Storm Watch 6, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
727 PM PST SUN MAR 6 2016

.DISCUSSION...THE FORECAST WAS UPDATED THIS EVENING TO ISSUE A
HIGH WIND WARNING FOR THE COAST FROM AROUND GOLD BEACH TO BANDON
THROUGH 9 PM PST. ALSO...TO LOWER SNOW LEVELS TONIGHT.

THE SURFACE LOW IS NOW JUST OFFSHORE FROM THE COOS AND DOUGLAS
COUNTY COAST AND WILL MOVE NORTHEAST TO THE VICINITY OF NEWPORT
DURING THE NEXT COUPLE OF HOURS. THERE IS A SLIGHT CHANCE OF
COASTAL THUNDERSTORMS DURING THE REMAINDER OF THE EVENING AND
THERE WILL BE A PERIOD OF MODERATE GUSTY WINDS INLAND DURING THE
REMAINDER OF THE EVENING AS THE FRONT MOVES EAST. THE MAIN BAND
OF PRECIPITATION IS WITH AND AHEAD OF THE FRONT AND EXTENDS FROM
THE VICINITY OF ROSEBURG AND GRANTS PASS...SOUTHWARD INTO SISKIYOU
COUNTY AND EASTWARD TO THE CASCADES. THE SNOW LEVEL HAS FALLEN TO
AROUND 4500 FEET EXCEPT 3000 TO 3500 FEET NEAR MOUNT SHASTA. THE
MAJORITY OF PRECIPITATION WILL OCCUR THROUGH AROUND MIDNIGHT BUT
THE SNOW LEVEL WILL CONTINUE TO FALL OVERNIGHT WITH A FEW FLURRIES
TO AROUND 3000 FEET...LOCALLY TO 2500 FEET. SNOWFALL WILL LINGER
LONGEST OVERNIGHT NEAR MOUNT SHASTA AND ACROSS MODOC COUNTY. THE
SNOWFALL AMOUNT FORECAST LOOKS APPROPRIATE WITH AROUND 6 INCHES
LIKELY AROUND MOUNT SHASTA WITH 3 TO 6 INCHES IN THE CASCADES AND
WARNER MOUNTAINS AND UP TO 3 INCHES ELSEWHERE ABOVE 3000 FEET.

THE FORECAST FOR MONDAY LOOKS ON TRACK WITH A SHORTWAVE IN A
WESTERLY FLOW ALOFT LIKELY TO BRING LIGHT SHOWERS...MAINLY IN
SOUTHWEST OREGON WEST AND NORTH OF JACKSON COUNTY. SHOWERS WILL
END EARLY MONDAY EVENING WITH A BREAK IN THE WEATHER INTO TUESDAY
MORNING AS A RIDGE BRIEFLY BUILDS TO THE WEST COAST. THIS WILL
LEAD TO A CHILLY START TO THE DAY ON TUESDAY. THE PATTERN BECOMES
ACTIVE AGAIN TUESDAY AFTERNOON WITH WARMER BUT WETTER WEATHER
LIKELY INTO NEXT WEEKEND.

&&

.AVIATION...FOR THE 07/00Z TAF CYCLE...VFR CONDITIONS WILL BE THE
PREDOMINATE CONDITION THIS EVENING, BUT COULD NOT RULE OUT TEMPORARY
MVFR CIGS IN SHOWERS. WIDESPREAD MVFR AND LOCAL IFR CIGS CAN BE
EXPECTED TONIGHT AS A COLD FRONT MOVES THROUGH. MODELS SHOW A
SURFACE LOW DEVELOPING JUST OFF THE COAST AND MOVING INLAND NEAR
CAPE BLANCO. THIS WILL RESULT IN INCREASING SOUTHEAST WINDS AT
MEDFORD AND STRONGER WINDS EAST OF THE CASCADES, INCLUDING KLAMATH
FALLS. WITH FALLING FREEZING LEVELS, LOCAL IFR IS POSSIBLE OVER THE
EAST SIDE TONIGHT, INCLUDING KLAMATH FALLS, WITH PERIODS OF SNOW.
/FB

&&

.MARINE...UPDATED 100 PM PST SUN 06 MAR 2016...A LOW PRESSURE WILL
MOVE THROUGH THIS AFTERNOON AND EVENING WITH A BRIEF PERIOD OF SOUTH
GALES, MAINLY SOUTH OF CAPE BLANCO. SEAS REMAIN VERY HIGH THROUGH
TONIGHT...THEN SUBSIDE BUT REMAIN HAZARDOUS TO SMALL CRAFT EARLY
THIS WEEK. ANOTHER SERIES OF FRONTS TUESDAY THROUGH THURSDAY WILL
BRING A RENEWED THREAT OF GALE TO STORM FORCE WINDS AND VERY STEEP,
WARNING LEVEL SEAS. MARINERS ARE URGED TO STAY TUNED TO NATIONAL
WEATHER SERVICE FORECASTS FOR UPDATES ON THIS PERIOD OF STORMY
WEATHER. /FB

&&

.PREV DISCUSSION... /ISSUED 110 PM PST SUN MAR 6 2016/

DISCUSSION...06/12Z NAM/GFS/EC IN.

