Area Forecast Discussion
Issued by NWS Portland, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPQR 311010
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
245 AM PDT FRI JUL 31 2015

.SYNOPSIS...STRONG UPPER LEVEL HIGH PRESSURE WILL KEEP VERY HOT
WEATHER IN PLACE TODAY. UPPER LEVEL HIGH PRESSURE WILL MOVE EAST OF
THE REGION AND ALLOW TEMPERATURES TO GRADUALLY COOL THROUGH THE
MIDDLE OF NEXT WEEK. MONSOONAL MOISTURE FROM THE SOUTH WILL BRING A
SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM TO THE OREGON CASCADE
CREST LATE IN THE WEEKEND AND EARLY NEXT WEEK...BUT CONFIDENCE
REMAINS LOW.


&&

.SHORT TERM...TODAY THROUGH MONDAY...WATER VAPOR SATELLITE IMAGERY
EARLY THIS MORNING REVEALS A RELATIVELY FLAT UPPER LEVEL RIDGE OF
HIGH PRESSURE EXTENDING WEST-NORTHWESTWARD ACROSS OREGON. DEBRIS
CLOUDS FROM EARLIER THUNDERSTORMS OVER NORTHERN CALIFORNIA AND
SOUTHWEST OREGON ARE BEGINNING TO PUSH INTO LANE COUNTY...BUT THESE
SHOULD GENERALLY DISSIPATE THIS MORNING. A SURFACE PRESSURE ANALYSIS
SHOWS THERMAL LOW PRESSURE LIES SOLIDLY EAST OF THE CASCADES EARLY
THIS MORNING. THIS SHOULD ALLOW COOLER MARINE AIR TO BEGIN FILTERING
INTO THE INTERIOR PORTIONS OF THE SOUTHWEST WASHINGTON AND NORTHWEST
OREGON...AND PRODUCE HIGH TEMPERATURES A COUPLE DEGREES COOLER THAN
YESTERDAY. THE COOLING WILL LIKELY BE MOST PRONOUNCED IN THE LOWER
COLUMBIA RIVER VALLEY...AND LIKELY LEAST NOTICEABLE ACROSS THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY AND CENTRAL COLUMBIA RIVER
GORGE. INHERITED TEMPERATURE FORECAST AND HEADLINES CAPTURE THIS
WELL.

AS THE UPPER LEVEL RIDGE AXIS SHIFTS NORTH OF THE REGION OVER THE
WEEKEND...MID LEVEL SOUTHERLY FLOW SHOULD ENSUE AND BRING AN
INCREASE IN MID TO UPPER LEVEL CLOUDS. CURRENT MODEL SOUNDINGS SHOW
SOME OF THE INITIAL MOISTURE WILL LIKELY BE TOO HIGH TO PRODUCE
ELEVATED THUNDERSTORMS ON SATURDAY...BUT THIS MAY BEGIN TO CHANGE
TOWARDS SATURDAY NIGHT OR SUNDAY ACROSS EASTERN LANE AND LINN
COUNTIES. CONFIDENCE REMAINS LOW THOUGH...AS MODELS DO NOT REALLY
SHOW MUCH IN THE WAY OF A MID LEVEL TRIGGER.

MEANWHILE...BETWEEN THE INCREASE IN MID AND UPPER LEVEL CLOUDS
SPREADING NORTHWARD AND STRENGTHENING LOW LEVEL ONSHORE FLOW THROUGH
EARLY NEXT WEEK...EXPECT HIGH TEMPERATURES TO TREND DOWNWARD SEVERAL
DEGREES EACH DAY DURING THIS PERIOD. UNFORTUNATELY...NOT SURE THERE
WILL BE ONE DAY WHERE WE CAN SAY IT IS GOING TO FEEL NOTICEABLY
BETTER THAN THE DAY BEFORE...BUT THE GOOD NEWS IS THAT BY THE TIME
EARLY NEXT WEEK ROLES AROUND...IT WILL BE NOTICEABLY COOLER THAN THE
TRIPLE DIGIT HEAT OF YESTERDAY AND TODAY.

ADDED A MENTION OF HAZE TO EASTERN LANE COUNTY FOR TODAY AND TONIGHT
DUE TO SMOKE SPREADING NORTHEASTWARD FROM THE STOUTS FIRE. WE MAY
SEE ADDITIONAL ISSUES WITH SMOKE FROM THE STOUTS FIRE DEPENDING ON
FIRE BEHAVIOR OVER THE WEEKEND AS THE AFOREMENTIONED MID LEVEL FLOW
TURNS SOUTHERLY. FORTUNATELY...LOW LEVEL WESTERLY TO NORTHWESTERLY
WINDS WILL CONTINUE INTO EARLY NEXT WEEK AND SHOULD HELP PREVENT
SMOKE FROM BECOMING TOO BIG OF A PROBLEM IN OUR VALLEYS. /NEUMAN


