Sunrise 5:30 AM   Sunset 8:45 PM Moonrise 5:09 PM   Moonset 3:03 AM

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PZZ210 Columbia River Bar- 229 Am Pdt Mon May 20 2024
In the main channel -
General seas - 6 ft subsiding to 4 ft Tuesday morning.
First ebb - Ebb current of 4.81 kt at 322 am Monday. Seas 6 ft.
SEcond ebb - Ebb current of 3.08 kt at 339 pm Monday. Seas 5 ft.
Third ebb - Ebb current of 5.26 kt at 359 am Tuesday. Seas 4 ft.

PZZ200 229 Am Pdt Mon May 20 2024
Synopsis for the southern washington and northern oregon coast - After a weak ridge of high pressure moves overhead today our next front arrives Tuesday morning another burst of northwesterly wind come Tuesday night. High pressure returns mid-week followed by another weather disturbance Friday into Saturday.

FXUS66 KPQR 200937 AFDPQR

Area Forecast Discussion National Weather Service Portland OR 237 AM PDT Mon May 20 2024

SYNOPSIS
Stratus across portions of the region this morning with low temperatures falling to the mid 30s for some areas in the southern Willamette Valley and upper Hood River Valley.
Dry and mostly sunny today. A weather system will bring more widespread but generally light rain across the region Tuesday.
Showers with a thunderstorms possible on Wednesday. Will maintain unsettled with near to slightly below average temperatures for rest of the week into the weekend.

SHORT TERM
Monday through Wednesday...Satellite imagery early Monday morning shows stratus forming along the western slopes and foothills of the Coast Range and Cascades. HRRR and sounding guidance indicates this stratus could spread up the Columbia River Valley as well as back build from the eastern Cascades into portions of the Willamette Valley, including into the Portland metro area. Stratus will dissipate through the morning hours and should be mostly clear by midday. Temperatures as of 2 AM remain fairly mild with 40s across the lowlands and the upper Hood River Valley and 30s in the higher elevations of the Coast Range and Cascades. Will still keep the Frost Advisory in place through 8 AM as dew point temperatures have fallen into the upper 30s in the lowlands, and HRRR indicates a 20-50% chance of temperatures falling to or below 35 degrees this morning for the southern Willamette Valley south of Salem.

For the rest of today, expect mostly clear skies and dry weather under a period of brief upper level ridging. Temperatures will be warmer than previous days, warming to the mid to upper 60s across the interior lowlands. However, probabilities of reaching 70 degrees for the Portland metro area have decreased to 30-45% based on latest NBM guidance, likely due to the lingering stratus. However, if stratus is not as thick as forecast or does not last as late into the afternoon, then would not be surprised if some metro locations reach the low 70s this afternoon.

Ensembles indicate the next frontal system is slated to move through NW Oregon and SW Washington Tuesday. This front and associated upper trough are moving in from the northwest, so it will bring some colder air along with it as well as a band of widespread stratiform rain across the region. The Willamette Valley will likely be rain shadowed due to the direction of the flow with higher precipitation amounts in SW Washington (including lowlands), the Coast Range, and Cascades. NBM indicates only a 20-40% probability of 0.25 inch or higher rain amounts in 24 hours in the central and southern Willamette Valley ending 5am Wednesday. These probabilities increase to 40-50% in the Portland/Vancouver metro area, and 75-90% in the lowlands north of Clark County. The Coast Range and Cascades north of a line from Tillamook to Government Camp are forecast to receive the highest QPF, anywhere from 0.75-1.25 inch. NBM indicates 50-70% probability of QPF greater than 0.75 inches for these areas through Tuesday night. Snow levels will remain above 5500-6000 feet through Tuesday, so snow at or below pass level is not expected. As the front will move through the region throughout the day, daytime temperatures in central Oregon may not fall as much as areas to the north. Expect lowland highs in the mid 50s to mid 60s, warmest in Lane County.

