582
FXUS66 KMFR 190515
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1015 PM PDT SUN MAY 18 2025
..NEW AVIATION SECTION
AVIATION (06Z TAFS)
THIS CYCLE WILL BE NOTED BY VFR CONDITIONS TRANSITIONING TO MVFR
TONIGHT (OR CLOSE TO IT) WITH THE ONE EXCEPTION BEING THE COAST
WHERE IFR TO LIFR CONDITIONS (65-90%) WILL BE POSSIBLE THROUGH
PARTS OF TOMORROW. AN UPPER LEVEL SYSTEM IS BRINGING A NARROW
LAYER OF MOISTURE INTO THE REGION, AND THIS MAY SQUEEZE OUT SOME
LIGHT RAINFALL FOR COASTAL AREAS (50%-80%) BUT QUESTIONS REMAIN
FOR INLAND AREAS. ROSEBURG COULD END UP WITH SOME LIGHT RAINFALL
AS WELL. HOWEVER, THERE IS A CHANCE THESE SHOWERS MAY BE TOO
ISOLATED AND NOT IMPACT THE TERMINAL. SOMETHING TO CONSIDER IN
SUBSEQUENT TAFS BECAUSE THERE WILL BE SHOWERS AROUND TOMORROW.
-GUERRERO
PREV DISCUSSION
/ISSUED 918 PM PDT SUN MAY 18 2025/
DISCUSSION...A PROGRESSIVE PATTERN WILL CONTINUE OVER THE AREA
FOR THE NEXT SEVERAL DAYS. LOW PRESSURE WILL HANG OUT TO THE NORTH
NEAR THE BRITISH COLUMBIA COAST AND DISTURBANCES COME ALONG EVERY
NOW AND THEN IN MOSTLY ZONAL FLOW TO THE SOUTH (OVER US).
CURRENTLY, WE'RE BENEATH A WEAK SHORT WAVE RIDGE, BUT CLOUDINESS
PERSISTS, ESPECIALLY WEST OF THE CASCADES AS WEAK WARM ADVECTION
MOVES IN FROM THE PACIFIC. THIS LED TO A FEW WEAK RETURNS ON
RADAR NEAR THE CURRY COAST AND INTO NORCAL EARLIER THIS EVENING,
BUT MOST PRECIP WAS ALOFT. A FEW SPRINKLES WERE REPORTED AT
CRESCENT CITY. THE NEXT UPPER TROUGH/FRONT WILL BRING DEEPER
MOISTURE OVERNIGHT INTO MONDAY WITH SOME SHOWERS ALONG THE COAST,
INTO THE UMPQUA BASIN AND OVER TO THE CASCADES. BEST MOISTURE
STAYS NORTH AND WEST OF THE ROGUE VALLEY THOUGH A BRIEF SHOWER/OR
A FEW SPRINKLES CANNOT BE RULED OUT DOWN HERE EITHER. AROUND A
TENTH TO PERHAPS UP TO A QUARTER OF AN INCH OF RAIN IS IN THE
FORECAST FOR THE COAST RANGE MOUNTAINS AND OVER TO THE CASCADE
FOOTHILLS/CASCADES NORTH OF HIGHWAY 140. LESSER AMOUNTS CAN BE
EXPECTED IN THE VALLEYS, GENERALLY LESS THAN A TENTH OF AN INCH
NORTH OF THE UMPQUA DIVIDE. THERE'S ONLY ABOUT A 20% CHANCE THAT
WE GET ANYTHING MEASURABLE HERE IN MEDFORD. SAME GOES FOR MOST OF
NORCAL AND AREAS EAST OF THE CASCADES WHERE THE FRONT WILL BE
BARELY NOTICEABLE, EXCEPT THAT AFTERNOON WNW BREEZES WILL KICK IN
AGAIN (ABOUT 25-30 MPH). -SPILDE
AVIATION...19/00Z TAFS...LOW TO MID LEVEL CLOUDS WILL RESULT IN
VFR/MVFR CONDITIONS THROUGH MOST OF THIS TAF CYCLE. ALONG THE
COAST WE COULD SEE IFR CONDITIONS DEVELOP OVERNIGHT AS OUR NEXT
SYSTEM ADVECTS MOISTURE ALONG THE COAST UNDER A STABLE ATMOSPHERE.
