Sunrise 5:59 AM   Sunset 8:18 PM Moonrise 12:00 AM   Moonset 7:40 AM

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PZZ210 Columbia River Bar- 223 Pm Pdt Sun Apr 28 2024
.small craft advisory in effect through Tuesday evening - .
In the main channel -
General seas - 7 to 9 ft through Monday evening.
First ebb - Ebb current of 2.4 kt at 830 pm Sunday. Seas 7 to 8 ft.
SEcond ebb - Ebb current of 5.11 kt at 841 am Monday. Seas 6 to 7 ft.
Third ebb - Ebb current of 2.2 kt at 933 pm Monday. Seas 7 to 8 ft.

PZZ200 223 Pm Pdt Sun Apr 28 2024
Synopsis for the southern washington and northern oregon coast - Winds and seas slowly build Sunday evening as the next system moves through the waters Sunday night through early Monday. Another system quickly follows Monday night through Tuesday. Through the end of the week, expect an active weather pattern with periods of relatively calmer conditions.

FXUS66 KPQR 282207 AFDPQR

Area Forecast Discussion National Weather Service Portland OR 307 PM PDT Sun Apr 28 2024

SYNOPSIS
Multiple colder weather systems to move through NW Oregon and SW Washington tonight into Monday morning and again Monday night into Tuesday, bringing continuing showers along with chances of isolated thunderstorms. Snow levels drop tonight down to 2500-3000 feet by tomorrow morning with snow at times expected over the Cascades through Tuesday. Dry and warmer weather returns Wednesday with unsettled weather returning late this week into the weekend.

SHORT TERM
Sunday afternoon through Wednesday...Radar imagery early Sunday afternoon shows showers are becoming more widespread across NW Oregon and SW Washington as the next weather system approaches the region. This upper trough and associated surface front are slated to move through the region late tonight into early Monday quickly followed by another weather system Monday night into Tuesday. Showers are expected to continue into Tuesday with these systems. The IVT associated with these are very low (less than 250 kg/ms), so expecting mostly showers instead of stratiform rain through Tuesday. A few bands of moderate rain are possible ahead of and along each front, with the Monday night through Tuesday front packing a little more punch. Current QPF through 5pm Monday is 0.1-0.3 inch for the inland valleys and 0.4-1 inch for the coast and mountains. Additional QPF through 5am Wednesday is 0.25-0.5 inch for inland valleys and 0.3-1.25 inch for the coast and mountains. For both systems, Lane county is expected to be on the lower end of these estimates as the strongest portion of each system remains north of Lane county. These are colder systems as they originate from west of Alaska, and as such they is forecast to bring colder air aloft into the region. Latest observations indicate this colder air aloft is beginning to push into the region this afternoon, with colder temperature expected tomorrow into Tuesday. This will cause both thunderstorm chances and lower snow levels.

First, as colder air moves in aloft, instability is forecast to increase. This afternoon only has a weak chance of isolated thunderstorms with CAPE values only expected to increase to 150-250 J/kg, mainly along and north of the Columbia River, including the Portland/Vancouver metro area, and the north Oregon coast and Cascades. There are better chances for isolated thunderstorms across the region both tomorrow and Tuesday along and behind each frontal passage with CAPE values increasing to 200-400 J/kg and 0-6 km shear of 45-55 kts. Heavy rain, small hail, gusty winds, and lightning are the main impacts expected with any strong shower or thunderstorm that forms.

Additionally, snow levels will begin dropping this evening into Monday as the cold air continues moving into the region. Expect snow levels to fall to 3500-4000 ft by this evening and 2500-3000 ft by tomorrow morning. As there will be a couple decent shots of precipitation with the front, expecting snow amounts of 2-8 inches above 2500 ft with up to 10-14 inches above 5000 ft. Elevations down to 2000 ft could see a dusting to an inch or so, especially in heavier showers. A Winter Weather Advisory remains in effect for the Cascades through tomorrow morning. Lighter snow is expected to continue tomorrow afternoon through Tuesday, though since conditions will turn to more scattered showers, there will likely not be much widespread additional accumulation except for potentially Tuesday morning with the second frontal passage.

