123
FXUS66 KPQR 192242
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
342 PM PDT FRI APR 19 2024
UPDATED AVIATION AND MARINE DISCUSSION.
SYNOPSIS
HIGH PRESSURE HOLDING STEADY OVER THE REGION
THROUGH TONIGHT, WITH EAST TO NORTHEAST WINDS ON THE WEST SLOPES
OF THE CASCADES AND TO SOME DEGREE, THE COAST RANGE. COOLER FOR
SATURDAY, AS A FRONT MOVES ACROSS THE REGION. THIS COULD RESULT
IN SPOTTY LIGHT RAIN INTO SATURDAY NIGHT. DRY AND MILD
CONDITIONS RETURN BY THE START OF THE UPCOMING WEEK, WITH COOLER
SHOWERY WEATHER RETURNING BY THE MIDDLE OF NEXT WEEK.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
A PATTERN CHANGE
IS ON DECK AS A WEAK FRONTAL SYSTEM IS EXPECTED TO CROSS OVER
THE REGION STARTING LATE TONIGHT/EARLY SATURDAY MORNING. THIS
WILL BRING COOLER DAYTIME HIGHS SATURDAY AND SUNDAY. OFFSHORE
FLOW WILL SLOWLY WEAKEN AND BECOME ONSHORE THROUGH THE OVERNIGHT
HOURS, WHICH WILL ENABLE COOLER MARINE AIR TO INFILTRATE ACROSS
THE REGION. MODELS HAVE SLOWED THE FRONT, AND CURRENT GUIDANCE
HAVE LIGHT RAIN STARTING ALONG THE COAST SATURDAY MORNING AND
ARRIVING INLAND BY THE AFTERNOON. AT THIS TIME CURRENT GUIDANCE
HAS THIS BEING A TYPICAL SPRING HIGH POP/LOW QPF EVENT WITH THE
COAST HAVING AROUND 0.10 TO 0.20 INCHES, INLAND AREAS HAVING
0.05 TO 0.10 INCHES AND THE CASCADES HAVING 0.15 TO 0.25 INCHES.
ALSO, WITH THE ONSHORE FLOW A.K.A. THE AIR CONDITIONING AND
CLOUDS, EXPECT DAYTIME HIGHS IN THE MID 50S TO MID 60S ON
SATURDAY AND LOW 50S TO LOW 60S ON SUNDAY. THE PATTERN CHANGES
AGAIN SUNDAY/MONDAY AS HIGH PRESSURE OFFSHORE WILL START
BUILDING INLAND. THIS WILL END THE SHOWER POTENTIAL, WITH
MORNING MARINE CLOUDS GIVING WAY TO MIXTURE OF SUNSHINE AND
CLOUDS FOR THE START OF THE UPCOMING WEEK. -42
LONG TERM...MONDAY THROUGH THURSDAY
THE EARLY PART OF NEXT
WEEK WILL BE CHARACTERIZED BY A SHORT WAVE RIDGE ACROSS THE WEST
COAST. DRY AND MILD CONDITIONS ARE EXPECTED UNDER MOSTLY SUNNY
TO PARTLY CLOUDY SKIES. TEMPERATURES ACROSS THE INTERIOR VALLEYS
WILL REACH INTO THE UPPER 60S TO NEAR 70 WITH A BUMP INTO THE
LOW 70S ON TUESDAY. A SERIES OF DISTURBANCES WILL APPROACH THE
PNW TOWARD THE MIDDLE/END OF NEXT WEEK. THE FIRST DISTURBANCE
LOOKS LIKE IT WILL BE ON THE WEAKER SIDE BUT COULD BRING
INCREASING CLOUDS, COOLER TEMPS, AND VERY LIGHT RAIN. THE SECOND
DISTURBANCE WILL FOLLOW QUICKLY ON THE HEELS OF THE FIRST LATER
IN THE WEEK AND COULD BRING A BETTER SHOT OF RAIN TO THE AREA.
MODEL GUIDANCE VARIES AT THIS POINT REGARDING TIMING AND
STRENGTH SO CHANGES SHOULD BE MONITORED IN THE COMING DAYS.
-BATZ
AVIATION
VFR THIS EVENING. WEAK GAP FLOW THROUGH EAST-WEST
ALIGNED TERRAIN IS CAUSING GUSTY WINDS AROUND KPDX, KHIO, AND
KTTD. WINDS ARE GUSTING AS HIGH AS 25 KT. HIGH PRESSURE BEGINS TO
ERODE THIS EVENING AND WILL SEE A HIGH LEVEL VFR STRATUS SHIELD
DEVELOP AFTER 10Z SATURDAY. WILL SEE A WIND DIRECTIONAL SHIFT
ALONG THE COAST AS A WEAK FRONT PUSHES IN FROM THE PACIFIC.
PRECIPITATION IS EXPECTED, THOUGH NOT LOOKING AT ANY IMPACTS TO
VIS. CEILINGS WILL BEGIN TO LOWER AFTER 18Z SATURDAY STARTING
ALONG THE COAST, ESPECIALLY AT KONP. THERE IS AROUND A 75% CHANCE
THAT IFR CONDITIONS WILL BE PRESENT FROM KTMK SOUTHWARD ALONG THE
COAST. INLAND LOCATIONS WILL STAY VFR. WHILE THE PROBABILITY IS
VERY LOW (LESS THAN 10%), AREAS ALONG THE COLUMBIA RIVER WEST OF
KKLS MAY SEE SOME PATCHY FOG RIGHT AROUND SUNRISE. HOWEVER, WITH
THE HIGH STRATUS SHIELD IN PLACE, IT WILL LIKELY INSULATE ENOUGH
FOR FOG FORMATION TO BE INHIBITED.
NOTES: WIND AT KHIO WILL BE UNAVAILABLE OVERNIGHT BETWEEN 04Z AND
13Z. THE ASOS AT KTTD IS ONLY AVAILABLE VIA THE DIAL IN OPTION.
THE AWOS AT KMMV IS STILL OUT OF COMMISSION. AS IT IS NOT
MAINTAINED LOCALLY BY THE NATIONAL WEATHER SERVICE, THERE IS NO
ESTIMATED TIME OF REPAIR.
PDX AND APPROACHES...VFR THROUGH THE NEXT 24 HOURS. GUSTY EAST
WINDS DUE TO HIGH PRESSURE WILL PERSIST THROUGH THE EARLY EVENING.
PERIODS OF LIGHT RAIN THROUGH SATURDAY. NO OTHER CONCERNS AT THIS
TIME.-MUESSLE
MARINE
HIGH PRESSURE DISSIPATES TONIGHT AND A WEAK FRONT MOVES
INLAND SATURDAY. MAIN IMPACT WILL BE INCREASING WINDS WHICH HAS
INITIATED A SMALL CRAFT ADVISORY THROUGH SUNDAY MORNING. WINDS
BECOME NORTHERLY AND WILL PERSIST THROUGH MID-WEEK. -MUESSLE
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 11 AM SATURDAY TO 2 AM PDT SUNDAY
FOR PZZ251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
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