007
FXUS66 KMFR 161735
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
935 AM PST THU JAN 16 2025
..NEW AVIATION SECTION
AVIATION (18Z TAFS)
OUR REPEATING PATTERN OF WESTSIDE VALLEY FOG CONTINUES WITH IFR
CONDITIONS FOR TERMINALS ON THE WESTSIDE (KOTH, KRBG, KMFR). WE
WILL SEE CONDITIONS IMPROVE TO VFR THIS AFTERNOON FOR MEDFORD
(70%), BUT MVFR CONDITIONS ARE LIKELY (55%) FOR NORTH BEND AND
ROSEBURG. FOG AND IFR/LIFR CONDITIONS ARE LIKELY (60%-70%) TO
RETURN THIS EVENING FOR THE WESTSIDE TERMINALS WITH THE ONE
EXCEPTION BEING NORTH BEND WHICH MAY STAY JUST ABOVE MVFR.
-GUERRERO
PREV DISCUSSION
/ISSUED AT 310 AM PST THURS JAN 16 2025/
DISCUSSION...A STRONG HIGH PRESSURE RIDGE REMAINS IN PLACE OVER
THE REGION THIS MORNING. THIS PATTERN WILL BRING CONTINUED DRY
WEATHER AND STABLE CONDITIONS TO THE AREA TODAY. STRONG INVERSIONS
ALONG WITH LIGHT WINDS AND LINGERING BOUNDARY LAYER MOISTURE ARE
RESULTING IN AREAS OF VALLEY FOG AND FREEZING FOG THIS MORNING, WITH
FOG MOST WIDESPREAD IN SOUTHWEST OREGON VALLEYS WEST OF THE
CASCADES. AREAS OF DENSE FOG ARE PRESENT, ESPECIALLY IN THE UMPQUA
BASIN AND NEAR GRANTS PASS, AND FREEZING FOG IS OCCURING FOR VALLEYS
IN JOSEPHINE COUNTY AND PORTIONS OF THE ROGUE VALLEY IN JACKSON
COUNTY. ACROSS JACKSON COUNTY, AREAS OF VALLEY FOG AND FREEZING FOG
HAVE DEVELOPED NORTH AND NORTHWEST OF MEDFORD (INCLUDING WHITE CITY,
EAGLE POINT, CENTRAL POINT, GOLD HILL AND ROGUE RIVER) AND HAS BEEN
MORE PATCHY FROM MEDFORD SOUTH. AREAS OF FREEZING FOG MAY INCREASE
EARLY THIS MORNING IN THE MEDFORD AREA AND TO THE SOUTH, BUT
OVERALL, EXPECT THE WORST CONDITIONS TO BE NORTH OF MEDFORD. DENSE
FOG AND FREEZING FOG ADVISORIES ARE IN EFFECT THROUGH THIS MORNING.
PLEASE SEE THE NPWMFR FOR DETAILS.
UNDER STRONG HIGH PRESSURE, AIR STAGNATION AND THE POTENTIAL FOR
REDUCED AIR QUALITY WITH TRAPPED POLLUTANTS, REMAINS A CONCERN
TODAY. MODELS CONTINUE TO SHOW LOW MIXING HEIGHTS AND LIGHT
TRANSPORT WINDS INTO FRIDAY. SO, THE AIR STAGNATION ADVISORY
(NPWMFR) REMAINS IN EFFECT THROUGH FRIDAY AFTERNOON FOR INLAND
VALLEYS ACROSS SOUTHWEST OREGON.
