765  
FXUS66 KPQR 062118  
AFDPQR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PORTLAND OR  
218 PM PDT SUN JUL 6 2025  
   
SYNOPSIS  
WEAK HIGH PRESSURE ALOFT WITH ONSHORE FLOW AT THE  
SURFACE. WARMING TEMPERATURES THROUGH TUESDAY WITH MODERATE  
HEATRISK IN THE INLAND LOWLANDS MONDAY AND TUESDAY. COOLER ON  
WEDNESDAY AND THURSDAY AS A BROAD LOW ALOFT MOVES NORTHWARD.  
FOR THE LATTER PART OF THE WEEK WARMING RETURN AS HIGH PRESSURE  
ALSO RETURNS.  
 
 
   
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT  
BROAD AREA OF  
HIGH PRESSURE BUILDS THROUGH THE START OF THE WEEK. AT THE SAME  
TIME, AN UPPER LEVEL LOW WILL PARK OVER NORTHERN CALIFORNIA  
THROUGH TUESDAY. WITH RIDGE OF HIGH PRESSURE POLE-WARD ALONG  
WITH AN UNDERCUTTING LOW, THIS CREATES A REX BLOCKING PATTERN.  
NOW, THIS BLOCKING PATTERN IS VERY WEAK, GIVEN THAT THE UPPER  
LEVEL RIDGE IS NOT VERY ROBUST. HOWEVER, THIS PATTERN WILL BRING  
ABOUT A WARMING AND DRYING TREND FOR THE FORECAST AREA THROUGH  
TUESDAY NIGHT. DAYTIME HIGHS AT THIS TIME ARE FORECASTED TO BE  
IN THE UPPER 80S TO LOW 90S FOR INLAND LOCATIONS AND INTO THE  
UPPER 60S TO LOW 70S ALONG THE COAST. HIGHEST TEMPERATURES ARE  
EXPECTED ON MONDAY. ON TUESDAY, THE UPPER LEVEL LOW THAT IS  
FORMING THE REX BLOCK, WILL START TO MEANDER NORTHWARD ALONG THE  
CALIFORNIA COAST. AS THAT UPPER LEVEL LOW MOVES NORTHWARD, THE  
GREAT BASIN SURFACE LOW WILL ALSO RESULT IN A TIGHTENING OF THE  
PRESSURE GRADIENT ALONG THE CASCADES AND COULD SEE GUSTS UP TO  
30 MPH FOR THE CENTRAL AND EASTERN PARTS OF THE COLUMBIA RIVER  
GORGE ON TUESDAY.  
 
MONDAY AND TUESDAY WILL ALSO HAVE MODERATE HEATRISK FOR THE  
WILLAMETTE VALLEY, CLARK COUNTY LOWLANDS AND THE GORGE. THOSE  
SENSITIVE TO HEAT SHOULD TAKE PRECAUTIONS AND EVERYONE SHOULD  
REMAIN HYDRATED. /42  
   
LONG TERM...WEDNESDAY THROUGH SATURDAY  
AS WEDNESDAY  
APPROACHES, THE REX BLOCK WILL CONTINUE TO BREAK DOWN AS BOTH  
THE UPPER LEVEL RIDGE BECOMES MORE ZONAL AND THE UPPER LEVEL LOW  
CONTINUES TO PUSH EASTWARDS TOWARDS EASTERN OREGON. THIS  
PATTERN CHANGE WILL ALSO BRING ABOUT RELATIVELY COOLER AND  
MOISTER AIR INTO THE REGION. 850 MB TEMPERATURES WILL DROP FROM  
16-18 DEG C ON TUESDAY TOWARD 8-10 DEG C ON WEDNESDAY AND  
THURSDAY. ONE NEWER FEATURE THAT HASN'T BEEN REALIZED YET IN  
PREVIOUS MODEL RUNS IS A WEAK MESO-LOW AND SHORTWAVE TROUGH AT  
THE MID-LEVELS FORMING OVER WASHINGTON. THE ADDED INSTABILITY  
COMBINED WITH MOISTER AIR AND COOLING TEMPERATURES IS BRINGING A  
SLIGHT CHANCE (LESS THAN 25%) OF VERY LIGHT PRECIPITATION TO  
SOUTHWEST WASHINGTON, AND LESS THAN A 10% CHANCE OF ISOLATED  
SHOWERS ALONG THE CENTRAL OREGON CASCADES. CONFIDENCE IS VERY  
LOW THOUGH AS THE PATTERN COULD EASILY SHIFT IF THE LOW TRACKS A  
BIT FURTHER NORTH. OVERALL, MOST PLACES SHOULD REMAIN DRY. WITH  
ALL THAT SAID, ANY PRECIPITATION THAT DOES FALL WILL BE LIGHT,  
BRIEF AND RESULT IN LITTLE TO NO ACCUMULATIONS.  
 
