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000
FXUS66 KMFR 112220
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
320 PM PDT TUE MAR 11 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...THERE ARE TWO ITEMS
OF PARTICULAR INTEREST IN THE SHORT TERM FORECAST. THE FIRST IS
GUSTY EASTERLY (NORTHEAST TO SOUTHEAST) WINDS THAT WILL CONTINUE
THROUGH THIS EVENING...AND MORE NARROWLY OVER THE HIGHER TERRAIN
OF SOUTHWEST OREGON AND THE SOUTHERN ROGUE VALLEY THROUGH THE NIGHT.
THE SECOND ITEM IS A COLD FRONT ON FRIDAY IN WHICH THE GFS, NAM,
AND ECMWF HAVE TRENDED BACK TOWARD A STRONGER ALTHOUGH STILL NOT
VERY STRONG SOLUTION.

GUSTS TO 30 MPH HAVE BEEN REPORTED IN SOUTHERN JACKSON COUNTY AND
AT THE PARKER MOUNTAIN RAWS IN THE SISKIYOU MOUNTAINS/FAR
SOUTHWEST KLAMATH COUNTY...AND TO 35 MPH IN THE SHASTA VALLEY...AND 40
MPH AT THE SLATER BUTTE RAWS IN NORTHWEST SISKIYOU COUNTY. THE NAM
INDICATES GRADIENTS IN SOUTHWEST OREGON WILL REACH A PEAK AROUND
06Z/11 PM PDT THIS EVENING. WITH SOME LOW LEVEL DRYING...VALLEY
LOW CLOUDS IN SOUTHWEST OREGON ARE EXPECTED TO BE A LITTLE SLOWER
TO DEVELOP IN THE UMPQUA AND ILLINOIS VALLEYS AND MAY NOT DEVELOP
IN THE ROGUE VALLEY AT ALL. A WEAK UPPER LEVEL TROUGH WILL MOVE
INTO BRITISH COLUMBIA ON WEDNESDAY AND WEAKEN THE RIDGE OVER OUR
REGION. THE EFFECTS WILL BE A FEW CIRRUS CLOUDS, AND WEAKER WINDS.
BUT, WITH A CHANGE TO WEAK SOUTHERLY WINDS, IT WILL ACTUALLY BE
GENERALLY A BIT WARMER ON WEDNESDAY.

THERE WILL BE LITTLE CHANGE IN THE WEATHER FROM WEDNESDAY INTO
THURSDAY...PERHAPS A DEGREE OR TWO OF COOLING AS THE RIDGE WEAKENS
FURTHER BUT REMAINS IN PLACE.

THE MODEL SOLUTIONS FOR THE COLD FRONT EXPECTED ON FRIDAY/DAY 3 HAS
REVERTED BACK TO HOW IT LOOKED A FEW DAYS AGO WHEN FRIDAY WAS DAY
7 OR 8 OF THE FORECAST. THERE WAS GOOD AGREEMENT ON A VERY SPRING-
LIKE SYSTEM WITH MODERATE RAIN FOCUSED ON WASHINGTON AND NORTHERN
OREGON BUT LIGHT RAIN AT THE SOUTHERN EDGE OF THE FRONT EXTENDING
TO COOS AND DOUGLAS COUNTIES. I BUMPED UP POPS JUST CLOSE TO THE
GFS MOS GUIDANCE FOR NOW, AS I WAS RELUCTANT TO BUY IN COMPLETELY
TO THE CHANGE TO MEASUREABLE RAIN REACHING NORTH BEND, ROSEBURG,
AND CRATER LAKE. BUT, IF FUTURE RUNS OF THE MODEL DATA ARE CONSISTENT,
A FURTHER BUMP UP WILL BE WARRANTED. THE REMAINDER OF SOUTHWEST
OREGON AND NORTHERN PORTIONS OF SOUTH CENTRAL OREGON COULD RECEIVE
SOME SPRINKLES WHILE NORTHERN CALIFORNIA IS LIKELY TO REMAIN DRY.


