High Surf Advisory 11, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
349 AM PST TUE DEC 22 2015

.DISCUSSION...A SERIES OF DISTURBANCES WILL PRODUCE FREQUENT
PERIODS OF LIGHT TO MODERATE RAIN AND SNOW THROUGH THURSDAY NIGHT.
CURRENT SNOW LEVELS OF 3500 TO 4000 FEET WILL RISE TO ABOVE 4500
FEET THIS AFTERNOON, THEN DROP TO AROUND 2000 FEET BY TONIGHT.
SNOW AMOUNTS WILL VARY DEPENDING ON ELEVATION AND LOCATION, BUT
GENERALLY SPEAKING, AMOUNTS WILL BE HIGHEST ON THE WEST FACING
SLOPES OF THE CASCADES. WITH ONGOING SNOW IN THE FORECAST AND
HOLIDAY TRAVEL INCREASING TRAFFIC OVER THE PASSES AND ALONG AREA
HIGHWAYS, HAVE CONTINUED THE WINTER WEATHER ADVISORY FOR SNOW AND
WIND THROUGH WEDNESDAY AFTERNOON. HAVE ALSO EXPANDED THE COVERAGE
A BIT INTO THE WESTERN FOOTHILLS OF THE CASCADES, AS LATEST MODEL
RUNS HAVE BUMPED UP PRECIPITATION THERE, AND SOME MORE LOCALLY
TRAVELED HIGHWAYS WILL LIKELY BE IMPACTED BY WEDNESDAY MORNING.

MUCH OF THE SNOW THIS MORNING IS THE RESULT OF A WARM FRONT
APPROACHING THE REGION AHEAD OF THE NEXT TROUGH WITHIN THE SWIFT
WESTERLY FLOW ALOFT. THIS WARMER AIR WILL BE THE REASON FOR
SLIGHTLY HIGHER SNOW LEVELS LATER THIS MORNING AND THIS AFTERNOON,
BUT A COLD FRONT WILL FOLLOW RATHER QUICKLY LATE THIS AFTERNOON
AND INTO THE EVENING. WINDS WILL INCREASE AND SNOW LEVELS WILL
FALL TO AROUND 3500 FEET TONIGHT WITH THE APPROACH OF THE COLD
FRONT, THE SNOW LEVELS ARE EXPECTED TO FALL FURTHER BEHIND THE
FRONT BY WEDNESDAY MORNING. A POST-FRONTAL SHORTWAVE TROUGH WILL
CONTINUE PRECIPITATION ON WEDNESDAY. PRECIPITATION RATES THROUGH
WEDNESDAY WILL BE RATHER REMARKABLY CONSISTENT, WITH LITTLE BREAK
BETWEEN SYSTEMS. WIDESPREAD LIGHT PRECIPITATION IS EXPECTED,
MAINLY ON THE WEST SIDE, WITH MORE MODERATE INTENSITY
PRECIPITATION OVER THE CASCADES AND SISKIYOU MOUNTAINS, WHERE
UPSLOPING FLOW WILL BE STRONGEST. PLEASE SEE THE WINTER WEATHER
ADVISORY STATEMENT /PDXWSWMFR/ FOR DETAILS.

CONFIDENCE IS NOT AS HIGH IN THE FORECAST BEYOND WEDNESDAY, BUT
IS IMPROVING AS MODELS BEGIN TO CONVERGE ON A COMMON SOLUTION. AS
A RESULT, THERE IS INCREASING POTENTIAL FOR A COLDER SYSTEM TO
BRING LOW ELEVATION SNOW LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING. THERE IS STILL SOME DISAGREEMENT ON THE DETAILS OF TIMING
AND AMOUNTS, BUT THERE IS GENERAL AGREEMENT WITH SNOW LEVELS
FALLING TO AROUND 1000 FEET, AND SNOWFALL AMOUNTS ON THE ROGUE
VALLEY FLOOR COULD FALL INTO THE 1 TO 2 INCH RANGE BETWEEN
THURSDAY MORNING AND CHRISTMAS MORNING, WHILE ELEVATIONS ABOVE
2000 FEET COULD RECEIVE 3 TO 6 INCHES WITH UP TO A FOOT IN THE
MOUNTAINS DURING THE SAME TIME FRAME. SOME OF THE THURSDAY MORNING
SNOW MAY MELT WITH AFTERNOON HEATING, BUT LOWER NIGHTTIME
TEMPERATURES AND LIGHT SCATTERED SHOWERS CONTINUING THROUGH
THURSDAY NIGHT COULD MAKE UP FOR SOME OF THAT MELT. THUS...THERE
IS A HIGH PROBABILITY OF SNOW REMAINING ON THE GROUND FOR MOST
LOCATIONS ABOVE 1000 FEET FOR CHRISTMAS MORNING.

