Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 221513
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
813 AM PDT FRI AUG 22 2014

.DISCUSSION...22/12Z NAM IN.

LOW STRATUS THIS MORNING ALONG THE COAST AND IN THE UMPQUA
BASIN...AND SOME HIGHER CLOUDS OVER SOUTHEAST SISKIYOU AND MODOC
COUNTIES. THERE IS ALSO LOTS OF SMOKE ALOFT EMANATING FROM SEVERAL
FIRES IN WESTERN SISKIYOU COUNTY.

A LONG WAVE UPPER LEVEL TROUGH REMAINS OVER THE PACIFIC NORTHWEST
THIS MORNING...WITH THE TROUGH AXIS RUNNING FROM BRITISH
COLUMBIA...THROUGH EASTERN WASHINGTON AND EASTERN OREGON...AND
INTO EXTREME WESTERN NEVADA. THE MEDFORD CWA REMAINS UNDER WEST TO
NORTHWEST FLOW ALOFT.

THE TROUGH WILL MOVE EAST...BUT THIS WILL BE A SLOW PROCESS DUE TO
SHORT WAVES DIVING DOWN THE BACKSIDE OF THE TROUGH. ONE SUCH WAVE
WILL MOVE THROUGH THIS AFTERNOON AND EVENING. IT WILL BE DRY DUE
TO ITS MOSTLY OVERLAND TRAJECTORY AND THE MAIN EFFECT WILL BE TO
ENHANCE OFFSHORE LOW LEVEL FLOW TONIGHT.

HEIGHTS WILL RISE SATURDAY AS THE TROUGH MOVES OUT AND ONSHORE
FLOW WILL RETURN SATURDAY NIGHT INTO SUNDAY. HOWEVER...ONE MORE
STRONG SHORT WAVE WILL DIVE DOWN SUNDAY NIGHT...WHICH WILL DIG OUT
ANOTHER TROUGH OVER THE PACIFIC NORTHWEST.

ONCE THAT TROUGH MOVES OUT MONDAY THE OFFSHORE LONG WAVE RIDGE
WILL BUILD IN IN EARNEST...AND THIS WILL KICK OFF ANOTHER HEAT
WAVE FOR THE INLAND PORTIONS OF THE MEDFORD CWA. OFFSHORE LOW
LEVEL FLOW WILL PEAK MONDAY NIGHT.

EXPECT CONTINUED DRY CONDITIONS INTO THE MIDDLE OF THE WEEK. THE
THERMAL TROUGH WILL MOVE INLAND WEDNESDAY...AND THIS WILL BRING
THE HOTTEST TEMPERATURES OF THE WEEK TO THE WEST SIDE VALLEYS. MEDFORD
HIGHS WILL FLIRT WITH THE CENTURY MARK WEDNESDAY.

THE UPPER RIDGE WILL SLOWLY WEAKEN AROUND THE MIDDLE OF THE WEEK...AND
THE AXIS WILL BREAK TO THE EAST OF THE AREA WEDNESDAY. THE MEDIUM
RANGE MODELS DIVERGE ON WHAT WILL HAPPEN NEXT. THE 22/06Z GFS
BRINGS IN ANOTHER LONG WAVE TROUGH THURSDAY. IF THIS VERIFIES THIS
WILL BRING IN SOME CLOUD COVER AND COOLER WEATHER. AT THIS POINT
IT LOOKS LIKE ASSOCIATED PRECIPITATION WILL REMAIN NORTH OF THE
AREA. ONCE THAT TROUGH MOVES INLAND...ANOTHER OFFSHORE FLOW EVENT
WILL DEVELOP FRIDAY NIGHT. MEANWHILE THE 22/00Z EC SOLUTION GOES
WITH CONTINUED WEAK RIDGING WITH THE AXIS WELL TO THE EAST OF THE
CWA. THIS WOULD BE A DRY AND WARMER SOLUTION...ALTHOUGH THE EC
GUIDANCE DOES SHOW A COOLING TREND INLAND FROM THURSDAY ON.

&&

.AVIATION...BASED ON THE 22/12Z TAF CYCLE...THE MARINE LAYER HAS
MADE A PUSH INLAND THIS MORNING...BRINGING STRATUS WITH MVFR CIGS TO
THE COAST AND INTO THE UMPQUA BASIN. STRATUS WILL BURN OFF TO VFR
BY MID MORNING AT THE COAST...BUT RETURN BY THE EVENING.
ADDITIONALLY...SMOKE FROM NEARBY WILDFIRES WILL REDUCE VISIBILITY
MAINLY IN SISKIYOU COUNTY. ELSEWHERE...VFR CONDITIONS WILL PERSIST
FOR THE NEXT 24 HOURS. -BPN

&&

.MARINE...UPDATED 200 AM PDT FRI 22 AUG 2014...WINDS AND SEAS WILL
BEGIN TO BUILD LATER TODAY AS  A THERMAL TROUGH PATTERN
DEVELOPS. THIS WILL RESULT IN A RETURN OF GUSTY NORTH WINDS
AND WIND DRIVEN SEAS, WHICH WILL LAST THROUGH AT LEAST TUESDAY. THE
STRONGEST WINDS AND STEEPEST SEAS WILL BE OVER THE SOUTHERN OUTER
WATERS SOUTH OF GOLD BEACH DURING THE AFTERNOONS AND EVENINGS.
THERE IS SOME UNCERTAINTY REGARDING WIND STRENGTH THROUGH THE
WEEKEND, BUT WINDS ARE EXPECTED TO REMAIN BELOW GALE STRENGTH.
WITH NORTH WINDS CONTINUING FOR SEVERAL DAYS, HAVE OPTED TO ISSUE
A HAZARDOUS SEAS WATCH FOR THE SOUTHERN OUTER WATERS BEGINNING
SATURDAY AFTERNOON, BUT MUCH WILL DEPEND ON THE STRENGTH AND THE
EXTENT OF THE AFFECTED AREA AS TO HOW STEEP THE SEAS MAY BECOME.
CONFIDENCE SHOULD INCREASE OVER THE NEXT SEVERAL FORECAST CYCLES.
-BPN

&&

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

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM
        SATURDAY TO 11 PM PDT TUESDAY FOR PZZ356-370.
     HAZARDOUS SEAS WATCH FROM SATURDAY AFTERNOON THROUGH TUESDAY
        EVENING FOR PZZ356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS AFTERNOON
        TO 11 PM PDT TUESDAY FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM THIS AFTERNOON TO 11 PM
        PDT TUESDAY FOR PZZ376.

$$

15/15/15




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