THIS COULD ALSO LEAD TO LIGHT PRECIPITATION (75%-85%) ALONG/NEAR
THE COAST STARTING TONIGHT AND GOING THROUGH PARTS OF MONDAY
AFTERNOON. THIS COULD BE THE RESULT AROUND THE KRBG TERMINAL AS
WELL, BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE AT THIS TIME,
BUT DID MENTION A VICINITY SHOWER POSSIBLE FOR MONDAY. THAT SAID,
MAY CHANGE THIS IF CONFIDENCE INCREASES AND WILL ADD IN SUBSEQUENT
TAFS.
-GUERRERO
MARINE...UPDATED 800 PM SUNDAY, MAY 18, 2025...A WEAK FRONTAL
SYSTEM WILL MOVE ACROSS THE WATERS TOMORROW. THIS WILL RESULT IN
BREEZY SOUTH WINDS FROM PORT ORFORD NORTHWARD, ESPECIALLY WITHIN 20
NAUTICAL MILES OF SHORE. WINDS WILL BECOME NORTHWESTERLY BEHIND THE
FRONT LATE TOMORROW AFTERNOON, AND STEEP WEST-NORTHEST SWELL BUILDS
INTO THE WATERS. ADDITIONALLY, A THERMAL TROUGH WILL RESULT IN THE
POTENTIAL FOR BREEZY NORTH WINDS AND STEEP SEAS SOUTH OF CAPE BLANCO
LATE TUESDAY INTO WEDNESDAY. WINDS AND SEAS TREND LOWER BEGINNING ON
THURSDAY.
-GUERRERO
PREV DISCUSSION... /ISSUED 430 PM PDT SUN MAY 18 2025/
UPDATED AVIATION SECTION
AVIATION (00Z TAFS)...
LOW TO MID LEVEL CLOUDS WILL RESULT IN VFR/MVFR CONDITIONS THROUGH
MOST OF THIS TAF CYCLE. ALONG THE COAST WE COULD SEE IFR
CONDITIONS DEVELOP OVERNIGHT AS OUR NEXT SYSTEM ADVECTS MOISTURE
ALONG THE COAST UNDER A STABLE ATMOSPHERE. THIS COULD ALSO LEAD TO
LIGHT PRECIPITATION (75%-85%) ALONG/NEAR THE COAST STARTING
TONIGHT AND GOING THROUGH PARTS OF MONDAY AFTERNOON. THIS COULD BE
THE RESULT AROUND THE KRBG TERMINAL AS WELL, BUT CONFIDENCE WAS
NOT HIGH ENOUGH TO INCLUDE AT THIS TIME, BUT DID MENTION A
VICINITY SHOWER POSSIBLE FOR MONDAY. THAT SAID, MAY CHANGE THIS
IF CONFIDENCE INCREASES AND WILL ADD IN SUBSEQUENT TAFS.
-GUERRERO
PREV DISCUSSION... /ISSUED 229 PM PDT SUN MAY 18 2025/
DISCUSSION...NORTHWESTERLY FLOW ALOFT CONTINUES TO BRING CLOUDY
SKIES TO THE UMPQUA VALLEY AND OVER ELEVATED TERRAIN, BUT OTHERWISE
COOL TEMPERATURES AND MILD CONDITIONS CONTINUE THIS AFTERNOON.
