Friday, May24, 2019 L-36.com


Marine Weather and Tides
Stevenson, WA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 5:27AMSunset 8:45PM Friday May 24, 2019 6:38 AM PDT (13:38 UTC) Moonrise 12:10AMMoonset 9:35AM Illumination 70% Phase: Waning Gibbous; Moon at 20 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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7 Day Forecast for Marine Location Near Stevenson, WA
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location: 45.68, -121.9     debug


Area Discussion for - Portland, OR
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Fxus66 kpqr 241014 cca
afdpqr
area forecast discussion... Corrected
weather service portland or
255 am pdt Fri may 24 2019
corrected advisories to remove small craft advisory for rough
columbia river bar

Synopsis An upper low will move south down the british columbia
coast and over washington and northwest oregon bringing scattered
showers to the area. Cooler weather will accompany this system with
temperatures falling below normal for the weekend. By Saturday,
colder air will bring snow levels down to the higher cascade passes.

No significant accumulations are expected but those planning
recreation for the holiday weekend will be impacted. Weak ridging
late Sunday and Monday will reduce the shower threat and warm
temperatures back above normal.

Short term Today through Sunday... A shortwave digging down the
british columbia and washington coast today will re-establish a low
over the pacific northwest this afternoon. Surface troughing to the
north of the forecast area has already turned low level onshore flow
more westerly, resulting in a deepening marine layer along the coast
and spreading inland into the western valleys. On satellite images,
evidence of the incoming marine air mass is seen with the intrusion
of marine clouds seen spreading up the lower columbia valley as well
as into the south end of the willamette valley. A second upper low
is expected to drop down and deepen off the coast Saturday, with an
even cooler air mass while adding some mid and upper level moisture.

The increase in moisture, in the low levels today and deeper
Saturday, will bring an increase in cloud cover for today through
Saturday, along with chances for showers to most of the region. The
coolest air aloft moves across late in the day both today and
Saturday, which coupled with diurnal heating will result in the best
instability each day, giving the best chances for showers in the
afternoons and evenings. The subsequent troughs will bring
progressivle lowering snow levels, dipping to 5000 to 6000 ft by
Saturday, although warm ground will make it difficult to sustain
accumulations in all but the heaviest snow showers at that
elevation. The switchover to a marine air mass will result in a
rather substantial drop in high temperatures today and Saturday,
with highs dropping back below seasonal normals.

Saturday night and Sunday the now fairly deep but compact upper low
drops southeast into the desert southwest. This brings the pattern
back to something similar to this past Wednesday, with the forecast
area in the cyclonic flow on the northwest side of the low.

Instability and moisture rotating in from the northeast will put the
main threat for showers and thunderstorms over the cascades, with a
lesser threat for the showers to drift westward back into the inland
valleys. A more northerly low level flow coupled with warming 850 mb
temperatures are likely to allow temperatures in the inland valleys
to warm back into the 70s.

Long term Sunday night through Thursday... No changes. Previous
discussion follows. A broad, strong upper-level trough finally
starts to kick this persistent upper-level ridge that has been
nearly stationary off the west coast off to the east, meaning a
pattern change is in store next week. With the shift of high
pressure inland early next week, we will see partly cloudy skies and
little to no shower activity Tuesday through Thursday. We will also
see temperatures inland get up into the mid-to-upper 70s. Persisting
onshore flow should keep temperatures from getting too warm next
week.

Aviation The marine layer has deepened quite a bit overnight,
thickening from around 2000 ft deep as of 00z to around 3500 ft
or possibly deeper per 09z esrl astoria profiler data. It also
appears the inversion may be weakening some as cooler air moves
in aloft. The result thus far (as of 09z) is spotty MVFR stratus
north of a ksle-ktmk line while stratus becomes more widespread
to the south. The weakening marine inversion may hold off low
clouds for many inland terminals until after sunrise, but most of
the forecast area should fill in with MVFR or lowVFR clouds as
mixing increases during the mid-morning through afternoon hours.

Expect scattered showers to develop by 18z and continue through
at least 03z. Another weak disturbance may keep showers going
into tonight.

