916
FXUS66 KMFR 180920
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
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
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.
-GUERRERO/HERMANSEN
MARINE...UPDATED 200 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.
-GUERRERO/HERMANSEN
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
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