.LONG TERM...SATURDAY THROUGH TUESDAY NIGHT...AFTER RIDGING WITH
SIGNIFICANT WARMING ON SATURDAY, PREVIOUS RUMORS OF A FRONT COMING
THROUGH ON SUNDAY HAVE STOPPED AND THE ECMWF HAS BEEN CHASTISED
AND HAS FALLEN IN LINE WITH THE GFS. HOWEVER...THE ECMWF REMAINS
UN- RECALCITRANT AND IS BRINGING A FRONT THROUGH THE RIDGE SUNDAY
MORNING. I HAVE OPTED TO IGNORE THIS MINI PROTEST AND KEEP THE
REGION DRY THROUGH THE WEEKEND. BOTH THE GFS AND ECMWF ARE ALMOST
IDENTICAL IN DEEPENING AN ALMOST FULL LATITUDE TROUGH...AT AROUND
140W SUNDAY MORNING...AND CLOSING THE LOW BY TUESDAY MORNING. FROM
THERE CONFIDENCE IS VERY LOW...WITH THE GFS SLOWLY MIGRATING THE
CLOSED UPPER LOW TO JUST OFFSHORE OF NORTHERN CALIFORNIA BY
WEDNESDAY MORNING...AND THE ECMWF. NO CONFIDENCE WAS ADDED BY THE
ENSEMBLES...WHO...IN FEELING UNCOMFORTABLE WITH THE
CONFLICT...HAVE DECIDED EN MASSE NOT TO SHOW AND ONLY THREE
INDIVIDUAL PLOTS HAVE BEEN BRAVE ENOUGH TO DISPLAY. SVEN


&&

.AVIATION...BASED ON THE 11/12Z TAF CYCLE...

OFFSHORE FLOW WILL INTENSIFY OVERNIGHT WITH RIDGETOPS RELATIVE
HUMIDITIES DROPPING INTO THE 10-25% RANGE. EVEN WITH THE VERY DRY
OFFSHORE FLOW, AM STILL EXPECTING THAT FOG WILL FORM IN THE WEST SIDE
VALLEYS A LITTLE BEFORE OR AROUND SUNRISE...BUT IT SHOULD BE LESS
EXTENSIVE AND BURN OFF MORE QUICKLY THAN IT DID THIS MORNING. THE REST OF
THE REGION SHOULD REMAIN VFR THROUGH WEDNESDAY EVENING. SVEN

&&

.MARINE...A THERMAL TROUGH ALONG THE OREGON COAST IS BRINGING
STRONG NORTH TO NORTHEAST WINDS TO THE WATERS...STRONGEST BEYOND
5 NM FROM SHORE IN THE AREA FROM CAPE BLANCO SOUTHWARD WITH GUSTS
NEAR 35 KTS THROUGH THIS EVENING. STEEP WIND DRIVEN SEAS ARE ALSO
EXPECTED DUE TO MODERATE NORTH WINDS. WINDS WILL TAPER OFF TONIGHT
INTO WEDNESDAY MORNING. SMALL CRAFT ADVISORY LEVEL SEAS ARE
EXPECTED ACROSS THE AREA. HOWEVER FOR AREAS BEYOND 10 NM FROM
SHORE FROM PORT ORFORD SOUTH, SEAS ARE EXPECTED TO BE VERY STEEP AND
AT HAZARDOUS SEAS WARNING LEVELS.

THE NEXT FRONTAL SYSTEM WILL REMAIN WELL NORTH OF THE WATERS BUT
IT WILL GENERATE A RAPIDLY INCREASING LONG PERIOD WEST TO
NORTHWEST SWELL WEDNESDAY NIGHT THROUGH WEDNESDAY NIGHT. SEAS WILL
DIMINISH THURSDAY INTO FRIDAY. THEN ANOTHER FRONTAL SYSTEM WILL
ARRIVE FRIDAY WITH AN INCREASING WEST TO NORTHWEST SWELL FRIDAY
NIGHT THROUGH SATURDAY INTO SUNDAY.


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR ORZ026.

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT
     THIS EVENING FOR PZZ350-356-370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
     EVENING FOR PZZ350-356-370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM WEDNESDAY TO 5
     AM PDT THURSDAY FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 AM PDT WEDNESDAY FOR
     PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PDT WEDNESDAY
     FOR PZZ376.

$$

DW/SBN/JRS