752  
FXUS66 KPQR 230457  
AFDPQR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PORTLAND OR  
857 PM PST TUE JAN 22 2019  
   
SYNOPSIS
 
A SERIES OF FRONTS TRAVERSING THE REGION THROUGH THE  
MIDDLE OF THE WEEK WILL BRING PERIODS OF VALLEY RAIN AND MOUNTAIN  
SNOW BEFORE HIGH PRESSURE BRINGS DRIER WEATHER LATE IN THE WEEK AND  
THIS WEEKEND.  
 

 
   
SHORT TERM...TONIGHT THROUGH FRIDAY
 
WARM FRONT WAS PUSHING INLAND  
ACROSS SW WA THIS EVENING, LIFTING MOST OF THE STRATIFORM RAIN AND  
SNOW ASSOCIATED WITH THE ISENTROPIC LIFT NORTH OF THE FORECAST AREA.  
THE WARM FRONT WAS ALSO BRINGING A MILDER AIR MASS, MOST NOTABLY IN  
RISING SNOW LEVELS OVER THE CASCADES. A FINAL BAND OF RAIN WAS SEEN  
IN RADAR ALREADY MOVING INLAND OVER SW WA COAST, AND EXTENDING  
OFFSHORE TO THE SW. THIS WAS PRECEDING THE COLD FRONT WHICH IS  
EXPECTED DROP SE AND INLAND LATE TONIGHT. WILL LET THE ADVISORY FOR  
SNOW IN THE SOUTH WA CASCADES RUN ITS COURSE THIS EVENING AND EXPIRE  
AT 10 PM, BY WHICH TIME SNOW LEVELS WILL BE QUICKLY RISING TO 6K FT.  
A FAIRLY STRONG LOW LEVEL ONSHORE FLOW FOLLOWS THE COLD FRONT, WHICH  
WILL KEEP GOOD CHANCES FOR SHOWERS GOING INTO WED, ESP OVER WEST  
FACING SLOPES WHERE OROGRAPHIC LIFT WIL BE MOST PROMINENT.  
 
REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...WEDNESDAY INTO  
WEDNESDAY NIGHT, THE OVERALL TREND WILL BE TOWARDS THE AREA DRYING  
OUT. IN LOCATIONS THAT CLEAR, AREAS OF LATE NIGHT AND MORNING FOG  
WILL DEVELOP WEDNESDAY NIGHT AND EARLY THURSDAY. BOTH THE ECMWF AND  
GFS SHOW A SHORTWAVE MOVING THROUGH BRIEFLY SOMETIME BETWEEN  
THURSDAY AFTERNOON AND FRIDAY MORNING. FOR NOW, HAVE TRENDED TOWARDS  
THE ECMWF WITH THE TIMING, PUTTING SOME LOW POPS IN THE FORECAST FOR  
THE POSSIBILITY OF SOME LIGHT SHOWERS WITH THE SHORTWAVE THURSDAY  
DURING THE DAY, MOSTLY LIMITED TO THE CASCADE FOOTHILLS.  
 
UPPER HIGH PRESSURE CENTERED NEAR THE CALIFORNIA COAST SHIFTS  
EASTWARD BEGINNING FRIDAY, BRINGING THE RIDGE AXIS CLOSER TO THE  
OREGON/WASHINGTON COAST. THIS WILL BEGIN A PERIOD OF DRY WEATHER WITH  
LOWLAND LATE NIGHT/MORNING FOG. BOWEN  
   
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
 
OPERATIONAL MODELS AND  
THEIR ENSEMBLES ARE IN GOOD AGREEMENT THE AREA WILL REMAIN UNDER A  
LARGE RIDGE INTO EARLY NEXT WEEK. THIS WILL PRODUCE A MULTI-DAY  
STRETCH OF DRY WEATHER, MILD TEMPERATURES, AND AREAS OF LATE NIGHT  
AND MORNING VALLEY FOG. EAST WINDS BECOME INCREASINGLY LIKELY LATE IN  
THE WEEKEND INTO EARLY NEXT WEEK. MODELS DIVERGE REGARDING THE  
PATTERN BY TUESDAY WITH REGARDS TO THE LOCATION OF THE RIDGE AXIS.  
THERE IS SOME POSSIBILITY THAT THE RIDGE AXIS WILL MOVE BACK WEST,  
ALLOWING A SHORTWAVE TO MOVE THROUGH THE LOCAL AREA, SPARKING  
SHOWERS. FOR NOW, HAVE INTRODUCED SOME LOW POPS FOR TUESDAY.  
 
