000 FXUS66 KPQR 142217 AFDPQR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PORTLAND OR 300 PM PDT SAT JUL 14 2007 .SYNOPSIS...A STRONG RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE INTERIOR WESTERN STATES THROUGH THE WEEKEND WITH AN UPPER LEVEL LOW OVER THE NORTHEAST PACIFIC. A WEAK PACIFIC FRONT WAS OFF THE COAST THIS AFTERNOON AND WILL BRUSH MAINLY THE COASTAL AREAS TONIGHT AND SUNDAY. PIECES OF THE OFFSHORE LOW MAY AFFECT SOUTHWEST WASHINGTON AND NORTHWEST OREGON AT TIMES DURING THE MIDDLE OF NEXT WEEK. && .SHORT TERM...A RATHER STRONG UPPER LEVEL RIDGE REMAINED OVER THE INTERIOR OF THE WESTERN U.S. THIS AFTERNOON...WITH AN UPPER LOW CENTERED AROUND 44N/143W IN THE NORTHEAST PACIFIC. A WEAK PACIFIC FRONT OUT AHEAD OF THE LOW WAS INSIDE 130W THIS AFTERNOON AND MAKING SLOW PROGRESS TOWARD THE COAST. THE RESULTANT SOUTHERLY FLOW OVER OUR AREA CONTINUES TO RESULT IN SOME MID AND HIGHER LEVEL CLOUDS OVER THE FORECAST AREA. THE NATIONAL WEATHER SERVICE DOPPLER RADAR IS DETECTING SOME WEAK ECHOES BUT CLOUD HEIGHT OBSERVATIONS SUGGEST NONE OF THIS IS LIKELY REACHING THE GROUND. THE MODELS DO SHOW A LITTLE INSTABILITY OVER THE HIGHER CASCADES THIS AFTERNOON AND EVENING IN THE SOUTHERLY FLOW...BUT THIS IS TEMPERED A BIT BY THE ONSHORE FLOW WITH THE THERMAL TROUGH REMAINING TO THE EAST OF THE CASCADES. WILL KEEP THE SLIGHT CHANCE FOR THUNDERSTORMS OVER THE CASCADES. THE OFFSHORE FRONT BEGINS AFFECTING THE COAST TONIGHT...THEN LIFTS NORTH SUNDAY BEFORE GETTING VERY FAR INLAND. MAIN EFFECT INLAND WILL BE SOME MORNING CLOUDS SUNDAY AND A BIT COOLER TEMPERATURES. ON MONDAY NOT A LOT OF CHANGE AS THERE WILL PROBABLY BE SOME MORNING CLOUDS INLAND THROUGH COASTAL GAPS AGAIN...BUT SOUTHERLY FLOW INCREASES AGAIN AHEAD OF THE OFFSHORE LOW AS THE OFFSHORE LOW RELOADS AND INTENSIFIES. RECENT MODEL RUNS INDICATE THAT WE COULD START SEEING A FEW SHOWERS AT LEAST AROUND THE MOUNTAINS ON TUESDAY AS THE OFFSHORE LOW APPROACHES. TOLLESON && .LONG TERM...THE MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SHOWING THE OFFSHORE LOW DIGGING DOWN THE COAST AND THEN SWINGING ONSHORE DURING THE EARLY PART OF THE EXTENDED PERIOD. THIS COULD BRING A FEW SHOWERS TO OUR AREA. HAVE EASED INTO THIS SCENARIO IN THE GRIDS FOR NOW. SHOULD DRY OUT FOR THE END OF THE WEEK THOUGH STILL SOME ONSHORE FLOW IN SOUTHWEST FLOW ALOFT WITH 500 MB HEIGHTS NEAR 580 DM. FAIR AMOUNT OF SPREAD IN THE ENSEMBLES BY NEXT WEEKEND SO WILL STAY NEAR CLIMATOLOGY FOR NOW. TOLLESON && .AVIATION...VFR CONDITIONS PREVAILING INLAND TONIGHT INTO SUN MORNING. APPEARS A CLOUD DECK AROUND 4000 FT ARRIVES SUN MORNING AS A PACIFIC FRONT BRUSHES THE COAST. THE COAST WILL LIKELY RECEIVE MVFR CIGS ALONG WITH SOME SHOWERS TONIGHT. ARRIVAL OF LOWER CIG EXPECTED ABOUT 06Z RIGHT ALONG THE CENTRAL COAST AND A LITTLE LATER UP NORTH. HOWEVER IFR STRATUS HAS BEEN SKIRTING RIGHT ALONG THE COASTLINE THROUGH THE DAY AND MAY CONTINUE INTO THE EVENING. THOUGH EXPECT IT TO BECOME LESS OF A THREAT AS THE FRONT NEARS...MIXING UP THE LOWER LAYER. && .MARINE...A PACIFIC FRONT WILL CONTINUE APPROACH THE WATERS TONIGHT AND BRUSH THE COASTAL WATERS LATE TONIGHT AND SUN MORNING. WINDS WILL GET CLOSE TO SMALL CRAFT LATER TONIGHT AND EARLY SUNDAY. SEAS WILL REMAIN BELOW 10 FEET. && .PQR WATCHES/WARNINGS/ADVISORIES... WA/OR...NONE. && .PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION) AST 33-1-2 PDX 11---1 SLE 11---1 EUG 11--11 $$ MORE WEATHER INFORMATION ONLINE AT... http://weather.gov/portland THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.