Marine Weather and Tides
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|Sunrise 4:55AM||Sunset 11:16PM||Thursday July 18, 2019 7:52 PM AKDT (03:52 UTC)||Moonrise 10:12PM||Moonset 5:13AM||Illumination 96%|
7 Day Forecast for Marine Location Near Anchor Point, AKHourly EDIT Help
Area Discussion for -  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxak68 pafc 190023|
southcentral and southwest alaska forecast discussion
national weather service anchorage ak
423 pm akdt Thu jul 18 2019
Analysis and upper levels
A good portion of southern alaska is under the influence of an
upper level col, the "saddle point" in between the ridges and
troughs. It is characterized by weak and disorganized flow. Ridges
are attempting to build in from the yukon westward into the copper
river basin and from the bering sea eastward into southwest
alaska. So what does this mean? With warm and unstable conditions
over southcentral alaska, showers and thunderstorms will form
this afternoon and evening preferentially along the mountains.
They won't move very far or very fast, staying mainly along the
mountains and keeping the valleys mostly dry and sunnier.
Ridging over the bering into southwest alaska is producing
widespread low clouds and patchy fog. Tight pressure gradients
between high pressure in the bering and low pressure in the gulf
(along with supporting low level flow) are leading to gusty winds
along the south side of the alaska peninsula. Observations
indicate the strongest wind gusts are in the 30 to 40 kt range.
Models remain in fairly good agreement through the next few days,
with just some minor differences in position of large scale
features. The most challenging part of the forecast will be
determining the extent of clouds and smoke in this weak flow
regime with increasing stability (which can trap both clouds
and smoke). Overall, forecast confidence is above average.
Panc...VFR conditions and light winds will persist. The primary
challenge will be the smoke forecast. Light southerly flow this
evening into the overnight hours will again carry smoke northward
from the swan lake fire. Thus, there is potential for reduced
visibilities Friday morning.
Fire weather concerns will diminish as we head through the next
few days. Most of southwest alaska has already stabilized under
the influence of the upper ridge building in from the west and
associated intrusion of "marine air" from the bering sea.
Southcentral remains unstable, but storms will initiate primarily
over interior mountains and weak storm motion will keep them from
propagating very far. Expect cloud cover to gradually increase
each day through the weekend, leading to more stable conditions.
Thunderstorms will likely be confined to the copper river basin by
Saturday and Sunday.
Smoke from the swan lake fire did move up into the anchorage area
overnight through this morning with a light southerly surface
wind. The 12z anchorage sounding also showed a steep inversion
off the surface which trapped the smoke. The light southerly flow
and overnight inversions make it likely that periods of smoke
will persist in the anchorage area the next few days.
Short term forecast southcentral alaska (days 1 and 2)
Ridging from the bering sea into the interior coupled with the low
over the gulf of alaska is keeping the southern mainland in the
col between these systems through Friday night, thus flow overall
is very weak. Moisture wrapping around the gulf of alaska low from
the east is staying along the coast and south of the chugach
mountains for the most part, although mid to high level moisture
is expected to advect into the copper river basin. The offshore
north flow will remain weak northerly through this evening then
the flow aloft will become weak varying from southwest to
southeast Friday. The flow then becomes weak northerly again
Saturday. The temperatures around the 5000 foot level (850 mb)
over the copper river basin to the susitna valley down across cook
inlet currently around 10 to 14 c will gradually cool to 8 to 10 c
through Saturday. This will result in lower high temperatures,
with the warmest temperatures this evening and Friday.|
On the convective side, the most unstable region will be over the
susitna valley this evening and expand into the copper river basin
Friday afternoon and evening.
The return to warmer and drier conditions is allowing for
increased wild fire activity and smoke production. The increased
smoke coupled with generally light flow and overnight stable
conditions will result in more smoke across the southern mainland.