Ensemble guidance remains in good agreement (85% of WPC 500mb clusters) that a closed upper low tracking south along the BC coast Monday and Tuesday will continue the southern track along the northern Washington coast Tuesday night before moving southeast into eastern Oregon through the day Wednesday. This pattern will allow onshore flow to continue with another round of showers. Some uncertainty remains on exactly how deep into Oregon the low will track with some clusters hedging the low mostly along the Washington/Oregon border with others pushing it farther east into east central Oregon. However, this would only affect the amount of precipitation expected but not the overall impacts. Generally expecting light precipitation less than 0.15 inch in the lowlands with upslope flow producing 0.25-0.75 inch over the higher terrain. However, there could be widespread thunderstorm chances in the afternoon and evening hours depending on how deep the trough moves into Oregon as the cold core moves aloft. Heavier showers and small hail would be likely in this scenario. -HEC

LONG TERM
Thursday through Sunday...Thursday is looking mainly dry as brief ridging builds in the eastern Pacific.
However, ensembles are beginning to show the potential for a weak shortwave to form on the back end of the closed low on Thursday, which would keep light shower chances continuing, mainly for the higher elevations. WPC 500 mb clusters continue to indicate a general trough pattern Friday into the weekend, though specific details on timing and location of weather systems and any potential precipitation amounts are still very uncertain at this time. One aspect that does seem a little more certain is temperatures are expected to remain fairly mild through the weekend. NBM indicates a 75-95% chance that interior lowland temperatures will warm back into the 60s and remain in the 60s through the weekend. -HEC

AVIATION
Current satellite imagery early this morning shows a low stratus deck continuing to thicken along the western slopes of the Cascades and Cascade foothills due to persistent upslope flow.
High resolution guidance remains confident in this layer back building further west into the north Willamette Valley and Portland/Vancouver metro by 12-14z ushering in high-end MVFR cigs before breaking up by 18-21z Mon returning conditions to VFR.
Elsewhere, (excluding KAST where MVFR cigs are also anticipated this morning) expect generally VFR conditions with scattered cloud cover as the region maintains north/northwest flow aloft.
Winds will be mostly calm to start the day then pick up to 5-10 kt with occasional gusts to 18-22 kt possible during the afternoon into the early evening along the coast and in the Willamette Valley before decreasing again overnight.

PDX AND APPROACHES...Headed through this morning guidance continues to suggests a 70-90% chance of MVFR cigs between roughly ~12-18z due to low clouds in the Cascade foothills shifting westward overhead. Otherwise, once this layer breaks up 18-20z expect predominately VFR conditions with scattered cloud cover.
Winds will be northwesterly and around 5-10 kt although occasional gusts around 15-20 knots will be possible around 22-03z. -Schuldt

MARINE
Small Craft Advisory conditions will persist for the outer waters today with N-NW wind gusts near 20-22 knots to start before the concern shifts to steeper seas of ~7-8ft at 7-8 seconds. Fortunately, calmer conditions return tonight into early Tuesday morning, albeit briefly, before the next frontal passage arrives on Tuesday bringing rain and a burst of northwesterly winds. Confidence is high (70-80%) wind gusts reach into the 20-25 knot range for the outer waters north of Cape Foulweather Tuesday evening/night in the post-frontal environment – additional Small Craft Advisories may be needed. A northwesterly swell of 8 to 10 feet at 9-10 seconds then arrives Wednesday morning as winds begin to subside. Looking ahead, calmer winds/seas return Thursday followed by the potential for yet another weather disturbance moving into the region late Friday/Saturday continuing the rather progressive and active weather pattern. -Schuldt

PQR WATCHES/WARNINGS/ADVISORIES

OR...Frost Advisory until 8 AM PDT this morning for ORZ116>118-121- 124-125.

WA...None.

PZ...Small Craft Advisory until 5 AM PDT early this morning for PZZ251>253.

Small Craft Advisory until 11 PM PDT this evening for PZZ271>273.

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Knappa
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Mon -- 12:16 AM PDT     7.94 feet High Tide
Mon -- 04:04 AM PDT     Moonset
Mon -- 05:35 AM PDT     Sunrise
Mon -- 07:34 AM PDT     0.37 feet Low Tide
Mon -- 01:10 PM PDT     6.40 feet High Tide
Mon -- 06:09 PM PDT     Moonrise
Mon -- 07:13 PM PDT     1.96 feet Low Tide
Mon -- 08:47 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION

Knappa, Knappa Slough, Columbia River, Oregon, Tide feet

Harrington Point
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Mon -- 12:08 AM PDT     7.39 feet High Tide
Mon -- 04:04 AM PDT     Moonset
Mon -- 05:35 AM PDT     Sunrise
Mon -- 07:28 AM PDT     0.23 feet Low Tide
Mon -- 01:02 PM PDT     5.79 feet High Tide
Mon -- 06:10 PM PDT     Moonrise
Mon -- 07:07 PM PDT     2.08 feet Low Tide
Mon -- 08:47 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION

Harrington Point, Columbia River, Washington, Tide feet

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