textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior...

- Warm conditions peak Saturday and Sunday, with valley high temperatures ranging between the mid 70s and lower 80s. Temperatures cool to below 70 degrees beginning Monday.

- Dry conditions prevail Saturday, though isolated thunderstorms are possible south of Fairbanks. Widespread showers return beginning early next week.

- A Wind Advisory is in effect for the Eastern Alaska Range from 10 AM Sunday through 12 AM Tuesday for gap winds gusting to 55 mph through Isabel Pass.

West Coast and Western Interior...

- Warm temperatures continue Saturday, with inland highs reaching the mid to upper 70s and coastal areas in the 60s to near 70. A Heat Advisory is in effect from 5 AM to 8 PM AKDT Saturday for the Noatak and Lower Kobuk Valleys and the Seward Peninsula for temperatures reaching 75 to 80 degrees.

- Isolated to scattered thunderstorms are possible in the Lower Yukon Delta area Saturday afternoon. Substantial moisture brings moderate to heavy rainfall potential to the southwest coast and inland areas Sunday night into Monday.

- The overall pattern shifts late Sunday into Monday as a low pressure system moves inland, cooling temperatures and bringing elevated precipitation chances through midweek.

North Slope and Brooks Range...

- Warm conditions continue across the northern slopes of the Brooks Range and Arctic Plains through Sunday, with highs reaching the 60s and 70s, approaching 80 near Umiat. Onshore easterly winds keep the Eastern Arctic Coast cooler, with highs in the 50s.

- Mostly dry conditions prevail Saturday and Sunday before rain chances return by Monday.

SYNOPSIS

Warm conditions will prevail through the weekend across Northern Alaska before cooler and wetter weather takes over by early next week. A persistent ridge will keep the Interior and North Slope mostly clear and dry through Saturday, though a passing shortwave will trigger isolated to scattered afternoon thunderstorms from the Southwestern Interior through the Central and Eastern Interior. On Sunday, a pattern shift begins as a Bering Sea low advances inland, driving the ridge eastward and pushing a surface front across the Alaska Range. This system will bring gusty gap winds through mountain passes, cooler temperatures, and widespread rainfall that will persist across the state through much of next week.

SHORT TERM /THROUGH SUNDAY NIGHT/

The 576 decameter ridge entrenched over the Interior will dictate the region's weather through Saturday night. This feature continues to deflect systems away from the region while maintaining widespread clearing. Beneath the high pressure dome, 850 mb temperatures reaching 11-14C will support high temperatures in the mid to upper 70s, with some locations approaching the lower 80s. The peak warmth will concentrate across the Central and Eastern Interior, as well as areas directly north of the Alaska Range, though highs in the 70s will extend into the Western Interior and parts of the North Slope. The potential for high temperatures to reach 75 to 80 degrees has prompted a Heat Advisory from 5 AM to 8 PM AKDT Saturday for the Noatak and Lower Kobuk Valleys, as well as interior portions of the Seward Peninsula.

A shortwave tracking around the outer margin of the ridge will bring chances for isolated thunderstorms Saturday afternoon. This activity will focus across an arc stretching from the southern half of the Western Interior south of the Seward Peninsula through through the southern half of the Central and Eastern Interior.

A pronounced synoptic transition unfolds on Sunday, marking a shift toward cooler and wetter conditions for Northern Alaska. Aloft, the ridge that has dominated the pattern will be nudged eastward into the Yukon as low pressure takes over. An initial shortwave rotating around a stronger low toward the Kuskokwim Delta will be quickly overtaken by the low itself Sunday into Monday. This primary low will completely dislodge the remnant ridge, directing a plume of deep moisture into the Western Interior alongside an organized cold front advancing across the Alaska Range. Expect widespread rainfall and strengthening winds to spread into the Central and Eastern Interior by Sunday night into early Monday morning. A Wind Advisory is in effect for the Eastern Alaska Range North of Trims Camp from 10 AM Sunday to 12 AM AKDT Tuesday for southerly winds of 25 to 35 mph with gusts up to 55 mph. Overall rainfall totals through Tuesday will range from 0.5 to 1.5 inches across the Western Interior, with lighter amounts expected farther north and east.

