Thursday, August24, 2017 L-36.com


Marine Weather and Tides
Clam Gulch, 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 6:32AMSunset 9:30PM Thursday August 24, 2017 2:40 AM AKDT (10:40 UTC) Moonrise 8:38AMMoonset 8:38PM Illumination 5% Phase: Waxing Crescent; Moon at 2 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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PKZ140 Cook Inlet North Of Kalgin Island- 258 Pm Akdt Wed Aug 23 2017
Tonight..Variable wind less than 10 kt becoming ne 10 kt after midnight. Seas 2 ft. Rain.
Thu..NE wind increasing to 20 kt. Seas building to 5 ft. Rain.
Thu night..NE wind 20 kt. Seas 6 ft. Rain showers.
Fri and Fri night..N wind 20 kt. Seas 5 ft.
Sat through Sun..SE wind 10 kt. Seas 2 ft.
Mon..NE wind 15 kt. Seas 3 ft.

7 Day Forecast for Marine Location Near Clam Gulch, AK
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location: 60.23, -151.48     debug


Area Discussion for -
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Fxak68 pafc 240026
afdafc
southcentral and southwest alaska forecast discussion
national weather service anchorage ak
426 pm akdt Wed aug 23 2017

Analysis and upper levels
Upper levels show a longwave trough over the main portion of the
state with a lobe extending into the bering sea, where an upper
level low is moving slowly eastward. Satellites show that this
system is well developed, with a broad cirrus shield beginning to
slide over the copper river basin and southcentral. At the
surface, radar shows showers moving through southwest alaska just
ahead of the front. Upper level jet support in the form of a jet
streak moving south into the base of the trough is aiding the low
to strengthen as it moves eastward, which is reflected in near
gale force winds in the central aleutians.

Model discussion
Models are in good agreement on low placement, although the 12z
nam was slow on moving the front into southcentral. Model data
also shows increased wind speeds in the west around the low center
as the low gains upper level support. In the west, a nam GFS blend
was chosen to increase speeds across the area, while in the east,
nam was chosen for wind strength but timing was adjusted to match
current observations.

Aviation
Panc... Timing on the turnagain arm wind and downsloping remains
the big questions for today. The gradient looks to increase in the
afternoon as the front approaches the west, so am increasing the
winds even more after 06z. This should also impact -shra moving
over the airport as conditions will dry during the strongest
turnagain winds. CIGS are dropping in SW flow ahead of the front,
and are not expected to hit MVFR conditions, but may cross the 050
ft mark which will impact airport ops. If southeasterly flow picks
up earlier ahead of the front, CIGS may not drop at 00z and
showers will be negligible.

Short term forecast southcentral alaska (days 1 and 2)
A very typical late-summer storm is taking shape which will bring
widespread rain and wind to southcentral alaska and the gulf of
alaska the next couple days (with the notable exception of the
copper river basin which will be much drier). A leading upper
level wave combined with instability in the lower to mid levels
is bringing showers to some areas this afternoon, particularly
south to west facing slopes which are benefiting from low level
upslope flow. A neutrally tilted short-wave trough over the
eastern bering sea will become negatively tilted as it enters the
western gulf tonight, leading to development of widespread steady
rain. The mean low level flow will gradually back toward the
southeast and strengthen out ahead of a surface frontal system.

This often results in downslope drying from the western kenai to
anchorage and the mat valley. However, with strong upward vertical
motion, a more southerly component to mid level flow, and a bit
of remaining instability expect rain to fall in all of these
areas.

As the front makes its way toward the north gulf coast a barrier
jet will form, bringing high end gale force winds to the immediate
coast. The northward progression of the front will rapidly stall
on Thursday as the upper-level short-wave trough rotates back
westward toward a new upper level low dropping into bristol bay.

Thus, expect the strongest winds to remain over southern prince
william sound (near interface with the gulf). The approaching
front will also kick up wind through turnagain arm. Ageostrophic
flow will favor stronger winds in western turnagain arm tonight
while geostrophic flow will favor stronger winds through portage
valley eastern turnagain arm as the front arrives Thursday
afternoon.

The heaviest rain will fall in western prince william sound thanks
to persistent strong east to southeast low level flow, with 3 to 6
inches of rain possible through Friday afternoon. Do not expect
any flooding problems, though there will be some decent rises in
small streams of the eastern kenai peninsula. Rain will break up
into showers for inland areas Thursday afternoon as a now
vertically stacked low moves from bristol bay into the gulf and
upper level flow becomes more easterly. The bulk of rain will then
remain along the gulf coastal areas through Friday, with a chance
of showers over the rest of the area as weak upper waves head
inland.