THURSDAY WILL BE DRY ONCE AGAIN WITH NEAR NORMAL HIGH  
TEMPERATURES IN THE 80S INLAND. AS THE LATTER PART OF THE WEEK  
AND THE WEEKEND APPROACHES, MODELS ARE SHOWING A BROAD, UPPER  
LEVEL RIDGE RETURNING TO THE EASTERN PACIFIC. SOME MODELS ARE  
ALSO SHOWING A MESO-LOW DEVELOPING AGAIN NEAR NORTHERN  
CALIFORNIA. EITHER OF THESE SCENARIOS LOOK TO BRING BACK A  
WARMING PATTERN FOR THE REGION AND COULD EASILY BE A REPEAT (OR  
VERY SIMILAR) OF MONDAY AND TUESDAY. AS A RESULT, DAYTIME HIGHS  
COULD WARM RIGHT BACK INTO THE UPPER 80S TO LOW 90S FOR INLAND  
LOCATIONS, WHILE THE COAST WARMS INTO THE 70S. THE FORECAST WILL  
CONTINUE TO EVOLVE THROUGH THE WEEK AND WILL LIKELY CHANGE AS  
DETAILS BECOME MORE CLEAR. /42  
 
 
   
AVIATION  
CLEAR SKY VFR CONDITIONS ACROSS THE REGION TODAY AS  
HIGH PRESSURE BUILDS OVERHEAD. GUIDANCE DEPICTS MARINE STRATUS  
RETURNING TO COASTAL TERMINALS 04-08Z MON, WITH A 30-50% CHANCE  
FOR MVFR CONDITIONS OR LOWER AT KAST A 50-70% CHANCE ALONG THE  
IMMEDIATE COASTLINE INCLUDING KONP. INCREASING SUBSIDENCE AND THE  
SHALLOW NATURE OF THE MARINE LAYER SUGGEST PROBABLE IFR CIGS WITH  
THE POTENTIAL FOR SOME PATCHES OF LIFR FOG ALONG THE CENTRAL COAST  
NEAR KONP, BREAKING OUT TOWARDS VFR AGAIN 16-18Z MON. OTHERWISE,  
VFR WILL PREVAIL THROUGH THE PERIOD AT THE INLAND TERMINALS. WINDS  
WILL CONTINUE TO FOLLOW A DIURNAL TREND, WITH N-NW WINDS  
INCREASING TO 10-15 KT WITH GUSTS TO 20-25 KT 20-23Z SUN. WINDS  
WILL DIMINISH BACK TO AROUND 5 KT AFTER 06Z MON.  
 
PDX AND APPROACHES...VFR PREVAILS THROUGH THE PERIOD UNDER CLEAR  
SKIES. NW WINDS 10-12 KT WITH GUSTS TO AROUND 20 KT, EASING TO  
AROUND 5 KT AFTER 06Z MON. /CB  
 
 
   
MARINE  
A TYPICAL SUMMERTIME PATTERN PERSISTS THROUGH MUCH OF  
THE COMING WEEK AS SURFACE HIGH PRESSURE OFFSHORE MAINTAINS NORTH  
TO NORTHWEST WINDS ACROSS THE COASTAL WATERS. INLAND HEATING WILL  
DRIVE A STRENGTHENING COASTAL PRESSURE GRADIENT THROUGH MONDAY,  
WHICH IS IN LINE WITH CURRENT OBSERVATIONS SHOWING GUSTS  
INCREASING TO 20-25 KT OVER THE WATERS. SMALL CRAFT ADVISORIES  
REMAIN IN EFFECT THROUGH MONDAY EVENING AS WIND GUSTS INCREASE A  
BIT MORE TO 25 TO 30 KT LATER TODAY INTO MONDAY. EXPECT THE  
STRONGEST GUSTS SOUTH OF CAPE FALCON, WHILE CONDITIONS WILL BE  
MORE MARGINAL TO THE NORTH ACROSS THE MOUTH OF THE COLUMBIA RIVER  
AND THE SOUTH WASHINGTON COASTAL WATERS. SEAS WILL REMAIN IN THE  
4-6 FT RANGE, COMPRISED MAINLY OF SHORT PERIOD WIND-DRIVEN WAVES  
AND A MODEST, MID-PERIOD WESTERLY SWELL. /CB  
 
 
   
PQR WATCHES/WARNINGS/ADVISORIES  
 
OR...NONE.  
WA...NONE.  
PZ...SMALL CRAFT ADVISORY UNTIL 10 PM PDT MONDAY FOR PZZ251>253-  
271>273.  
 
 
 
 
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