textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior... - Wind gusts as high as 25 mph in the valleys and 35 in the higher terrain are expected Wednesday with widespread showers as a front continues to drift east through the day.

- Thursday is expected to be drier with mixed clouds/sun. Rain will likely make a return Friday morning as another low approaches from the Bering.

- Gusty southerly winds are expected through the Alaska Range passes overnight Thursday through much of Friday. Wind gusts up to 55 mph are expected to peak early Friday morning and slowly weaken through the day. A wind advisory has been issued.

- Highs are expected to remain in the 50s and lower 60s for much of the week.

West Coast and Western Interior... - A low approaches the West Coast Thursday and is expected to bring gusty east to northeast winds and periods of moderate to heavy rainfall to the West Coast and Western Interior through Friday.

- Rainfall totals will be around 0.50" to 1.50" Thursday/Friday for most of the Western Interior with the highest amounts in the YK Delta, Seward Peninsula, and the southern slopes of the Brooks Range.

- Winds gust 30 to 50 mph across the West Coast and as high as 35 mph in some areas along the Western Interior as the low moves through the area Thursday PM.

- Highs remain in the low to mid 50s through the end of the week with some areas seeing as low as the upper 40s Wednesday. North Slope and Brooks Range... - Scattered rain (at lower elevations) and snow (at higher elevations) showers are expected to persist across the area through the end of the day Wednesday. Remaining snow accumulations up to 3 inches possible above 4000 feet.

- Another round of heavier rain and snow showers are expected Friday in the Central Brooks Range. Snow accumulations are expected mostly Friday morning with 2 to 5 inches expected above 3500 feet. This snow may melt somewhat in the afternoon.

- Highs in the upper 30s to the 40s Wednesday warm back into the 40s/50s by Friday except Atigun Pass which stays in the upper 20s to lower 30s.

SYNOPSIS

Relatively benign weather expected through Wednesday as the previous low exits the region and another low approaches the West Coast Thursday. This next storm system is expected to bring gusty winds and periods of moderate to heavy rain to the West Coast, Western Interior, and Central Brooks Range. Snow is possible at higher elevations in the Brooks Range and at the highest points of the Interior with this system. Cool weather follows this system and continues into next week.

SHORT TERM /THROUGH SATURDAY/

At the start of the forecast period, Wednesday, broad troughing rests over much of Northern Alaska. A weak surface low with a great deal of vorticity wrapped into it moves east through the center of the trough. This is causing breezy and showery conditions to sweep across the Interior Wednesday. Some weak ridging over the Bering Sea allows for higher pressure to fill in behind the low.

Thursday sees another Bering Sea storm approach the West Coast. This one is a mess of several features. These include a larger low to the west of majority of impacts, an occluded front that connects this low to another, weaker, low farther east, and then a warm and cold front that rotate around this more eastern low. This messy system moves south of the Seward Peninsula from the Western Bering Sea towards Western Alaska late Thursday through Friday afternoon. Once over the mainland, it loses much of its remaining organization Friday. At the upper levels the lows lose their distinction and are absorbed into the broader trough pattern but a rapidly weakening surface low will direct a large amount of remaining moisture into the southern slopes of the Central Brooks Range. Rising snow levels will cause much of this precipitation to fall as rain, but some snow is possible above 3500 feet Friday morning. This could make conditions along the Dalton Highway near Atigun Pass worse Friday morning. At this broad area of low surface pressure pushes inland Friday, southerly winds increase through the Alaska Range Passes. These winds will be primarily caused by pressure gradient forcing due to higher pressure weakening more rapidly north of the Alaska Range.

As this system exits to the northeast Saturday, higher pressure once again attempts to build into the area from the high in the North Pacific. A strong upper level low then seeks to push south from the Arctic Ocean towards Northern Alaska which will quickly end the higher pressure trend.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

At the start of the extended forecast period, late Saturday, a strong and cold upper level low pushes southeast towards the region from north of Eastern Siberia. This low will have to push through the building ridge in the Bering Sea to reach the mainland. There is some uncertainty on how well it will be able to do this. It is currently more likely that the low will be strong enough to push through the higher pressure over the Bering and Interior and towards the Gulf of Alaska. Should this be the case we can expect a quick rush of colder temperatures, showers with snow at higher elevations, and some gusty west/northwesterly winds.

It is possible that the ridge will keep the low trapped farther north for a bit longer. This will keep cooler conditions more confined to the northwest portions of the state with greater snow accumulations possible in the Western Brooks Range. This is currently the less likely solution for the extended forecast period. This solution too sees the low eventually win out and so the extended forecast period is likely to end with broad troughing over the state leading to cool and showery weather.

Coastal Hazard Potential... No major concerns. The low approaching the West Coast Thursday does not have a track that supports any impactful water level rises. Water levels 1 to 2 feet above the normal high tide line are possible along the Norton Sound Coast with up to 4 feet above normal possible in the far eastern Norton Sound. There may be some minor beach erosion possible.

FIRE WEATHER

Cloudy, cool, and rainy weather continues to significantly limit any remaining favorable fire weather potential in Northern Alaska. Maximum temperatures are struggling to get above the mid 60s in even the warmest areas through the rest of August. Thursday will be relatively dry in the Interior, as showers from the previous system disperse just in time for another wet system to arrive in Southwest Alaska and spread across the state through the weekend.

Focusing on the upper Tanana Valley, gusty northwesterly winds are expected Wednesday and early Thursday afternoon. Light chinooking off the Alaska range may begin as early as late Thursday afternoon, which would bump RHs down into the mid 30% range on Thursday. Temperatures will be in the low 60s, preventing RHs from dropping much lower. Winds will strengthen and reach their peak on Friday, gusting over 50 mph through Windy and Isabel Pass, and around 20mph for other parts of the Valley. However, the arrival of the wetter air mass should work against chances for relative humidity below 40%. Rain will once again struggle to make its way into the upper Tanana Valley, even as the widespread rain reaches the Interior on Friday. Wetting rain will be possible, but not guaranteed Friday night into Saturday.

HYDROLOGY

Periods of moderate to heavy rainfall across the West Coast and Western Interior are expected to lead to some water level rises across rivers in those regions, but no flooding is expected.

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory from 1 AM to 10 PM AKDT Friday for AKZ849. MARINE...Small Craft Advisory from 7 AM to 6 PM AKDT Thursday for PKZ801-850-851. Gale Warning from 10 AM to 4 PM AKDT Thursday for PKZ801. Small Craft Advisory from 10 AM to 6 PM AKDT Thursday for PKZ802-816-817-853. Small Craft Advisory from 1 PM to 6 PM AKDT Thursday for PKZ803>806-852-854. Gale Warning from 4 PM to 6 PM AKDT Thursday for PKZ805.