IT SHOULD BE NOTED THAT MODELS SUGGEST THE FLOW WILL TURN WEAKLY  
OFFSHORE SATURDAY, PARTICULARLY ALONG THE CENTRAL OREGON COAST. WITH  
850MB TEMPERATURES CLIMBING INTO THE 11-13C RANGE, MANY LOCATIONS  
ALONG THE COAST, IN THE COAST RANGE, AND EVEN IN THE CASCADE  
FOOTHILLS WILL CLIMB INTO THE UPPER 50S TO LOW 60S. EVEN MID TO  
UPPER 60S DO NOT APPEAR OUT OF THE QUESTION. WILLAMETTE VALLEY  
TEMPERATURES WILL BE A LITTLE MORE TRICKY GIVEN AREAS OF MORNING FOG  
COULD HAMPER TEMPERATURES. HELD TEMPERATURES ON THE WARM SIDE TO EVEN  
SLIGHTLY ABOVE MODEL GUIDANCE FOR MOST AREAS, BUT STILL KEPT  
TEMPERATURES WELL SHY OF RECORDS FOR NOW. RECORDS ARE POSSIBLE FOR  
AREAS OF THE COAST PRONE TO DOWNSLOPE WINDS, THOUGH. BOWEN/NEUMAN  
 

 
   
AVIATION
 
A WARM FRONT MOVED EAST OF THE AREA THIS EVENING.  
RADAR AND SATELLITE SHOWS A WELL DEFINED COLD FRONT APPROACHING  
THE NORTH OREGON AND SOUTH WASHINGTON COAST AS OF 04Z. CURRENT  
TIMING HAS THE FRONT MOVING TO KPDX AND VICINITY AROUND 06Z AND  
SOUTH AND EAST OF KEUG BY 09Z. AS THE FRONT MOVES THROUGH,  
WIDESPREAD MVFR AND POSSIBLE IFR CONDITIONS WILL RETURN INLAND.  
COASTAL AREAS ARE EXPECTED TO REMAIN IN MVFR AND IFR CATEGORY  
INTO WED MORNING.  
 
KPDX AND APPROACHES...AS OF 04Z VFR IN THE AREAS, BUT WILL LIKELY  
RETURN TO MVFR WITH CIGS AROUND 2500 FEET AND REDUCED VISIBILITY  
AS WELL AS THE COLD FRONT MOVES THROUGH. THERE MAY BE A SHORT  
PERIODS OF IFR WITH AND AFTER THE FRONT. GENERALLY EXPECT MVFR  
CIGS 1500-2500 FEET THROUGH MUCH OF WED, THROUGH MAY TREND TO LOW  
VFR LATE IN THE DAY. /MH  
 

 
   
MARINE
 
A GALE WARNING CONTINUES FOR THE NORTHERN MARINE ZONES  
TONIGHT AS A COLD FRONT MOVES THROUGH THE WATERS. WINDS HAVE  
BEEN GUSTING IN THE 30 TO 40 KT RANGE THIS EVENING AND SHOULD  
EASE SOME BY MIDNIGHT. GUSTS TO 35 KT WILL LIKELY CONTINUE  
THROUGH AT LEAST 2 AM WED. A FOLLOWING TROUGH REACHES THE WATERS  
BY 5 AM WED WILL KEEP WINDS GUSTY BUT BELOW GALE FORCE. /MH  
 
SEAS AROUND 8 TO 11 FT AND WILL BUILD INTO THE LOW TEENS THROUGH  
THE EVENING IN RESPONSE TO THE WARM FRONTAL PASSAGE TONIGHT. A  
SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR SEAS FROM THIS AFTERNOON  
THROUGH WED AFTERNOON. SEAS EXPECTED TO BE NEAR OR ABOVE 10 FT  
INTO EARLY THU.  
 
AFTER THE FRONTAL PASSAGE, A BENIGN PATTERN DEVELOPS UNTIL THIS  
WEEKEND. THIS WEEKEND, CURRENT OPERATIONAL MODELS SHOW A THERMAL  
TROUGH DEVELOPING ALONG THE COAST IN A VERY SIMILAR MANNER TO  
OUR TYPICAL SUMMER SYSTEMS. WINDS AND SEAS ARE EXPECTED TO REMAIN  
BELOW ADVISORY LEVELS DURING THIS TIME, BUT SMALL CRAFT ADVISORY  
WINDS COULD DEVELOP UNDER THE NORTHERLY FLOW BY THE START OF  
NEXT WEEK. /42  
 

 
   
PQR WATCHES/WARNINGS/ADVISORIES
 
 
OR...NONE.  
WA...WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR SOUTH  
WASHINGTON CASCADES.  
 
PZ...GALE WARNING UNTIL 4 AM PST WEDNESDAY FOR COASTAL WATERS FROM  
CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.  
 
SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PST WEDNESDAY FOR  
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60  
NM.  
 
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST  
WEDNESDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO  
FLORENCE OR OUT 60 NM.  
 
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM  
PST WEDNESDAY.  
 

 
 

 
 
INTERACT WITH US VIA SOCIAL MEDIA:  
WWW.FACEBOOK.COM/NWSPORTLAND  
WWW.TWITTER.COM/NWSPORTLAND  
 
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON  
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THIS AREA IS  
COMMONLY REFERRED TO AS THE FORECAST AREA.  
 
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