By Rod Hill on 2013-09-27
Below is a statement from the National Weather Service. Weekend rains in Portland, will likely break records.
Expected rainfall of more than 2.00" will break the all-time PDX September rain record which is 4.30" back in 1986.
.SYNOPSIS...AUTUMN IS WASTING NO TIME GETTING STARTED IN THE PACIFIC NORTHWEST. A VERY VERY WET PATTERN IS BEGINNING...WITH THE FIRST SYSTEM IN A SERIES SPREADING IN TODAY WITH DECENT RAINS. THE NEXT STRONGER AND WETTER FRONT IS FORECAST TO RAMP UP THE RAIN AND COASTAL WIND ON SATURDAY CONTINUING INTO SATURDAY NIGHT. THE NEXT EVEN POSSIBLY STRONGER SYSTEM IS FORECAST TO BRING MORE HEAVY RAIN AND WIND TO THE FORECAST AREA LATER SUNDAY AND SUNDAY NIGHT. LOOK FOR RECORD RAINS THIS WEEKEND INTO MONDAY. COOL AND SHOWERY WEATHER SHOULD THEN LINGER WELL INTO NEXT WEEK. && .SHORT TERM...TODAY THROUGH MONDAY...THE MODELS ARE GETTING MORE CONSISTENT WITH THE DETAILS OF OUR HEAVY RAIN EPISODE THROUGH THIS WEEKEND INTO EARLY NEXT WEEK. THESE STORMS WILL HAVE TROPICAL MOISTURE WITH THEM...SOME FROM FORMER WESTERN TYPHOON PABUK. THESE SERIES OF STORMS WILL PRODUCE RECORD RAINFALLS IN OUR AREA...AS WELL AS STRONG WINDS AT THE COAST AND LOCALLY INLAND...AND HIGH SEAS NEAR THE COAST. THE FIRST SYSTEM WAS ALREADY SPREADING ONSHORE THIS MORNING. THE RAIN WILL REACH THE PORTLAND AREA LATER THIS MORNING...AND SPREAD SOUTH THROUGH THE DAY. THIS SYSTEM HAS 1.5 PWS FEEDING IT...AND SHOULD PRODUCE MODERATE RAINS MUCH OF THE AREA INTO THE EVENING. THE NEXT STRONGER FRONTAL SYSTEM AS MOISTURE FROM PABUK IN IT. THE RAINS WILL INCREASE ON SATURDAY IN THE WARM ADVECTION AHEAD OF THE SYSTEM ALONG THE FRONTAL BOUNDARY LEFT OVER FROM THE SYSTEM TODAY. HEAVY RAIN WILL INCREASE THROUGH THE DAY ON SATURDAY ACROSS MOST OF THE FORECAST AREA. THE GFS AND ECMWF MODELS BOTH SHOW THE ASSOCIATED COLD FRONT APPROACHING THE COAST IN THE AFTERNOON...AND MOVING ONSHORE SATURDAY NIGHT. THIS WILL BRING MORE HEAVY RAIN...WITH STRONG WINDS AT THE COAST AND LOCALLY INLAND. THE RAIN WILL LIKELY BRING AREAS OF URBAN AND SMALL STREAM FLOODING. THE WINDS COULD CAUSE TREE DAMAGE AND POWER DISRUPTIONS ESPECIALLY AT THE COAST AND OVER THE COAST RANGE BUT POSSIBLY IN THE VALLEYS AS WELL. IF THE MODELS ARE TO BE BELIEVED...THERE MIGHT BE A BRIEF REPRIEVE OR DECREASE IN THE RAIN LATE SATURDAY NIGHT AND EARLY SUNDAY...BUT NOW THE MODELS ARE FOCUSING ON ANOTHER STRONG LOW APPROACHING THE COAST SUNDAY AFTERNOON AND SWINGING THROUGH SUNDAY NIGHT AND EARLY MONDAY. THIS WILL BRING MORE VERY HEAVY RAIN TO OUR AREA...AS WELL AS POSSIBLY STRONG WINDS AT THE COAST AS WELL AS INLAND. THE WINDS WITH THIS SYSTEM MAY BE STRONGER THAN THE SATURDAY STORM...WITH GUSTS NEAR THE COAST UP NEAR 80 MPH POSSIBLE IF THE CURRENT MODELS ARE CORRECT. PRECIPITATION AMOUNTS THROUGH MONDAY STILL LOOK TO BE 7 TO 10 INCHES IN THE CASCADES AND THE COAST RANGE...WITH 2.5 TO 3.5 INCHES OR MORE IN THE VALLEYS. THIS IS A VERY SIGNIFICANT RAIN EVENT FOR OUR AREA... VERY UNUSUAL FOR LATE SEPTEMBER AND MORE LIKE A LATE OCTOBER OR NOVEMBER OR LATER EVENT. TOLLESON .