&&


.LONG TERM...MONDAY NIGHT THROUGH FRIDAY...AN UPPER LEVEL TROUGH WILL
GRADUALLY APPROACH THE REGION FROM THE NORTHWEST. CONFIDENCE IS
RELATIVELY HIGH THAT MORE SEASONAL AVERAGE TEMPERATURES AND PERIODS
OF MORNING CLOUDS AND AFTERNOON SUNSHINE WILL RETURN TOWARDS THE
MIDDLE OF THE WEEK. MODELS CONTINUE TO WAVER ON THUNDERSTORM CHANCES
NEAR THE CASCADE CREST EARLY NEXT WEEK. GENERALLY KEPT THE SLIGHT
CHANCE MENTION GOING GIVEN UNCERTAINTY. IN ADDITION...MODELS SUGGEST
SHOWERS MAY SPREAD INTO AT LEAST FAR NORTHWEST OREGON AND SOUTHWEST
WASHINGTON LATER IN THE WEEK. CONFIDENCE REMAINS LOW IN THIS
SCENARIO...BUT INTRODUCED SLIGHT CHANCE POPS ACROSS OUR NORTHWEST
ZONES AS A RESULT. /NEUMAN


&&


.AVIATION...VFR CONDITIONS WILL CONTINUE TODAY AND TONIGHT OVER
INLAND AREAS OF NW OREGON AND SW WA. ALONG THE COAST EXPECT VFR
CONDITIONS TODAY...EXCEPT THERE IS A 20 PERCENT CHANCE FOR BRIEF IFR
CONDITIONS IN FOG AT KONP THROUGH 17Z THIS MORNING. TONIGHT IFR CIGS
AND FOG BECOME LIKELY AT KAST AFTER 09Z AS MARINE AIR BEGINS TO PUSH
BACK IN.

KPDX AND APPROACHES...VFR CONDITIONS TODAY AND TONIGHT.


&&


.MARINE...HIGH PRES LINGERING OVER THE OFFSHORE WATERS THROUGH SUN
WILL KEEP N WINDS BLOWING OVER THE COASTAL WATERS THROUGH THE
WEEKEND. EXPECT THE WINDS TO PICK UP SOME LATER TODAY AS THE TROUGH
OF LOW PRES OVER WESTERN OREGON MOVES FURTHER INLAND...RESULTING IN
WIND GUSTS RISING INTO THE 20 TO 25 KT RANGE FROM LATE TODAY INTO
SUN. SEAS WILL REMAIN DOMINATED BY N TO NW WIND WAVES AND FRESH
SWELL...KEEPING SEAS STEEP AND AT TIMES NECESSITATING AN ADVISORY
FOR HAZARDOUS SEAS MAINLY DURING LATE AFTERNOON TO OVERNIGHT HOURS.

THE HIGH PRES WEAKENS BY LATE SUN AND MON...ALLOWING A WEAK COLD
FRONT TO MOVE S INTO THE WATERS LATE MON. SYSTEM LOOKS WEAK ENOUGH
TO ALLOW WINDS AND SEAS TO DROP BELOW SMALL CRAFT CRITERIA.


&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...EXCESSIVE HEAT WARNING UNTIL 9 PM PDT THIS EVENING FOR CENTRAL
     COLUMBIA RIVER GORGE-CENTRAL WILLAMETTE VALLEY-GREATER
     PORTLAND METRO AREA-SOUTH WILLAMETTE VALLEY-UPPER HOOD
     RIVER VALLEY-WESTERN COLUMBIA RIVER GORGE.

     RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR CENTRAL
    OREGON CASCADE FOOTHILLS-EAST SLOPES OF THE CENTRAL OREGON
   COAST RANGE-MT. HOOD NATIONAL FOREST WEST OF CASCADE
  CREST-NORTH OREGON CASCADE FOOTHILLS-NORTH OREGON COAST RANGE-
     WILLAMETTE NATIONAL FOREST-WILLAMETTE VALLEY.

     HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR CASCADE FOOTHILLS
     IN LANE COUNTY-CENTRAL COAST RANGE OF WESTERN OREGON-COAST
     RANGE OF NORTHWEST OREGON-LOWER COLUMBIA-NORTHERN OREGON
     CASCADE FOOTHILLS.

WA...EXCESSIVE HEAT WARNING UNTIL 9 PM PDT THIS EVENING FOR CENTRAL
     COLUMBIA RIVER GORGE-GREATER VANCOUVER AREA-WESTERN
     COLUMBIA RIVER GORGE.

     RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR CLARK COUNTY
     LOWLANDS-EAST WILLAPA HILLS-EXTREME SOUTH WASHINGTON
     CASCADES AND FOOTHILLS.

     HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR I-5 CORRIDOR IN
     COWLITZ COUNTY.

PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM THIS AFTERNOON TO 5 AM
     PDT SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
     FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS
    AFTERNOON TO 7 AM PDT SATURDAY FOR COASTAL WATERS FROM CASCADE
   HEAD OR TO FLORENCE OR OUT 60 NM.

&&

$$

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. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.