LONG TERM /MONDAY THROUGH FRIDAY/

Broad troughing and cool, unsettled weather will prevail across Northern Alaska throughout the extended forecast period as the stagnant blocking pattern breaks down. High temperatures will drop significantly, broadly dropping below 70 degrees across the region from Tuesday onward as the upper ridge axis shifts eastward into the Yukon and Northwest Territories. Aloft, model consensus shows reasonable agreement regarding the primary trough progressing eastward, though uncertainty remains mid to late week concerning the timing and track of a secondary low developing upstream over the Bering Sea.

A low pressure system in the eastern Bering Sea will maintain strong southerly flow through the Alaska Range on Monday, with winds gusting up to 55 mph possible through Isabel Pass before easing on Tuesday morning. Southerly winds will direct a plume of deep moisture into Western Alaska, bringing widespread rainfall to the Western Interior and the Alaska and Brooks Ranges. The wettest locations, particularly in the Southwestern Interior and Western Brooks Range, could see localized rainfall accumulations exceeding one inch on Monday. From Tuesday onward, precipitation across the Interior and North Slope will become more scattered as the principal low moves inland and weakens. While the potential for heavy rainfall diminishes mid to late week, periods of showers will persist across the region. Temperatures will remain near normal though the remainder of the forecast period.

Coastal Hazard Potential... No coastal hazard concerns are expected.

FIRE WEATHER

At the start of the weekend, fairly warm and dry weather continues over most of Northern Alaska as upper level ridging remains over the state. A shortwave feature embedded in the overall flow has moved south over the Central/Eastern Interior early Saturday morning, which is working to support scattered showers and a few isolated thunderstorms across the region. Precipitation amounts from Friday generally ranged from T-0.10" with locally higher amounts closer to 0.50" at higher elevations. A similar trend is expected through Saturday afternoon as the shortwave feature pushes farther south towards the Alaska Range. Along with this feature, another pre- frontal system in the Gulf of Alaska lifts north into the YK Delta Saturday afternoon, fueling additional isolated to scattered showers and thunderstorms across Southwest Alaska into Sunday. The highest thunderstorm activity will likely be from the Upper Kuskokwim Valley towards the Nulato Hills. Naturally, cooler temperatures and higher min RHs will be expected where the most active weather develops. Elsewhere, high temperatures will rise back into the upper 70s/low 80s, especially in the Yukon Flats, Upper Tanana Valley, and Arctic Plains. For coastal regions, temperatures will continue to be a bit more mild in the mid to upper 60s. As for min RHs, they should generally fall between 30-40% with isolated areas seeing below 30% possible Sunday afternoon.

Looking towards Sunday, a more dramatic change in the pattern starts to take shape as a low tracks northeast across the Alaska Peninsula and into Bristol Bay Sunday morning/afternoon. As this low approaches the state, a brief period of southerly flow sets up over the Alaska Range yielding the potential for southerly gap winds through the passes. A Wind Advisory is in effect Sunday morning through late Sunday night for winds gusting up to 55 mph expected. In addition to gusty winds, this system brings with it quite a bit of moisture from the Gulf and is expected to bring widespread showers to much of Northern Alaska, including portions of the Central/Eastern Interior. A few isolated thunderstorms may develop ahead of any frontal boundary that develops, but activity should be fairly limited for the most part. By early next week, temperatures will cool to around seasonable norms with plenty of rain and cloud cover to usher in more fall-like weather.

HYDROLOGY

Expect water levels to rise on rivers throughout the Kuskokwim Delta and Western Interior as 0.5 to 2.0 inches of rain falls from Sunday night into Tuesday. Rivers are expected to remain within their banks, and no flooding is expected.

AFG WATCHES/WARNINGS/ADVISORIES

AK...Heat Advisory from 5 AM to 7 PM AKDT Saturday for AKZ814-816- 818-823. Wind Advisory from 10 AM Sunday to 7 PM AKDT Monday for AKZ849. MARINE...Small Craft Advisory until 4 AM AKDT Saturday for PKZ857. Small Craft Advisory until 4 AM AKDT Saturday for PKZ858.