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... THE EXTENDED MODELS CURRENTLY INDICATE THE HEAVIER RAIN WILL BE WINDING DOWN SUN NIGHT. HOWEVER...EXPECT PERIODIC SHOWERS...SOMETIMES HEAVY...TO CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE GULF OF ALASKA LOW PUSHES TOWARD THE PAC NW. THE TIMING OF THE INDIVIDUAL SHORTWAVES THAT WILL DRIVE THE MORE ORGANIZED SHOWERS IS SOMEWHAT UNCERTAIN...BUT THE CONFIDENCE IN THE SHOWERY PATTERN IS HIGH. THERE IS SOME INDICATION THAT A SHORTWAVE RIDGE WILL PROVIDE A BRIEF BREAK FROM THE RAIN SOMETIME DURING THE SECOND HALF OF THE WEEK...BUT THE DETAILS AND TIMING OF THIS FEATURE ARE VERY MUCH UP IN THE AIR AT THIS POINT. TEMPERATURES ARE EXPECTED TO RUN A GOOD 5 TO 10 DEG BELOW NORMAL THROUGH MUCH OF NEXT WEEK. PYLE && .AVIATION...INLAND...VFR EARLY WITH LOCAL IFR CONFINED TO KHIO. RAIN BEGINNING EXPECTED TO BEGIN AROUND 16Z TO 17Z IN THE NORTH INTERIOR...18Z TO 19Z SOUTH. CHANCES FOR MVFR CIGS INCREASE LATER IN THE AFTERNOON...AND BECOME LIKELY THIS EVENING FOR MOST LOCATIONS. AT THE COAST...MVFR OR LOWER CONDITIONS ON THE NORTH COAST WILL SPREAD DOWN THE COAST LATER THIS MORNING AS A FRONT SPREADS RAIN INTO THE AREA. KPDX AND APPROACHES...VFR CONDITIONS THROUGH MID AFTERNOON IN LIGHT RAIN. MVFR CIGS EXPECTED IN THE AFTERNOON/EVENING AS A FRONT STALLS AND RAIN CONTINUES AT TIMES. && .MARINE...WINDS HAVE INCREASED TO SMALL CRAFT CONDITIONS (20 TO 25 KT) THIS MORNING IN ADVANCE OF A SET OF PROGRESSIVELY STRONGER PACIFIC FRONTS. EXPECT THERE WILL BE A PERIOD OF LATER THIS AFTERNOON AND EVENING BELOW 20 KT IN MANY SPOTS...BUT WILL KEEP THE SMALL CRAFT ADVISORY GOING DUE TO SOME UNCERTAINTY ON WHEN WINDS RAMP BACK UP. WINDS INCREASE TO GALES (35 KT TO 45 KT) SAT...LASTING INTO THE EVENING. LATEST MODELS ARE A LITTLE FASTER FOR SAT SYSTEM SO HAVE BUMPED UP TIMING A LITTLE...AND MAY NEED TO BUMP IT UP AGAIN...BUT WILL MAKE THIS DECISION THIS AFTERNOON WHEN AN UPGRADE TO WARNING IS LIKELY. SOME LOCAL GUSTS TO NEAR 50 KT CLOSE TO SHORE POSSIBLE SAT AFTERNOON OR EARLY EVENING AS THE FRONT MOVES ASHORE...ESPECIALLY AS THE FRONT NEARS...AS THERE MAY BE A CONVECTIVE ELEMENT TO THE FRONT THAT CAN CREATE LOCALIZED STRONGER GUSTS. A NEW DEVELOPMENT IN 00Z FRI GFS/ECMWF MODELS IS ANOTHER STRONG SYSTEM FOR SUN AFTERNOON. EARLIER MODEL RUNS WERE DEPICTING IT MUCH WEAKER. THIS SYSTEM MAY BE AS STRONG OR STRONGER THAN SAT SYSTEM. HAVE CONTINUED THE TREND MODELS HAVE SHOWN TOWARD THE STRONGER SOLUTION. THIS COULD BE A STORM BUT LOOKS TO AT LEAST BE A GALE. EXPECT TO HAVE SOMETHING OUT FOR THIS SYSTEM BY MID AFTERNOON AT THE LATEST. SEAS REMAIN BELOW 10 FT THROUGH FRI NIGHT...THEN BUILD INTO THE MID TEENS SAT. LONGER PERIOD WESTERLY SWELL ARRIVES SAT NIGHT AND WILL LIKELY EXCEED 20 FT BY SUN AFTERNOON. WITH PERIODS IN THE MID TEENS BEACHES USUALLY EXPERIENCE HIGH SURF CONDITIONS WITH SEAS OF THIS MAGNITUDE. /KMD
Fall begins with strong Pacific Storm