Saturday, October21, 2017

Marine Weather and Tides
False Pass, 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 8:59AMSunset 6:28PM Saturday October 21, 2017 7:49 AM AKDT (15:49 UTC) Moonrise 9:39AMMoonset 7:09PM Illumination 2% Phase: Waxing Crescent; Moon at 1 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 False Pass, AK
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location: 54.93, -164.47     debug

Area Discussion for -
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Fxak68 pafc 211238
southcentral and southwest alaska forecast discussion
national weather service anchorage ak
438 am akdt Sat oct 21 2017

Analysis and upper levels
An arctic trough that is slowly moving down the west coast is
becoming the primary driver for much of the weather over the
south mainland. A weak low moving through north gulf coast under
the east side of this trough brought light accumulation's of
snowfall to lower elevations throughout the night, which are
expected to continue into the morning hours. Further west over
southcentral, the lower levels of the atmosphere remain dry enough
after 48 hours of offshore flow to prevent much of this snow from
reaching the ground other than a few areas of flurries with
little no accumulation. A deeper low is moving through the
southwest coast, bringing snow showers to the kuskokwim delta
coast into western bristol bay. Behind this low, a broad area of
northerly flow between it and high pressure over the western
aleutians is producing widespread ocean effect rain snow showers
as cold air advects over the relatively warm waters of the bering.

With little change in the overall pattern these showers are
expected to continue with persistent northerly flow this weekend.

Model discussion
The models are in reasonable synoptic scale agreement through
Sunday, though they continue to struggle with placing
snowfall over southcentral and the southwest coast which is
providing the primary short term forecast challenge. This model
agreement begins to break down on Monday with regards to the track
of another developing low that will quickly move through the gulf,
especially from the 00z guidance. There was a trend overnight with
the 06z NAM by bringing this low much further to the west, which
is now more in line with the gfs. There however remains
significant differences between the latest GFS nam and the
ec gem, so forecast changes were minimal for the morning updates.

The models are beginning to come into agreement with a chance for
southcentral snow sometime late Monday or Tuesday, however with
significant differences in the timing of the snow the forecast
continues to indicate a chance for a broad time frame.

Panc... Ceilings hovering around 5000 ft today should be the
primary impact as the anchorage bowl will remain on the very
western edge of the cloud cover. A few snowflakes may also fall
from these clouds today, but otherwise expect continuedVFR
conditions with N winds up to 10 kt becoming light this evening.

Short term forecast southcentral alaska (days 1 and 2)
The weak wave moving over prince william sound and into the
northern cook inlet region has brought some snow showers to the
sound and flurries west of the kenai and chugach mountains.

There may be some small snow accumulations in the prince william
sound area today (including portage), but most of the area will
see no more than a dusting of snow at best. Tracking and timing
the weak impulses that will be moving over southcentral alaska
this weekend is difficult. The best description of the situation
is that there will be a few snow showers in the area but no real
accumulations as the storm that could have brought some went well
to the east of the area. Best chance for some snow for the cook
inlet to susitna region (including the major population centers)
will be Monday into Monday night where models are showing an upper
level wave rotating around the main low moving through the region
which could bring some small snow accumulations along with it.

Short term forecast southwest alaska (days 1 through 3)
Scattered to numerous snow showers are expected to continue across
coastal locations through Sunday afternoon as an upper level low
parks itself over the yk delta. Shower activity may linger into
Monday but the overall coverage of showers is expected to diminish
as the upper level low weakens and shifts eastward. A shortwave
wrapping around the low pressure system on Sunday morning will
spin up a surface low south of the alaska peninsula and quickly
push it northeastward near shelikof strait by late Sunday night.

This will create a small area of increased chances of measurable
snowfall across the bristol bay area but have little impact
otherwise. After an unseasonably warm first half of the month,
temperatures will actually be slightly below normal today and
Sunday and then begin to warm up early next week.

