AFDSEW AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SEATTLE WA 1106 AM PST SUN JAN 28 2024 .SYNOPSIS....SOME LINGERING SHOWERS, ESPECIALLY ACROSS THE CASCADES, THIS MORNING BUT A MILD AND LESS WET DAY IS EXPECTED ACROSS THE REGION. THE NEXT SYSTEM REMAINS MOSTLY OFFSHORE, BUT SPREADS SOME MOISTURE ACROSS THE OLYMPIC PENINSULA AND NORTH CASCADES. A WEAK SYSTEM MOVES IN MONDAY NIGHT, WITH THE NEXT STRONGER ATMOSPHERIC RIVER TAKING AIM AT THE REGION LATE TUESDAY. AN UPPER LEVEL TROUGH WILL ARRIVE BY NEXT WEEKEND FOR A TURN TOWARD COOLER TEMPERATURES, SHOWERY PRECIPITATION, AND LOWERING SNOW LEVELS. && .SHORT TERM /TODAY THROUGH TUESDAY/...AN ACTIVE MORNING WITH THE HEAVY RAIN OVERNIGHT PUSHING ACROSS THE REGION RESULTING IN HANDFUL OF RIVER POINTS REACHING MINOR FLOOD STAGE. SEE MORE DETAILS IN THE UPDATED HYDROLOGY SECTION BELOW. OTHERWISE, LINGERING RAIN GRADUALLY TAPERS FOR A MILD DAY ACROSS THE REGION THE SYSTEM TONIGHT REMAINS MOSTLY OFFSHORE, BUT SOME RAIN MAY CLIP THE FAR NORTHERN AND WESTERN PORTIONS OF THE OLYMPIC PENINSULA AND PERHAPS PART OF THE NORTH CASCADES. ANY RAINFALL FROM THIS SYSTEM IS NOT EXPECTED TO BE HYDROLOGICALLY SIGNIFICANT. REMAINDER OF THE PREVIOUS SHORT TERM DISCUSSION FOLLOWS. 12 MODELS REMAIN IN AGREEMENT THAT OVERNIGHT TONIGHT AND INTO MONDAY WILL LIKELY STAY DRY FOR MUCH OF THE CWA...ALTHOUGH CANNOT RULE OUT A STRAY SHOWER OVER FAR NORTHERN PORTIONS OF THE OLYMPIC PENINSULA OR ALONG THE CANADIAN BORDER...THANKS TO A BUILDING RIDGE OVER THE ROCKIES. AS THE ASSOCIATED RIDGE AXIS SHIFTS EASTWARD, ECMWF AND ENSEMBLES SHOW A WEAKER SYSTEM ENTERING THE AREA TUESDAY MORNING FOLLOWED QUICKLY BY A SHORTWAVE RIDGE IN THE AFTERNOON, ALLOWING FOR ANOTHER BREAK TO CONTINUE INTO TUESDAY NIGHT. DAYTIME HIGH TEMPS CONTINUE TO REMAIN QUITE MILD IN THE SHORT TERM WITH WIDESPREAD UPPER 50S TO AROUND 60 EXPECTED TODAY, UPPER 50S TO LOWER 60S FOR MONDAY AND DROPPING SLIGHTLY TUESDAY WITH HIGHS AKIN TO THOSE OF TODAY. DURING THIS WARM STREAK, MAY CONTINUE TO SEE RECORDS SET...AS WAS THE CASE YESTERDAY IN SOME SPOTS. OVERNIGHT LOWS WILL ALSO REMAIN MILD, REMAINING IN THE UPPER 40S TO LOWER 50S. .LONG TERM /WEDNESDAY THROUGH SATURDAY/...SYSTEM ON THE DOORSTEP LATE TUESDAY NIGHT/WEDNESDAY MORNING WILL USHER IN A PRETTY WET PERIOD AS THE FRONT PUSHES IN WEDNESDAY THEN THE UPPER LEVEL TROUGH FOLLOWS SUIT THURSDAY. THE INITIAL FRONT CONTINUES TO LOOK TO HAVE ATMOSPHERIC RIVER SUPPORT. RAINFALL AMOUNTS WEDNESDAY WILL VARY WITH ANYWHERE FROM A HALF-INCH TO AN INCH AND A HALF EXPECTED ON THE OLYMPIC PENINSULA WHILE LOCATIONS EAST AND NORTH OF PUGET SOUND LIKELY TO SEE A LITTLE LESS WITH RANGES OF A QUARTER OF AN INCH TO AROUND AN INCH. ADDITIONAL RAINFALL THURSDAY WILL ADD INSULT TO INJURY, HOWEVER IS NOT EXPECTED TO BE ANYWHERE NEAR THE AMOUNTS OF WEDNESDAY WITH MOST LOCATIONS SEEING FROM A TENTH TO A QUARTER OF AN INCH. REGARDLESS, THIS PERSISTENT RAINFALL WILL CONTINUE TO TRIGGER AREA RIVERS. THIS WILL BE DISCUSSED FURTHER IN THE HYDROLOGY