Small Craft Advisory 14, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
249 PM PST FRI JAN 22 2016

.SHORT TERM...A WELL-DEFINED LOW PRESSURE SYSTEM IS MOVING TOWARDS THE
COAST...CLEARLY EVIDENT ON SATELLITE IMAGERY. THE LOW WILL BRING
MODERATE TO OCCASIONALLY HEAVY PRECIPITATION TO THE SOUTHWESTERN
OREGON COAST AND PORTIONS OF NORTHERN CALIFORNIA...AND GUSTY WINDS
TO MUCH OF THE FORECAST AREA.

LIGHTNING HAS BEEN OBSERVED WITH THIS LOW...AND HAVE ADDED AND
MAINTAINED THUNDERSTORM COVERAGE AT THE COAST AND OVER THE COASTAL
WATERS THROUGH SATURDAY MORNING. WINDS HAVE ALREADY STARTED TO
INCREASE AHEAD OF THE LOW IN THE SHASTA VALLEY...AND A WIND ADVISORY
AT NPWMFR HAS BEEN ISSUED FOR BOTH THE SHASTA VALLEY AND PORTIONS OF
THE EAST SIDE. LOCAL MOS GUIDANCE AND WRF OUTPUT SUPPORT AN ADVISORY
FOR THIS EVENT WITH WIND GUSTS TO ABOUT 50 MPH EXPECTED.

SNOW IMPACTS FOR THIS SYSTEM ARE FOCUSED OVER NORTHERN
CALIFORNIA...AS IS TYPICAL WITH STORMS WITH HEFTY SOUTHERLY FLOW
LIKE THIS. MOST DATA POINTS TO SNOW AFFECTING AREAS 4000 FEET AND
ABOVE...WITH SNOW LEVELS REMAINING ABOVE 4000 FEET UNTIL SATURDAY
MORNING. ROAD SURFACE TEMPERATURES ARE FORECAST TO REMAIN ABOVE
FREEZING EVEN AT SNOWMANS SUMMIT...BUT WITH THE POTENTIAL FOR A
PERIOD OF MODERATE SNOWFALL SATURDAY MORNING...THINK THAT SNOW COULD
STICK ON THE ROADS. THEREFORE...HAVE ISSUED WINTER WEATHER ADVISORY
AT WSWMFR THROUGH SATURDAY AFTERNOON. SNOW WILL IMPACT THE
CASCADES AS WELL...AND MORESO ON SATURDAY AS UPSLOPE PRECIPITATION
BECOMES MORE OF A FACTOR AND SNOW LEVELS DROP TO 4000 TO 4500 FEET.

A GENERAL BREAK IN SIGNIFICANT STORMS IS EXPECTED LATE SATURDAY
THROUGH MONDAY.

.LONG TERM...MONDAY THROUGH FRIDAY...OVERALL THE PATTERN WILL BE
DOMINATED BY AN UPPER RIDGE. THIS RIDGE SHOULD GRADUALLY FLATTEN OUT
AND WEAKEN TOWARDS THE END OF NEXT WEEK. THIS WILL GIVE US A
RELATIVE BREAK IN THE WEATHER FROM NEXT MONDAY INTO NEXT THURSDAY.
THERE WILL STILL BE A CHANCE FOR RAIN, BUT IT SHOULD BE MAINLY
CONFINED TO THE MARINE WATERS AND COAST. FURTHER INLAND ODDS ARE IT
WILL STAY DRY UNTIL AT LEAST THURSDAY. TEMPERATURES ARE EXPECTED TO
BE MILD DURING THE DAY. THE MODELS DIFFER TOWARDS THE END OF THE
WEEK. ON FRIDAY, THE EC SHOWS MORE RIDGING AND KEEPS US IN THE WARM
SECTOR WHILE THE GFS SHOWS A TROUGH AND A COLD FRONT MOVING THROUGH
WITH COOLER TEMPERATURES AND LOWER SNOW LEVELS. THEREFORE CONFIDENCE
IN THE FORECAST FOR FRIDAY IS LOW. STAY TUNED FOR UPDATES. AFTER
FRIDAY...THE MODELS HINT A GENERAL TROUGHINESS OVER THE PAC NW WITH
COOLER AND UNSETTLED WEATHER A POSSIBILITY. - PETRUCELLI

&&

.AVIATION...FOR THE 22/18Z TAF CYCLE...LOW CLOUDS HAVE DISSIPATED
AND VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING. HIGH LEVEL
CLOUDS WILL INCREASE THIS AFTERNOON WITH MID LEVEL CLOUDS BY THIS
EVENING. THIS SHOULD BE ENOUGH TO PREVENT LOW LEVEL CLOUDS AND FOG
FROM DEVELOPING. LOW PRESSURE WILL BRING AREAS OF MVFR BACK TO THE
COAST LATE THIS EVENING AND LATE TONIGHT FOR INLAND WESTSIDE. GUSTY
SOUTHEAST WINDS ARE POSSIBLE TONIGHT IN MEDFORD AND THIS AFTERNOON
AT KLAMATH FALLS. -PETRUCELLI

&&

.MARINE...WEST SWELL WITH SUBSIDE, BUT REMAIN HIGH TODAY. LOW
PRESSURE WILL APPROACH THE WATERS THIS EVENING, THEN MOVE OVERHEAD
EARLY SATURDAY MORNING. SOUTH WINDS WILL INCREASE AS THE LOW
APPROACHES, THEN A WIND SHIFT WILL OCCUR FROM SOUTH TO NORTH AS
THE LOW MOVES ACROSS THE WATERS SATURDAY MORNING THEN SEAS WILL
SUBSIDE INTO EARLY NEXT WEEK.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY FROM 10 PM THIS EVENING TO 10 AM PST SATURDAY FOR
     ORZ030-031.

CA...WIND ADVISORY FROM 10 PM THIS EVENING TO 10 AM PST SATURDAY FOR
     CAZ085.
     WIND ADVISORY UNTIL 8 AM PST SATURDAY FOR CAZ081.
     WINTER WEATHER ADVISORY UNTIL 4 PM PST SATURDAY ABOVE 5000 FEET
     FOR FOR CAZ080.
     WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST
     SATURDAY ABOVE 4000 FEET FOR FOR CAZ082-083.

PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING FROM 10 PM THIS EVENING TO 10 AM PST
     SATURDAY FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST THIS
     EVENING FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 10 AM SATURDAY TO 4
     AM PST SUNDAY FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR PZZ376.

NSK/MAP/MAP