Area Forecast Discussion

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today through Thursday)...

Today is the break between the last system and a stronger low that is in the Bering Sea and bring a wet pattern back to Southcentral for Wednesday which will persist into Thursday and beyond.

The warm front from the Bering low will move up Cook Inlet from the southwest Tuesday night and will probably bring in some light rain to Anchorage and the Matanuska Valley late tonight as it does so. Being late at night, the precipitation type is in question, especially with the snow that has mixed in with the showers even during the afternoon hours the past two days. However, with the warm front increasing showers and stratiform precipitation 9instead of convection with showers), rain looks to be most likely at lower elevations. The expected freezing level over Anchorage for tonight should be between 1500 and 2000 ft for Anchorage. That, and southeasterly surface winds increasing late tonight should tip the scales to rain for Anchorage and the Matanuska Valley lower elevations.

By Wednesday afternoon, the main front edges into Southcentral and brings with it the the deep moisture to start what will be a multi-day rain event for the Gulf coast and even some other more inland areas. There is a bit of a question with how much the rain will be mitigated by downsloping for the leeward side of the mountains. Models have some very diverse solutions about this, especially for Anchorage. However, the IVT values Wednesday afternoon into Thursday are significant enough that this deep moisture and extra lift associated with the jet streak will be enough to override downsloping and bring widespread rain into the region.

This moisture moves over the Copper River Basin for Wednesday night into Thursday, but Glennallen and other lower elevations are more likely to remain mostly dry in the downslope as well as get some strong and gusty southerly winds.

Seward, in particular, may see the most amount of rain in this system. From Wednesday through Friday, Seward could see 2 to upwards of 3 inches of rainfall.

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

Rain and snow showers continue to taper off over the Southwest Mainland as a ridge builds into the region. A strong low is currently over the Shemya and Adak regions, bringing mixed precipitation and gusty winds to those areas. This front will slowly makes its way northeastward over the next few days. A strong front from the low is pushing eastward, also bringing mixed precipitation and gusty winds to the Aleutians and the Pribilof Islands. 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. Gap areas in the Fox Islands and the Alaska Peninsula will see stronger gusts as the front passes.

The front will push onshore by this afternoon, bringing light to moderate snowfall and gusty winds to Nunivak Island and the Kuskokwim Delta. These gusty winds and snowfall will combine to promote localized blowing snow conditions, reducing visibility to 1/2 mile or less at times into Wednesday morning. Inland areas north and west of Bethel will see blowing snow as well. Also, a period of freezing rain mixed with snow is expected over the Kuskokwim Delta early Wednesday morning. Due to this threat, the Winter Weather Advisory now includes the inland Kuskokwim Delta. By Wednesday afternoon, temperatures will warm above freezing and precipitation will reduce in intensity over the Southwest Mainland as the front pushes eastward. The low itself will be positioned west of the Pribilof Islands by this time, bringing more gusty winds and precipitation over the Aleutians and Pribilof Islands. Gap areas over the Fox Islands and Alaska Peninsula will once again see stronger gusts during this period.

The low will weaken as it moves northeastward. By Friday, winds and chances for precipitation will have diminished over the Bering and the Southwest Mainland. However, lingering showers will prevail across Southwest Alaska. These will likely be rain during the day and a mix of rain and snow at night.

-CL/JAR

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 continue through the morning, tapering off by around 20Z, and remain light through the remainder of the day. VFR conditions will likely prevail through most of the period, with a slight chance of conditions briefly dipping into MVFR with passing showers after 12Z on Wednesday. Winds could become gusty out of the southeast by Wednesday morning.