Hazardous Seas Warning 15, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
906 PM PST MON FEB 1 2016

.DISCUSSION...AN OCCLUDED FRONT WILL MOVE INTO THE COASTAL WATERS
TONIGHT WITH THE WARM FRONT SLIDING INLAND OVER SISKIYOU COUNTY.
SHORT TERM GUIDANCE BRINGS PRECIPITATION TO THE COAST AROUND
MIDNIGHT WITH PRECIPITATION SPREADING INLAND ALONG THE LINE FROM
ROSEBURG SOUTHWARD INTO WESTERN SISKIYOU COUNTY AROUND 4 AM. LIGHT
SNOW IS POSSIBLE AGAIN IN THE ROGUE VALLEY LATE TONIGHT TOWARD THE
MORNING HOURS. WE HAVE UPDATED THE GRIDS TO REFLECT HIGHER CHANCE
OF LIGHT SNOW SHOWERS ESPECIALLY ON THE SOUTH END OF JACKSON
COUNTY.

&&

.AVIATION...FOR THE 02/00Z TAF CYCLE...VFR CONDITIONS AND SOUTHERLY
WINDS AHEAD OF A WEAK FRONT EXPECTED AT ALL TAF SITES THIS EVENING.

COAST AND UMPQUA BASIN...THE FRONT WILL PASS OVER THE AREA EARLY
TUESDAY MORNING, BRINGING MVFR CIGS...SHOWERS...AND WIDESPREAD
TERRAIN OBSCURATIONS. IF THE FRONT COMES IN WETTER THAN
EXPECTED...IFR CIGS COULD DEVELOP.

ROGUE VALLEY...THE FRONT WILL BRING MVFR VIS AND TERRAIN
OBSCURATION. THOUGH PRECIPITATION IS POSSIBLE, THE CURRENT
EXPECTATION IS FOR DOWNSLOPING TO PREVENT ANY ACCUMULATION. THAT
SAID...SNOW LEVELS TONIGHT AND EARLY TUESDAY MORNING WILL DROP TO
AROUND 1300 FEET IN THE ROGUE VALLEY THUS ANY PRECIPITATION THAT
ACCUMULATES WILL LIKELY BE SNOW.

CASCADES AND EAST...EXPECT LIGHT SNOW EARLY TUESDAY MORNING WITH
MVFR CIGS AND VIS. TERRAIN OBSCURATIONS EXPECTED. CONDITIONS WILL
IMPROVE TUESDAY AFTERNOON. -MSC

&&

.MARINE...UPDATED 240 PM PST MON 1 FEB 2016...SOUTHERLY WINDS WILL
CONTINUE THIS EVENING AHEAD OF A WEAK FRONT. THIS FRONT WILL BRING
WILL BRING RAIN...INCREASING AND SHIFTING WINDS...AND A PERIOD OF
ELEVATED SEAS ON TUESDAY. SEAS IN AREAS WILL REACH ADVISORY
CONDITIONS LATE TONIGHT AND TUESDAY FROM THIS FRONT. WEDNESDAY...A
STRONGER COLD FRONT WILL THEN MOVE IN WITH SOUTH GALES AND VERY
STEEP SEAS POSSIBLE. THIS FRONT WILL BE FOLLOWED BY A HEAVY, LONG
PERIOD WEST SWELL WEDNESDAY NIGHT AND THURSDAY THAT IS CURRENTLY
EXPECTED TO PEAK AROUND 18 FEET AT 18 SECONDS THURSDAY MORNING.
-MSC

&&

.PREV DISCUSSION... /ISSUED 445 PM PST MON FEB 1 2016/

DISCUSSION...01/12Z NAM/GFS IN.

THE NORTHERN HEMISPHERIC CHART SHOWS A 4 WAVE PATTERN AROUND THE
GLOBE...WHICH IS GENERALLY A PROGRESSIVE PATTERN. THERE IS A JET
STREAM NOW DIVING SOUTH ALONG 130W AND MOVING ONSHORE OVER
NORTHERN CALIFORNIA BEFORE HEADING NORTHEAST. SOUTHERN OREGON AND
NORTHERN CALIFORNIA ARE ON THE COLD SIDE OF THE JET WITH COLD
TEMPERATURES AND LOW SNOW LEVELS.

ZOOMING CLOSER IN...A WEAK LONG WAVE TROUGH HAS MOVED ONSHORE...
BUT ONE MORE SHORT WAVE MOVING DOWN THE BACK SIDE OF THE TROUGH
AND THROUGH THE MEDFORD CWA THIS MORNING. THERE WILL BE SOME LIGHT
SHOWERS AROUND TODAY...MOSTLY ALONG THE COAST AND IN THE CASCADES.
AMOUNTS WILL BE VERY LIGHT WITH SNOW LEVELS IN THE 1500-2500 FOOT
RANGE. THE MEDFORD AREA GOT A DUSTING OF SNOW OVERNIGHT.

