Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 300120
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
620 PM PDT SAT AUG 29 2015

UPDATED MARINE, AVIATION, AND HEADLINE SECTIONS

.AVIATION...FOR THE 30/00Z TAF CYCLE...
MVFR CONDITIONS ALONG AND NEAR THE COAST THIS EVENING WILL CONTINUE
OVERNIGHT AS A SECONDARY COLD FRONT PUSHES INTO THE AREA. THIS
FRONT WILL SPREAD SHOWERS AND MVFR CLOUDS INTO THE UMPQUA BASIN
AND EASTWARD INTO VALLEY AREAS NEAR THE COASTAL MOUNTAINS. EXPECT
PARTIAL TERRAIN OBSCURATIONS TO DEVELOP TONIGHT THROUGH SUNDAY
OVER AND NEAR THE CASCADES WITH NEAR TOTAL TERRAIN OBSCURATIONS
DEVELOPING OVER THE UMPQUA DIVIDE AND COAST RANGE. SLIGHT
IMPROVEMENT IN CEILINGS IS EXPECTED SUNDAY AFTERNOON AS THE FRONT
WEAKENS. BTL

&&

.MARINE...UPDATED 615 PM PDT SATURDAY 29 AUGUST 2015... ADVISORY
LEVEL SOUTH WINDS WILL CONTINUE NORTH OF CAPE BLANCO THROUGH 2 AM
PDT BEFORE GRADUALLY DIMINISHING AS LOW PRESSURE CONTINUES TO MOVE
ONSHORE ACROSS THE PACIFIC NORTHWEST AND WESTERN CANADA. ADVISORY
LEVEL SEAS WILL GENERALLY CONTINUE THROUGH SUNDAY. A SECONDARY
COLD FRONT PUSHING ACROSS THE WATERS TONIGHT THROUGH SUNDAY
MORNING WILL BRING SHOWERS. LATE SUNDAY AND MONDAY HIGH PRESSURE
WILL BRIEFLY BUILD BEFORE UNSETTLED CONDITIONS RETURN TUESDAY
THROUGH THE END OF THE WEEK. BTL

&&

.DISCUSSION... /ISSUED 232 PM PDT SAT AUG 29 2015/
THE SURFACE LOW, WHICH TRACKED A BIT FURTHER OFFSHORE THAN
EXPECTED THIS MORNING, HAS MOVED WELL TO THE NORTH AND IS NOW
MAKING ITS WAY ONSHORE ALONG VANCOUVER ISLAND. WINDS HAVE ALREADY
STARTED TO DIMINISH, BUT DAYTIME MIXING WILL KEEP BREEZY WINDS
ACROSS THE AREA THROUGH THIS EVENING. RADAR IMAGERY SHOWS SOME
SHOWERS CONTINUING ALONG THE COAST, BUT AMOUNTS SHOULD BE LIGHT,
AND LITTLE TO NO RAIN SHOULD MAKE IT FAR INLAND.

A SECONDARY FRONT WILL APPROACH THE AREA AND PASS THROUGH THE REGION
LATE THIS EVENING AND TONIGHT. THIS SHOULD BRING ANOTHER ROUND OF
WIND AND RAIN TO THE COAST AND WEST SIDE, BUT NOWHERE NEAR THE
EXTENT AS SEEN THIS MORNING. EXPECT A QUARTER INCH TO A HALF INCH AT
THE COAST AND IN THE COASTAL RANGES, WITH LESS THAN A TENTH FOR THE
REST OF THE WEST SIDE. AGAIN, VERY LITTLE MOISTURE IS EXPECTED TO
MAKE IT EAST OF THE CASCADES. THE COOLER AIR WILL ALSO KEEP AREA
TEMPERATURES WELL BELOW NORMAL FOR THIS TIME OF YEAR.

AFTER A BRIEF PERIOD OF RIDGING AND NEAR NORMAL TEMPERATURES MONDAY
INTO TUESDAY MORNING, ANOTHER TROUGH IS FORECAST TO DIG SOUTH OVER
THE PACIFIC NORTHWEST, AND THIS WILL BRING ANOTHER CHANCE FOR
PRECIPITATION TUESDAY NIGHT INTO WEDNESDAY. MODELS HAVE BACKED OFF
AB IT WITH THE MOISTURE CONTENT WITH THIS SYSTEM, SO HAVE DROPPED
POPS A BIT TO COME INTO LINE WITH THE NEW THINKING. CURRENT
SOLUTIONS WOULD SUGGEST THAT THE EVENT WOULD BE SIMILAR TO THE
FRONTAL PASSAGE TONIGHT.

LOOKING TOWARDS THE END OF THE WEEK, THE GFS AND ECMWF CONTINUE TO
KEEP THE REGION UNDER WHAT WOULD NORMALLY BE CONSIDERED A FALL
PATTERN. THEREFORE, HAVE KEPT BELOW NORMAL TEMPERATURES IN PLACE
THROUGH THE REMAINDER OF THE TERM. THE MODELS ARE NOT RESOLVING ANY
PARTICULAR WAVE THAT WOULD PRODUCE PRECIPITATION, SO HAVE KEPT MUCH
OF THE EXTENDED DRY. HOWEVER, GIVEN THE PATTERN, WOULD NOT BE
SURPRISED IF A LATE WEEK TROUGH IS RESOLVED BY THE MODELS IN LATER
RUNS. -BPN

&&

.FIRE WEATHER...UPDATED 200 PM PDT SATURDAY 29 AUGUST
2015...GENERAL BROAD UPPER TROUGHINESS IS EXPECTED TO PRODUCE
COOL, MOIST, ONSHORE FLOW OVER THE ENTIRE REGION THROUGH THE
UPCOMING WEEK. THIS WILL RESULT IN BELOW NORMAL TEMPERATURES AND
ABOVE NORMAL HUMIDITIES WITH TYPICAL DIURNALLY DRIVEN WIND
CONDITIONS. A WEAK COLD FRONT WILL BRING LIGHT RAIN TO WEST SIDE
LOCATIONS TONIGHT INTO SUNDAY MORNING, THEN THE NEXT CHANCE FOR
SUBSTANTIAL PRECIPITATION (MAINLY WEST SIDE) COMES WEDNESDAY INTO
THURSDAY AS ANOTHER FRONT MOVES THROUGH. -WRIGHT

&&

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

CA...NONE.

PACIFIC COASTAL WATERS...
- SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT SUNDAY
  FOR PZZ350-356-370-376.
- SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 AM PDT SUNDAY FOR
  PZZ350-370.

$$

BTL/BPN/TRW


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