THE NORTHERN HEMISPHERIC 500 MB CHART CONTINUES TO SHOW A WAVE
NUMBER OF FIVE AROUND THE GLOBE WITH SIGNIFICANT LONGITUDINAL
FLOW...INDICATIVE OF AN ACTIVE PROGRESSIVE PATTERN...WHICH IS
CERTAINLY THE CASE AROUND HERE.

COMPARED TO YESTERDAY IT IS RELATIVELY SEDATE THIS AFTERNOON. THE
WINDS HAVE DIMINISHED AND FLOODING IS NO LONGER A CONCERN...BUT
SNOW WILL BE A CONCERN THROUGH EARLY MONDAY MORNING. SNOW LEVELS
ARE RUNNING 3500-4000 FEET...SO SOME PASSES MAY SEE SIGNIFICANT
SNOW...ESPECIALLY AROUND THE MOUNT SHASTA AREA. HEAVY SURF
CONTINUES ALONG THE COAST AND THERE WILL BE A SHORT PERIOD OF GALE
FORCE WINDS THIS AFTERNOON OVER THE SOUTH WATERS AS ANOTHER SYSTEM
MOVES THROUGH THE COASTAL WATERS. THE WINDS WILL MAINTAIN AN
OFFSHORE COMPONENT WHICH ARGUES AGAINST WARNING LEVEL HIGH WINDS
OCCURRING AT THE COAST AS COASTAL DAMMING WILL NOT SET UP.

CURRENTLY THE PACIFIC NORTHWEST IS UNDER MODERATE SOUTHWEST FLOW
ALOFT BETWEEN AN OFFSHORE LONG WAVE TROUGH AND A LONG WAVE RIDGE
OVER THE EASTERN U.S. THE STORM DOOR REMAINS OPEN AND THE PACIFIC
NORTHWEST IS VULNERABLE TO SHORT WAVE EJECTED BY THE OFFSHORE
TROUGH...AND THE TROUGH ITSELF WHEN IT MOVES ONSHORE.

EJECTED SHORT WAVES WILL CONTINUE TO MOVE THROUGH THE AREA UNTIL
THE LONG WAVE TROUGH MOVES ONSHORE MONDAY MORNING. EXPECT CONTINUED
SHOWER ACTIVITY...WHICH WILL BE ENHANCED LATE SUNDAY AFTERNOON AND
EVENING AS A STRONGER SHORT WAVE MOVES THROUGH ALOFT AND PUSHES A
FRONT ONSHORE. SNOW LEVELS OF 3500-4000 FEET WILL DROP TO 2500-3500
FEET TONIGHT...SO SOME PASSES MAY SEE SIGNIFICANT SNOW...ESPECIALLY
AROUND THE MOUNT SHASTA AREA. HEAVY SURF CONTINUES ALONG THE COAST
AND THERE WILL BE A SHORT PERIOD OF GALE FORCE WINDS THIS AFTERNOON
OVER THE SOUTH WATERS AS THE FRONT MOVES ONSHORE.

A LONG WAVE RIDGE WILL BUILD INTO THE WEST COAST MONDAY
AFTERNOON...BRINGING A SHORT BREAK IN THE ACTION. THERE WILL STILL
BE SOME SHOWERS AROUND MONDAY AFTERNOON...BUT MONDAY NIGHT AND
TUESDAY MORNING LOOKS DRY. THE RIDGE AXIS WILL BREAK TO THE EAST
OF THE AREA TUESDAY AFTERNOON AND THE STORM DOOR WILL OPEN ONCE
AGAIN. THE NEXT FRONT WILL PROCEED APACE...MOVING ONSHORE TUESDAY
AFTERNOON. THIS FRONT WILL BECOME PARALLEL TO THE UPPER LEVEL
FLOW AND OSCILLATE BACK AND FORTH OVER THE AREA WHILE LOWS
DEVELOP AN MOVE NORTHEAST ALONG THE FRONTAL BOUNDARY. INITIALLY
SNOW LEVELS WILL BE AROUND 3000 FEET BUT WILL QUICKLY RISE TO
ABOVE 6000 FEET OVER MOST OF THE CWA.  SUSTAINED MODERATE
PRECIPITATION AND POSSIBLE FLOODING WILL BE THE PRIMARY CONCERN
DURING THIS INTERVAL.