THE RIDGE WILL WEAKEN SLIGHTLY TONIGHT AS AN UPPER LEVEL SHORTWAVE
TROUGH MOVES DOWN THE EASTERN SIDE OF THE RIDGE AND INTO THE REGION,
PASSING BY EAST OF THE AREA ON FRIDAY. A DRY COLD FRONT IS FORECAST
TO ONSHORE THURSDAY EVENING AND NIGHT. HOWEVER PRECIPITATION CHANCES
ARE GENERALLY BELOW 10% EVEN ALONG THE COASTAL MOUNTAINS. AS THIS
DISTURBANCE MOVES DOWN THE RIDGE AND TO THE EAST, IT WILL WEAKEN THE
INVERSIONS SLIGHTLY AND MODELS CONTINUE TO SHOW A SLIGHTLY
IMPROVEMENT IN MIXING BY LATE FRIDAY AFTERNOON. HOWEVER, EXPECT ANY
IMPROVEMENTS TO BE BRIEF AS MODELS AND ENSEMBLES CONTINUE TO SHOW
HIGH CONFIDENCE IN THE UPPER RIDGE STRENGTHENING THIS WEEKEND AND
REMAINING CENTERED JUST OFFSHORE. TO EAST OF THE AREA, A DEEPENING
LONGWAVE TROUGH WILL DEVELOP. THIS PATTERN MAY RESULT IN BREEZY TO
GUSTY EASTERLY WINDS DEVELOPING LATER IN THE WEEKEND. THIS PATTERN
CONTINUES INTO MONDAY.
UNDER THIS PATTERN OF THE RIDGE CENTERED OFFSHORE AND A DEEPENING
LONGWAVE TROUGH TO THE EAST, EXPECT EASTERLY FLOW OVER THE AREA,
WITH SOME BREEZY TO GUSTY WINDS DEVELOPING ON THE RIDGES FRIDAY
NIGHT INTO THE WEEKEND. ADDITIONALLY, TEMPERATURES WILL TREND COOLER
FRIDAY AND ON THE WEEKEND, WITH COLDER THAN NORMAL OVERNIGHT LOW
TEMPERATURES EXPECTED. THE PROBABILITY FOR LOW TEMPERATURES LESS
THAN 28 DEGREES IS FAIRLY HIGH(~80-100%) FOR MANY INLAND VALLEY WEST
OF THE CASCADES SATURDAY MORNING THROUGH MONDAY MORNING. NOTE, THE
UMPQUA VALLEY MAY REMAIN SLIGHTLY LESS COLD, BUT STILL NEAR OR BELOW
FREEZING. EAST OF THE CASCADES, SUMMER LAKE AND LOCATIONS IN THE
HIGH DESERT ARE EXPECTED SEE TEMPERATURES IN THE LOWER TEENS TO
SINGLE DIGITS WITH TEMPERATURES IN THE TEENS FOR KLAMATH FALLS,
LAKEVIEW AND ALTURAS. DAYTIME TEMPERATURES ARE EXPECTED TO BE NEAR
NORMAL DURING THIS PERIOD.
EARLY TO MID NEXT WEEK, ENSEMBLES CONTINUE TO SHOW DRY WEATHER IS
LIKELY WITH A HIGH PRESSURE RIDGE IN PLACE. WHILE SOME WEAK
DISTURBANCES ARE FORECAST TO MOVE IN FROM THE WEST AND NORTHWEST,
MODELS CONTINUE TO SHOW DRY WEATHER DURING THIS PERIOD. LATE NEXT
WEEK, BEGINNING AROUND THURSDAY NIGHT AND FRIDAY THERE IS A SLIGHT
CHANCE FOR A SHORTWAVE TROUGH AND FRONT TO MOVE INTO THE REGION AND
BRING SOME LIGHT PRECIPITATION INTO THE AREA. THIS CHANCE IS LOW AND
NATIONAL BLEND OF MODELS SHOWS 10-25% CHANCES FOR PRECIPITATION FROM
THE CASCADES WEST, BEGINNING THURSDAY NIGHT.
AVIATION...15/12Z TAFS...LIFR LEVELS ARE PRESENT DUE TO FOG IN THE
ROGUE AND UMPQUA VALLEYS THIS MORNING. THESE AREAS ARE EXPECTED TO
CLEAR EARLY THIS AFTERNOON. CHANGES IN THE UPPER LEVEL PATTERN MAY
PREVENT FOG FROM RETURNING TONIGHT. A WEAK FRONT PASSING OVER THE
AREA MAY BRING ENOUGH MIXING TO LIMIT FOG DEVELOPMENT, ALTHOUGH THE
FRONT MAY STILL BRING MVFR CEILINGS TO AREAS WEST OF THE CASCADES
NEAR THE END OF THIS TAF PERIOD.
