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Incoming storm to bring high winds, snow and rain

Multiple watches and warnings have been issued into Tuesday
Published: Nov. 30, 2020 at 10:46 AM AKST
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ANCHORAGE, Alaska (KTUU) - It’s the calm before the storm, as much of the state prepares for an incoming winter storm. Ahead of the rather pronounced low that is weakening, many areas are already seeing a slew of winter weather products being issued.

Alaska Futuretrack
Alaska Futuretrack(Alaska's News Source)

ANALYSIS

A weakening low just south of the Aleutian chain is set to track to the northeast over the next 36 hours. As the system tracks into the Gulf of Alaska it will bring with it a multitude of impacts that will be felt from the Alaska Peninsula, into Southcentral and eventually Southeast Alaska. The storm is tapping into plenty of moisture from the Pacific and warmth from the tropics, meaning temperatures are expected to rise well above freezing in the coming days. This will lead to very slick roads at the surface and heavy, wet snow in higher elevations of the mountains. The effects of the storm will linger into Wednesday as the system stalls out just to the south, keeping the warmer conditions and wintry mix in the forecast.

WATCHES AND WARNINGS

Numerous watches, warnings and advisories have been issued, as the impacts from the storm will be felt all the way into the Interior. The greatest impacts though will be along coastal regions and Southeast Alaska, where the heaviest rain and highest winds will occur.

Click through the gallery for all Watches and Warnings that have been issued ahead of the storm.

SOUTHCENTRAL IMPACTS

While everything is quiet across Southcentral outside of some patchy freezing fog and flurries this morning, the activity ramps up through the day. An incoming front will push across Kodiak Island through the day bringing increasing clouds and an initial batch of snow. As the front tracks through Southcentral most locations will start off as snow. Portions of the Kenai will likely see upwards of 4-6 inches of snow before the warmer air takes over. Locations near Prince William Sound will also see upwards of 6 inches of snow as the fetch of moisture will lead to heavy snowfall rates at times. Beginning late tonight and into Tuesday, the warmer air moves in. This will lead to rapidly rising temperatures above freezing and a transition to a wintry mix. The only exception will be portions of the Susitna Valley, where temperatures will stay below freezing for longer leading to higher snowfall totals. It’s there where a winter storm warning has been issued. Additionally, the avalanche danger will be significant, as heavy wet snow and warmer temperatures will lead to a higher risk of avalanches in the backcountry.

Snow:

Most of the snow will fall later today and into early Tuesday ahead of the warmer air. It’s here where some locations could see in excess of a foot of snow.

CitySnowfall Accumulation ForecastExpected Transition
Kodiak2-4″12-1 PM Monday
Kenai2-3″After 3 AM Tuesday
Seward4-6″After 3 PM Monday
Anchorage1-2″After 9 AM Tuesday
Susitna Valley18-36″After 3 PM Tuesday
Whittier1-2″12-1 PM Monday
Valdez1-3″After 6 PM Monday

Winds:

Winds will also be a concern with this system, however, it will primarily impact coastal regions and mountain passes. As the storm moves closer to Southcentral, winds could gusts upwards of 40-60 mph, with the highest winds occurring along Turnagain Arm. Depending on the placement of the winds, we could see them bend into the Anchorage bowl leading to gusts upwards of 20 mph into Tuesday. These winds will also be a big driver in pushing warmer air into Southcentral leading to the wintry transition, if not a cold rain in the warmer spots.

Travel conditions are expected to deteriorate through the day Tuesday. As the wintry mix takes over and temperatures warm above freezing, there will be slick and icy roads. Be cautious and alert when driving over the next 24 to 36 hours. With temperatures expected to stay above freezing into Wednesday, the slick spots will remain with us through the middle of the week. By Wednesday night, as the low tracks through Southcentral, we’ll once again tap into cold air. This will lead to a transition back to snow and icy roads to develop overnight into Thursday. The impacts of this event will be felt through most of the week.

SOUTHEAST IMPACTS

The greatest impacts of this storm will be felt in Southeast Alaska. Numerous watches and warnings have been issued, as excess rain and high winds will impact the region through Wednesday. While things are quiet to start off the day, expect conditions to gradually decline as the wintry mix/rain moves in later today. One area of concern will be the heavy rain that is expected for the region, following an area that has already seen 3-5 inches of rain in the past few days. Just yesterday, Ketchikan saw a record 4.94 inches of rain with an additional 5-10 inches likely through the middle of the week. The only area that will likely stay snow the entire event will be portions of the Haines and Klondike Highways, where upwards of 2 feet of heavy, wet snow is likely.

Snow

With temperatures already above freezing across much of Southeast, snow will be minor in comparison to the expected impacts from rain and winds. However, snow is possible upon onset, with the heaviest snow expected to fall across the Northern Panhandle. With warmer temperatures moving in, expect snow depth in many areas to take a hit.

Rain

By far, rain will be the single greatest impact of this event. The system is setting up in such a way that an atmospheric river will continue to pump in plenty of moisture through the middle of the week. Much of Southeast is under a flood watch in anticipation of over 6 inches of rain. This rain, which will be heavy at times, will lead to the potential for mudslides or landslides, along with power outages and downed trees. The fetch of moisture could lead to reduced visibility and the threat for hydroplaning through the middle of the week. Be extra cautious when on the roads and refrain from using cruise control when driving through storms like this. The heaviest rain is expected to fall early Tuesday morning and last through most of the day. While there is a small chance of a wintry mix, temperatures warming into the 40s will limit the opportunity, meaning that heavy rain will be the primary precipitation type with this event. It’s possible that by the end of this event, some locations in Southeast could see upwards of 10 inches of rain.

Winds

In addition to the rain, high winds will blow into Southeast over the next 24 to 36 hours. The winds will initially arrive later tonight, where gusts upwards of 65 mph are possible. These winds will be sustained out of the southeast, keeping the moisture and warmer temperatures in the forecast. High wind warnings have been issued for portions of Southeast through the day Tuesday. With winds expected to remain a threat with this system, downed trees and power lines on an already saturated ground is likely. Any winds will gradually subside into Wednesday, with gusty winds still likely but not as high.

While many of the watches and warnings last through either Tuesday or Wednesday, the atmospheric river set-up will keep rain in the forecast for most of the week. This, along with low pressures moving out of the Pacific Ocean, will add to an already wet ground, meaning impacts from this storm could be felt well into the weekend.

Stay with Alaska’s Weather Source as we continue to fine tune the forecast over the next 24 hours.

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