UPPER FLOW LOOKS TO BECOME MORE ZONAL ON MONDAY. THIS WILL ALLOW FOR
MOST INLAND AREAS TO WARM TO SEASONAL LEVELS, ALTHOUGH COASTAL
AREAS AND THE UMPQUA VALLEY MAY STAY COOLER. A WEAK FRONT WILL MOVE
ALONG THE ZONAL FLOW, BRINGING THE POSSIBILITY OF LIGHT SHOWERS WEST
OF THE CASCADES. SHOWER CHANCES OVER CURRY, COOS, AND DOUGLAS
COUNTIES WILL BE MODERATE TO HIGH (40-80% CHANCES) THROUGH THE DAY
MONDAY, BUT AMOUNTS WILL BE LIGHT. HIGHER TERRAIN COULD SEE UP TO
0.3 TO 0.5 INCHES, WITH WEST SIDE VALLEYS GETTING LESS THAN 0.1
INCH OF RAIN.
ZONAL FLOW CONTINUES THROUGH THE WEEK, ALLOWING TEMPERATURES TO WARM
SLIGHTLY AND STEADILY THROUGH THE WEEK. FROM THE MIDDLE TO THE END
OF THE WEEK, THE OREGON COAST WILL BE IN THE LOW TO MID 60S. WEST
SIDE VALLEYS WILL BE IN THE MID TO HIGH 70S, WHILE AREAS EAST OF THE
CASCADES LOOK TO BE IN THE LOW TO MID 70S. SOME SMALLER ATMOSPHERIC
DISTURBANCES REMAIN IN THE FORECAST. A BUNDLE OF UPPER LEVEL
INSTABILITY LOOKS TO MOVE OVER THE AREA WEDNESDAY AND THURSDAY.
WHILE SLIGHT SHOWER CHANCES (10-30%) ARE IN THE FORECAST, ANYTHING
THAT DOES FORM WILL BE OVER HIGHER TERRAIN AND WILL BE JUST BARELY
MORE THAN A TRACE AT MOST. ON FRIDAY, A WEAK FRONT LOOKS TO PASS
OVER THE AREA WITH EVEN LOWER SHOWER CHANCES (5-15%) AND SOME GUSTY
WINDS TO HIGHER TERRAIN.
AN UPPER RIDGE LOOKS TO START BUILDING ON SATURDAY, BRINGING STABLE
CONDITIONS THROUGH THE WEEKEND AND WARMER TEMPERATURES ON SUNDAY.
CURRENT DETERMINISTIC GUIDANCE MOVES THE RIDGE AXIS TO THE EAST AS
THE RIDGE DEVELOPS, WHICH WILL LIMIT ADDITIONAL HEATING. CURRENT NBM
AND ECMWF GUIDANCE BRINGS THE OREGON COAST UP TO THE HIGH 60S WHILE
WEST SIDE VALLEYS LOOK TO BE IN THE LOW TO MID 80S. AREAS EAST OF
THE CASCADES COULD REACH THE MID 70S TO LOW 80S. THERE IS SOME
UNCERTAINTY WITH THIS WARMING, AS GFS DETERMINISTIC IMAGERY SHOWS A
TROUGH MOVING SOUTH OF THE AREA, WHICH WOULD ALLOW FOR COOLER
TEMPERATURES. METEOGRAM MEMBERS FOR THE GFS GENERALLY LEAN A LITTLE
COOLER AS WELL, WITH HIGHS SAYING IN THE MID TO HIGH 70S. A FEW
MEMBERS DO MATCH UP WITH THE RIDGE TEMPERATURES, REACHING THE LOW TO
MID 80S.
GIVEN THE DIVERGING MODEL OUTCOMES FOR THE WEEKEND, THERE'S NO
SURPRISE THAT UNCERTAINTY CONTINUES INTO THE FOLLOWING WEEK.
METEOGRAMS FOR BOTH ECMWF AND GFS SHOW CHANCES FOR PRECIPITATION,
BUT THE TIMING IS SOMEWHAT SCATTERED THROUGH THE WEEK AND AMOUNTS
VARY. FORECAST HIGHS DO TREND BACK DOWN TO SEASONAL LEVELS FOR
MEMORIAL DAY AND BEYOND, AT LEAST FOR NOW. -TAD
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM PDT
MONDAY FOR PZZ350-356-370-376.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page