Area Forecast Discussion
Issued by NWS Anchorage, AK
FXAK68 PAFC 270020
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
420 PM AKDT WED OCT 26 2016
.ANALYSIS AND UPPER LEVELS...
IR satellite imagery this afternoon shows the intensifying surface
low spinning well to the south of the Alaska Peninsula. The
associated upper level trough and surface baroclinicity are
supporting widespread showers across the southwest mainland
although the main low remains well to the south. In addition, the
associated low level jet on the eastern side of the surface low is
supporting gusty winds through channeled terrain across the Alaska
Peninsula and Kodiak Island. To the west of this system, strong
downward vertical motion is occurring across the Bering and
supporting widely scattered showers and relatively benign
conditions. Across Southcentral, high pressure is partly
maintaining its hold, but upper level clouds associated with the
Alaska Peninsula baroclinic zone continue to push eastward into
the region. As a result, sunny skies are currently limited to the
Copper River Basin.
Models remain in generally good agreement in the short term as the low
pressure system south of the Alaska Peninsula drifts into the
southern Gulf of Alaska. Models are still showing much more
disagreement on the development of a triple point along the front
that pushes into Bristol bay Friday. Currently the Canadian model
shows the best compromise between the solutions in terms of
strength and track, but there is still a lot of uncertainty in how
it will develop and bring gusty winds to the southwest mainland
For PANC...LIGHT winds and VFR conditions will persist into
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Low pressure south of the Akpen will gradually move southeast
through Fri. An associated front will swing across the Gulf to the
north Gulf coast tonight through Thu. This will bring small craft
level winds to Kodiak Island and Gales to the northwest Gulf
coast and Shelikof Strait through Thu morning. Rain will affect
Kodiak Island through Thu, and then will remain mainly offshore
until some affects the north Gulf coast Thu night into Fri.
Interior zones will be dry with increasing clouds through Fri.
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The low currently south of the Alaska Peninsula will continue
east and further into the Gulf of Alaska pulling the frontal
system/deformation band stretched across Bristol Bay and into
Southwest Alaska off to the east tonight through Thursday morning.
The next frontal system will approach the Kuskokwim Delta coast
Thursday night and the Bristol Bay area Friday. Strong
southeasterly winds will increase substantially along the coast
Thursday night and spread further inland Friday.
.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
An area of low pressure near the western Aleutians will lift east
northeast into the southern Bering as it weakens tonight. A
strengthening low off of the Kamchatka Peninsula will continue to
deepen as it tracks northeastward through the western Bering
while an associated front crosses to the northern and eastern
Bering Thursday night and Friday. A compact but strong frontal
wave developing to the west of Saint Matthew Island Thursday night
will bring storm force winds to the waters north and east of Saint
Matthew Island and the waters north of Nunivak Island Thursday
night through Friday morning. A potentially larger but lower
confidence triple point feature will develop over the eastern
Aleutians Friday morning and lift north into the eastern Bering
.LONG TERM FORECAST (Days 3 through 7)...
A very active weather pattern currently over the for the
Bering/Aleutians and southwest Mainland will continue into early
next week. The front associated with a gale force low over the
northern Bering will weaken as it moves the southwest coast,
bringing rain and gusty southerly winds to the area. This front
will also have enough strength to force the persistent Mainland
ridging well east of the area. This will allow for a portion of
the front to move into the Gulf, bringing a chance of rain back to
the north Gulf coast with a cloudy (but generally dry) and warm weekend
Starting Sunday, yet another strong low will begin moving through
the western Aleutians. The models have come into much better
agreement in the placement of this low through Monday, allowing
winds/seas over the region to be significantly increased with
today`s forecast update. There is now high confidence that this
will become at least a storm force low with at least 30 ft seas over
the central Bering and Aleutians, and has the potential to bring
hurricane force winds to the region with its much stronger
dynamics than the last 2 systems that have moved through the area.
Without the protection of a strong blocking ridge over the
Mainland, the front associated with this low will then move into
the Gulf, bringing increasing winds and chances of rain back into
the north Gulf Coast and Southcentral into early next week. Deep
and warm southerly flow will also accompany this front, allowing
temperatures to rise well above normal late this weekend into the
middle of next week for most of the south Mainland.
MARINE...Storm 181 185.
Gale 120 130 131 132 138 150 155 165 170 171 172 173 174
175 176 177 178 179 180..
SYNOPSIS AND MODEL DISCUSSION...EN
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR