037
FXUS66 KPQR 202220
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
220 PM PST MON JAN 20 2025
SYNOPSIS
HIGH PRESSURE OVER THE AREA WILL PERSIST THROUGH AT
LEAST THURSDAY, WITH MOSTLY SUNNY DAYS AND CHILLY NIGHTS.
THURSDAY NIGHT INTO FRIDAY, A WEAK FRONT WILL MOVE OVER THE
AREA AND INCREASE CHANCES FOR LIGHT PRECIPITATION. AT THIS
POINT, NO WINTER WEATHER CONCERNS.
SHORT TERM...NOW THROUGH WEDNESDAY NIGHT
DRY WEATHER WITH
MOSTLY SUNNY SKIES PREVAIL THROUGH THE REST OF THE AFTERNOON AS
HIGH PRESSURE REMAINS OVER THE REGION. BREEZY EASTERLY WINDS
CONTINUE THROUGH THE COLUMBIA RIVER GORGE AND EASTERN
PORTLAND/VANCOUVER METRO AREA, HOWEVER, WINDS WILL GRADUALLY
WEAKEN THIS EVENING AS KTTD-KDLS PRESSURE GRADIENTS LOOSEN.
TONIGHT INTO TUESDAY MORNING, AN UPPER LEVEL SHORTWAVE TROUGH
WILL QUICKLY BRUSH THE REGION, INCREASING MID TO HIGH LEVEL
CLOUD COVER. NO PRECIPITATION IS EXPECTED FOR OUR AREA FROM THIS
SHORTWAVE, BUT IT WILL RETURN ONSHORE FLOW WITH WESTERLY WINDS
THROUGH THE GORGE. EXPECT ANOTHER CHILLY NIGHT; SINCE WINDS ARE
FORECAST WEAKER, IT DOESN'T LOOK LIKE APPARENT (FEELS-LIKE)
TEMPERATURES WILL MEET CRITERIA FOR ANY COLD ADVISORY.
SKIES SHOULD BEGIN TO CLEAR MORE BY TUESDAY AFTERNOON AS THE
UPPER LEVEL RIDGE RE-BUILDS. HIGH PRESSURE PERSISTS THROUGH
AT LEAST WEDNESDAY, MAINTAINING SUNNY SKIES AND CHILLY NIGHTS.
-ALVIZ
LONG TERM...THURSDAY THROUGH SUNDAY
THE FIRST PATTERN SHIFT
OF THE WEEK ARRIVES ON THURSDAY AFTERNOON. A FRONT FROM THE GULF
OF ALASKA WILL SHIFT SOUTHWARD THROUGH THE DAY. THERE ARE
INCREASED CHANCES FOR PRECIPITATION BUT THE HIGHEST ACCUMULATIONS
WILL BE OBSERVED ALONG THE MOUNTAINS. COLD AIR WILL STILL BE IN
PLACE AT THE SURFACE WITH 850 MB TEMPERATURES AROUND -4 DEG C.
WHILE PRECIPITATION WILL BE FAIRLY LIGHT, IF A STRONGER BAND OF
PRECIPITATION SETS UP, COULD SEE COLDER AIR MIX DOWN FROM ALOFT
AND BRING A BIT OF SNOWFALL TO THE COLUMBIA RIVER GORGE. AT THIS
POINT, NO CONCERNS FOR SIGNIFICANT WINTER WEATHER ON THURSDAY
INTO FRIDAY.
MOVING INTO THE WEEKEND, THE MAJORITY OF WPC CLUSTER ANALYSES
SHOW TROUGHING MOVING SOUTHWARD INTO THE GREAT BASIN AND
SOUTHWESTERN US. AT THE SAME TIME, GUIDANCE IS SHOWING
POSITIVELY TILTED RIDGING OF BUILDING OVER THE PACIFIC
NORTHWEST, WHICH WOULD CONTINUE THE REPEATED TREND OF DRY
WEATHER WITH SUNNY SKIES AND CHILLY NIGHTS. -ALVIZ/MUESSLE
AVIATION
HIGH PRESSURE OVER THE AIRSPACE WILL MAINTAIN VFR
CONDITIONS THROUGH MOST OF THE TAF PERIOD. COULD SEE A RETURN OF
LIFR FOG OVERNIGHT AROUND 12Z TUESDAY FOR KHIO AND AREAS SOUTH
OF KMMV ONCE WINDS BEGIN TO DECREASE THIS EVENING.
EXPECT OFFSHORE EASTERLY WINDS THROUGHOUT MOST OF THE AREA, WITH
LIGHT NORTHERLY WINDS IN THE CENTRAL/SOUTHERN WILLAMETTE VALLEY.
THIS AFTERNOON, EXPECT STRONG EASTERLY WINDS THROUGH THE
COLUMBIA RIVER GORGE AND REACHING NEAR THE METRO, WITH GUSTS UP
TO 30-35 KT IN THE GORGE. AROUND 06-12Z TUESDAY, EXPECT WINDS
THROUGHOUT THE AIRSPACE TO DECREASE BELOW 5 KT AND BECOME
SOUTHERLY IN THE CENTRAL/SOUTHERN WILLAMETTE VALLEY.
COLD OVERNIGHT TEMPS AND CLEAR SKIES CONTINUE, SUPPORTING FROSTY
CONDITIONS ON THE GROUND AND FREEZING FOG POSSIBLE.
PDX AND APPROACHES...CLEAR SKIES AND VFR CONDITIONS EXPECTED
THROUGH THE TAF PERIOD. WILL SEE EASTERLY WINDS 10-15 KT WITH
GUSTS UP 20 KTS UNTIL 00Z TUESDAY AND DECREASE THEREAFTER. GUSTY
EAST WINDS WITH GUSTS UP TO 25-30 KT AT KTTD UNTIL AROUND 06Z
TUESDAY. ~HALL
MARINE
HIGH PRESSURE OVER LAND CURRENTLY MAINTAINS OFFSHORE
FLOW OVER THE WATERS TODAY. THIS HIGH PRESSURE WILL WEAKEN
TONIGHT INTO TOMORROW AS A WEAK DISTURBANCE MOVES OVER THE AREA
FOR A PERIOD OF LIGHT AND VARIABLE WINDS. HIGH PRESSURE WILL
REBUILD OVER THE NE PACIFIC ON WEDNESDAY, RETURNING NORTH WINDS
THROUGH THE REST OF THE WEEK AND INTO THE WEEKEND. THERE IS A
50-75% CHANCE THAT WIND GUSTS OF 21 KT RETURN TO THE WATERS LATE
THURSDAY THROUGH FRIDAY BUT TIMING AND STRENGTH STILL REMAINS A
BIT UNCERTAIN.
A SERIES OF NW SWELLS WILL MAINTAIN 6-8 FT SEAS THROUGH
WEDNESDAY MORNING. FRIDAY, A LARGER SWELL WILL BRING A 60-80%
CHANCE OF SEAS BUILDING ABOVE 10 FEET FOR THE OUTER COASTAL
WATERS. ~HALL
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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