839
FXUS66 KMFR 072048
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
ISSUED BY NATIONAL WEATHER SERVICE PORTLAND OR
148 PM PDT WED MAY 7 2025
DISCUSSION
SATELLITE IMAGE SHOWS A SOUTHWEST FLOW OVER THE
AREA.
A WEAK SHORTWAVE WILL RIDE UP ALONG THE SOUTHWEST FLOW LATE THIS
AFTERNOON AND EVENING. THIS WILL RESULT IN BREEZY WINDS FOR THE
INTERIOR WEST SIDE VALLEYS AND EAST OF THE CASCADES LATE IN THE
AFTERNOON AND EARLY THIS EVENING. THIS WILL ALSO RESULT IN AN
INCREASING ONSHORE FLOW WITH MORE CLOUD COVER EXPECTED MAINLY
ALONG THE COAST AND UMPQUA DIVIDE LATE TONIGHT INTO THURSDAY
MORNING. COULD NOT RULE OUT A FEW ISOLATED SHOWERS OVER THE
NORTHERN CASCADES, BUT THAT WILL BE THE EXCEPTION.
IT WILL REMAIN DRY THROUGH THE FIRST HALF OF THE WEEKEND, WITH
ABOVE NORMAL TEMPERATURES FOR THE INTERIOR. AFTERNOON TEMPERATURES
THURSDAY WILL BE SIMILAR TO TODAY, WITH FURTHER WARMING ON
FRIDAY.
DRY WEATHER WILL CONTINUE INTO SATURDAY. AN UPPER TROUGH WILL
APPROACH FROM THE WEST DURING THE DAY RESULTING IN SLIGHTLY COOLER
AFTERNOON TEMPERATURES FOR THE INTERIOR ALONG WITH GUSTY
AFTERNOON AND EARLY EVENING BREEZES.
THE UPPER TROUGH WILL DIG SOUTHEAST TOWARDS THE AREA SUNDAY, AND
BRING A CHANCE FOR PRECIPITATION ALONG THE COAST TO START, THEN
FARTHER INLAND DURING THE DAY SUNDAY. THE ORIGIN OF THE UPPER
TROUGH IS FROM THE GULF OF ALASKA WHICH TYPICALLY RESULTS IN MUCH
COOLER AND WETTER CONDITIONS. THEREFORE AFTERNOON TEMPERATURES
SUNDAY COULD END UP 10-15 DEGREES COOLER ON AVERAGE FOR THE
INTERIOR.
THE UPPER TROUGH WILL REMAIN A FIXTURE OVER THE AREA FOR THE
START OF NEXT WEEK, WITH CONTINUED COOL AND UNSETTLED WEATHER.
PRECIPITATION AMOUNTS WILL BE NOTABLE, AT LEAST FOR THIS
TIME OF THE YEAR, ESPECIALLY ALONG THE COAST, COASTAL MOUNTAINS IN
SOUTHWEST OREGON, CASCADES AND EVEN PORTIONS OF THE EAST SIDE.
CURRENTLY 48 HOUR PRECIPITATION TOTALS COULD END UP BETWEEN 0.75
TO AN INCH ALONG THE COAST, AND CASCADES, 1-2 INCHES FOR THE
COASTAL MOUNTAINS, 0.25 TO 0.60 FOR THE INTERIOR WEST SIDE
VALLEYS, AND 0.20-050 FOR PORTIONS OF THE EAST SIDE.
SNOW LEVELS ARE LIKELY TO LOWER TO 5000 FEET SUNDAY NIGHT INTO
MONDAY, AND THIS WILL BRING SOME SNOW TO THE HIGHER CASCADE
PASSES. HOWEVER GIVEN THE TIME OF THE YEAR AND RECENT WARMING
RESULTING WARM GROUND TEMPERATURES, WINTER IMPACTS SHOULD BE
MINIMAL.
TUESDAY AND POSSIBLY WEDNESDAY COULD END UP BRING TRANSITION
DAYS, WITH THE UPPER TROUGH EXPECTED TO SHIFT OUT OF THE AREA.
HOWEVER, THE ECMWF AND GFS ENSEMBLE MEAN, AND THE CLUSTERS SHOW
VARYING SOLUTIONS REGARDING THE PROGRESSION OF THE UPPER TROUGH.
REGARDING THE CLUSTERS, THE MAJORITY OF THEM SHOW A SLOWER
PROGRESSION OF THE UPPER TROUGH.
THE OPERATIONAL MODELS SHOW SIMILAR SOLUTIONS WITH THE UPPER
TROUGH PUSHING SOUTHEAST OF THE AREA TUESDAY WITH UPPER RIDGING
BUILDING IN WEDNESDAY, WHICH CLOSELY RESEMBLES THE ECMWF ENSEMBLE
MEAN. -PETRUCELLI
AVIATION...07/18Z TAFS.
CEILINGS HAVE LIFTED TO VFR NORTH OF
CAPE BLANCO, WHILE IFR CEILINGS REMAIN OVER BROOKINGS. INLAND,
FLIGHT LEVELS REMAIN AT VFR UNDER HIGH CLOUDS TO START THE TAF
PERIOD. AN APPROACHING WEAK FRONT IS EXPECTED TO BRING MVFR
CEILINGS AND ISOLATED SHOWERS TO THE OREGON COAST THIS AFTERNOON
AND EVENING. THE UMPQUA VALLEY MAY ALSO SEE PERIODS OF MVFR
CEILINGS. OTHER INLAND AREAS WILL SEE CEILINGS LOWER BUT REMAIN AT
VFR HEIGHTS. RAIN SHOWERS ARE POSSIBLE OVER THE CASCADES BUT WILL
BE RARE OVER LOWER ELEVATION AREAS. WINDS WILL INCREASE THIS
AFTERNOON AND EVENING AS WELL, BUT IMPROVE OVERNIGHT.
MARINE...UPDATED 200 PM WEDNESDAY, MAY 7, 2025
BELOW ADVISORY
SEAS CONTINUE TODAY. A WEAK FRONT WILL BRING BREEZY SOUTHWESTERLY
WINDS AS WELL AS A SLIGHT INCREASE IN WESTERLY SWELL THIS
AFTERNOON AND EVENING. SEAS REMAIN BELOW ADVISORY LEVEL UNTIL
NORTHERLY WINDS INCREASE UNDER A WEAK THERMAL TROUGH EARLY
THURSDAY MORNING. STEEP SEAS ARE EXPECTED TO BUILD SOUTH OF PORT
ORFORD AND BEYOND 5 NM FROM SHORT FROM THURSDAY MORNING THROUGH
LATE THURSDAY NIGHT.
BELOW ADVISORY SEAS LOOK TO RETURN ON FRIDAY AND REMAIN THROUGH
SUNDAY MORNING. ACTIVE WEATHER IN THE FORECAST FOR SUNDAY
AFTERNOON MAY BRING MARINE SHOWERS, GUSTY SOUTH TO SOUTHWEST
WINDS, AND STEEP SEAS. -TAD
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 8 AM TO 11 PM PDT
THURSDAY FOR PZZ356-376.
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