SECTION BELOW. ALTHOUGH MOST OF THE RAIN ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL FALL THURSDAY, THE TROUGH DOES LINGER OVER THE AREA FOR THE REMAINDER OF THE FORECAST PERIOD. THIS WILL NOT ONLY KEEP THE RISK OF SHOWERS PRESENT BUT DRAG TEMPS FROM ABOVE NORMAL TO BELOW NORMAL WITH HIGHS LATE IN THE WEEK RANGING FROM THE LOWER TO MID 40S. A RETURN TO OVERNIGHT LOWS GETTING INTO THE 30S IS EXPECTED, HOWEVER THE CHANCES OF GETTING DOWN TO FREEZING APPEAR SLIM AT THIS TIME...HELPING TO KEEP ANY PRECIP THAT FALLS MAINLY OF THE LIQUID VARIETY. 18 && .AVIATION...MOIST S/SW FLOW CONTINUES ACROSS WESTERN WA THIS MORNING WITH RAIN ACTIVITY DIMINISHING OVER THE REGION. MOST TERMINALS SHOULD REMAIN MVFR TO VFR THIS AFTERNOON WITH FURTHER CLEARING AND RAISES IN THE CEILINGS. HIGH PRESSURE KEEPS RAIN MOSTLY OFFSHORE TONIGHT INTO MONDAY. KSEA...RAIN HAS TAPERED OFF THIS MORNING WITH CIGS IN MVFR RANGE, LIKELY IMPROVING TO VFR THIS AFTERNOON. S WIND AROUND 5 TO 9KT. DRIER CONDITIONS THIS AFTERNOON WITH CEILINGS IMPROVING AFTER 20Z. 33/KRISTELL && .MARINE...WINDS AND SEAS REMAIN ELEVATED OVER THE COASTAL WATERS THROUGH MIDWEEK AS A SERIES OF PACIFIC FRONTAL SYSTEMS CLIP THE REGION. SEAS WILL BUILD TO 10 TO 15 FEET ON MONDAY. THE SYSTEM TUESDAY NIGHT AND WEDNESDAY MAY BRING GALE FORCE WINDS. 33/KRISTELL && .HYDROLOGY...THE THREAT OF RIVER FLOODING WILL CONTINUE TODAY AND THROUGH EARLY THIS WEEK FOR PARTS OF WESTERN WASHINGTON. HEAVY RAINFALL FELL ACROSS THE REGION EARLY THIS MORNING FROM AN ATMOSPHERIC RIVER. THE HEAVIEST QPF TOTALS WERE IN THE OLYMPIC PENINSULA AND IN THE NORTH CASCADES. A FEW ADDITIONAL RIVERS CROSSED INTO MINOR FLOOD STAGE THIS MORNING (NOOKSACK RIVER AT NORTH CEDARVILLE, SOUTH FORK NOOKSACK RIVER AT SAXON BRIDGE, STILLAGUAMISH RIVER AT ARLINGTON). FLOOD WARNINGS HAVE BEEN ISSUED FOR THIS RIVERS FOR THE RISE INTO MINOR FLOOD STAGE, WITH A DROP EXPECTED LATER THIS EVENING BELOW MINOR FLOOD STAGE. THE SKOKOMISH RIVER HAS CRESTED IN MODERATE FLOOD STAGE, AND IS EXPECTED TO FALL INTO MINOR FLOOD STAGE EARLY THIS WEEK. ADDITIONAL RIVERS MAY CROSS INTO MINOR FLOOD STAGE LATER TODAY, AND WILL ISSUE ADDITIONAL FLOOD WARNINGS IF NEEDED. ADDITIONAL ROUNDS OF HEAVY RAINFALL ARE EXPECTED THIS WEEK. THE FIRST ROUND ON MONDAY NIGHT WILL AGAIN BE FOCUSED ON THE OLYMPIC PENINSULA AND THE NORTH CASCADES, BUT MAY NOT LEAD TO ADDITIONAL FLOOD IMPACTS. A MORE IMPACTFUL SYSTEM MAY ARRIVE AROUND TUESDAY EVENING, AND COULD BRING ENOUGH RAIN TO LEAD TO ADDITIONAL FLOODING, ESPECIALLY ON RIVERS RUNNING HIGH AFTER THIS WEEKEND`S PREVIOUS RAIN. HPR && .SEW WATCHES/WARNINGS/ADVISORIES... WA...NONE. PZ...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM PST TUESDAY FOR GRAYS HARBOR BAR. SMALL CRAFT ADVISORY UNTIL 8 AM PST MONDAY FOR EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS. SMALL CRAFT ADVISORY UNTIL 4 PM PST MONDAY FOR COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM- COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER OUT 10 NM. &&