039
FXUS66 KMFR 180956
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
256 AM PDT FRI SEP 18 2026
KEY MESSAGES
* LOW IMPACT WEATHER EXPECTED THIS WEEKEND AND THROUGH MUCH OF
NEXT WEEK.
* COOLER THAN NORMAL TEMPERATURES CONTINUE TODAY, RETURNING TO
SEASONABLE VALUES THIS WEEKEND AND THROUGH NEXT WEEK. HIGH
TEMPERATURES PEAK AROUND 5-10 DEGREES ABOVE NORMAL ON SUNDAY.
* DRY CONDITIONS EXPECTED THROUGH AT LEAST THURSDAY NEXT WEEK.
NEXT CHANCE FOR PRECIPITATION POSSIBLE NEXT WEEKEND (9/25-9/27).
DISCUSSION
UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER
EASTERN OREGON THIS MORNING, AND NORTHERLY FLOW ON THE BACK SIDE
OF THIS LOW PRESSURE IS MAINTAINING SOME ISOLATED SHOWER ACTIVITY
EAST OF THE CASCADES. SKIES ARE CLEAR FOR AREAS FROM THE CASCADES
TO THE COAST RANGE, AND THE MARINE LAYER BLANKETS THE COAST AND
COASTAL WATERS. MARINE STRATUS WILL CONTINUE PUSHING INLAND THIS
MORNING, EVENTUALLY MAKING IT INTO THE UMPQUA BASIN SHORTLY BEFORE
SUNRISE. OTHERWISE, STATUS QUO IS EXPECTED THROUGH THE MORNING
HOURS TODAY.
AFTER BRINGING ALMOST 1700 LIGHTNING STRIKES TO THE REGION SINCE
LATE TUESDAY, LOW PRESSURE WILL SHIFT EASTWARD INTO WESTERN IDAHO
THIS AFTERNOON. ISOLATED SHOWERS EAST OF THE CASCADES WILL DIMINISH
BY LATE MORNING/EARLY AFTERNOON AS THIS HAPPENS AND CLOUDS WILL
GRADUALLY DISSIPATE ACROSS THE EAST SIDE. THE MARINE LAYER WILL
GRADUALLY PEEL BACK TO THE IMMEDIATE COAST LATER TODAY AS WELL, SO
EXPECT A MOSTLY SUNNY TO SUNNY DAY ACROSS THE FORECAST AREA THIS
AFTERNOON. HIGH TEMPERATURES TREND WARMER TODAY, MORE NOTICEABLY SO
FOR AREAS THAT WERE UNDER PERSISTENT CLOUD COVER YESTERDAY, BUT
STILL HOVER AROUND 3 TO 7 DEGREES BELOW NORMAL (LOW-MID 80S WEST
SIDE/LOW 70S EAST SIDE).
LOW IMPACT WEATHER IS EXPECTED THROUGHOUT THE FORECAST PERIOD AT
THIS TIME (THROUGH EARLY FRIDAY 9/25). DRY CONDITIONS ARE EXPECTED
THROUGH THIS TIME WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES
(MID 80S WEST/UPPER 70S EAST). SHORTWAVE RIDGING PASSES THROUGH THE
REGION THIS WEEKEND, MAINTAINING THE WARMING TREND AND BRINGING THE
WARMEST TEMPERATURES OF THE FORECAST PERIOD. HIGHS PEAK IN THE UPPER
80S-LOW 90S FOR THE WEST SIDE/UPPER 70S-LOW 80S FOR THE EAST. WEAK
LOW PRESSURE MOVES INTO CENTRAL/SOUTHERN CALIFORNIA MONDAY,
WEAKENING AND PUSHING THE RIDGE EASTWARD AND TURNING THE FLOW ZONAL
BY TUESDAY.
THE FLOW AMPLIFIES AGAIN TOWARD THE LATTER HALF OF NEXT WEEK AS
UPPER LEVEL TROUGHING DEEPENS OVER THE EASTERN PACIFIC AND HIGH
PRESSURE STRENGTHENS OVER THE INTERIOR CONUS. AS TO BE EXPECTED AT
THIS TIMEFRAME IN THE FORECAST, THERE IS DISAGREEMENT ON THE
PLACEMENT OF THE RIDGE/TROUGH SET UP, BUT LONGER RANGE GUIDANCE IS
POINTING TO AT LEAST SOME PRECIPITATION POTENTIAL (15-20%) ALONG THE
COAST AS EARLY AS THURSDAY NIGHT OR FRIDAY. AT THIS TIME, CHANCES
FOR PRECIPITATION FARTHER INLAND QUICKLY DROP OFF. BEYOND THAT,
ENSEMBLES ARE HINTING AT A WETTER AND COOLER PATTERN TAKING HOLD FOR
THE LAST WEEK OF SEPTEMBER, THOUGH DETAILS LIKE PRECIP AMOUNTS AND
INLAND EXTENT REMAIN YET TO BE SEEN.
AVIATION...18/06Z TAFS
MVFR TO IFR LEVELS CONTINUE ALONG THE
OREGON COAST UNDER MARINE STRATUS. LIFR LEVELS ARE POSSIBLE EARLY
FRIDAY MORNING, WITH LEVELS RISING THROUGH THE DAY, BECOMING MAINLY
MVFR BY EARLY AFTERNOON. IFR RETURNS ALONG THE COAST FRIDAY EVENING.
INLAND TERMINALS ARE EXPECTED TO BE MAINLY VFR LEVELS THROUGH THE
TAF PERIOD EXCEPT FOR AREAS OF IFR/MFR IN THE UMPQUA EARLY FRIDAY
MORNING, LIFTING TO VFR AROUND 18Z.
MARINE...UPDATED 1200 AM PDT FRIDAY, SEPTEMBER 17, 2026
LIGHT
NORTHERLY WINDS AND LOW SEAS WILL PERSIST THROUGH TONIGHT. GUSTY
NORTH WINDS RETURN SATURDAY WITH STEEP SEAS LIKELY DEVELOPING SOUTH
OF CAPE BLANCO BY LATE SATURDAY EVENING INTO SUNDAY, POSSIBLY
REACHING AS FAR NORTH AS COOS BAY OR REEDSPORT. NORTH WINDS AND WIND
DRIVEN SEAS ARE LIKELY TO BUILD TO A PEAK MONDAY, AND REMAIN NEAR
THAT LEVEL ON TUESDAY, WITH GALES POSSIBLE SOUTH OF CAPE BLANCO.
CONDITIONS LOOK TO IMPROVE FOR THE LATTER HALF OF NEXT WEEK.
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
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