AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
847 PM PDT SUN MAR 15 2020

.UPDATE...DRY CONDITIONS INTO THE WEEK. PATCHY MID AND HIGH CLOUDS
AROUND THE SOUTH SOUND THIS EVENING. BREEZY CONDITIONS WILL BECOME
LIGHT INTO MONDAY AS FRASER OUTFLOW EASES AND HIGH PRESSURE BUILDS
INTO THE AREA.

&&

.SYNOPSIS...DRY WEATHER IS IN STORE FOR MUCH OF THE WEEK AHEAD AS
HIGH PRESSURE BUILDS OFFSHORE AND THEN MOVES SLIGHTLY ONSHORE. THE
WEEK WILL START OFF COOLER WITH MORNING LOWS BELOW FREEZING IN
SPOTS. TEMPERATURES COULD BUILD TO NEAR 60 DEGREES IN MANY PLACES
ACROSS W WASHINGTON BY THE END OF THE WEEK.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...RELATIVELY BENIGN
WEATHER IS IN STORE. TEMPERATURES WILL START OFF COOLER, WITH
MORNING LOWS STILL AT OR BELOW FREEZING, MODERATING INTO THE WEEK.
LAST WEEK`S LOW IS SLIDING OFF TOWARD THE SOUTH, WHILE UPPER LEVEL
RIDGING IS OCCURRING IN THE GULF OF ALASKA. THIS UPPER LEVEL
RIDGE WILL SETTLE IN TOWARD BRITISH COLUMBIA AND MAKE A SMALL
ADJUSTMENT EAST AND SLIGHTLY MORE ONSHORE. THIS WILL SET UP MANY
LOCALES IN W WA TO BE ON TRACK FOR A 60 DEGREE DAY, OTHERWISE
HIGHS WILL BE IN THE MID TO UPPER 50S AS THE WEEK PROGRESSES.
SUNNY AND DRY CONDITIONS ARE EXPECTED.

.LONG TERM /THURSDAY THROUGH SUNDAY/...THE GULF OF ALASKA RIDGE
SHOWS SIGNS OF WEAKENING BY THURSDAY EVENING AND ALLOWING A LOW TO
DROP INTO THE AREA. THAT BEING SAID, A FAIR BIT OF THE MODELS
RESOLVE THIS LOW, BUT THE DISAGREEMENT LIES IN HOW FAR INLAND THE
LOW IS PROGGED TO MOVE. GFS ENSEMBLES HAVE TRENDED TOWARD TRACKING
THE LOW MUCH FURTHER INLAND INTO W WA BRINGING MORE RAIN AND
BREEZY CONDITIONS, WHILE ECMWF ENSEMBLES ARE KEEPING IT WELL
OFFSHORE AND LIMITING POSSIBLE IMPACTS. AT THIS POINT, IT IS TOO
EARLY TO MAKE A DETERMINATION AND MORE MODEL CONVERGENCE IS
REQUIRED IN ORDER TO GET A MORE CLEAR PICTURE OF THE LATE WEEK
TIMEFRAME.

IF IT IS ANY CONSOLATION, LONG RANGE MODEL PROJECTIONS INDICATE
POSITIVE HEIGHT ANOMALIES OVER THE GULF OF ALASKA AND NEGATIVE
HEIGHT ANOMALIES OVER CALIFORNIA OUT TO AT LEAST 7 DAYS. THIS ALL
SUGGESTS THAT THE EXTENDED RANGE FORECAST MAY STAY ON THE DRIER AND
SUNNIER SIDE.

&&

.AVIATION...EASTERLY FLOW ALOFT WITH AN UPPER LEVEL LOW SOUTH OF
THE AREA. HIGH PRESSURE WILL BUILD INTO THE AREA FOR MOSTLY CLEAR
SKIES, WITH A FEW HIGH CLOUDS. BREEZY NORTHERLY SURFACE WINDS WILL
SUBSIDE TONIGHT. VFR CIGS.

KSEA...VFR CIGS WITH SOME HIGH CLOUDS. NORTHERLY SURFACE WINDS 10
TO 20 KNOTS WILL EASE TO 7 TO 14 KNOTS EARLY TONIGHT. JD

&&

.MARINE...FRASER OUTFLOW WINDS WILL EASE INTO TONIGHT. SMALL CRAFT
ADVISORIES FOR MOST WATERS INTO THIS EVENING. SCA LEVEL WINDS FOR
WEST ENTRANCE OF THE STRAIT OF JUAN DE FUCA, NORTHERN INLAND
WATERS, AND PUGET SOUND INTO EARLY MONDAY MORNING. LIGHTER WINDS
MONDAY AS HIGH PRESSURE BUILDS IN OVER THE NEXT FEW DAYS. JD

&&

.HYDROLOGY...NO RIVER FLOODING IS EXPECTED OVER THE NEXT 7 DAYS.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR COASTAL
     WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-
     COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO
     60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
     SHOALWATER 10 TO 60 NM.

     SMALL CRAFT ADVISORY UNTIL 7 AM PDT MONDAY FOR NORTHERN INLAND
     WATERS INCLUDING THE SAN JUAN ISLANDS-PUGET SOUND AND HOOD
     CANAL.

     SMALL CRAFT ADVISORY UNTIL 5 AM PDT MONDAY FOR WEST ENTRANCE
     U.S. WATERS STRAIT OF JUAN DE FUCA.

&&