textproduct: Fairbanks

SYNOPSIS

Scattered to widespread showers, isolated/scattered thunderstorms, and breezy winds with gusts to around 20-30 mph will accompany a cold front as it tracks north across Northern Alaska this weekend. Along the leading edge of the front is where we are expecting best chances for scattered thunderstorms, with the primary corridor being across the Central/Eastern Interior north through the Brooks Range. Stronger storms will be capable of producing gusty winds, frequent lighting, small hail, and heavy rain. Convection will subside this evening into early Sunday morning, with limited instability for the rest of Sunday inhibiting any additional thunderstorm development. Highs in the 60s/70s to near 80 across the Interior today will give way to the 50s/60s starting Sunday which will continue into early next week. Behind the front, a Bering Sea low will move onshore into Southwest Alaska Sunday into Monday and help to bring reinforcing, daily scattered showers across our region into early next week.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- A cold front will continue to lift north across the Interior this weekend with scattered showers and thunderstorms, southwest wind gusts up to 30 mph, and accompanying colder temperatures starting Sunday.

- Additional rainfall amounts through Monday will be around 0.10- 0.25" in the Tanana Valley and 0.25-1.25" in the Alaska Range and north of the Tanana. Highest totals are expected to be around Eagle.

- Following the cold front this weekend, scattered showers will continue early to mid next week as a Bering Sea low moves inland. Very limited coverage of thunderstorms on Sunday will give way to isolated thunderstorms Monday onwards for the Upper Tanana and Fortymile Country.

- Highs in the 60s/70s to near 80 today will give way to the 50s/60s starting Sunday which will continue into early next week. Gradually warming temperatures are expected back by midweek.

West Coast and Western Interior...

- A cold front will continue to lift north across Western Alaska this weekend with scattered to widespread showers, southwest wind gusts up to 30 mph, and accompanying colder temperatures.

- While the bulk of rainfall has already fallen across the Southwest Interior with around 0.50-1.50" inches observed from Lake Minchumina to St. Mary's, additional widespread moderate amounts will shift north tonight into Sunday.

- Additional rainfall for St. Lawrence Island, Southern/Eastern Seward Peninsula, and West-Central/Northwest Interior will be around 0.25-0.75" with highest totals in the Middle Yukon Valley.

- Following the cold front this weekend, scattered showers will continue early to mid next week as a Bering Sea low moves inland.

- Highs in the 60s/70s to near 80 today in the Western Interior will give way to the 50s/60s starting Sunday which will continue into early next week. Gradually warming temperatures are expected back by midweek. Locally cooler conditions will exist along the coast.

North Slope and Brooks Range...

- A cold front will continue to lift north across far Northern Alaska this weekend into Monday with scattered showers and thunderstorms and wind gusts up to 30 mph.

- Total rainfall amounts with this system through Monday are expected to be around 0.25-0.75" in the Brooks Range and a T-0.25" across the Southern Arctic Plains and Eastern Arctic Coast. Snow showers will be possible across highest elevations of the Brooks Range and along the Eastern Arctic Coast.

- While temperatures will see a cooling trend in the Brooks Range into early next week, southerly flow will lead to warming conditions across the North Slope. Highs regionwide will trend to being in the 40s/50s/60s starting Sunday.

- Following the cold front this weekend, scattered showers will continue early to mid next week as a Bering Sea low moves inland.

FORECAST ANALYSIS AND DISCUSSION

Today through Monday. Early afternoon satellite imagery shows a 542 dm low centered west of St. Paul with a 575 dm ridge of high pressure centered over Yellowknife in the Northwest Territories. In between these two features, a cold front and shortwave trough continue to lift north, with the boundary extending from St. Lawrence Island through the Interior and down to Southeast Alaska. Along this front, scattered to widespread precipitation is expected to continue to lift north with observed rainfall amounts across the Southwest Interior around 0.50-1.50" inches from Lake Minchumina to St. Mary's. Isolated to scattered thunderstorms will accompany the leading edge of this front, as evident by the latest radar and satellite data showing scattered thunderstorm development across the Central and Eastern Interior north through the Brooks Range. Stronger storms today will be capable of producing wind gusts up to 30 mph, small hail, heavy rain, and frequent lightning. Cloud tops with these strong storms ongoing today are around 35-45k feet indicated by satellite, radar, and PIREPS, indicative of the very unstable airmass out ahead of the cold front. Breezy wind gusts up to 30 mph will also fill in behind the passing front tonight into Sunday, with winds remaining elevated into Monday especially north of Fairbanks across higher elevations of the Interior.