Daytime temperatures are forecast to remain fairly steady in the mid to upper 50s for the lowlands and 30s to low 40s for the higher terrain. Nighttime temperatures will cool a bit each day, with morning lows tomorrow down to the low 40s for the lowlands then potentially falling to the upper 30s for Tuesday and Wednesday mornings. May need to keep an eye out for frost potential Wednesday morning if clouds clear out enough for radiative cooling, especially in the outlying valley areas and the Coast Range. Could also see some locally breezy winds at times with each frontal passage with brief periods of gusts up to 20-25 mph, locally up to 30 mph along the coast and 40-45 mph over the high Cascades.

By Wednesday, ensemble guidance agreement continues in increase in dry weather returning as ridging builds, though there is uncertainty on whether this dry period will last beyond Wednesday. More details on that below in the Long Term discussion. However, temperatures are forecast to warm back near seasonal normals for late April with NBM indicating 70-90% probability of temperatures rising back into the 60s. -HEC

LONG TERM
Thursday through next Sunday...Forecast confidence continues to drop off dramatically after the midweek period as guidance struggles with how to handle multiple disturbances presently over the west and central north Pacific. As longwave troughing exits the western US, it remains uncertain whether the next weaker system will maintain enough momentum to bring rain to SW Washington and NW Oregon. Latest NBM guidance basically shows a 50/50 chance of some light precipitation Thursday, then suggests a drier period of uncertain length. For Friday, 12z LREF grand ensemble shows a fairly normal distribution of 850 mb temps between 0 deg C and +10 deg C, with about 50% of members falling between +4 and +7 deg C.

The majority of EC/GFS/CMC ensemble members want to bring troughing back to the Pac NW by next weekend, with cool/unsettled weather returning. However this is far from certain. While 20% of NBM members suggest high temps Friday will fail to reach 65 def F in the Willamette Valley, another 20% suggest highs will reach 80 deg F for the PDX metro. For Saturday, 20-30% of members suggest the Willamette Valley will reach the 70s, while 10% suggest another day reaching 80 degrees for the PDX metro. While our forecast is much closer to seasonal norms than the warmer members, with cooler/wetter wx returning by the weekend, the warmer members illustrate how there is still potential for upper ridging to hold on longer than what the majority of members and ensemble means suggest. Weagle

AVIATION
Scattered showers continue across NW Oregon and SW Washington through the TAF period as a weak front moves through the region. Ceilings will hover around low-end VFR and high-end MVFR, with showers occasionally lowering ceilings and visibilities. Chances of widespread MVFR ceilings increase along the coast after 23z Sunday and inland around 06-10z Monday, raising around 18z Monday. Mountains are expected to remain obscured through the TAF period. West to southwest winds through the TAF period with occasional gusts up to 20 kts.

There's a 15-20% probability of thunderstorms for much of the region through at least 06z Tuesday. Probabilities decrease inland briefly after 06z Monday, increasing to 15-25% after 12z Monday.
Current confidence in thunderstorms occurring at any single terminal are too low to include in TAFs at this point.

Notes: The ASOS at KTTD is only available via the dial in option.
The AWOS at KMMV is still out of commission, but a tentative work around has been implemented. There is no estimated time of full repair and restoration for either of these locations.

PDX AND APPROACHES...Mixture of low-end VFR and high-end MVFR conditions with scattered showers through the TAF period.
Slight chance (15-20% probability) for thunderstorms 20Z Sunday through 06Z Monday, increasing again to 15-25% after 12z Monday.
Southwest winds 9-13 kts with gusts to 15-18 kts. -HEC

MARINE
Active weather is expected to continue into midweek. A surface front moving through the waters this evening through early Monday will bring another round of elevated winds along with steep and choppy seas through miday Monday. Generally westerly winds with gusts up to 25 kt and seas of 6 to 9 ft at 10 to 13 seconds through Monday. A Small Craft Advisory remains in effect through Monday afternoon.

A series of weak fronts will move through the waters Monday night into Tuesday and again late Tuesday into Wednesday, bringing elevated winds and seas at times. Some models are suggesting that small craft conditions could develop with each frontal passage.
Will continue to monitor the situation as it develops. -HEC

PQR WATCHES/WARNINGS/ADVISORIES
OR...Winter Weather Advisory from 8 PM this evening to 11 AM PDT Monday for ORZ126>128.
WA...Winter Weather Advisory from 8 PM this evening to 11 AM PDT Monday for WAZ211.
PZ...Small Craft Advisory until 11 PM PDT Tuesday for PZZ210- 251>253-271>273.

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