AFDSEW AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SEATTLE WA 845 PM PDT WED MAR 18 2020 .UPDATE...DRY WEATHER THROUGH THE WEEK. CLEAR SKIES INTO TONIGHT WITH LOW CLOUDS EARLY THURSDAY MORNING WITH A MARINE PUSH TONIGHT. PATCHY FOG MAY DEVELOP AS WELL. MAINLY CLEAR SKIES BY THE AFTERNOON. TEMPERATURES TONIGHT WILL BE IN THE LOW TO MID 30S WITH UPPER 50S, EVEN LOW 60S, FOR TOMORROW HIGHS. JD && .SYNOPSIS...A BENIGN WEATHER PATTERN WILL REMAIN IN PLACE ACROSS THE PACIFIC NORTHWEST THROUGH MUCH OF THE WEEKEND, ALLOWING FOR CONDITIONS TO REMAIN DRY AND WARM. A SYSTEM PASSING OFFSHORE WILL SPREAD SOME CLOUDS INTO THE REGION ON THURSDAY, HOWEVER THE NEXT CHANCE OF PRECIPITATION WILL BE LATE SUNDAY INTO EARLY NEXT WEEK AS A SYSTEM DROPS DOWN FROM THE GULF OF ALASKA. && .SHORT TERM /TONIGHT THROUGH SATURDAY/...A PRETTY NICE AFTERNOON ACROSS WESTERN WASHINGTON TODAY AS UPPER LEVEL RIDGING RESIDES ACROSS THE REGION AND SATELLITE SHOWS THAT STRATUS HAS CLEARED ACROSS THE SOUTHERN INTERIOR. TEMPERATURES ACROSS THE REGION ARE PRIMARILY IN THE LOW TO MID 50S. CONDITIONS WILL REMAIN CLEAR THROUGH THE EVENING HOURS, HOWEVER ANOTHER MARINE PUSH SHOULD MAKE ITS WAY INTO PORTIONS OF THE SOUND BY THURSDAY MORNING. OVERNIGHT LOWS WILL PRIMARILY BE IN THE MID 30S. APART FROM MORNING LOW CLOUDS, MID TO HIGH LEVEL CLOUD COVER WILL INCREASE ACROSS WESTERN WASHINGTON ON THURSDAY AS AN UPPER LEVEL LOW DROPS DOWN ALONG THE BRITISH COLUMBIA COAST FROM THE GULF OF ALASKA. THIS LOW WILL CONTINUE TO MOVE FURTHER OFFSHORE AS IT TRAVERSES SOUTHWARD, LEAVING WESTERN WASHINGTON DRY. HIGH TEMPERATURES WILL CONTINUE TO TREND WARMER, REACHING INTO THE MID TO UPPER 50S FOR MOST AREAS. UPPER LEVEL RIDGING WILL TAKE HOLD OF THE AREA AGAIN ON FRIDAY, ALLOWING FOR 500 MB HEIGHTS TO CLIMB. ANOTHER ROUND OF MORNING CLOUDS WILL GIVE WAY TO SUNNY SKIES AND THE WARMER TEMPERATURES. AFTERNOON HIGHS WILL BE IN THE UPPER 50S, WITH A FEW SPOTS NEARING 60. THE UPPER LEVEL RIDGE WILL REMAIN IN PLACE ON SATURDAY, KEEPING MOST OF THE AREA HIGH AND DRY. A FEW MODELS SUGGEST A WEAK UPPER LEVEL DISTURBANCE DROPPING DOWN FROM BRITISH COLUMBIA THAT COULD BRING A FEW POPS TO THE MOUNTAINS LATE IN THE DAY. THUS, HAVE INCLUDED A SLIGHT CHANCE FOR NOW. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...A MORE PROGRESSIVE WEATHER PATTERN IS ON TAP FOR THE LONG TERM, AS DETERMINISTIC MODEL RUNS BRING AN UPPER LEVEL TROUGH DOWN THE BRITISH COLUMBIA COAST AND INTO WESTERN WASHINGTON LATE SUNDAY INTO MONDAY. DETERMINISTIC MODELS START TO DIVERGE ON TRACK EARLY NEXT WEEK, HOWEVER ECMWF AND GFS ENSEMBLE MEANS CONTINUE TO SUGGEST PERSISTENT RIDGING ACROSS THE GULF OF ALASKA AND PERSISTENT UPPER LEVEL TROUGHING ALONG THE US WEST COAST. THIS WOULD CONTINUE TO SUGGEST A WET AND UNSETTLED PATTERN DURING THE LONG TERM. 14 && .AVIATION...NORTHERLY FLOW ALOFT WILL TRANSITION SOUTHWESTERLY THURSDAY AFTERNOON WITH RIDGING OVER THE PACIFIC NORTHWEST. THE AIR MASS IS MAINLY DRY, WITH SOME MOISTURE NEAR THE SURFACE, AND STABLE. VFR CIGS THROUGH EARLY TONIGHT. MARINE PUSH TONIGHT INTO THURSDAY MORNING. LOW CLOUDS POSSIBLE 09Z-18Z WITH IFR CIGS, ESPECIALLY ACROSS THE COAST AND SOUTHERN PUGET SOUND. PATCHY FOG IS POSSIBLE AS WELL. VFR CIGS FOR THURSDAY AFTERNOON WITH SOME HIGH CLOUDS. LIGHT WINDS. KSEA...VFR CIGS INTO TONIGHT. STRATUS POSSIBLE EARLY THURSDAY MORNING WITH IFR/MVFR CIGS. PATCHY FOG POSSIBLE AS WELL. VFR CIGS BY THE AFTERNOON WITH HIGH CLOUDS. LIGHT WINDS. JD && .MARINE...SMALL CRAFT ADVISORY ISSUED FOR THE CENTRAL AND EASTERN PORTIONS OF THE STRAIT OF JUAN DE FUCA FOR TONIGHT WITH A WEAK MARINE PUSH. MAINLY LIGHT WINDS ON THURSDAY FOR MOST WATERS WITH SOUTHERLIES OFFSHORE. A WEAK MARINE PUSH FOR THURSDAY EVENING INTO THURSDAY NIGHT. STRONGER MARINE PUSH EXPECTED FRIDAY EVENING INTO FRIDAY NIGHT FOR SCA WINDS. JD && .HYDROLOGY...RIVER FLOODING IS NOT EXPECTED OVER THE NEXT 7 DAYS. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...NONE. PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA. &&