Kpdx and approaches... Areas of MVFR will likely fill in after
sunrise, with MVFR likely for the pdx metro terminals by 16z.

Isolated to scattered showers are expected to develop by 18z and
continue through the afternoon, favoring the higher terrain.

Ceilings should generally lift into the 3500-4500 ft range by
20z, persisting into early evening. Weagle

Marine A mostly dry cold front is moving SE across the or
waters this morning, with n-nw winds expected to increase to 15
to 25 kt behind the front. Stronger winds further to the north
will build seas to 11 to 13 ft in wind wave fresh swell for the
outer waters by late this evening, with seas potentially up to
15 ft in the far NW corner of our forecast area. Made no changes
to existing advisories, though they may be starting a few hours
too early especially for the southern waters. By this afternoon
sca winds can be expected throughout the coastal waters, except
possibly the southern inner waters... Though would not be
surprised if they see 20-25 kt gusts as well. Squally showers may
briefly produce localized gusts 30-35 kt, especially for the
northern and outer waters.

Another disturbance and possible weak surface low will travel
south from vancouver island Saturday, bringing a general easing
trend in the winds through Sat night before more typical late
spring early summer n-nw winds take over Sunday afternoon. N-nw
swell is expected to slowly subside below late Sat sat night due
to the lighter winds to our north. Depending on where this
disturbance ends up as it heads into california, winds may ease a
bit once again Mon tue. Weagle

Pqr watches warnings advisories
Or... None.

Wa... None.

Pz... Small craft advisory for winds until 11 am pdt Saturday for
waters from CAPE shoalwater wa to florence or from 10 to
60 nm.

Small craft advisory for hazardous seas until 5 pm pdt Saturday
for waters from CAPE shoalwater wa to cascade head or from
10 to 60 nm.

Small craft advisory for winds until 11 pm pdt this evening for
coastal waters from CAPE shoalwater wa to cascade head or
out 10 nm.

Small craft advisory for hazardous seas from 8 am this morning
to 5 pm pdt Saturday for coastal waters from cape
shoalwater wa to cascade head or out 10 nm-waters from
cascade head to florence or from 10 to 60 nm.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
LOPW1 - 9440422 - Longview, WA 63 mi39 min 58°F1015.8 hPa (+0.5)

Wind History for Longview, WA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure

Wind History from CZK (wind in knots)
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Last 24hr24------------------------SW12
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SW6W6----SW65SW5
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1 day ago53------------------------322SW632SE2E21S2
2 days ago----------------------------1214334434

Tide / Current Tables for Vancouver, Columbia River, Washington (dubious accuracy)
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Vancouver
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Fri -- 01:12 AM PDT     Moonrise
Fri -- 02:48 AM PDT     1.01 feet Low Tide
Fri -- 04:33 AM PDT     1.08 feet High Tide
Fri -- 05:30 AM PDT     Sunrise
Fri -- 07:34 AM PDT     0.70 feet Low Tide
Fri -- 10:38 AM PDT     Moonset
Fri -- 11:26 AM PDT     1.70 feet High Tide
Fri -- 08:07 PM PDT     -0.00 feet Low Tide
Fri -- 08:44 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.31.21.111.11.10.90.70.711.41.71.61.30.90.70.60.50.40.2-00.10.51

Tide / Current Tables for Knappa, Knappa Slough, Columbia River, Oregon
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Knappa
Click for Map
Fri -- 12:40 AM PDT     2.81 feet Low Tide
Fri -- 01:18 AM PDT     Moonrise
Fri -- 05:32 AM PDT     Sunrise
Fri -- 05:37 AM PDT     7.33 feet High Tide
Fri -- 10:40 AM PDT     Moonset
Fri -- 01:25 PM PDT     0.18 feet Low Tide
Fri -- 07:42 PM PDT     6.57 feet High Tide
Fri -- 08:50 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.92.93.64.96.37.27.36.85.74.32.91.60.70.20.31.22.64.15.56.46.56.15.24.3

Weather Map and Satellite Images
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wmap_P
GOES Local Image of PacificNorthwest    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Portland, OR (9,2,3,4)
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Ground Weather Radar Station Portland, OR
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Disclaimer:
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.