Late Friday and overnight into Saturday, weak southerly flow
should push smoke up across the anchorage area into the mat-su. Of
course, how much smoke is predicated on how active the wild fires
Short term forecast southwest alaska (days 1 and 2)
Cloudy conditions will remain under the ridge that has made its
way across southwest alaska. Only a slight chance of thunderstorms
are in the forecast over the alaska range since there is still
instability in the models that could produce convective activity.
Onshore flow will keep the mainland under this influence for the
next few days as this stable pattern continues. This flow brought
fog to coastal areas last night into the morning hours and could
also bring stratus and fog to inland areas for tonight and
tomorrow morning. Another concern for today's forecast is the
smoke from wildfires over the kuskokwim valley into the bristol
bay region. Smoke was observed drifting from sleetmute down to the
iliamna region as northerly flow continues over the area.
Short term forecast bering sea aleutians (days 1 and 2)
Gap winds south of the akpen stretching from dutch harbor to
kodiak island were the biggest concern for today's forecast.
Observations showed northerly sustained small craft advisory
winds, with gusts reaching gale force criteria. These conditions
will last well into tomorrow before diminishing tomorrow night. Out
over the bering, winds remain below these thresholds. Stratus and
patchy fog will remain to blanket the bering and part of the
aleutians as the ridge continues to be the dominant weather
Marine (days 3 through 5; Saturday evening through Monday)
Sub gales are expected to persist through Monday over the bering
and gulf. Seas may increase to at or near 10 feet in the western
bering by Sunday afternoon ahead of a front, but will remain
lower elsewhere. No significant systems appear likely for the
Long term forecast (days 4 through 7; Sunday through Wednesday)
Long range models are similar to yesterday, in general showing an
upper level trough over siberia, a ridge over the mainland and a
pair of low pressures off the bc coast and tracking south of the
aleutians, respectively. The main challenge involves how these
systems interact. The early part of next week does not indicate a
particularly wet pattern for southcentral, though afternoon
convection may be possible over the mountains. Confidence remains
low mid-week and beyond. The GFS remains a slight outlier with
both a much stronger siberian trough and upper level gulf low
where as the european and ensembles are not as aggressive. The
gfs solution would generally bring colder temperatures and more
precipitation while the latter solutions would bring drier
conditions and more seasonable temperatures.
Afc watches warnings advisories
Fire weather... None.
Synopsis and model discussion... Seb
southcentral alaska... Sa
southwest alaska bering sea aleutians... Ah
marine long term... Ap
Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
|Stations||Dist||Age||Wind||Air Temp||Water Temp||Waves||Pressure||DewPt|
|46108 - Central Cook Inlet - 175||12 mi||52 min||52°F||2 ft|
|OVIA2 - 9455500 - Seldovia, AK||24 mi||52 min||51°F||1009.7 hPa (+0.0)|
|HMSA2||25 mi||20 min||SW 5.1 G 9.9||63°F||1009.6 hPa||53°F|
|HMRA2 - Kachemak Bay Reserve, AK||26 mi||82 min||W 8||63°F||1009 hPa||55°F|
|FILA2 - Flat Island Light, AK||31 mi||22 min||SSW 4.1 G 7||62°F||1010.5 hPa||53°F|
Wind History for Nikiski, AK(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|Homer, Homer Airport, AK||20 mi||59 min||WSW 8||7.00 mi||Fair||66°F||54°F||65%||1010.1 hPa|
|Seldovia, Seldovia Airport, AK||24 mi||59 min||Var 3||7.00 mi||Fair||69°F||57°F||66%||1010.1 hPa|
Wind History from AHO (wind in knots)
|1 day ago||W||SW||SW||Calm||E||NE||W||Calm||Calm||NE||E||NE||NE||NE||NE||E||S||W||W||W||SW||W||W|
|2 days ago||E||S||Calm||Calm||NE||Calm||NW||Calm||Calm||Calm||Calm||Calm||NE||E||E||SE||SW||SW||SW||SW||SW||W||W |
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