Thursday, December13, 2018 L-36.com


Marine Weather and Tides
Unalaska, 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 10:04AMSunset 3:44PM Thursday December 13, 2018 1:58 PM AKST (22:58 UTC) Moonrise 12:21PMMoonset 10:23PM Illumination 38% 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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PKZ171 Unalaska Bay- 356 Am Akst Thu Dec 13 2018
.small craft advisory today and Friday...
Today..W wind 25 kt diminishing to 15 kt in the afternoon. Seas 4 ft subsiding to 2 ft in the afternoon.
Tonight..NE wind 10 kt increasing to 20 kt after midnight. Seas 3 ft building to 6 ft after midnight. Freezing spray.
Fri..NE wind 25 kt. Seas 9 ft. Freezing spray.
Fri night..N wind 25 kt. Seas 10 ft.
Sat..N wind 20 kt. Seas 7 ft.
Sun through Mon..NW wind 30 kt. Seas 12 ft.


7 Day Forecast for Marine Location Near Unalaska, AK
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location: 53.89, -166.54     debug


Area Discussion for -
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Fxak68 pafc 131358
afdafc
southcentral and southwest alaska forecast discussion
national weather service anchorage ak
458 am akst Thu dec 13 2018

Analysis and upper levels
The main synoptic feature continues to be the elongated trough
positioned from the central bering to the kenai peninsula. This
feature is beginning to shear apart into two closed lows in the
mid-levels. The first of these mid-level shortwaves is lifting
north into the southern mainland from cook inlet and as associated
with both an occluded low in the eastern gulf and a meso-low over
the kenai peninsula continuing to produce snow from kenai north
to talkeetna. Here, snowfall amounts have been light, on the order
of 2 to 6 inches. However, a locations underneath the center of
the low and areas aided by upslope flow and better dendritic
growth due to cold air advection (upper hillside of anchorage)
have seen upwards of 6 to 12 inches of new snow. The second
shortwave dropping southeast into the eastern bering is associated
with a vertically stacked low anchored over norton sound. Cold,
arctic air is wrapping around this low and pushing over the bering
and western mainland where overnight lows in the interior of the
southwest have fallen from 0 to 15 below. Elsewhere, a shortwave
ejecting from the parent low over the eastern bering is crossing
over the eastern aleutians and akpen bringing a mix of rain and
snow showers, along with gusty small-craft winds from dutch
harbor to sand point. Farther west, a developing north pacific low
is pushing clouds and gales across the western aleutians.

Model discussion
Guidance remains in good agreement in the handling of the
synoptic fields. The NAM continues to be a bit faster with the
movement of the low along the eastern kenai peninsula late
Thursday. The ec is the weakest of the solutions, favoring more
of an open trough than a closed low. Guidance is also in good
agreement concerning the next low entering the western gulf late
Friday into Saturday with the first trough moving along the
southcentral coast on Friday and the larger occlusion pinwheeling
through the gulf into the weekend. Here a blend of the GFS and nam
is used to resolve subtle differences and take a middle of the
ground approach. The higher resolution namnest is used in the
short term to better resolve local-effect winds.

Aviation
Panc... Light snow will continue across the airport complex
through mid-morning with some clearing through the afternoon and
early evening hours. Lower ceilings and light snow returns again
later tonight into early Friday morning. Expect periods of MVFR
and ifr conditions this morning improving toVFR this afternoon.

MVFR conditions return later this evening. Light northerly winds
will also increase this evening.

Short term forecast southcentral alaska (days 1 and 2)
The overall pattern over southcentral alaska remains the same
from yesterday with the cold upper level low over southwest
mainland alaska. This low continues to send short waves over
southcentral alaska which have brought snowfall with them over
land and snow showers over the gulf of alaska and prince william
sound.

A meso-low could been seen very clearly on the radar over the
northern kenai peninsula. This low drifted very slowly eastward
overnight and enhanced the snowfall over anchorage and into the
matanuska valley. As of early Thursday morning, this meso-low is
moving over western turnagain arm and as it moves eastward, the
snowfall will end over the northern cook inlet region. There may
even be some partial clearing by the afternoon as the upper level
wave which helped this meso-low develop moves out of the area.

Another upper level disturbance is over southern kodiak island
this morning and will track through the gulf of alaska today so
the snow with that disturbance will remain only over those areas.

Yet another short wave will move over the cook inlet region
tonight bringing another chance of snow to southcentral.

The pattern begins to change Friday night into Saturday when a
storm force low moves into the gulf of alaska from the south.

