FXUS66 KPQR 220428
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
827 PM PST MON DEC 21 2009
.SYNOPSIS...SHOWERS WILL CONTINUE TONIGHT THROUGH TUESDAY IN COOL
ONSHORE FLOW. SNOW WILL FALL IN THE COAST RANGE...CASCADES AND
FOOTHILLS...AS WELL AS THE HIGHER HILLS IN THE WILLAMETTE VALLEY.
SHOWERS WILL TAPER OFF MIDDAY TUESDAY. DRY WEATHER WILL PREVAIL
THROUGH AT LEAST CHRISTMAS AS A STRONG UPPER LEVEL RIDGE BUILDS ALONG
THE COAST. BRISK EAST WINDS WILL DEVELOP NEAR THE COLUMBIA
RIVER GORGE WEDNESDAY NIGHT AND MAY CONTINUE THROUGH THE WEEKEND AS
THE RIDGE CONTINUES TO HOLD.
&&
.SHORT TERM...SHOWERS CONTINUE TO MOVE ACROSS THE FORECAST AREA THIS
EVENING IN COOL ONSHORE FLOW. ACCORDING TO NWS PROFILER...
CAMERAS...AND SURFACE OBSERVATIONS THE SNOW LEVEL IS RIGHT AROUND
1500 FEET...AND BRIEFLY DOWN TO AROUND 1000 FEET IN HEAVIER SHOWERS.
THE SNOW LEVEL WILL SETTLE DOWN TO 800 TO 1000 FEET OVERNIGHT AS 850
MB TEMPS BOTTOM OUT AT AROUND -6 DEGREES TUESDAY MORNING. THIS MEANS
THAT HILLTOPS AT AND ABOVE 1000 FEET COULD SEE A QUICK SLUSHY INCH
OF SNOW OVERNIGHT IF A HEAVIER SHOWER MOVES OVERHEAD. THE LOW LEVEL
FLOW WILL STAY STRONGLY ONSHORE SO NO THREAT OF SNOW TO THE VALLEY
FLOOR. WILL MAINTAIN ALL CURRENT WINTER WEATHER ADVISORIES FOR SNOW.
SHOWERS WILL EASE LATER TUESDAY AND TUESDAY NIGHT AS AN UPPER LEVEL
RIDGE BUILDS OVERHEAD. THE MODELS ARE NOW IN BETTER AGREEMENT KEEPING
US DRY THROUGH THE SHORT TERM. THE MAIN FORECAST ISSUES IN THE
WEDNESDAY-THURSDAY TIME FRAME WILL BE THE DEVELOPMENT OF GUSTY EAST
WINDS NEAR THE GORGE AND VALLEY FOG AWAY FROM THE GORGE.
.LONG TERM...THE UPPER LEVEL RIDGE TRANSITIONS THROUGH THE FORECAST
AREA THROUGH THE END OF THE WEEK...WITH DRY WEATHER CONTINUING
FRIDAY AFTER LATE NIGHT AND EARLY MORNING VALLEY FOG. MODELS VARY A
LOT WITH THE BREAKDOWN OF THE RIDGE NEXT WEEKEND AND THE ARRIVAL OF
ANY SUBSEQUENT SYSTEMS...AS SHOWN BY INCREASING ENSEMBLE SPREADS.
HAVE LOWERED POPS THROUGH THE EXTENDED TO SLIGHTLY BELOW CLIMATOLOGY
GIVEN THE CONTINUED INFLUENCE OF THE RIDGE. BROWN
&&
.AVIATION...CONDITIONS MOSTLY VFR AND SHOULD REMAIN VFR
TONIGHT...WITH JUST POCKETS OF MVFR ASSOCIATED WITH SHOWERS. STILL
SEEMS REASONABLE THAT LOWER DECK WILL GEL OVER AFTER 08Z...WITH
MOSTLY MVFR AND LOW VFR CIGS ACROSS REGION...ESPECIALLY AGAINST
THE CASCADES. SHOWERS SHOULD DECREASE TUE AFTERNOON.
KPDX AND APPROACHES...MOSTLY VFR WITH SCATTERED SHOWERS. WILL
TREND TO MORE MVFR...WITH CIGS 2500 TO 3000 FT...AFTER 08Z.
ROCKEY/WOLFE.
&&
.MARINE...SMALL CRAFT ADVISORY FOR WINDS AND SEAS WELL INTO TUE.
WINDS GRADUALLY EASING TUE... WITH WORST CONDITIONS EXPECTED
TONIGHT. SEAS WILL GRADUALLY EASE TUE NIGHT AND WED. NO MAJOR
WEATHER EXPECTED FROM WED THROUGH FRI AS HIGH PRES OVER PAC NW
KEEPS COASTAL WATERS DRY WITH OFFSHORE WINDS.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL NOON PST TUESDAY FOR UPPER HOOD
RIVER VALLEY-WESTERN COLUMBIA RIVER GORGE.
WINTER WEATHER ADVISORY UNTIL NOON PST TUESDAY FOR CASCADE
FOOTHILLS IN LANE COUNTY-NORTHERN OREGON CASCADE FOOTHILLS.
WINTER WEATHER ADVISORY UNTIL 10 AM PST TUESDAY FOR CENTRAL
COAST RANGE OF WESTERN OREGON-COAST RANGE OF NORTHWEST
OREGON.
WA...WINTER WEATHER ADVISORY UNTIL NOON PST TUESDAY FOR WESTERN
COLUMBIA RIVER GORGE.
WINTER WEATHER ADVISORY UNTIL NOON PST TUESDAY FOR SOUTH
WASHINGTON CASCADE FOOTHILLS.
WINTER WEATHER ADVISORY UNTIL 10 AM PST TUESDAY FOR WILLAPA
HILLS.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST TUESDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM PST TUESDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR FROM
10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 5 PM
PST TUESDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
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.
