textproduct: Fairbanks

SYNOPSIS

A Bering Sea low pressure system will move into the Gulf of Alaska this weekend. This system will rotate a series of disturbances up into the Alaskan Range and Kuskokwim valley with cloudy, cooler and showery conditions into Saturday. Behind this system a high pressure ridge builds over the North Slope with a stationary front setting up just south of the Brooks Range. A warming and drying trend will occur Sunday into Tuesday for much of the Interior and Northern Alaska. Isolated showers and thunderstorms will occur this weekend over the mountains and along the stationary frontal boundary.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Clouds, showers and cooler conditions will increase over the Alaskan Range this weekend. Isolated showers and thunderstorms will continue over the White Mountains and Fortymile Country.

- Otherwise a warming and drying trend will occur across the Interior Saturday into Monday with daytime temperatures in the 70s and lower 80s.

West Coast and Western Interior... - The Southwest Coast and Kuskokwim Valley will dry out on Saturday except for isolated showers and thunderstorms over the higher terrain of the Western Interior.

- Temperatures remain in the 50s and 60s today across most of the region, but there will be a gradual warm-up this weekend.

North Slope and Brooks Range.. - High pressure develops over Northern Alaska with a gradual warming and drying trend into Monday. Foggy conditions will develop along the Arctic Coast.

- Gusty northerly winds will continue into Saturday across the Brooks Range with 20 to 30 mph winds through the passes.

- Isolated thunderstorms are possible over the Brooks Range this evening and Saturday.

FORECAST ANALYSIS AND DISCUSSION

The low pressure system in the Bering Sea will impact the Southwest Coast and Kuskokwim Valley with cloudy, cooler and showery conditions. Those areas begin to temporarily warm and dry Sunday into Monday as this system moves southeast into the Gulf of Alaska. Clouds and showers will spread up into the Alaskan Range this weekend.

Farther north behind a weak arctic trough, a high pressure ridge extending from Siberia develops over the Arctic Coast and North Slope by Sunday. The airmass will be stable under this ridge diminishing shower and lightning activity through Monday. As this ridge builds, a northerly pressure gradient develops tonight into Saturday across the Brooks Range resulting in gusty northerly winds. This downslope flow will enhance the warming and drying in the northern Interior. The arctic trough results in a stationary front forming near latitude 65 that will provide lift to isolated convection on Saturday and a little farther south on Sunday.

Shortwave energy and associated moisture from the Yukon remains over the upper Tanana Valley, Fortymile Country and the Yukon Flats today. This moisture will shift east from Alaska this weekend with some warming and drying developing. Isolated afternoon and evening thunderstorms will still pop over the mountains of the Eastern Interior this weekend especially near latitude 65 in the vicinity of the aforementioned stationary front.

FIRE WEATHER

Over the next several days, two features will be the primary drivers of our weather: a ridge building across the interior and a low along the west coast undercutting the state, moving into the Panhandle. Touching on the ridge first, this feature will be responsible for the warming and drying trend, with critical min RH of 20 to 30 percent expanding its footprint across the interior. Temperatures are going to trend up, with 75F to 85F expected for most of the Interior and Yukon Flats by Mon/Tue. Isolated thunderstorms continue, mainly over the mountains. Expect this ridge to persist into Wednesday before breaking down, setting the stage for a critical fire weather pattern. One note is a signal for southerly flow to develop across the Alaska Range Wednesday, helping to expand the hot and dry footprint across the Tanana.

Now the low undercutting the state comes into play. This feature will move across the great Gulf of Alaska, through the weekend, picking up ample moisture. As this system makes landfall over Southeast the middle of next week, moisture will move across the Coast mountains and begin to slide into B.C. This will serve as a critical ingredient as the ridge begins to funnel this moisture into the interior and break down, bringing potential elevated thunderstorm activity back to much of the region near the end of next week.

One note is general troughing on the southwest coast by mid week next week, helping to bring ample moisture and moderating fire weather to our southwest near McGrath/Middle Yukon.

EXTENDED FORECAST DAYS 4-7

Tuesday through Friday

High pressures will be the dominant weather feature over Northern Alaska early next week until the next Bering Sea low pressure system moves in. 850mb temperatures peak in the 10-15C range under this dome of stable air next Tuesday through Thursday. Above normal temperatures with dry conditions are expected throughout much of the Interior and on the North Slope. Will need to monitor for heat advisories especially on the Yukon Flats. The next upstream Bering Sea low pressure system begins to impact southwest Alaska on Tuesday before moving eastward into the Gulf of Alaska on Thursday. Shortwave energy and moisture will circulate up into the Southwest Coast, Kuskokwim Valley and the Alaska Range as this system tracks through. Models continue to undercut the high pressure ridge over Northern Alaska with increasing convection in the southeasterly flow during this time. While shower and storm coverage should be scattered in Southwest Alaska and along the Alaska Range...farther north isolated thunderstorm activity is expected at this time. Additional shortwaves should undercut the ridge in the easterly flow Thursday and Friday potentially increasing lightning coverage. We will continue to monitor that situation for the potential fire weather implications.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. PK...Small Craft Advisory for PKZ805-810. Small Craft Advisory for PKZ806. Small Craft Advisory for PKZ807-816-817-851-853-854-856. Small Craft Advisory for PKZ850.