Monday, January22, 2018 L-36.com


Marine Weather and Tides
Chenega, AK

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 9:37AMSunset 4:45PM Monday January 22, 2018 1:23 AM AKST (10:23 UTC) Moonrise 11:26AMMoonset 11:50PM Illumination 31% Phase: Waxing Crescent; Moon at 6 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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PKZ129 Passage Canal- 922 Pm Akst Sun Jan 21 2018
.small craft advisory tonight...
Tonight..W wind 25 kt diminishing to 10 kt after midnight. Gusts to 35 kt near whittier in the evening. Seas 3 ft. Freezing spray. Snow showers.
Mon..W wind 10 kt. Seas 2 ft.
Mon night..W wind 10 kt. Seas 2 ft. Widespread snow showers.
Tue..W wind 15 kt. Seas 2 ft.
Tue night..W wind 20 kt. Seas 3 ft.
Wed..W wind 25 kt. Seas 4 ft.
Thu..W wind 20 kt. Seas 3 ft.
Fri..W wind 15 kt. Seas 2 ft.

7 Day Forecast for Marine Location Near Chenega, AK
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location: 60.33, -148.15     debug


Area Discussion for -
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Fxak68 pafc 220146
afdafc
southcentral and southwest alaska forecast discussion
national weather service anchorage ak
446 pm akst Sun jan 21 2018

Analysis and upper levels
A highly amplified pattern remains over the region. There is an
upper level trough over mainland alaska extending into the gulf.

An upper level closed low is at the southern end of this trough
over the southwest gulf, and another closed low further north
along the arctic coast of the state. There is a blocking ridge
over the central bering sea, with a trough over the southwest
bering. Strong northerly flow is over the west coast of the
mainland and the eastern bering sea. Weak ridging is over the
yukon extending into inland portions of south central alaska. Some
moisture is over the northern gulf that is bringing precipitation
to the gulf coast and extending inland to some degree. There is a
weakening negatively tilted front over the western aleutians and
southwest bering.

Model discussion
The numerical models are in fairly good agreement through Tuesday
afternoon on the major synoptic features. Some differences are
evident over the gulf with how the models handle the numerous weak
surface lows. There is also some disagreement on precipitation,
especially for inland areas of southcentral. Therefore forecast
confidence is near normal.

Aviation
Panc... Some snow showers are possible during the TAF period. This
could briefly lower conditions to MVFR mainly on Monday afternoon,
otherwiseVFR is expected to be predominant at this time.

.Short term forecast southcentral alaska (days 1 and 2: Monday and
Tuesday)...

the weather is becoming increasingly active and interesting for
southcentral over the next couple days. Here are some details:
tonight:
off-and-on snow showers and flurries are ongoing across much of
southcentral this evening. The snow is being caused by a weak
disturbance progressing northwestward out of the gulf towards a
digging upper level low currently over far northern alaska. No
significant accumulations of snow are expected from this first
wave as much of the energy associated with it is being sheared
apart. The flurry threat, if you can call it such, will end after
midnight. Otherwise, outflow winds through the gaps continue this
evening with a weak surface low over the northern gulf helping
drag the cold air now well entrenched over interior alaska out
through the gaps. As this low weakens tonight, so too will the
winds. The cold, dry air moving over the relatively warmer waters
of the gulf and prince william sound is making for good conditions
for mariners to experience heavy freezing spray in the windier
locations through kamishak bay, the barren islands region,
shelikof strait, and perhaps some local concerns in any narrow
gaps and fjords.

Monday:
during the day will be the calm between systems, though scattered
snow showers will continue through western prince william sound
and the north gulf coast through much of the day. Any small lows
over the northern gulf will be absorbed into a stronger low over
the southern gulf, so relaxing pressure gradients will continue to
have winds area-wide on the decline through the day.

Monday night into Tuesday:
upper level dynamics will be the forcing for the next snow event
for nearly all of southcentral. An upper level low over the
southern gulf will slowly track northward overnight. To its north,
a shortwave extending from the upper low will circulate westward
across the northern gulf towards southcentral. Meanwhile, the
aforementioned upper low over far northern alaska will be moving
southbound as a trough over the alaska range slowly moves
southeastward. As a result, a zone of deformation and stronger
lift will develop over most of southcentral and bring a long-
duration light snow event through those areas starting Monday
evening and persisting right through Tuesday morning.

Throughout this event, winds in the lowest levels will be light
with no downsloping expected, the current thinking is that the
entire area will get roughly equal amounts of snow. No one area
looks to be favored over any other with this event. Temperatures
throughout the event will be in the teens to low 20s, which is
plenty cold enough for the snow to be a light, powdery, fast-
accumulating consistency. Fortunately the light winds will
preclude there being any visibility restrictions from blowing
snow.

On Tuesday afternoon, the upper level trough over the alaska range
will have moved eastward over southcentral, ending the snow.

Behind it Tuesday night, a sharp line of clearing skies will also
progress eastward, resulting in lots of sunshine by Wednesday.

Short term forecast southwest alaska (days 1 and 2)
The main forecast challenge in the short term is how low will the
wind chill values drop tonight, mainly for the kuskokwim delta.

