Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 291631
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
931 AM PDT FRI AUG 29 2014

.UPDATE...THE ONLY UPDATE MADE THIS MORNING WAS TO A FEW SKY GRIDS
TO ACCOUNT FOR THE CLOUD COVER ALONG THE COAST AND IN THE COASTAL
VALLEYS EXPECTED TO PERSIST INTO THE AFTERNOON. ASIDE FROM THIS
CHANGE THE REST OF THE FORECAST LOOKS ON TRACK AND WILL NOT
UPDATE ANYTHING ELSE. THIS MORNINGS VISIBLE SATELLITE ALSO SHOWS
SMOKE FROM THE JULY COMPLEX WILDFIRES AFFECTING THE SOUTHWESTERN
PORTION OF JACKSON COUNTY, THE SOUTHERN PORTION OF KLAMATH COUNTY,
AND ALMOST ALL OF LAKE COUNTY. THERE IS ALSO SOME HIGH CIRRUS
CLOUDS ABOVE THE SMOKE AND SOME OF THE HIGHER CLOUDS FROM POST
TROPICAL STORM MARIE ARE FILTERING INTO NORTHERN AND CENTRAL
CALIFORNIA. SEE THE PREVIOUS DISCUSSION FOR MORE DETAILS ON THE
WINDS EXPECTED LATER THIS AFTERNOON. MND

&&

.PREV DISCUSSION... /ISSUED 204 AM PDT FRI AUG 29 2014/

DISCUSSION...29/00Z NAM/GFS IN.

AREAS OF LOW CLOUDS ALONG THE COAST AND IN THE COQUILLE VALLEY THIS
MORNING...ALONG WITH SOME HIGHER CLOUDS STREAMING THROUGH OVER
NORTHERN CALIFORNIA AND EXTREME SOUTHERN OREGON. THERE IS ALSO A LOT
OF SMOKE COMING OFF THE WESTERN SISKIYOU COUNTY FIRES. OTHER THAN
THAT...MOSTLY CLEAR SKIES PREVAIL.

SEVERAL WEAK SYSTEMS WILL MOVE ONSHORE TO THE NORTH OVER THE NEXT
SEVERAL DAYS. THE FIRST ONE WILL MOVE ONSHORE TODAY. IT WILL PUSH
A COLD FRONT ONSHORE AHEAD OF IT. WHILE THIS FRONT WILL BE
DRY...GUSTY WINDS WILL DEVELOP AHEAD OF IT. WINDS WILL BE STRONGEST
THIS AFTERNOON AND EVENING FROM THE CASCADES EAST WITH SPEEDS OF
15 TO 25 MPH WITH GUSTS AS HIGH AS 35 MPH. THE WEST SIDE WILL ALSO
BE BREEZY BUT WINDS WILL BE LIGHTER THAN THE EAST SIDE. INLAND
TEMPERATURES WILL STILL BE ABOVE NORMAL TODAY...BUT 5-10 DEGREES
COOLER THAN THURSDAY. THE DYNAMICS ALOFT WILL CRANK UP THE DEPTH
OF THE MARINE LAYER...SO EXPECT MORE INLAND PENETRATION OF STRATUS
IN THE NIGHTTIME HOURS.

THE SECOND SYSTEM WILL MOVE IN SATURDAY. EXPECT A REPLAY OF THE
FRIDAY WINDS SATURDAY AFTERNOON AND EVENING. THERE ALSO MAY BE
SOME DRIZZLE ALONG THE COAST WITH THIS SYSTEM AS THE MARINE LAYER
DEPTH WILL CONTINUE TO INCREASE. EXPECT MARINE CLOUDS TO FILL UP
THE UMPQUA BASIN SATURDAY NIGHT...BUT IT LIKELY WON`T BE THICK
ENOUGH TO SPILL OVER INTO THE ROGUE VALLEY. INLAND TEMPERATURES
WILL COOL ANOTHER 5-10 DEGREES TO VALUES ANYWHERE FROM JUST BELOW
TO NEAR 10 DEGREES BELOW NORMAL.