EXTENDED DISCUSSION...WEDNESDAY THROUGH SUNDAY. THE PATTERN IN
THE EXTENDED PERIOD HAS NOT CHANGED. IT'S STILL GOING TO REMAIN
FAIRLY ACTIVE WITH A SERIES OF STORMS MOVING THROUGH THE FORECAST
AREA. AS ALWAYS, THE TIMING OF EACH ONE COULD VARY FROM ONE DAY TO
THE NEXT, SO STAY TUNED FOR THE LATEST UPDATES. CONFIDENCE REMAINS
HIGH WE'LL HAVE ABOVE NORMAL PRECIPITATION THROUGH THE PERIOD. THE
MODELS CONTINUE TO SHOW THE STRONGEST OF THESE STORMS IN TERMS OF
PRECIPITATION WILL BE WEDNESDAY THROUGH THURSDAY AFTERNOON.
HOWEVER THE MODELS ARE STARTING TO SHOW THE WARM FRONT LIFTING
NORTH OF THE AREA THURSDAY AFTERNOON WHICH COULD GIVE US A BREAK
IN THE RAINFALL. IF THIS PANS OUT, THIS WILL LESSEN THE THREAT FOR
FLOODING (IT WILL STILL NEED TO BE MONITORED CLOSELY). THUS HAVE
ADJUSTED POPS DOWN DURING THIS TIME PERIOD. ANY BREAK WON'T LAST
LONG WITH THE COLD FRONT EXPECTED TO BRING A RETURN OF MODERATE TO
HEAVY PRECIPITATION WEDNESDAY EVENING THROUGH AT LEAST THURSDAY
MORNING. THE GFS CONTINUES TO SHOW THE FRONT MOVING THROUGH THE
AREA THURSDAY AFTERNOON. MEANWHILE, THE EC AND CANADIAN SHOW
SLOWER SOLUTIONS WITH THE FRONT NOT MOVING THROUGH UNTIL THURSDAY
EVENING. GIVEN THE UPPER FLOW WILL BE NEARLY PARALLEL TO THE
FRONT, SUSPECT THE SLOWER SOLUTION IS THE WAY TO GO AND WE'LL
CONTINUE TO LEAN TOWARDS THE SLOWER SOLUTION. THE SOUTHWEST UPPER
FLOW WILL ALSO ENHANCE PRECIPITATION RATES ALONG THE COAST AND
COASTAL MOUNTAINS. IN A NUT SHELL THIS MEANS WE COULD HAVE A 12-18
HOUR PERIOD OF MODERATE TO HEAVY PRECIPITATION WHICH COULD RESULT
IN URBAN AND SMALL STREAM FLOODING. ALSO THERE'S A CHANCE SOME OF
THE MAINSTEM RIVERS, LIKE THE COQUILLE AT COQUILLE COULD REACH
FLOOD STAGE THURSDAY EVENING OR NIGHT. KEEP IN MIND WERE STILL
SEVERAL DAYS OUT AND THE DETAILS COULD CHANGE, BUT IT'S SOMETHING
WE'LL NEED TO KEEP A CLOSE EYE ON. THE MODELS CONTINUE SHOW
DIFFERENT SOLUTIONS ON FRIDAY, THEREFORE NO CHANGES WERE MADE.
ANOTHER AND STRONGER FRONT COULD IMPACT THE AREA NEXT SATURDAY.
-PETRUCELLI

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING UNTIL 9 PM PST THIS EVENING FOR ORZ021-022.
     WINTER WEATHER ADVISORY UNTIL 4 AM PST MONDAY ABOVE 3500 FEET
     FOR ORZ029>031.
     HIGH SURF ADVISORY UNTIL 6 AM PST MONDAY FOR ORZ021-022.
     WINTER WEATHER ADVISORY UNTIL 4 AM PST MONDAY ABOVE 3500 FEET
     FOR ORZ025-027-028.

CA...WINTER WEATHER ADVISORY UNTIL 4 AM PST MONDAY ABOVE 3500 FEET
     FOR FOR CAZ085.
     WINTER WEATHER ADVISORY UNTIL 4 AM PST MONDAY ABOVE 3500 FEET
     FOR FOR CAZ080>084.

PACIFIC COASTAL WATERS...GALE WARNING UNTIL 9 PM PST THIS EVENING
     FOR PZZ350-356-370-376.
     HAZARDOUS SEAS WARNING UNTIL 2 AM PST MONDAY FOR
     PZZ350-356-370-376.

DW/JRS/FJB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
928 PM PST SUN MAR 6 2016

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

0927 PM     SNOW             1 WSW MOUNT SHASTA      41.32N 122.34W
03/06/2016  M3.0 INCH        SISKIYOU           CA   TRAINED SPOTTER

            SINCE 3 PM PST OBSERVER LOCATION 1.2 MILES
            WEST OF I-5 & LASSEN LN..

&&

NWS MEDFORD OR
IRIS SYSTEM