Sunrise 5:50 AM   Sunset 8:23 PM Moonrise 3:19 AM   Moonset 3:23 PM

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PZZ210 Columbia River Bar- 239 Pm Pdt Sat May 4 2024
.small craft advisory in effect until 11 pm pdt this evening - .
In the main channel -
General seas - 6 to 7 ft.
First ebb - Ebb current of 4.46 kt at 228 pm Saturday. Seas 5 to 6 ft.
SEcond ebb - Ebb current of 5.55 kt at 305 am Sunday. Seas 7 ft.
Third ebb - Ebb current of 4.53 kt at 323 pm Sunday. Seas 7 ft.

PZZ200 239 Pm Pdt Sat May 4 2024
Synopsis for the southern washington and northern oregon coast - Active weather persists through into early next week with additional disturbances moving through the waters. Calmer more summer-like weather returns around the middle of next week accompanied by northerly winds.

FXUS66 KPQR 042133 AFDPQR

Area Forecast Discussion National Weather Service Portland OR 233 PM PDT Sat May 4 2024

SYNOPSIS
Steady light to moderate rain will continue across the lowlands of SW Washington and NW Oregon through Sunday with light to moderate snow over the Cascades above 4000 feet.
Travel impacts in the Cascades will largely occur tonight into Sunday morning when road temperatures become cool enough for snow to stick. Another round of rain and Cascades snow is expected Monday as the next system moves onshore, with post- frontal showers lingering into Tuesday. A significant warming and drying trend is expected later in the week as high pressure builds over the region.



SHORT TERM
Saturday Afternoon through Tuesday...Radar imagery shows showers continuing across NW Oregon and SW Washington this afternoon. The surface front has pushed into eastern Oregon through the morning with satellite imagery indicating the associated upper closed low pressure system approaching the Oregon/California border. Ensemble guidance remains in solid agreement that the closed low will move onshore along the Oregon/California border this evening, moving slowly east through northern California into Nevada tonight through Sunday morning. NW Oregon and SW Washington is currently situated on the northeastern side of the closed low and will remain on the north side of this closed low through Sunday.
Enough moisture will wrap around this low to allow precipitation to continue across the region through Sunday. The heaviest bought of precipitation for most locations should taper off tonight and become lighter as the region transitions from the northeast to north side of the low except for over the Cascades where orographics will keep precipitation more steady. The following precipitation amounts have been recorded since rain began Friday: 1.25 to 2.5 inches along the coast and Coast Range, 0.75 to 2 inches in the lowland valleys, and 0.4 to 1.5 inches for the Cascades and adjacent western foothills. Highest amounts have been roughly in and south of Lincoln County.
Additional QPF amounts through 5pm Monday are as follows: 0.5 to 2 inches along the coast and Coast Range, 0.5 to 1.25 inches in the interior lowlands, and 1 to 3 inches along the Cascades and adjacent foothills.

Since this is a colder weather system, snow levels have lowered to around 4000 feet this morning and will lower to around 3000-4000 feet tonight through Sunday. Webcams show snow did begin right around 10am this morning over mountain passes.
However, as of 2pm, a limited amount of snow seems to be sticking to roads due to warm road temperatures lingering. Only in the past hour do webcams show slushy snow beginning to stick along Willamette Pass. As temperatures remain cool this afternoon and lower overnight, expect more snow to begin accumulating along roadways. Despite the higher QPF for the Cascade passes, snow accumulations should remain fairly low for the passes due to the marginal thermal profile and resulting low snow-to- liquid ratios. By far, the most significant deviations our forecast makes from NBM were in the snow-to- liquid ratios (SLRs). Our SLRs were largely based on the more reasonable WPC guidance, though we lowered the SLRs 10-15% from even the WPC guidance (and 30-40% below NBM guidance). This was necessary to get the SLRs below 10:1 for the passes, where NBM was showing SLRs in the 13:1 to 16:1 for the passes and even higher than that for higher elevations. Such SLRs would be difficult to achieve for the passes even in the middle of winter, much less the middle of spring. Even then, a Winter Weather Advisory remains in effect through 6 pm Sunday as at least 4 to 8 inches of snow are expected at pass level. NBM and HRRR (SLR of 10:1)
indicate a 60-90% probability of at least 8 inches above 4000 feet generally along and south of Highway 20 through 5pm Sunday.
Since the snow ratios on both these are both a bit high, would expect 8 inches to be the higher end of snow accumulation at the passes, with up to 14 inches above 5000 feet.