AFTER THAT SYSTEM MOVES OUT TO THE EAST SATURDAY NIGHT...A BROAD
LONG WAVE RIDGE WILL BUILD IN FROM THE WEST. THE MEDFORD CWA WILL
REMAIN UNDER DRY NORTHWEST FLOW ALOFT SUNDAY AND MONDAY. THE MARINE
LAYER DEPTH WILL DECREASE IN RESPONSE TO STRONGER SUBSIDENCE ALOFT.
SUNDAY TEMPERATURES INLAND WILL BE ABOUT THE SAME AS SATURDAY...BUT
A WARMING TREND WILL COMMENCE MONDAY AS THE RIDGE BUILDS IN MORE
STRONGLY.

LONG TERM DISCUSSION FROM THE THURSDAY AFTERNOON AFD...MONDAY
THROUGH THURSDAY. A HIGH PRESSURE RIDGE FAR OFFSHORE FROM
CALIFORNIA ON THE WEEKEND WILL BUILD EAST TO THE COAST ON LABOR
DAY. THIS WILL RESULT IN AN ONSHORE NORTHWEST LOW LEVEL FLOW WITH
A MARINE PUSH OF LOW CLOUDS TO THE COAST NORTH OF CAPE BLANCO
SUNDAY NIGHT THAT IS LIKELY TO LINGER INTO MONDAY AFTERNOON.
ELSEWHERE IN THE AREA, IT WILL REMAIN MOSTLY CLEAR WITH HIGH
TEMPERATURES RETURNING TO AROUND NORMAL. THE RIDGE WILL BUILD
INLAND TUESDAY WITH A FEW DEGREES OF ADDITIONAL WARMING.

THE 12Z GFS AND ECMWF MODEL SOLUTIONS BEGIN TO DIVERGE MORE
NOTICEABLY AFTER TUESDAY. THE ECMWF IS STRONGER/DEEPER, FASTER,
AND FURTHER SOUTH WITH THE ARRIVAL OF A TROUGH FROM THE GULF OF
ALASKA INTO THE PACIFIC NORTHWEST AT MID-WEEK. WE HAVE GONE WITH A
MODEL BLEND. THE GFS SOLUTION WOULD BE CONTINUED VERY WARM AND
DRY FOR OUR AREA WHILE THE ECMWF WOULD INDICATE A RETURN TO NEAR
NORMAL OR SLIGHTLY BELOW NORMAL TEMPERATURES AND THE POSSIBILITY
OF WEAK INSTABILITY ON THE EAST SIDE.

&&

.AVIATION...BASED ON THE 29/12Z TAF CYCLE...IFR CIGS WILL CONTINUE
IN COOS COUNTY WITH SATELLITE IMAGERY SHOWING DEEP PENETRATION
INLAND. SHORT TERM MODELS BRING LOW CLOUDS AND MVFR CIGS INTO THE
UMPQUA BASIN AROUND SUNRISE TODAY AND THIS LOOKS REASONABLE. IFR
CIGS EXTEND ALONG THE COAST DOWN INTO SOUTHERN CURRY COUNTY AND WILL
BE SLOW TO BURN OFF SUCH THAT WE MAY NOT SEE VFR AT ALL AT THE COAST
TODAY. ELSEWHERE VFR CONDITIONS WILL PREVAIL EXCEPT FOR AREAS OF
WILDFIRE SMOKE PRODUCING MVFR/IFR VISIBILITIES IN SISKIYOU COUNTY.
THE PLUME FROM THOSE FIRES WILL ALSO PRODUCE AREAS OF HAZE AND MID
TO HIGH LEVEL CIGS DOWNWIND, PARTICULARLY ACROSS THE REST OF
NORTHERN CALIFORNIA AND INTO THE KLAMATH BASIN, WHERE OCCASIONAL
MVFR VIS IS POSSIBLE AT KLMT. /FB

&&

.MARINE...UPDATED 200 AM PDT FRI 29 AUG 2014...VERY SHORT PERIOD
SEAS WILL CONTINUE IN PART OF THE MARINE ZONE THIS MORNING. CHOPPY
SEAS WILL EXPAND CLOSER TO THE COAST AND COME WITHIN MARINE ZONE 356
THIS AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE COASTAL WATERS
THIS AFTERNOON. EXPECT INCREASING NORTHWEST SWELL LATE SATURDAY INTO
SUNDAY. BEHIND THIS SYSTEM, THERE IS A CHANCE FOR MODERATE NORTH
WINDS AND STEEP SEAS TO DEVELOP EARLY NEXT WEEK. /FB

&&

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

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
     5 AM PDT SATURDAY FOR PZZ356.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT SATURDAY
     FOR PZZ376.

$$

MND/BPN/MND






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