410
FXUS66 KMFR 181728
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1028 AM PDT SUN MAY 18 2025
UPDATE
UPDATED AVIATION DISCUSSION.
AVIATION...18/18Z TAFS
VFR LEVELS ARE PRESENT ACROSS NORTHERN
CALIFORNIA AND SOUTHERN OREGON. THE ONE EXCEPTION IS SOME LOCAL MVFR
CEILINGS THROUGH 20Z IN THE UMPQUA, INCLUDING AT ROSEBURG AND AREAS
OF HIGHER MOUNTAIN OBSCURATIONS OVER THE SOUTHERN OREGON CASCADES
THROUGH EARLY AFTERNOON. GUSTY WINDS ARE FORECAST OVER AREAS EAST OF
THE CASCADES THIS AFTERNOON, THEN CALMING INTO THE EVENING. LATE
THIS EVENING, MVFR CEILINGS ARE EXPECTED TO DEVELOP ALONG THE COAST.
PREV DISCUSSION
/ISSUED 844 AM PDT SUN MAY 18 2025/
DISCUSSION...THE FORECAST IS ON TRACK FOR THIS MORNING. SHOWERS
ARE LARGELY ABSENT ON RADAR, WITH SOME POSSIBLE LINGERING
ACTIVITY OVER AREA PEAKS AT MOST. NORTHWEST FLOW ALOFT CONTINUES
TO BRING CLOUD COVER THAT BANKS UP AGAINST THE CASCADES, KEEPING
SKIES WEST OF THE CASCADES AT LEAST PARTLY CLOUDY. TO THE EAST,
SKIES ARE GENERALLY CLEARER ALTHOUGH CLOUDS REMAIN OVER HIGHER
TERRAIN. TEMPERATURES STAY COOL TODAY AHEAD OF WARMING TO SEASONAL
LEVELS AND A WEAK FRONT ON MONDAY.
PLEASE SEE THE PREVIOUS DISCUSSION FOR MORE DETAILS ON THE SHORT-
AND LONG-TERM DISCUSSION. -TAD
AVIATION...18/12Z TAFS...SHOWERS WILL CONTINUE NEAR THE CASCADES
THROUGH THIS MORNING. VFR CONDITIONS WILL PREVAIL INLAND WITH A
MIXTURE OF MVFR/VFR AT THE COAST, INCLUDING KOTH. SCATTERED MVFR IS
POSSIBLE IN THE UMPQUA BASIN INCLUDING KRBG THROUGH THE EARLY
MORNING. ANY AREAS OF LOWER FLIGHT CONDITIONS SHOULD IMPROVE TO
VFR BY AFTERNOON. NORTHWEST WINDS WILL PICK UP AGAIN TODAY,
ESPECIALLY EAST OF THE CASCADES WITH GUSTS NEAR 20-30 KT POSSIBLE
IN THE AFTERNOON.
MARINE....UPDATED 800 AM SUNDAY, MAY 18, 2025...EXPECTING
RELATIVELY QUIET CONDITIONS THROUGH THE REMAINDER OF THE WEEKEND. A
WEAK FRONTAL SYSTEM WILL MOVE THROUGH THE AREA MONDAY AFTERNOON WITH
WINDS VEERING FROM THE SOUTH TO NORTHWEST. THESE NORTHERLY WINDS
WILL INCREASE ON TUESDAY IN CONJUNCTION WITH THE DEVELOPMENT OF A
THERMAL TROUGH. BUILDING SEAS ON TUESDAY MAY BECOME HIGH AND STEEP
WITH THE COMBINATION OF WIND WAVES AND A BUILDING WEST-NORTHWEST
SWELL AROUND 13 SECONDS. CONDITIONS MAY IMPROVE SLIGHTLY STARTING
WEDNESDAY AND CONTINUE THROUGH LATER PARTS OF THE WEEK.
PREV DISCUSSION... /ISSUED 220 AM PDT SUN MAY 18 2025/
DISCUSSION...THE UPPER LEVEL TROUGH HAS MOVED TO THE EAST, BUT
ONSHORE FLOW WILL KEEP SHOWERS LINGERING ALONG THE CASCADES
THROUGH THIS MORNING. DAYTIME HIGHS TODAY WILL INCREASE A FEW
DEGREES FOR WEST SIDE VALLEYS, BUT TEMPERATURES WILL STAY BELOW
NORMAL FOR THIS TIME OF YEAR.
CONDITIONS THROUGH THE WEEK LOOK TO BE DEFINED BY ZONAL FLOW ALOFT.
TEMPERATURES RISE TO MORE SEASONAL LEVELS ON MONDAY, WITH MID 60S
ALONG THE OREGON COAST AND LOW TO MID 70S FOR WEST SIDE VALLEYS.
EAST SIDE AREAS LOOK TO BE IN THE MID TO HIGH 60S. A WEAK FRONT
LOOKS TO BRING LIGHT SHOWERS TO COOS, CURRY, AND DOUGLAS COUNTIES
AS WELL AS THE CASCADES THROUGH THE DAY MONDAY. A BUNDLE OF UPPER
LEVEL INSTABILITY THEN PASSES OVER THE AREA ON LATE WEDNESDAY OR
EARLY THURSDAY, BUT EXPECTED DRY CONDITIONS OFFER LITTLE TO FUEL
ANY DEVELOPMENT. ISOLATED OR SCATTERED SHOWERS ARE POSSIBLE WEST
OF THE CASCADES, BUT CHANCES ARE LOW. BY FRIDAY, WEST SIDE
VALLEYS WARM TO MID TO HIGH 70S, WITH HIGH 60S TO MID 70S EAST OF
THE CASCADES.
AN UPPER RIDGE LOOKS TO DEVELOP OVER THE WEEKEND, BRINGING A PERIOD
OF DRY, STABLE WEATHER. ADDITIONAL WARMING IS POSSIBLE ON SATURDAY,
WHILE GUIDANCE POINTS TO SUNDAY BEING NOTICEABLY WARMER. THERE'S
STILL SOME UNCERTAINTY WITH HOW WARM TEMPERATURES WILL GET OVER THE
WEEKEND, WHICH DEPENDS ON WHERE THE RIDGE DEVELOPS. USING MEDFORD
AS AN EXAMPLE, ECMWF AND GFS METEOGRAMS FAVOR HIGH 70S TO MID 80S
WHILE NBM PROBABILISTIC GUIDANCE HAS A 55% CHANCE FOR SUNDAY
HIGHS TO EXCEED 85 DEGREES. THE FORECAST BEYOND NEXT SUNDAY
REMAINS UNCERTAIN AS WELL, WITH ECMWF METEOGRAM GUIDANCE STARTING
TO SHOW UNIFORM SIGNALS FOR LIGHT SHOWERS AT NORTH BEND FOR
MEMORIAL DAY. THE GFS AND NBM SHOW LOWER CHANCES BUT THE CHANCES
THAT DO APPEAR MATCH UP WELL WITH THE ECMWF. -TAD/BPN
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
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