493
FXUS66 KMFR 172300
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
300 PM PST FRI JAN 17 2025
DISCUSSION
A LOT OF THE FREEZING FOG HAS CLEARED OUT, ALTHOUGH FOG AND SOME
STRATUS IS LINGERING IN A FEW OF THE VALLEYS THIS AFTERNOON AS
HIGH PRESSURE REMAINS IN CONTROL. SOME HIGHER CLOUDS ARE ALSO
MOVING OVERHEAD FILTERING OUT THE SUN AND KEEPING TEMPERATURES ON
THE COOLER SIDE THIS AFTERNOON.
HEADING INTO TONIGHT IT WILL BE MORE OF THE SAME WITH MOS GUIDANCE
AGAIN HINTING AT SOME FOG BUILDING INTO THE VALLEYS. MODEL
SOUNDINGS SHOWS SOME VERY DRY AIR IN THE MID LAYERS WITH LIGHTER
EAST FLOW ALOFT. GIVEN THE PERSISTENT MOISTURE TRAPPED IN THE
VALLEY, ITS HARD TO SEE FREEZING FOG NOT FORMING AGAIN IN THE
ROGUE, ILLINOIS AND UMPQUA VALLEYS WITH CLEAR SKIES TO THE EAST
AND SOUTH.
BY SATURDAY AFTERNOON, WE ARE WATCHING A COASTAL THERMAL TROUGH
AS TEMPERATURES STAY WARM AROUND THE BROOKINGS AREA. GUIDANCE IS
SUGGESTING HIGHS IN THE MID 50'S, WHICH SHOULD BE THE WARMEST
LOCATION IN OUR FORECAST AREA ON SATURDAY AFTERNOON. ESPECIALLY AS
THE FOG COULD LINGER INTO THE AFTERNOON HOURS ON SATURDAY GIVEN
HOW STRONG THE INVERSION IS.
BY SUNDAY, THE DEEP TROUGH COVERING BASICALLY ALL THE CONUS WILL
PUSH A SHORT WAVE DOWN THROUGH WASHINGTON INTO OREGON. THIS WILL
HELP USHER IN SOME EVEN COOLER AIR AND LIGHT EAST FLOW ALOFT. THE
IMPACTS ON THE PUBLIC SIDE WILL REMAIN PLENTY OF MORNING FREEZING
FOG AND COOLER THAN NORMAL TEMPERATURES ACROSS SOUTHERN OREGON,
ESPECIALLY EAST OF THE CASCADES INTO NEXT WEEK.
OTHERWISE, THE BEST CHANCE OF RAIN IS TOWARDS THE END OF NEXT WEEK
AROUND FRIDAY. THE MAJORITY OF ENSEMBLE MEMBERS ARE BRINGING
PRECIPITATION TO THE PACIFIC NORTHWEST TOWARDS THE END OF THE
WEEK WITH A 30 TO 40 PERCENT CHANCE OF RAIN OR SNOW ABOVE 4000
FEET. THIS DOESN'T LOOK LIKE A REAL WET EVENT LOOKING AT THE
INDIVIDUAL ENSEMBLE MEMBERS, SO JUST A LIGHTER SNOW ACCUMULATION
IN THE MOUNTAINS.
-SMITH
AVIATION...17/18Z TAFS
LOW CLOUDS AND FOG WILL PERSIST IN THE
ROGUE, AND ILLINOIS VALLEY AND GRANTS PASS AREA THROUGH THIS
MORNING. THE TAF SHOWS IMPROVING CONDITIONS AT MEDFORD TOWARDS 22Z,
BUT THIS COULD END UP BEING DELAYED BY AN HOUR OR SO IF THE LOW
CLOUDS AND FOG SHOW SIGNS OF A SLOWER BURN OFF. MEANWHILE, ROSEBURG
IS REPORTING MVFR CEILINGS WITH NO RESTRICTIONS OF VISIBILITY.
HOWEVER, LOCALIZED LOWER CEILINGS WITH LIMITED VISIBILITY UNDER 6
MILES IN PORTIONS OF THE UMPQUA BASING ARE POSSIBLE THIS MORNING.
LIKE YESTERDAY, LOW CLOUDS AND FOG SHOULD BURN OFF WITH CLEAR SKIES
LATER THIS AFTERNOON INTO THIS EVENING. A DRY COLD FRONT WILL USHER
IN A DRIER AIR MASS, BUT IT PROBABLY WON'T BE ENOUGH TO PREVENT LOW
CLOUDS AND FOG FROM FORMING AGAIN IN THE UMPQUA BASIN, ILLINOIS AND
ROGUE VALLEYS AND GRANTS PASS AREA LATER TONIGHT THROUGH THE END OF
THE TAF PERIOD. THE ONE THING THE DRY COLD FRONT COULD DO IS SHORTEN
THE DURATION OF FOG AND LOW CLOUDS.
ALONG THE COAST AND JUST OFFSHORE. VFR CONDITIONS ARE EXPECTED
THROUGH THE TAF PERIOD. VFR CONDITIONS ARE ALSO EXPECTED EAST OF THE
CASCADES THROUGH THE TAF PERIOD.
-MAP
MARINE...UPDATED 200 PM FRIDAY, JANUARY 17, 2025
A THERMAL TROUGH
REMAINS ALONG THE SOUTH OREGON COAST RESULTING IN MODERATE TO
OCCASIONALLY STRONG NORTH WINDS INTO TONIGHT. WINDS WILL BE STRONGEST
SOUTH OF PORT ORFORD AND BEYOND 10 NM FROM SHORE WHERE THE
COMBINATION OF WINDS AND SEAS WILL RESULT IN HAZARDOUS SEAS WARNING
CONDITIONS.
THE THERMAL TROUGH WILL WEAKEN LATE TONIGHT INTO SATURDAY WITH NORTH
WINDS GRADUALLY DIMINISHING. SMALL CRAFT CONDITIONS ARE STILL LIKELY
IN THE SOUTHERN OUTER WATERS SATURDAY.
WINDS AND SEAS WILL CONTINUE TO DIMINISH SATURDAY NIGHT WITH WINDS
AND SEAS REMAINING BELOW ADVISORY LEVELS THROUGH AT LEAST THE FIRST
HALF OF NEXT WEEK. -PETRUCELLI
MFR WATCHES/WARNINGS/ADVISORIES
OR...BEACH HAZARDS STATEMENT FROM SATURDAY AFTERNOON THROUGH SUNDAY
AFTERNOON FOR ORZ021-022.
CA...NONE.
PACIFIC COASTAL WATERS...BEACH HAZARDS STATEMENT FROM SATURDAY
AFTERNOON THROUGH SUNDAY AFTERNOON FOR PZZ350-356.
SMALL CRAFT ADVISORY UNTIL 4 AM PST SATURDAY FOR PZZ350-356-370-
376.
HAZARDOUS SEAS WARNING UNTIL 4 AM PST SATURDAY FOR PZZ356-376.
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