A relative lull in precipitation is possible Sunday night except for lingering Cascades showers as the upper low and its deformation zone shift into the Rockies. However, ensembles are in good agreement that a shortwave trough and reinforcing cold front will move onshore Monday morning, bringing another round of widespread precipitation Monday night through Monday afternoon with post- frontal showers persisting through Tuesday.
Upper level flow will be westerly with this system which will lead to quite a bit less accumulation in the lowlands (0.5-0.25 inch) than the Cascades (0.5-1 inch). Snow levels will remain around 3500-4000 feet with lower SLRs, so a few more inches of snow is possible over passes. Temperatures will remain below seasonal normal, with lowland highs stuck in the 50s through Tuesday. -HEC/Weagle

LONG TERM
Wednesday through Friday...Ensemble guidance confidence is high for a rapid shift in the weather pattern from cool and wet to warm and dry. This abrupt shift is the result of an upper level ridge that is set to build over the region, and all four clusters shown in WPC's 500 mb cluster analysis depict this ridge with varying amplitudes. The deterministic NBM currently suggests lowland highs in the 60s Wednesday, 70s Thursday (except 60s at the coast), and 80s Friday (except low 70s at the coast). The coolest model solutions are similar to the NBM 10th percentile, showing inland high temperatures peaking in the mid to upper 70s on Friday. Meanwhile, the warmest model solutions show highs near 90 degrees for the inland valleys. Either way, temperatures will be running above normal for this time of year by Thursday. The probability for high temperatures at or above 80 degrees on Friday has raised to 75-90% across the interior lowlands, which is quite high for a forecast that is six days out. Overall, the warmest temperatures of the year so far are likely to occur late this week high confidence this pattern will continue into at least Saturday.
This may draw some people to area rivers and/or lakes, but keep in mind water temperatures are still very cold and river currents will be swift with mountain snowmelt. If you make plans near area waterways, be very vigilant and wear a life vest as cold water shock and hypothermia will be a very real risk for anyone who goes into the water. -TK/HEC

AVIATION
Widespread bands of rainfall persist across western Oregon and SW Washington this afternoon. Current observations show flight conditions remain quite variable ranging from VFR to IFR across the terminals regionally, although most locations currently sit at MVFR. At least there is still high confidence (65-95% chance) based on the latest guidance for mainly MVFR conditions persist this evening through Sunday morning both the coastal and inland areas. It's worth noting there are chances(20-30%) for a period of IFR cigs at most inland sites Sunday morning between 12-18z; much higher chances (40-60%)
comparatively along the coast during this same period. Wind generally stay less than 10 kts inland but coastal areas appear a little breezier with westerly winds 10-20 kt.

PDX AND APPROACHES...A mix of VFR/MVFR conditions have quickly trended back to MVFR as rainfall rates have increased over the Portland/Vancouver metro area early this afternoon. It's certainly possible if these rainfall rates ease again after the band overhead passes we could see temporary windows of VFR cigs return roughly ~23-03z but in general anticipate MVFR conditions through the period. It's worth noting guidance gives around a 15-25% chance for IFR after 10z through 16z Sunday. Thus brief periods of IFR cigs will still need to be monitored. -Schuldt

MARINE
The active weather pattern continues into early next week before a shift to generally calmer conditions and a more summer-like pattern. A broad upper level low off the far southern Oregon coast will continue to progress inland into northern California tonight leading to a decrease in 15 to 25 knot gusts over the waters (highest beyond 10nm) and subsiding seas. After a quick break the next frontal system arrives Sunday bringing another round of gusts up to 25 kt as well as steep seas across most of the waters Sunday morning through Monday morning.
Following this front high pressure over the east-northeast Pacific begins build over the waters and bring breezy west to northwest winds (gusting 20-25 kt) across the waters later Monday into Tuesday. Also expect the arrival of a pounced WNW 9-11 ft swell at ~12 seconds Monday night. The high pressure shifts closer to the waters later next week followed by a larger offshore component to the wind in the Friday/Saturday timeframe. -Schuldt

PQR WATCHES/WARNINGS/ADVISORIES
OR...Winter Weather Advisory until 6 PM PDT Sunday for ORZ126>128.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ210- 251>253-271>273.
Small Craft Advisory from 11 AM Sunday to 8 AM PDT Monday for PZZ251-271.
Small Craft Advisory from 5 AM Sunday to 8 AM PDT Monday for PZZ252-253-272-273.

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