FXUS66 KSEW 092305
 AFDSEW
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE SEATTLE WA
 300 PM PST THU FEB 9 2012
 
 .SYNOPSIS...A WARM FRONT WAS MOVING THROUGH WESTERN WASHINGTON THIS 
 EVENING. A WEAKENING LOW PRESSURE SYSTEM WILL MOVE THROUGH THE AREA 
 FRIDAY. WEAK HIGH PRESSURE WILL BUILD INTO THE AREA SATURDAY NIGHT 
 AND SUNDAY MORNING. A FRONTAL SYSTEM WILL ARRIVE LATE SUNDAY AND 
 ANOTHER FRONT MAY REACH THE AREA LATE NEXT TUESDAY OR WEDNESDAY.
 
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 .SHORT TERM...A WARM FRONT IS MOVING THROUGH THE REGION THROUGH THIS 
 EVENING. THE VISIBLE SATELLITE IMAGE EARLY THIS AFTERNOON SHOWS AN 
 AREA OF LUMPIER DEEPER CLOUDS AND THE RADAR HAS PRECIP UNDER THOSE 
 JUST OFF THE COAST...AND THERE IS THE ADDITIONAL FRONTAL BAND JUST 
 OUTSIDE OF 130W WHICH WILL COME THROUGH ON FRIDAY. SO...RAIN IS 
 LIKELY THROUGH FRIDAY AS THE SOMEWHAT COMPLICATED TWO PART FRONTAL 
 SYS JUST OFFSHORE DRAGS THROUGH THE REGION. WEAK HIGHER PRES NOSES 
 IN OVER WRN WA SAT AND THE AREAS OF LIGHT RAIN WILL GIVE WAY TO A 
 MORE SHOWERY AIR MASS AS THE AIR ALOFT COOLS. THE SNOW LEVEL IS 
 RATHER HIGH IN THE MOUNTAINS TONIGHT BUT THAT WILL FALL OVER THE 
 WEEKEND. 19
 
 .LONG TERM...THE SYSTEM ON TAP FOR LATER SUNDAY IS MUCH MORE SPLIT 
 IN THE GLOBAL MODELS NOW. HAVE EASED BACK THE POPS AND DELAYED THAT 
 SYSTEM A BIT. MONDAY WILL SEE SOME SHOWERS AND THEN MONDAY NIGHT AND 
 TUESDAY ARE UP IN THE AIR. THE GFS HAS A SYSTEM MOVING THROUGH A 
 DIRTY RIDGE...THE ECMWF IS A NOTCH RIDGIER...ALTHOUGH 500MB HEIGHTS 
 IN THE 550S IS NOT MUCH OF A RIDGE. THE FCST IS JUST SORT OF NEAR 
 CLIMATOLOGY IN THE EXTENDED SINCE THE PROGS ARE PRETTY DIFFERENT ON 
 THE TIMING AND STRENGTH OF SHORTWAVES. 19
 
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 .HYDROLOGY...FLOODING IS UNLIKELY DURING THE NEXT 7 DAYS.
 
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 .AVIATION...SOUTHWESTERLY FLOW ALOFT THIS EVENING WILL BECOME MORE 
 SOUTHERLY TONIGHT. A SURFACE LOW WILL DEVELOP OFF THE COAST FRIDAY 
 WHILE A COLD FRONT MOVES INLAND. EASTERLY OR SOUTHEASTERLY SURFACE 
 PRESSURE GRADIENTS WILL CONTINUE THROUGH FRIDAY. AIR MASS IS MOIST 
 AND STABLE.
 
 CEILINGS WILL GENERALLY BE VFR AROUND 5K FT WITH OCCASIONAL LAPSES 
 INTO HIGH MVFR AROUND 3K FT. VISIBILITY VFR WITH LOCAL 4SM IN RAIN. 
 A POCKET OF IFR AROUND THE SOUTH SOUND SHOULD BE SHORT LIVED. AFTER 
 A SHORT PERIOD OF IMPROVEMENT TONIGHT...CONDITIONS WILL DETERIORATE 
 DURING THE DAY FRIDAY AS THE COLD FRONT AFFECTS THE WEATHER.
 
 KSEA...DISCUSSION ABOVE APPLIES. LIGHT WINDS WILL BECOME SOUTHEAST 
 4-8 KT. CHB
 
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 .MARINE...SMALL CRAFT ADVISORY WINDS WILL CONTINUE OVER MOST WATERS 
 WITH THE EXCEPTION OF PUGET SOUND. GRADIENTS WILL REMAIN STRONG 
 ENOUGH FOR SMALL CRAFT ADVISORY WINDS MOST WATERS THROUGH THE NIGHT 
 AND FRIDAY.
 
 NEXT SYSTEM IS A COLD FRONT AND AN ASSOCIATED LOW PRESSURE CENTER 
 THAT WILL AFFECT THE AREA FRIDAY. SMALL CRAFT ADVISORY WINDS ARE 
 LIKELY AGAIN OVER MOST WATERS. A WEAKER FRONT ARRIVES SUNDAY NIGHT.
 
 WESTERLY SWELL OF ABOUT 10 FEET THIS AFTERNOON WILL BUILD TO 13 FEET 
 TONIGHT AND TOP OUT AROUND 15-16 FEET FRIDAY. CHB
 
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 .SEW WATCHES/WARNINGS/ADVISORIES...
 WA...NONE.
 PZ...SMALL CRAFT ADVISORY ALL WATERS EXCEPT PUGET SOUND. 
      SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
 
 
 
 YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
 WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
 
 WWW.WEATHER.GOV/SEATTLE