With abundant clear skies across the southwest mainland,
radiational cooling won't be a problem tonight. Wind speeds of 15
to 25 mph are anticipated for the upper parts of the region, when
combined with the low temperatures forecasted drops the wind
chill values to lower than -40 f. Thus, the wind chill advisory
issued earlier this afternoon looks good. Further upstream into
the kuskokwim valley, temperatures will be much colder. However,
wind speeds look to remain less than 15 mph, which is one of the
criteria needed for a advisory.

Otherwise, a persistent area of high pressure across the bering
will continue to funnel colder air into the area in an offshore
flow regime, with no sensible change in the pattern seen through
the next few days.

Short term forecast bering sea aleutians (days 1 and 2)
An area of high pressure will remain anchored across central
portions of the bering sea aleutians through the next few days.

This creates a rather stagnant pattern with a stalled gale force
front remaining in place across western portions of the chain, and
cold air continuing to pour into eastern portions of the bering
and into the eastern portions of the aleutians akpen. This will
bring continued freezing spray concerns to these eastern areas
through the period.

Long term forecast (days 3 through 7)
Beginning the extended period forecast Tuesday night, there will
be a rather potent cold upper level vortex over the northwest part
of alaska with associated troughing extending into the gulf of
alaska. Low level cyclonic flow will preferentially wrap around
the alaska range into the bering sea. Snow showers over parts of
southcentral will quickly be end late Tuesday (although they may
linger longer over the copper basin) as strong offshore flow
increases in response to cold air advection. Temperatures will
continue to drop across all of southern alaska as 850 temperatures
plummet to -20 to -30c on Thursday as the upper vortex moves
south across the region. As the upper low digs into the north
pacific, secondary cyclogenesis will develop in the gulf with
increasing chances of coastal precipitation (in the form of snow)
Thursday into Saturday. Some locations such as kodiak island may
see the potential for good accumulations should the setup develop
as current global models depict... Stay tuned.

Otherwise, the pattern looks to remain dominated by the eventual
large trough over the north pacific into the gulf of alaska, along
with high latitude blocking over eastern siberia, for the
remainder of the weekend into early next week. This will likely
result in dry and continued colder than average inland weather as
the general storm track remains south of the forecast area.

Afc watches warnings advisories
Public... Wind chill advisory 155.

Marine... Gale 128 130 131 138 150 155 165 172 180
heavy freezing spray 130 131 138 150 155 160 165 180 181.

Synopsis and model discussion... Bl
southcentral alaska... Jw
southwest alaska bering sea aleutians... Pd
long term... Ja


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
46081 - Western Prince William Sound 33 mi34 min W 5.8 G 7.8 29°F 38°F997.5 hPa (+1.1)29°F
46076 - Cape Cleare AK 58 mi94 min SSE 5.8 G 7.8 7 ft
SWLA2 - 9455090- Seward, AK 69 mi54 min 43°F

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Portage, Portage Glacier, AK48 mi31 minW 30.50 miSnow Freezing Fog17°F14°F88%999.8 hPa

Wind History from ATO (wind in knots)
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Last 24hrW6W6W7W6--W6NW8NW7W6W5W7W6W5W4W4W4W4W5W5W4W3W33W3
1 day agoNW5W5NW4W6NW6W4W6W6W5W6W64NW7W7W7
G15
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2 days agoCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmW3CalmW4W4NW3NW43W5W4

Tide / Current Tables for Chenega Island, Dangerous Passage, Prince William Sound, Alaska
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Chenega Island
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Mon -- 04:34 AM AKST     10.82 feet High Tide
Mon -- 09:29 AM AKST     Sunrise
Mon -- 10:40 AM AKST     3.22 feet Low Tide
Mon -- 11:25 AM AKST     Moonrise
Mon -- 04:11 PM AKST     10.24 feet High Tide
Mon -- 04:39 PM AKST     Sunset
Mon -- 10:54 PM AKST     1.10 feet Low Tide
Mon -- 11:49 PM AKST     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.65.17.69.610.710.79.98.46.54.73.53.34.46.38.29.610.2108.97.25.23.11.61.1

Tide / Current Tables for Eshamy Bay, Knight Island Passage, Prince William Sound, Alaska
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Eshamy Bay
Click for Map
Mon -- 04:36 AM AKST     11.32 feet High Tide
Mon -- 09:29 AM AKST     Sunrise
Mon -- 10:38 AM AKST     3.22 feet Low Tide
Mon -- 11:24 AM AKST     Moonrise
Mon -- 04:13 PM AKST     10.74 feet High Tide
Mon -- 04:38 PM AKST     Sunset
Mon -- 10:52 PM AKST     1.10 feet Low Tide
Mon -- 11:49 PM AKST     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.75.481011.111.210.48.86.74.83.53.34.56.58.51010.710.59.47.65.43.21.61.1

Weather Map and Satellite Images
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Weather Map
wmap_P
IR Satellite Image from GEOS
cpac_satellite

GOES Local Image of PacificNorthwest    EDIT
Geos

Wind Forecast for (5,6,7,8)
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Ground Weather Radar Station Middleton Is., AK
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weather_mapweather_map weather_map

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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.