONTINUE TRENDING COOLER, AND THIS
WILL LIMIT CRITICAL FIRE WEATHER CONDITIONS AFTER TODAY.
MEANWHILE, ONSHORE FLOW WILL GENERALLY MAINTAIN MODERATE TO GOOD
RECOVERIES WITH NIGHTLY MARINE PUSHES FOR COASTAL ZONES. THE
EXCEPTION TO THIS WILL BE THIS MORNING WHEN POOR RECOVERIES ARE
EXPECTED ALONG THE WARNERS AND SOUTHERN PORTIONS OF THE FREMONT-
WINEMA NATIONAL FOREST.
A SLIGHT CHANCE OF THUNDERSTORMS WAS ADDED TO THE FORECAST FOR
FRIDAY FOR SOUTHEAST PORTIONS FOR FWZS 652/285. GUIDANCE MAINTAINS
AN AREA OF REMNANT TROPICAL MOISTURE MOVING INTO CENTRAL
CA/NORTHWEST NV, WHICH LOOKS TO CLIP THE SOUTHEASTERN PORTIONS OF
THE REGION, BRINGING SOME SHOWERS AND ISOLATED THUNDERSTORMS FRIDAY
AFTERNOON/EVENING. THE BETTER INSTABILITY AND GREATER THUNDERSTORM
COVERAGE SHOULD REMAIN SOUTH AND EAST OF THE REGION. DRIER AIR IN
THE MID-LEVELS RETURNS SATURDAY AND THUNDERSTORMS SHIFT EASTWARD.
A STRONGER TROUGH ARRIVES NEXT WEEK, MAINTAINING COOLER/BELOW NORMAL
TEMPERATURES, HIGHER HUMIDITIES AND BRINGING THE POTENTIAL FOR
RAINFALL PRIMARILY ALONG THE COAST AND INTO THE UMQPUA BASIN. SEE
THE DISCUSSION ABOVE FOR MORE DETAILS.
MFR WATCHES/WARNINGS/ADVISORIES
OR...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS
EVENING FOR ORZ624-625.
CA...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS
EVENING FOR CAZ285.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 5
PM PDT SATURDAY FOR PZZ356-376.
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