A STRONG SHORT WAVE WILL MOVE OVER THE TOP OF THE RIDGE AND
ONSHORE LATE TONIGHT INTO TUESDAY MORNING. THE WAVE WILL WEAKEN
AS IT MOVES IN AND WON'T AMOUNT TO MUCH BY THE TIME IT GETS HERE.
IT WILL SLOW DOWN AND WEAKEN AS IT MOVES THROUGH THE AREA...MOVING
OUT TO THE EAST TUESDAY NIGHT. THIS WILL BRING A ROUND OF ENHANCED
SHOWER ACTIVITY MONDAY EVENING THROUGH TUESDAY MORNING. IT STILL
WON'T AMOUNT TO MUCH THOUGH...FLOODING IS NOT A CONCERN HERE. AN
OFFSHORE RIDGE WILL MOVE IN TUESDAY NIGHT INTO WEDNESDAY. A WARM
FRONT WILL LIFT NORTH THROUGH THE AREA TUESDAY NIGHT WITH VERY
LIGHT PRECIPITATION.

THE PATTERN WILL REMAIN PROGRESSIVE...AND THE RIDGE AXIS WILL
BREAK TO THE EAST OF THE CWA WEDNESDAY MORNING. THE NEXT LONG
WAVE TROUGH WILL MOVE IN RIGHT BEHIND IT...MOVING ONSHORE
WEDNESDAY EVENING. THE GFS AND EC SOLUTIONS HAVE CONVERGED WITH
THIS SYSTEM WITH REGARD TO STRENGTH...BUT THE GFS IS AROUND SIX
HOURS FASTER THAN THE EC. SO...THE GFS COLD FRONT MOVES ONSHORE
EARLY WEDNESDAY AFTERNOON WHILE THE EC MOVES IT IN DURING THE
EVENING. EITHER WAY...THIS WILL BRING A ROUND OF HEAVIER AND
WIDESPREAD PRECIPITATION TO THE AREA. IT WILL BE A SIGNIFICANT
SYSTEM...BUT ONCE AGAIN NO FLOODING IS EXPECTED. WINDS MAY REACH
GALE FORCE OVER THE COASTAL WATERS AND WIND ADVISORIES MAY BE
NECESSARY EAST OF THE CASCADES WEDNESDAY.

ANOTHER WEAKER RIDGE WILL MOVE IN WEDNESDAY NIGHT INTO THURSDAY
FOR ANOTHER BREAK IN THE ACTION. THE LAST OF THE SHOWERS WILL END
WEDNESDAY NIGHT AND THURSDAY INTO THURSDAY NIGHT LOOKS TO BE DRY
AND WARMER. THE RIDGE AXIS WILL BREAK TO THE EAST OF THE AREA
FRIDAY.

EXTENDED DISCUSSION...FRIDAY, FEB 5TH THROUGH TUESDAY, FEB 9TH.
FRIDAY INTO SATURDAY A PROGRESSIVE UPPER LEVEL SHORTWAVE TROUGH
APPEARS LIKELY TO BRING ANOTHER LIGHT TO MODERATE IN STRENGTH
FRONTAL SYSTEM THROUGH THE FORECAST AREA. THIS FRONT IS LIKELY TO
BE PRECEDED BY A SIMILARLY PROGRESSIVE AND HIGH AMPLITUDE UPPER
LEVEL RIDGE. THUS, SNOW LEVELS WITH IT WILL BE FAIRLY HIGH AT
LEAST INITIALLY- BETWEEN 5KFT AND 7KFT WITH MOST OF THE CASCADES,
SISKIYOUS, ANS EAST SIDE SEEING SNOW LEVELS 6KFT OR LOWER. THERE
DOES APPEAR TO BE SOME AMPLITUDE AND TRACK DIFFERENCES WITH THE
UPPER LEVEL SHORTWAVE TROUGH IN THE NUMERICAL MODELS, AS THE 18Z
GFS SHOWS SNOW LEVELS FALLING MORE SHARPLY WITH THE FRONT- FROM
ABOUT 5KFT TO NEAR 3KFT. PRECIPITATION AMOUNTS ARE ALSO VARYING
FROM RUN TO RUN FROM LESS THAN A HALF INCH ALONG THE COAST AND
COAST RANGE TO NEARLY AN INCH. THIS FRONT IS LIKELY TO BE THE LAST
FOR AT LEAST A FEW DAYS.

