Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 262229
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
229 PM PST MON JAN 26 2015

.DISCUSSION...CURRENT VISIBLE IMAGE SHOWS SCATTERED HIGH CLOUDS
MOVING UP FROM THE SOUTH. LOW CLOUDS ARE GRADUALLY BREAKING UP IN
THE ROGUE VALLEY NEAR MEDFORD AND IT HAS CLEARED OUT IN ROSEBURG.
HOWEVER GRANTS PASS REMAINS OVERCAST AND IT MAY ONLY BREAK OUT
BRIEFLY LATE THIS AFTERNOON, IF AT ALL. A WEAK FRONT WILL MOVE
TOWARDS THE AREA TONIGHT, BUT THERE WILL NOT BE ENOUGH MID OR HIGH
CLOUDS TO PREVENT FOG AND LOW CLOUDS FROM DEVELOPING IN THE
WESTSIDE VALLEYS. THEREFORE WE EXPECT BOTH TO FORM AGAIN THIS
EVENING AND CONTINUE THROUGH MOST OF TUESDAY MORNING FOR THE SAME
LOCATIONS.

THE AFORMENTIONED FRONT WILL BRING LITTLE OF ANY PRECIPITATION.
COULD NOT RULE OUT SOME PATCHY DRIZZLE NORTH OF CAPE BLANCO, BUT
THAT`S IT. AT THE SAME TIME A WEAK UPPER TROUGH IS EXPECTED TO
MOVE NORTH INTO NEVADA TUESDAY AND THE MODELS SHOW SOME QPF
BARELY MAKING IT INTO SOUTHERN MODOC AND SISKIYOU COUNTY. PREVIOUS
FORECAST HAD A SLIGHT MENTION OF SHOWERS WHICH LOOKED REASONABLE.

THE FRONT ON TUESDAY MAY BE ENOUGH TO WEAKEN OR BREAK THE
INVERSION FOR A BRIEF TIME WEST OF THE CASCADES TUESDAY AFTERNOON, THEN
THE INVERSION WILL STRENGTHEN WEDNESDAY AND CONTINUE INTO THE END
OF THE WEEK AS AN UPPER RIDGE MOVES BACK INTO THE REGION. SO HAVE
DECIDED TO EXTEND THE AIR STAGNATION ADVISORY UNTIL 10 AM PST
THURSDAY FOR WEST OF THE CASCADES. CONFIDENCE IS HIGHER THE
INVERSION WILL BREAK EAST OF THE CASCADES TUESDAY AFTERNOON WITH
MIXING HEIGHTS EXPECTED TO BE MUCH HIGHER. SO DID NOT CHANGE THE
END TIME OF THE AIR STAGNATION THERE.

LITTLE CHANGE IN THE WEATHER IS EXPECTED FROM WEDNESDAY INTO START
OF NEXT WEEKEND. IT WILL REMAIN DRY WITH PATCHY TO AREAS OF FOG
AT NIGHT INTO THE MORNING HOURS FOR THE WESTSIDE VALLEYS. THE GFS
AND EC SHOW THE UPPER RIDGE FLATTENING OUT SOME SUNDAY AND A
FRONTAL BOUNDARY WILL MOVE SOUTH BRINGING LIGHT RAIN TO THE
NORTHWEST PART OF THE AREA SUNDAY AFTERNOON. -PETRUCELLI

&&

.AVIATION...VFR CONDITIONS ARE
EXPECTED TO PREVAIL OVER THE AREA THIS AFTERNOON WITH SOME LINGERING
IFR IN THE ROGUE VALLEY NEAR GRANTS PASS AND THE ILLINOIS VALLEY.
DURING THE EVENING, AREAS OF IFR/MFR CIGS ARE EXPECTED TO MOVE INTO
THE COAST, INCLUDING AT KOTH. IFR CIGS ARE EXPECTED TO BECOME
WIDESPREAD LATE TONIGHT INTO TUESDAY MORNING ALONG COASTAL AREAS.
INLAND, EXPECT WEST SIDE VALLEYS TO HAVE FOG REDEVELOP LATE TONIGHT
WITH FOG CONTINUING INTO TUESDAY MORNING. AS A LOW MOVES UP INTO
EAST-CENTRAL CALIFORNIA AND NEVADA, HIGH AND MID CLOUDS WILL
INCREASE DURING THE MORNING, MAINLY OVER NORTHERN CALIFORNIA AND
EAST OF THE CASCADES. THIS LOW MAY BRING SOME LIGHT RAIN AND
ISOLATED MOUNTAIN OBSCURATIONS TO EASTERN SISKIYOU AND MODOC
COUNTIES LATE TUESDAY MORNING. /CC


&&

.MARINE...UPDATED AT 1130 AM MONDAY 26 JANUARY 2015...WEST SWELL
WILL GRADUALLY DIMINISH AND SOUTH WINDS WILL STAY BELOW ADVISORY
CRITERIA AT 10 TO 15 KT THROUGH WEDNESDAY. A WEAK FRONT MOVES OVER
THE WATERS TUESDAY...THEN DISSIPATES OVER THE AREA ON WEDNESDAY.
MODERATE NORTHERLY WINDS ARE EXPECTED THURSDAY INTO FRIDAY WITH THE
STRONGEST WINDS IN THE SOUTHERN OUTER WATERS AS HIGH PRESSURE BUILDS
IN TO THE NORTH...RESULTING IN INCREASED CHOP. -CC


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST THURSDAY FOR
     ORZ023-024-026-616-620-622.
     AIR STAGNATION ADVISORY UNTIL 11 AM PST TUESDAY FOR
     ORZ029>031-623>625.

CA...NONE.

PACIFIC COASTAL WATERS...NONE.

$$


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