.Short term forecast southwest alaska (days 1 through 3 Thursday
through Saturday)...

a deep upper level low over the southwest mainland will continue
to funnel very cold air from the arctic south into southwest
alaska. Some limited cloud cover from a weak shortwave moving
across the southern portion of bristol bay will help to slightly
moderate temperatures this morning, though areas with clear skies
will see temperatures in the negative single digits to even
negative teens this morning. The upper low center will slowly
shift north and east over the next couple of days, allowing
northerly flow to increase and even colder air to funnel into the
area. 850 mb (5000 ft) temperatures are expected to drop to -20c
by Fri Sat timeframe. This combined with decreasing cloud cover
will lead to the coldest temperatures of the season so far by
the weekend. Lows right now are expected to plummet to near -20f
for inland areas in the kuskokwim river delta and lower kuskokwim
river valley Saturday and possibly Sunday morning. Persistent
northerly flow around 10-15 mph will drop wind chills to near
advisory levels (-40f) in these locations, though if winds slacken
a bit these will be not as cold.

On Saturday, a weak deformation zone is expected to form on the
west side of a low pressure system tracking through the gulf of
alaska. This will lead to a band of snow developing on the western
side of the alaskan range that will slowly push west from iliamna
towards the kuskokwim river valley. As of now, no significant
accumulations are expected, but this should help to keep
temperatures a bit warmer that further west.

.Short term forecast bering sea aleutians (days 1 through
3 Wednesday night through Saturday)...

a weak shortwave will continue to push east across southern
bristol bay and the far eastern aleutians, brining some areas of
snow and rain. As the system pushes off to the east, ridging will
build in leading to cold northerly flow and some scattered
instability snow showers impacting the eastern half of the bering
and aleutians today. A sub-960 mb low will track east skirting
just south of the aleutians on Friday, bringing increased easterly
winds, though precip should stay just to the south. Ridging
builds in rapidly behind the departing system, bringing a return
to cold northerly flow and instability snow showers covering most
of the bering by Saturday.

Long term forecast (days 4 through 7)
The forecast period commences with the longwave trough extending
from southwest alaska to the north pacific and gulf of alaska. On
the 16th of december at 12z the GFS at 500 mb, has a closed low
churning over the gulf of alaska and a second one south of adak.

Generally speaking, expect this pair of disturbances to push
eastward. The primary sensible weather highlight for this forecast
package will be another round of snow for the anchorage and
girdwood Sunday and early Monday. That said, not expecting much
headway towards catching up to the normal climatological snowpack
for the month of december. The ECMWF has come into line with the
gfs and the GEFS ensemble mean early in the forecast period.

However, the consensus begins to erode rapidly by 00z Monday at
least south of the aleutian chain. By Tuesday, the global models
ping into another round of cyclogenesis near kamchatka which will
bring a front into the western aleutians actually warming up
places like attu, shemya and amchitka.

Afc watches warnings advisories
Public... None.

Marine... Gales... 132 150 155 172 174 176 177 352.

Heavy freezing spray... 140 181 185.

Synopsis and model discussion... Tm
southcentral alaska... Ez
southwest alaska bering sea aleutians... Kvp
long term... Ps


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
UNLA2 - 9462620- Unalaska, AK 1 mi46 min S 2.9 G 5.1 32°F 41°F994.6 hPa

Wind History for Unalaska, AK
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Unalaska, Unalaska Airport, AK1 mi62 minSSE 510.00 miMostly Cloudy30°F19°F66%995.6 hPa

Wind History from ADU (wind in knots)
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Tide / Current Tables for Dutch Harbor, Alaska (expired 1988-12-31)
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Dutch Harbor
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Thu -- 04:07 AM AKST     0.66 feet Low Tide
Thu -- 10:16 AM AKST     Sunrise
Thu -- 12:12 PM AKST     4.21 feet High Tide
Thu -- 02:20 PM AKST     Moonrise
Thu -- 05:44 PM AKST     Sunset
Thu -- 07:12 PM AKST     2.60 feet Low Tide
Thu -- 09:31 PM AKST     2.67 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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21.61.10.80.70.81.11.72.333.644.24.13.93.53.22.92.72.62.62.72.72.6

Tide / Current Tables for Kisselen Bay, Beaver Inlet, Unalaska Island, Alaska
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Kisselen Bay
Click for Map
Thu -- 12:59 AM AKST     0.67 feet Low Tide
Thu -- 09:11 AM AKST     5.82 feet High Tide
Thu -- 10:15 AM AKST     Sunrise
Thu -- 02:20 PM AKST     Moonrise
Thu -- 03:42 PM AKST     2.78 feet Low Tide
Thu -- 05:45 PM AKST     Sunset
Thu -- 06:40 PM AKST     3.71 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.90.70.81.42.23.14.155.65.85.75.14.43.73.12.82.83.23.63.73.53.22.62

Weather Map and Satellite Images
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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.
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Ground Weather Radar Station Bethel, AK
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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.