Gale Watch 4, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
100 AM PST SAT FEB 12 2011

.DISCUSSION...12/00Z NAM/GFS IN.

THE UNUSUALLY LONG JANUARY/FEBRUARY DRY SPELL WILL END THIS
WEEKEND FROM THE CASCADES WEST AND SISKIYOUS NORTH...THEN THE
PATTERN WILL DECISIVELY SHIFT TO A COLD...WET...AND UNSETTLED
PATTERN EARLY NEXT WEEK FOR THE WHOLE MEDFORD CWA.

A LONG WAVE RIDGE PERSISTS ALONG THE WEST COAST THIS MORNING...BUT
IT HAS WEAKENED IN THE PAST 24 HOURS AND FLOW ALOFT IS NOW NEARLY
ZONAL. ONE OF A SERIES OF SHORT WAVES MOVING OVER THE RIDGE IS NOW
MOVING ONSHORE OVER WASHINGTON STATE. DOWN IN THE MEDFORD
CWA...THERE ARE LOW CLOUDS AND FOG ALONG THE COAST BUT ONLY MID
AND HIGH LEVEL CLOUDS INLAND.

THE UPPER LEVEL FLOW WILL BECOME SOUTHWEST AND STRENGTHEN...BUT
THE MEDFORD CWA WILL REMAIN DRY THROUGH SATURDAY MORNING.

A STRONGER SHORT WAVE WILL MOVE ONSHORE TO THE NORTH SATURDAY
AFTERNOON (GFS) OR EVENING (NAM)...AND A WEAK COLD FRONT WILL MOVE
INTO SOUTHERN OREGON AT THAT TIME. THE ASSOCIATED PRECIPITATION
WILL BE LIGHT AND MOSTLY LIMITED TO THE NORTH COAST...UMPQUA
BASIN...AND THE ADJACENT CASCADES IF THE NAM VERIFIES. THE GFS IS
A BIT WETTER WITH MORE WIDESPREAD PRECIPITATION...BUT IT STILL
KEEPS THE BULK OF IT FROM THE CASCADES WEST AND SISKIYOUS NORTH.

MORE SHORT WAVES EMBEDDED IN THE SOUTHWESTERLY FLOW WILL FOLLOW
SUNDAY AND MONDAY...BUT THE STORM TRACK WILL MOVE BACK NORTH. THE
COLD FRONT WILL REVERSE AND MOVE BACK NORTH AS A WARM FRONT
SUNDAY AFTERNOON AND EVENING. PRECIPITATION WILL DIMINISH AS IT
DOES SO...BUT THE BREAK WILL BE SHORT-LIVED.

TWO STRONGER SYSTEMS WILL MOVE IN MONDAY AFTERNOON AND MONDAY
NIGHT. THE ASSOCIATED SURFACE FRONT WILL BE MUCH STRONGER THAN THE
WEEKEND SYSTEMS...WITH A LOT MORE RAIN AND WIND...AND A LOT COLDER
AIR BEHIND IT TOO. THERE WILL LIKELY BE HIGH WINDS WITH THIS SYSTEM
ALONG THE COAST MONDAY INTO MONDAY NIGHT...IN THE SHASTA
VALLEY MONDAY INTO MONDAY NIGHT...AND EAST OF THE CASCADES MONDAY
AFTERNOON THROUGH TUESDAY AFTERNOON. WILL ISSUE A HIGH WIND WATCH
FOR THOSE AREAS LATER THIS MORNING.  THERE WILL ALSO BE HEAVY
PRECIPITATION OVER EXTREME SOUTHWEST OREGON...WESTERN SISKIYOU
COUNTY...AND SOUTH CENTRAL SISKIYOU COUNTY MONDAY AFTERNOON
THROUGH TUESDAY NIGHT. SNOW LEVELS WILL INITIALLY BE NEAR 6000
FEET...BUT WILL DROP TO 3000 TO 3500 FEET BEHIND THE FRONT
TUESDAY. WATCHES WILL GO OUT FOR THOSE AREAS LATER TODAY OR
SUNDAY MORNING IF THE FORECAST REMAINS ABOUT THE SAME.

THE COLD AIR WILL REMAIN OVER THE AREA AS A TROUGH DIGS OFFSHORE
AND EJECTS SHORT WAVES OVER THE AREA. THE LONG WAVE TROUGH ITSELF
WILL MOVE ONSHORE WEDNESDAY...BUT ENERGY COMING DOWN THE BACKSIDE
OF THE TROUGH WILL CAUSE IT TO DIG SOUTH AND SLOW DOWN AS IT DOES
SO. SNOW LEVELS WILL FALL TO AROUND 2000 FEET TUESDAY NIGHT AND
WEDNESDAY. AT THIS POINT IT LOOKS LIKE THE COLD...WET...AND
UNSETTLED WEATHER WILL PERSIST INTO FRIDAY. FLOODING MAY BECOME AN
ISSUE IN THE COQUILLE RIVER BASIN SOMETIME DURING THE SECOND HALF
OF THE WEEK.

MOST OF THE PRECIPITATION WILL MOVE TO THE SOUTH OF THE MEDFORD
CWA SATURDAY AS THE TROUGH CONTINUES TO DIG TO THE SOUTH.
HOWEVER...ANOTHER SYSTEM WILL MOVE DOWN THE COAST...AND AT THIS
TIME IT LOOKS LIKE MORE PRECIPITATION WILL MOVE IN SATURDAY NIGHT.
HOWEVER...IT IS TOO FAR IN THE FUTURE TO TRY AND FORECAST THE EXACT
TIMING AND TRAJECTORY OF IT.

&&

.AVIATION...CONDITIONS WILL REMAIN VFR THROUGH SATURDAY AFTERNOON.
MVFR AND IFR CIGS/VSBYS WILL DEVELOP ALONG THE COAST OF DOUGLAS
AND COOS COUNTIES SATURDAY EVENING.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 7 AM TO
        10 PM PST SATURDAY FOR PZZ350-356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 7 AM SATURDAY TO 10
        PM PST SUNDAY FOR PZZ350-356-376.
     GALE WATCH FROM SATURDAY AFTERNOON THROUGH LATE SATURDAY NIGHT
        FOR PZZ370.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST SATURDAY FOR
        PZZ370.
     HAZARDOUS SEAS WATCH FROM SATURDAY AFTERNOON THROUGH LATE
        SATURDAY NIGHT FOR PZZ370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST SATURDAY
        FOR PZZ370.

15/15/05