SHOWERS WILL BE TAPERING OFF CHRISTMAS MORNING AS AN UPPER LEVEL
RIDGE BEGINS TO NUDGE INTO THE REGION. TEMPERATURES DROPPING INTO
THE 20S IN THE WEST SIDE VALLEYS WILL HELP TO PRESERVE ANY SNOW
THAT HAS STUCK WITH THE PREVIOUS DAY AND A HALF OF SNOW SHOWERS.
WEAK OFFSHORE FLOW SETS UP OVER THE WEST SIDE BY SATURDAY MORNING,
AND WITH ALL OF THE BOUNTIFUL MOISTURE FROM THE PAST WEEK, FOG,
POSSIBLY DENSE FREEZING FOG, WILL BE PRESENT IN THE WEST SIDE
VALLEYS. EAST OF THE CASCADES, TEMPERATURE WILL DROP INTO THE
SINGLE DIGITS AND BELOW ZERO IN PLACES, AS SNOWY SURFACES AND
CLEAR SKIES RESULT IN EXCELLENT RADIATIONAL COOLING. THE UPPER
RIDGE SLOWLY TRANSITIONS EAST WITH ANOTHER MORNING OF FREEZING FOG
POSSIBLE SUNDAY MORNING BEFORE THE NEXT FRONT BRINGS PRECIPITATION
TO THE AREA SUNDAY AFTERNOON INTO MONDAY MORNING. MODELS HAVE
VERY LITTLE AGREEMENT ON THE PATTERN EARLY NEXT WEEK, WITH THE GFS
REMAINING DRY, WHILE THE ECMWF PRODUCES ANOTHER POTENT FRONTAL
SYSTEM TUESDAY NIGHT INTO WEDNESDAY. WITH CONFIDENCE SO LOW, HAVE
KEPT AT LEAST A SLIGHT CHANCE OF PRECIPITATION IN THE FORECAST TO
ACCOUNT FOR THE WETTER SOLUTION, BUT SHOULD THE RIDGING OF THE GFS
INSTEAD VERIFY, VALLEY FOG WILL BE THE LIKELY RESULT. -BPN

&&

.AVIATION...FOR THE 22/06Z TAF CYCLE...AREAS OF MVFR CIGS WITH LOCAL
IFR CIGS WILL PERSIST THROUGH TUESDAY MORNING...WITH HIGHER TERRAIN
OBSCURED. CONDITIONS WILL IMPROVE SLIGHTLY IN THE AFTERNOON...BUT
THERE WON'T BE A LOT OF CLEARING TO VFR.   GUSTY WINDS WILL DEVELOP
AGAIN TUESDAY AFTERNOON ALONG THE COAST AND EAST OF THE CASCADES.
-JRS

&&

.MARINE...UPDATED 200 AM PST TUESDAY 22 DEC 2015...A WARM FRONT WILL
MOVE THROUGH THE WATERS TUESDAY AFTERNOON AND EVENING...BRINGING
WINDS UP TO GALES. INITIALLY GALES WILL BE CONFINED TO AREAS BEYOND
10 NM BUT AFTER 4 PM THE INNER WATERS NORTH OF CAPE BLANCO WILL ALSO
SEE GALE FORCE WINDS. GUIDANCE INDICATES NORTH BEND AIRPORT WILL SEE
WINDS IN THE 25 TO 40 KNOT RANGE SO CONFIDENCE IS HIGH THAT GALE
COULD COME ALL THE WAY TO THE COAST IN MARINE ZONE 350 WHICH IS
FLORENCE TO CAPE BLANCO. ANOTHER LOW MOVING DOWN FROM THE NORTH MAY
BRING GUSTY NORTH WINDS ON THURSDAY AFTERNOON. OFFSHORE FLOW WILL
DEVELOP FRIDAY NIGHT INTO SATURDAY.

SEVERAL ROUNDS OF HEAVY NORTHWEST SWELL WILL MOVE THROUGH BETWEEN
TONIGHT AND FRIDAY MORNING. THE SWELLS...IN COMBINATION WITH THE
VERY HIGH TIDES THAT WILL OCCUR THROUGH SUNDAY DEC 27...PEAKING THU
DEC 24....WILL LIKELY CREATE DANGEROUS BAR CONDITIONS AND PERIODS OF
HIGH SURF ALONG THE COAST. /FB

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 4 PM PST WEDNESDAY FOR
     ORZ023-025>030.
     HIGH SURF ADVISORY UNTIL 4 AM PST EARLY THIS MORNING FOR
     ORZ021-022.

CA...WINTER WEATHER ADVISORY UNTIL 4 PM PST WEDNESDAY FOR
     CAZ080-081-083.

PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING FROM 1 PM THIS AFTERNOON TO 4 PM PST
     WEDNESDAY FOR PZZ350-356-376.
     GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM PST THIS EVENING
     FOR PZZ356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST THIS
     EVENING FOR PZZ356-376.
     GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM PST THIS EVENING
     FOR PZZ350.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 1 PM PST THIS
     AFTERNOON FOR PZZ350-370.
     HAZARDOUS SEAS WARNING FROM 10 PM THIS EVENING TO 4 PM PST
     WEDNESDAY FOR PZZ370.
     HAZARDOUS SEAS WARNING UNTIL 4 AM PST EARLY THIS MORNING FOR
     PZZ370-376.

BPN/FJB/JRS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
1220 AM PST TUE DEC 22 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0301 PM     HEAVY RAIN       2 ESE ASHLAND           42.18N 122.66W
12/21/2015  M0.48 INCH       JACKSON            OR   TRAINED SPOTTER

            9 AM - 3 PM RAINFALL OBSERVER LOCATION 2 MI.
            S. OF ASHLAND AIRPORT.

&&

FB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
137 AM PST TUE DEC 22 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1200 AM     HEAVY RAIN       2 SSE COOS BAY          43.36N 124.22W
12/22/2015  M1.84 INCH       COOS               OR   TRAINED SPOTTER

            24 HOUR RAINFALL TOTAL ENDING AT MIDNIGHT.
            MONTHLY TOTAL IS NOW AT 23.23" OBSERVER
            LOCATION SOUTH OF COOS BAY.

&&

BS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
138 AM PST TUE DEC 22 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1200 AM     HEAVY RAIN       1 ENE BROOKINGS         42.06N 124.28W
12/22/2015  M2.95 INCH       CURRY              OR   TRAINED SPOTTER

            24 HOUR TOTAL ENDING AT MIDNIGHT. MONTHLY
            TOTAL SO FAR IS 29.93 INCHES. OBSERVER
            LOCATION IN TOWN NEAR SCHOOL COMPLEX.

&&

BS