Hi-res CAMS remain in reasonable agreement this weekend, lifting the front and associated shortwave north tonight into Sunday with steadier moderate to at times heavy bands of rain along the boundary itself. While the bulk of rainfall has already fallen across the Southwest Interior, additional amounts across the rest of our region will be 0.25-1.25" across higher elevations and in a U-shaped area from Eagle to Coldfoot to Galena with around a T-0.25" expected elsewhere while the Northwest Arctic Coast and Seward Peninsula look to remain dry. Light snow will also be possible across highest elevations of the Brooks and Alaska Ranges, also to include the Eastern Arctic Coast.

As the start of the next week approaches, a broad troughing pattern is looking to settle in across the state. This will continue to bring cooler temperature and isolated showers and thunderstorms throughout the middle portions of the week. Eventually, the cold front will stall somewhere over the Central Brooks Range as a strong Arctic trough swings energy westerly across the Arctic Ocean. There is a fair bit of disagreement amongst models with the positioning of where this front stalls. In addition, the low from the Bering will be moving across the YK-Delta, into the Upper Kuskokwim through the start of the week (hence the broad troughing mentioned previously). Models are showing this low to move into the northern portion of the gulf of Alaska sometime Tuesday. This could potentially setup another round of upper-level easterly flow across the Interior for the later half of the week.

FIRE WEATHER

A pattern change is underway as a low pressure system in the Bering Sea bringing a cold front through the Interior today. Ahead of this cold front, scattered thunderstorms continue to develop on the leading edge of the front with strong thunderstorms capable of producing wind gusts up to 30 mph, frequent lightning, small hail, and heavy rain through early Sunday morning. These thunderstorm chances will be in the Central and Eastern Interior north through the Brooks Range, and the Central Interior along the Tanana/Yukon River. The cold front will bring widespread wetting rains, gusty winds, and cooler temperatures. Most of the wetting rains will be associated with the frontal passage itself with up to 1.0" of rain in the Western Interior, Brooks Range, and Alaska Range. In the Upper Tanana Valley, Tanana Valley, and White Mountains precipitation amounts continue to trend downwards with up to 0.25" expected. Across the Interior higher amounts are possible due to the convective nature of the rain showers on Sunday. The showers on Sunday will be slow moving and could produce heavy rains in that area. After this front expect temperatures to remain cool through the middle of next week, with isolated to scattered rain showers remaining possible.

EXTENDED FORECAST DAYS 4-7

Tuesday through Friday. A Bering Sea low continues to move Eastward into the YK-Delta early next week, taking a southerly track across the Alaska Mainland. On Tuesday a ridge will divide the South West Interior from the South East Interior blocking a significant amount of vorticity maxima in the two localized areas. This allows more precipitation and wetting rains to these select locations on Tuesday afternoon. On Wednesday morning the trough will begin to move Eastward pushing the ridge towards Canada, which will allow for isolated to scattered showers in the Central/Eastern Interior. A trough will begin to deepen Wednesday afternoon along the West Coast. This trough has a possibility of bringing widespread rain showers along the West Coast Tuesday through Thursday morning. Winds are expected to remain light during this time period, while temperatures trend slightly below normal, as a combination of the cloud cover, precipitation and arctic air.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. PK...Small Craft Advisory for PKZ804. Small Craft Advisory for PKZ805-852. Small Craft Advisory for PKZ806. Small Craft Advisory for PKZ810-811-856. Small Craft Advisory for PKZ812. Brisk Wind Advisory for PKZ815. Small Craft Advisory for PKZ854. Small Craft Advisory for PKZ857. Small Craft Advisory for PKZ858.