Short term forecast southwest alaska (days 1 and 2)
Fairly straightforward with rain moving in with the low entering
bristol bay. The rain will being to turn more showery Friday into
Friday night with the low moving farther east in bringing in
northerly flow on Saturday. This northerly flow will not be
sufficient to dry out the area and the upper level trough
remaining over southwest mainland alaska will keep showers in the
area into the weekend.

Short term forecast bering sea aleutians (days 1 and 2)
The western and central bering sea will have high pressure
building over them Thursday and then another low will enter the
western bering leaving the ridge over the central bering. This
will bring areas of low clouds and fog in the these areas under
the ridge as typically happens. The eastern bering sea will see
marine gale force winds develop between the low in bristol bay and
the ridge in the central bering sea.

Long term forecast (days 4 through 7)
Beginning the extended period forecast Saturday night, there will
be a small upper level low somewhere in the vicinity of eastern
bristol bay and the alaska peninsula with a departing weak
shortwave trough moving east toward the yukon. There will be weak
upper level ridging over the northwest bering sea with an
undercutting pacific jet stream crossing the aleutian chain.

Showers will mainly be impacting the southcentral region with
drier air filtering over southwest alaska. A very brief drier
period will develop Monday as upper level heights build over
alaska ahead of a deepening north pacific low. Complex wave
mergers throw quite a bit of uncertainty in the overall forecast
of the low track, but it looks like a rather impressive surface
low will eventually develop and move north toward kodiak island
and the alaska peninsula region Monday night into Tuesday. With a
strong northeast pacific ridge axis in place, this low will have a
lot of potential for amplification along with heavy coastal rain
and strong winds. Expect rain to also impact most interior
locations Tuesday and Wednesday given the amount of moisture most
of the global models are progging. A lot of details remain
uncertain at this time, but the general idea is to expect a
dramatic uptick in wet weather along with potential higher impacts
to coastal regions. Stay tuned.

Afc watches warnings advisories
Public... None.

Marine... None.

Fire weather... None.

Synopsis and model discussion... Lf
southcentral alaska... Sb
southwest alaska bering sea aleutians... Ez
long term... Ja


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
NKTA2 - 9455760 - Nikiski, AK 32 mi52 min N 4.1 G 4.1 53°F 57°F1001.1 hPa
DRFA2 - Drift River Terminal, AK 41 mi40 min NNE 4.1 G 5.1 51°F 1001.1 hPa (-0.9)51°F
HMRA2 - Kachemak Bay Reserve, AK 44 mi70 min SSE 9.9 56°F 998 hPa46°F
46108 - Central Cook Inlet - 175 47 mi62 min 51°F2 ft

Wind History for Nikiski, AK
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Kenai, Kenai Municipal Airport, AK26 mi47 minN 49.00 miLight Rain52°F52°F100%1000.7 hPa

Wind History from AEN (wind in knots)
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Last 24hrCalmCalmCalmCalmCalmCalmCalmE3SE3SW8SW6SW8SW5SW4CalmCalmCalm3CalmCalmCalmW3NW3N4
1 day agoCalmCalmN4CalmSE3CalmCalmSW3CalmS3CalmSW8W7SW7W9W7SW6S7SW5SW6NE3CalmSE3Calm
2 days agoN15N13N12N12N11NE8NE9N10NE11NE11E7NE8NE9NE8NE9NE8NE7NE4NW4N5N6N4N3Calm

Tide / Current Tables for Ninilchik, Cook Inlet, Alaska
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Ninilchik
Click for Map
Thu -- 05:25 AM AKDT     21.94 feet High Tide
Thu -- 06:43 AM AKDT     Sunrise
Thu -- 10:38 AM AKDT     Moonrise
Thu -- 11:57 AM AKDT     -2.13 feet Low Tide
Thu -- 05:53 PM AKDT     21.73 feet High Tide
Thu -- 09:32 PM AKDT     Sunset
Thu -- 10:39 PM AKDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.52.37.513.518.721.621.518.914.38.73.2-0.8-2.1-0.24.410.416.320.421.720.216.711.76.42.1

Tide / Current Tables for Cape Ninilchik, Cook Inlet, Alaska
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Cape Ninilchik
Click for Map
Thu -- 05:25 AM AKDT     21.94 feet High Tide
Thu -- 06:43 AM AKDT     Sunrise
Thu -- 10:38 AM AKDT     Moonrise
Thu -- 11:47 AM AKDT     -1.93 feet Low Tide
Thu -- 05:53 PM AKDT     21.73 feet High Tide
Thu -- 09:32 PM AKDT     Sunset
Thu -- 10:39 PM AKDT     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-0.13.18.213.918.921.721.518.7148.22.7-1-1.90.45.11116.620.521.720.216.511.461.8

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

GOES Local Image of Alaska    EDIT
Geos

Ground Weather Radar Station Kenai, 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.