Tuesday, December18, 2018 L-36.com


Marine Weather and Tides
Point Possession, AK

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 10:09AMSunset 3:44PM Tuesday December 18, 2018 6:00 PM AKST (03:00 UTC) Moonrise 1:32PMMoonset 3:11AM Illumination 88% Phase: Waxing Gibbous; Moon at 11 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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PKZ121 Resurrection Bay- 314 Pm Akst Tue Dec 18 2018
Tonight..N wind 20 kt. Gusts to 30 kt near seward in the evening. Seas 4 ft. Freezing spray. Snow.
Wed..N wind 10 kt. Seas 2 ft. Snow.
Wed night..N wind 20 kt. Seas 4 ft. Freezing spray.
Thu and Thu night..N wind 15 kt. Seas 3 ft.
Fri through Sun..N wind 20 kt. Seas 4 ft.


7 Day Forecast for Marine Location Near Point Possession, AK
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location: 60.97, -150.21     debug


Area Discussion for -
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Fxak68 pafc 190108
afdafc
southcentral and southwest alaska forecast discussion
national weather service anchorage ak
408 pm akst Tue dec 18 2018

Analysis and upper levels
A negatively tilted long wave trough spreads over western alaska,
the alaska peninsula, eastern aleutians and into the western
gulf of alaska. This trough has an upper-level low anchored at
the base near kodiak island. Northwesterly flow on the backside of
the trough is creating gale force and some storm force winds
through the gaps in the alaska peninsula and kamishak bay. Cold
air advection is continuing over the bering and western mainland.

Offshore flow is continuing dry conditions over western mainland
which is keeping the area dry. A compact surface low is passing
through the central bering and moving over the alaska peninsula
near cold bay. The low is brining gusty winds and snowfall to the
pribilofs and the central aleutians. A front is moving over the
western aleutians which is consistent with an arm of the jet that
is pushing over the western and central aleutians. While most of
the jet is flowing well below the aleutian chain and the gulf, a
smaller, isolated segment is over the kenai peninsula to the
western alaska range. This segment of the jet is associated with a
deformation zone over the kenai peninsula. Southerly flow is
brining moisture to southcentral saturating the atmosphere. A meso
low has developed in prince william sound today. The combination
of this low with the deformation band is allowing for snow showers
to persist through southcentral.

Model discussion
Models all have a similar synoptic scale pattern through Thursday.

Differences are mainly in the placement of individual pressure
centers. So they have similar handling of gulf winds and wind
fields over the bering sea. For now will be leaning toward the
high resolution namnest to capture local effect winds.

Aviation
Panc... Periods of MVFR ifr visibilities and ceilings are expected
with snow showers through this evening. Generally expect snow to
diminish but some MVFR ceilings will linger into Wednesday
morning.

Short term forecast southcentral alaska (days 1 and 2)
The band that brought snow across anchorage today has pushed off
to the west and is draped across northern kenai peninsula and
southern susitna valley. Tonight the center of the main band
should stay primarily over the same area but spread out and bring
lighter snow to locations over the western kenai and anchorage.

However, guidance has been struggling to handle this feature and
the possibility remains that the band could push back over
anchorage and bring more snow than forecasted. Early Wednesday
morning the front that is approaching the north gulf coast will
push into southcentral alaska spreading more snow to most
locations with the heaviest along the coast and lighter amounts
inland. The front will have pushed through by Wednesday evening
and then snow will diminish throughout southcentral alaska through
Thursday allowing for colder temperatures across the area.

Short term forecast southwest alaska (days 1 and 2)
Dry and cold conditions continue across much of the southwest with
cold advection and offshore flow. Temperatures should continue to
run well below zero in the interior. Temperatures will likely be
warmer over the delta as low stratus and some flurries continue
through tonight. An occluded front currently over the western
aleutians will weaken by the time it arrives near the west coast,
but may still bring a shot a snow to the immediate coast late
Wednesday and Thursday.

Short term forecast bering sea aleutians (days 1 and 2)
A fairly compact surface low moves rapidly south across the ak pen
this afternoon and should enhance the northwesterly flow over the
western ak pen briefly this evening. The surface low will leave an
elongating deformation zone in its wake allow for moderate to
heavy snowfall to continue overnight. In addition to gusty winds
reducing visibility, snow accumulations will also be great enough
for a winter weather advisory. Please see the advisory for more
details. The strong northwesterly flow across the ak pen will
shift east tonight with ridging building in to the west ahead of
the occluded front. The gale force front with with some force
gusts will weaken late tonight through Wednesday as a frontal wave
develops along its boundary south of the aleutians and moves
east. This will tend to shear the front apart allowing the
northern portion of the front to weakening as it tracks toward the
southwest mainland and keeping fairly good precipitation
potential south along along the aleutians in the vicinity of the
developing wave.