HIGH PRESSURE WILL BUILD STRONGLY INTO THE AREA LATER THIS UPCOMING
WEEKEND INTO EARLY NEXT WEEK BRINGING WHAT APPEARS AS IF IT WILL BE
THE LONGEST BREAK BETWEEN STORMS IN OUR AREA SINCE NOVEMBER 26-30TH,
2015, WHEN WE HAD 5 CONSECUTIVE DRY DAYS. SUNDAY THROUGH NEXT
THURSDAY CURRENTLY LOOK AS IF THEY WILL BE DRY AND FAIRLY MILD DAYS.
WITH CONDITIONS CLEARING ALONG WITH LIGHT WINDS, SUSPECT WE'LL SEE A
LOT OF VALLEY FOG ON SUNDAY, BUT OFFSHORE FLOW WILL PROBABLY START
TO PUSH THIS OUT OF SOME VALLEYS AS EARLY AS MONDAY. EXPECT MOSTLY
SUNNY SKIES DURING THIS TIME PERIOD WITH VALLEY INVERSIONS YIELDING
MILD CONDITIONS IN THE MOUNTAINS. THIS MAY VERY WELL YIELD SOME
SPRING SKIING CONDITIONS IN THE MOUNTAINS.

HOW LONG THIS DRY PERIOD LASTS WILL BE CRITICAL TO HOW MUCH OUR AREA
CLIMBS OUT OF DROUGHT THIS SEASON, THOUGH THE CURRENT SNOWPACK
SHOULD GET MOST AREAS ALONG AND WEST OF THE CASCADES OUT OF DROUGHT.
CURRENT INDICATIONS FROM THE CLIMATE PREDICTION CENTER'S 8-14 DAY
FORECAST AND ENSEMBLE MODEL PREDICTIONS OF BOTH THE ARCTIC
OSCILLATION AND MADDEN JULIAN OSCILLATION FAVOR A RETURN TO STORM
ACTIVITY AROUND MID MONTH. THE VERY STRONG EL NINO ALSO FAVORS A
RETURN TO AN ACTIVE STORM TRACK. BTL

AVIATION...FOR THE 02/00Z TAF CYCLE...VFR CONDITIONS AND SOUTHERLY
WINDS AHEAD OF A WEAK FRONT EXPECTED AT ALL TAF SITES THIS EVENING.

COAST AND UMPQUA BASIN...THE FRONT WILL PASS OVER THE AREA EARLY
TUESDAY MORNING, BRINGING MVFR CIGS...SHOWERS...AND WIDESPREAD
TERRAIN OBSCURATIONS. IF THE FRONT COMES IN WETTER THAN
EXPECTED...IFR CIGS COULD DEVELOP.

ROGUE VALLEY...THE FRONT WILL BRING MVFR VIS AND TERRAIN
OBSCURATION. THOUGH PRECIPITATION IS POSSIBLE, THE CURRENT
EXPECTATION IS FOR DOWNSLOPING TO PREVENT ANY ACCUMULATION. THAT
SAID...SNOW LEVELS TONIGHT AND EARLY TUESDAY MORNING WILL DROP TO
AROUND 1300 FEET IN THE ROGUE VALLEY THUS ANY PRECIPITATION THAT
ACCUMULATES WILL LIKELY BE SNOW.

CASCADES AND EAST...EXPECT LIGHT SNOW EARLY TUESDAY MORNING WITH
MVFR CIGS AND VIS. TERRAIN OBSCURATIONS EXPECTED. CONDITIONS WILL
IMPROVE TUESDAY AFTERNOON. -MSC

MARINE...UPDATED 240 PM PST MON 1 FEB 2016...SOUTHERLY WINDS WILL
CONTINUE THIS EVENING AHEAD OF A WEAK FRONT. THIS FRONT WILL BRING
WILL BRING RAIN...INCREASING AND SHIFTING WINDS...AND A PERIOD OF
ELEVATED SEAS ON TUESDAY. SEAS IN AREAS WILL REACH ADVISORY
CONDITIONS LATE TONIGHT AND TUESDAY FROM THIS FRONT. WEDNESDAY...A
STRONGER COLD FRONT WILL THEN MOVE IN WITH SOUTH GALES AND VERY
STEEP SEAS POSSIBLE. THIS FRONT WILL BE FOLLOWED BY A HEAVY, LONG
PERIOD WEST SWELL WEDNESDAY NIGHT AND THURSDAY THAT IS CURRENTLY
EXPECTED TO PEAK AROUND 18 FEET AT 18 SECONDS THURSDAY MORNING.
-MSC

&&

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

PACIFIC COASTAL WATERS...GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR
     PZZ350-356-370-376.
     HAZARDOUS SEAS WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY
     EVENING FOR PZZ350-356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 10 AM TUESDAY TO 4
     AM PST WEDNESDAY FOR PZZ350-356.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST WEDNESDAY
     FOR PZZ370-376.

FJB/BTL/MSC