MARINE STRATUS REMAINS OVER AREA WATERS, BUT OFFSHORE WINDS HAVE
LIMITED DEVELOPMENT OVER AREA TERMINALS. BOTH BROOKINGS AND NORTH
BEND ARE CURRENTLY AT VFR, ALTHOUGH NORTH BEND HAS HAD PERIODS OF
LOWER LEVELS DURING PERIODS OF CALM OR NORTHERLY WINDS.
OTHER AREAS SHOULD REMAIN AT VFR THROUGH THE TAF PERIOD.
-TAD
MARINE...UPDATED 830 PM WEDNESDAY, JANUARY 15, 2025...SEAS REMAIN
BELOW ADVISORY LEVEL EARLY THIS MORNING, WITH MARINE STRATUS
DEVELOPING OVER AREA WATERS. A THERMAL TROUGH IS FORECAST TO REBUILD
THIS AFTERNOON, BRINGING GUSTY NORTHERLY WINDS THAT WILL REBUILD
STEEP SEAS IN WATERS SOUTH OF COOS BAY.
THE THERMAL TROUGH STRENGTHENS EARLY FRIDAY MORNING, WITH WINDS
INCREASING SOUTH OF CAPE BLANCO. THESE WINDS ARE EXPECTED TO BUILD
VERY STEEP AND HAZARDOUS SEAS IN WATERS SOUTH OF CAPE BLANCO, WITH
STEEP SEAS CONTINUING IN OTHER WATERS SOUTH OF COOS BAY. SMALL CRAFT
ADVISORIES AND A HAZARDOUS SEAS WARNING ARE IN PLACE TO DESCRIBE
THESE DETERIORATING CONDITIONS.
CONDITIONS IMPROVE ON SATURDAY NIGHT BUT ADVISORY LEVEL SEAS LOOK TO
CONTINUE THROUGH SUNDAY AND POSSIBLY INTO EARLY MONDAY MORNING.
-TAD
BEACH HAZARDS...UPDATED 830 PM PST WEDNESDAY, JANUARY 15,
2025...ANOTHER EPISODE OF SNEAKER WAVES WILL BE POSSIBLE SATURDAY
AFTERNOON INTO SUNDAY EVENING. THIS WOULD BE DUE TO A COMBINATION OF
NORTHERLY WIND WAVES, NORTHWEST SWELL AT 11 SECONDS, AND A LONG
PERIOD WEST-NORTHWEST SWELL AT 22 SECONDS. THE RISK IS EXPECTED TO
DIMINISH EARLY NEXT WEEK WITH A DIMINISHING SWELL PERIOD AND LESS
CHAOTIC SEA STATE.
SNEAKER WAVES ARE A TYPE OF WAVE THAT CAN RUN HIGHER UP THE BEACH
THAN A NORMAL WAVE. SNEAKER WAVES CAN POSSIBLY WASH OVER PATHWAYS OR
ROCK OUTCROPPINGS. THEY CAN LIFT AND CARRY LOGS, WHICH CAN THEN
STRIKE OR PIN BEACHGOERS. SNEAKER WAVES CAN KNOCK A PERSON OFF THEIR
FEET AND CARRY THEM OUT TO DEEPER WATERS, WHERE HYPOTHERMIA BECOMES
POSSIBLE. SNEAKER WAVES CAN POSE A LETHAL THREAT. AS THESE
CONDITIONS MAY OCCUR WHILE THE SUN IS DOWN, VISIBILITY WILL BE
LIMITED. ALWAYS KEEP YOUR EYES ON THE SEA AND USE EXTRA CAUTION.
MFR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL NOON PST FRIDAY FOR ORZ021-023>026-
029>031.
BEACH HAZARDS STATEMENT FROM SATURDAY AFTERNOON THROUGH SUNDAY
AFTERNOON FOR ORZ021-022.
DENSE FOG ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORZ023.
FREEZING FOG ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORZ024-
026.
CA...NONE.
PACIFIC COASTAL WATERS...BEACH HAZARDS STATEMENT FROM SATURDAY
AFTERNOON THROUGH SUNDAY AFTERNOON FOR PZZ350-356.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM PST
SATURDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING FROM 7 AM FRIDAY TO 4 PM PST SATURDAY FOR
PZZ356-376.
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