Marine
Gusts out of bays and passes between false pass and sitkinak
island will continue through the overnight hours. Strong cold
advection will push gusts to the 50-55 kt range. This winds will
quickly abate on by late morning Wed as the flow becomes more
westerly.

Long term forecast (days 3 through 7)
Friday's setup is looking similar to the model forecasts
yesterday with a low south of the akpen moving into the southern
gulf, bringing gusty offshore winds to the north gulf coast and
favorably aligned terrain gaps through Saturday afternoon. A
trough rotating through the gulf Saturday night and Sunday may
bring some precipitation to coastal areas then lift north on
Monday bringing a chance of snow to the copper river basin.

There is more confidence with a front moving over the western
aleutians and bering on Friday due to better model agreement
today. Strong winds will remain possible at times in the western
bering through Sunday. A deep low on Sunday will move north over
the western and central aleutians, which models have come in
better agreement on since yesterday. Better confidence in this low
brings increasing chances for gales over the aleutians and bering
through early next week. The exact intensity and placement of
this low has decent agreement, but is less certain as it moves
eastward through Tuesday. Stay tuned over the next few days as
this feature continues to be looked at.

Afc watches warnings advisories
Public... Winter weather advisory 181.

Marine... Gale 131 132 137 138 150 155 165 170 175 176 177
storm 130.

Heavy freezing spray 130 138 160 180 181 185.

Synopsis and model discussion... Ra bc
southcentral alaska... Dk
southwest alaska bering sea aleutians... Mso
long term... Ah jr


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
ANTA2 - 9455920 - Anchorage, AK 25 mi36 min N 7 G 8 20°F 31°F983.2 hPa
NKTA2 - 9455760 - Nikiski, AK 66 mi30 min NE 2.9 G 5.1 24°F 37°F983.4 hPa
SWLA2 - 9455090- Seward, AK 72 mi36 min 45°F979.6 hPa

Wind History for Anchorage, AK
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Anchorage, Ted Stevens Anchorage International Airport, AK18 mi67 minN 510.00 miOvercast21°F16°F81%983.1 hPa
Anchorage, Lake Hood Seaplane Base, AK20 mi67 minNNE 310.00 miOvercast19°F15°F84%983.4 hPa

Wind History from ANC (wind in knots)
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Last 24hrNE8NE8N4N7N5N5N6N4N6N6N6N4N9N4N7N6CalmN6N7N5N5N7N5N7
1 day agoNE3CalmCalmS4S5S6S5S4S6S6S5S6S4S5CalmSW4SW4CalmCalmCalmCalmCalmNE5NE7
2 days agoN10N5E7SE4S5SE4SE3SE5E4E4SE4E4E5E4E4E3CalmCalmCalmN5N7N3N34

Tide / Current Tables for Fire Island, Alaska
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Fire Island
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Tue -- 03:11 AM AKST     22.48 feet High Tide
Tue -- 04:11 AM AKST     Moonset
Tue -- 09:33 AM AKST     5.89 feet Low Tide
Tue -- 10:12 AM AKST     Sunrise
Tue -- 02:31 PM AKST     Moonrise
Tue -- 03:26 PM AKST     25.76 feet High Tide
Tue -- 03:42 PM AKST     Sunset
Tue -- 10:14 PM AKST     1.46 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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13.718.121.222.521.919.716.212.28.76.46.310.516.320.423.425.525.322.217.713.28.94.61.63.1

Tide / Current Tables for Anchorage (Knik Arm), Alaska
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Anchorage (Knik Arm)
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Tue -- 03:08 AM AKST     23.63 feet High Tide
Tue -- 04:10 AM AKST     Moonset
Tue -- 09:39 AM AKST     8.05 feet Low Tide
Tue -- 10:12 AM AKST     Sunrise
Tue -- 02:29 PM AKST     Moonrise
Tue -- 03:18 PM AKST     27.64 feet High Tide
Tue -- 03:40 PM AKST     Sunset
Tue -- 10:20 PM AKST     4.02 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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14.419.222.423.623.121.418.715.311.58.78.210.815.821.325.627.527.12521.516.911.76.94.24.8

Weather Map and Satellite Images
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wmap_P
GOES Local Image of Alaska    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.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Ground Weather Radar Station Kenai, AK
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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.