Area Forecast Discussion

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Light, periodic, lingering showers may persist into this evening across portions of southern Southcentral as a shortwave exits to the east. Otherwise, overall drier conditions are expected tonight and Tuesday.

The wetter pattern returns on Wednesday as a more robust low in the Bering will push its front into the region. Widespread precipitation is expected to begin as early as 4-6AM Wednesday morning for Kodiak and some higher elevations of the Chugach and Talkeetna Mountains. By mid-morning Wednesday, precipitation will spread to encompass almost the entirety of the Mat-Su Valleys, Kodiak Island, the north Gulf Coast and the Kenai Peninsula. There is a fluctuating chance for precipitation in Anchorage, as some models are hinting at downsloping while other track the precipitation up Cook Inlet and over Anchorage. The eastern Alaska Range and Wrangell mountains will see snow showers by Wednesday morning, though the valleys of the Copper River Basin are likely to remain drier.

Worry not! Precipitation is indeed expected to continue into Thursday and Friday morning as the Atmospheric River continue to pump moisture into Southcentral from the North Pacific. Rain or a rain/snow mix is expected to be the primary precipitation type Wednesday and Thursday for the lower elevations. With snow levels raising to 1500-2000 ft - higher elevations will continue to see all snow.

KM

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3: Today through Thursday morning)...

Rain and snow showers will persist tonight across the southwestern mainland as a series of upper-level disturbances moves in from the Bering Sea. The expectation is for continued showery precipitation across the area with westerly upslope enhancement along the Western Alaska Range and Aleutian Range. This activity will taper off through Tuesday morning as an upper- level shortwave ridge begins building into the southwest mainland by then. Despite the ridge moving in, expect another overcast day across Southwest for Tuesday as another low pressure system approaches.

Attention then quickly turns to the next significant Bering Sea system deepening tonight and Tuesday, remaining nearly stationary between Adak and Amchitka through early Wednesday morning. As the system spins between Amchitka and Adak, multiple frontal systems will be sent northward and eastward. The first of which will be today through tonight with Adak and the Pribilofs seeing light rain with the gustiest winds remaining confined to Adak.

The second and more widespread frontal push of moisture will arrive with moderate to heavy rain Tuesday morning to Adak and Atka, and will arrive to the Pribilofs and Nikolski/Unalaska/Akutan by late Tuesday morning to early Tuesday afternoon. By Tuesday afternoon, the storm strengthens to storm- force on the northern periphery of the system west of the Pribilofs. Heavy rain moves to False Pass, King Cove, Cold Bay, and Sand Point by Tuesday evening. Nunivak Island and the Kuskokwim Delta coast will see a period of snow at the onset of precipitation Tuesday evening and with gusty winds, will promote localized blowing snow conditions, reducing visibility to 1/2 mile or less at times into Wednesday morning. Heavy rain will not stay over the Alaska Peninsula too long as the moisture corridor shifts east to Kodiak Island by Wednesday morning with the Interior Kuskokwim Delta, Kuskokwim Valley, and Bristol Bay continuing to see light to moderate rain at times Wednesday morning through Wednesday evening.

The storm slowly pulls northeastward to the central Bering near the Pribilof Islands Thursday morning. By Wednesday afternoon, the storm will have pulled in substantial warmer air from the south, transitioning any remaining areas of snow to a rain/snow mix or plain rain. Rainfall will likely linger over the Pribilof islands into Thursday morning. For Thursday and beyond, an unsettled showery pattern is expected over much of the Bering, Aleutians, and Southwest Alaska.

-DAN/CL

LONG TERM FORECAST (Days 4 through 7: Friday through Monday)

Precipitation continues across much of Alaska through the weekend. A North Pacific low will enter the southern Bering near Adak Sunday morning, passing the Pribilof Islands Sunday night and pausing west of Nunivak Island on Monday. This system brings widespread gales across southern and eastern Bering and Bristol Bay before it weakens on Monday. The highest winds do not reach the mainland, and concern for coastal impacts is low due to shorefast ice and some added protection from the expansive ice floe over the eastern Bering Sea.

The associated front from this system will expand into the western Gulf of Alaska, drawing upon an extended moisture fetch. Coastal areas in the northern Gulf, Kodiak Island and higher elevations of the Alaska Range will likely see the most precipitation. Away from the coast, expect several days of light to moderate rain at lower elevations and snow at higher elevations. Southeasterly flow will allow some downsloping to the west of the Chugach and Kenai Mountains.

Model agreement on the track of this system has improved, keeping the low west to slightly northwest of Nunivak Island, with southerly flow bringing the main moisture plume into Southcentral and Southeast Alaska. The minority opinion of the ECMWF places the center of the system west of the Pribilofs, which would signal higher wind and precipitation for those islands, but elsewhere little would change. Shortwaves rotating around the center of the system will bring slightly less intense precipitation to Southwest Alaska through the first half of the week.

AVIATION

PANC...Gusty southerly winds will gradually decrease tonight to around 10 kts for much of Tuesday. VFR conditions will likely prevail through the period, with brief dips into MVFR with showers through this evening.