Short term forecast bering sea aleutians (days 1 through 3)
High pressure has begun to build across the western bering sea
which is a nice reprieve from the active pattern over the past
two weeks. However, this is expected to be rather short lived as
the remnants of ex-super typhoon lan moves toward the bering sea.

Latest model guidance suggests that an extratropical cyclone will
develop out ahead of lan Monday morning and all of the energy and
moisture associated with lan will phase with this system as lan
dissipates. From here, models have been in good agreement over the
past 48 hours that this low will then track into the western
bering sea on Monday. A large swath of storm force winds is
expected across the western bering sea as the low rapidly deepens.

A plethora of cold air over russia will act as a catalyst to the
rapid development with a strengthening jet also playing a role.

Hurricane force winds remain a good possibility, especially gusts,
with a very tight pressure gradient setting up on Monday. In
addition, seas will build to 30 ft across the bering sea with seas
upwards to 40 kt likely along the pacific side of the aleutian
islands. This system has the makings of a rather impressive and
impactful bering sea system and bears watching over the next
couple of days should any watches or warning become warranted.

Long term forecast (days 3 through 7)
An active pattern is expected through the long range forecast
through the middle of next week. Confidence remains higher in
cold air advection keeping temperatures below normal across much
of the bering aleutians and southern mainland through the
beginning of next week. During this time, the area will remain
under an unstable and showery regime as the colder air circulates
around the upper low parked over the western coast. This colder
air mass will change precipitation types mainly to snow over the
bering, southwest mainland, and interior portions of southcentral
alaska. Areas along the gulf coast, aleutian chain, and southern
cook inlet remain the exception, showing higher potential for a
rain snow mix under moderate temperatures.

Our focus then shifts to the remnants of typhoon lan tracking
into the western aleutians bering early next week, becoming the
dominant weather feature over much of the area through the end of
next week. Models remain in good agreement with tracking the
strong leading warm front into the western aleutians bering Monday
morning, and spreading eastward through the central and eastern
aleutians bering Tuesday. This will usher in a warm moist air mass
into the area from the north pacific, along with strong gusty
winds and rain. As the parent low tracks through the western
aleutians Tuesday and continues to occlude, the colder air
wrapping in behind the system should bring in some strong gusty
winds and a rain snow mix to the western aleutians through
Wednesday. This system will eventually spread the warmer air and
rain into the southern mainland Tuesday evening through the end
of the week.

Afc watches warnings advisories
Public... None.

Marine... None.

Synopsis and model discussion... Dek
southcentral alaska... Ez
southwest alaska bering sea aleutians... Mc
long term... Tp

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure

Wind History from AKF (wind in knots)
Last 24hr------------------------------------------------
1 day ago------------------------------------------------
2 days ago------------------------------------------------

Tide / Current Tables for Cape Mordvinof, Unimak Island, Alaska
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Cape Mordvinof
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Sat -- 02:33 AM AKDT     0.38 feet Low Tide
Sat -- 09:40 AM AKDT     Sunrise
Sat -- 10:20 AM AKDT     5.53 feet High Tide
Sat -- 11:38 AM AKDT     Moonrise
Sat -- 03:29 PM AKDT     3.25 feet Low Tide
Sat -- 07:39 PM AKDT     4.78 feet High Tide
Sat -- 07:43 PM AKDT     Sunset
Sat -- 09:09 PM AKDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Tide / Current Tables for Cape Sarichef, Unimak Island, Alaska
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Cape Sarichef
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Sat -- 01:20 AM AKDT     0.64 feet Low Tide
Sat -- 09:29 AM AKDT     4.62 feet High Tide
Sat -- 09:41 AM AKDT     Sunrise
Sat -- 11:39 AM AKDT     Moonrise
Sat -- 02:06 PM AKDT     3.31 feet Low Tide
Sat -- 06:48 PM AKDT     4.12 feet High Tide
Sat -- 07:46 PM AKDT     Sunset
Sat -- 09:12 PM AKDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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

GOES Local Image of Alaska    EDIT

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 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 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.