textproduct: Fairbanks

SYNOPSIS

Rain continues to be the big story across much of the northern AK through the holiday weekend as an active pattern sends system after system into the Interior, with the forecast kicking off with an atmospheric river continuing to move through Alaska on Saturday and periods of moderate to heavy rain expected as a result. While a brief lull in the widespread rain is possible on Sunday in the wake of one system, another system will swiftly move to replace it on Monday, followed by still another low which arrives Tuesday. Another brief break is possible for parts of Wednesday and Thursday, before a front sweeps in from the Bering on Friday.

KEY MESSAGES

Central and Eastern Interior...

- Widespread light through the first part of the day Saturday as a combination of a lingering atmospheric river and approaching upper disturbance track north through much of the Interior.

- Additional rainfall of 0.25 to as much as 1.00 inch will be possible through Saturday, when the heaviest rainfall begins to taper off.

- Series of systems continue to move through during the rest of the week, bringing rounds of rain to northern Alaska.

- Main stem rivers are expected to see noticeable rises over the next few days, but flooding is not expected to be an issue. However feeder streams and rivers could see water levels nearing bankfull in a few locations.

- A few showers possible over the forty mile country area, but overall drier weather persists for this portion of the Interior.

- Warmer conditions are expected to return for the Sunday and Monday timeframe with highs back in the upper 50's and lower 60's, even a bit warmer in locations not impacted by rainfall.

Central and Eastern Interior...

- Occasional showers will continue to track across the region over the next few days, but total additional rainfall will remain rather light.

- Higher water levels are expected once again throughout the Norton Sound through high tide Saturday morning. Afterwards more normal tide cycles are expected through the region for a few days.

- Past Saturday, periods of light rain interspersed with periods of drier weather expected through the upcoming week as multiple systems move up from the SW.

- Warmer than normal temperatures will continue across the region through the weekend with highs generally in the 50's to near 60 further inland.

North Slope and Brooks Range...

- Bands of precipitation will continue to push north over the Brooks Range through Sunday. Most precipitation will be light and predominantly in the form of rain.

- Snowfall through the weekend will be confined to elevations generally above 5500 feet with the possibility of mixed rain and snow at times near the Dalton through Atigun Pass.

- Low clouds and occasional showers will occur near the Arctic coastline through Saturday. However temperatures will be warming a bit above seasonal normals with readings in the 40's and 50's throughout much of the North Slope.

SHORT TERM /THROUGH MONDAY NIGHT/

The active weather pattern which has brought widespread periods of rain along with high surf to parts of the western Coast looks set to continue through the duration of the forecast time frame.

Radar and satellite imagery show that the initial atmospheric river has begun to slowly move E as the ridge over the Gulf of AK which had been blocking it is displaced. What's left of the plume of moisture over the interior will be cut off through the day on Saturday, as an already forming low over the Wood Hill Mountains moves NE through the day. Expect generally stratiform rain for most areas south of the Brooks Range with this system, although a few thunderstorms may be possible for upland parts of the forty mile country. Upwards of another additional 0.25 to 1.00 inch of rain will likely fall with this final surge from the atmospheric river before it heads past the Brooks Range by late Saturday with much of the remaining moisture being wrung out by the topography.

Sunday will feature a lull in the most active part of the pattern. Between the departing low exiting into the Arctic Ocean, and another low beginning to enter the Kuskokwim Delta area, the remainder of Northern AK will see precip relegated to scattered showers - with some areas liable to see some dry weather in a brief but welcome respite. Anticipate some fog development Sunday night into Monday morning with this brief lull, especially anywhere that skies attempt to clear. This respite will come to an end as said new low moves up to the NE from the Kuskokwim Delta. The newest low itself looks fairly disorganized - a symptom of the fact that its one of multiple low level circulations vying for dynamic support along a week trough axis stretching from the Gulf of Anadyr to the Gulf of Alaska. Consequently, it is likely that the low will have some difficulty holding together as it crosses the Alaska Range. Nevertheless, do anticipate a reasonable slug of moisture with this next system, and so even as the low itself falls apart, think that chances of periods of rain for the Brooks Range southward remain fairly high.

Temperatures through the short term will be on an overall upward trend, as each low brings with a surge of warm air advection -and without any significant cold air advection being rapped in along these systems NW flanks, expect that the marine airmass will manage to anchor itself across most of the Interior as even the North Slope will see some level of temperature recovery. Lows will remain solidly above freezing for everywhere except for areas of significant elevation as snow levels rise to 3-6k feet, with 4k+ ft for areas south of the North Slope.

LONG TERM /TUESDAY THROUGH THURSDAY/

The very active pattern continues, as the storm track continues to favor steering systems into Northern AK rather than the more commonplace Anchorage or SE AK tracks which are common around this time of year. Another system takes shape on Tuesday, as a deepening shortwave becomes a fully developed system and races up into our area. The low - between 995 and 1000 mb, is likely to make landfall somewhere in the Kuskokwim Delta Area before moving NE. Expect any chances of high surf to be mainly relegated to areas further South, towards locations like Bethel.

Chances of rain persist even after this, with the next brief lull in the active pattern arriving through Wednesday, as a weak ridge builds in the wake of the system ahead of yet another low and its accompanying front which are set to arrive between late Thursday and Friday. Ensembles indicate elevated IVT values with this late week system consistent with a plume of moisture, and think that another wet and rainy weekend is possible, although at this time, confidence in timing or in precip totals remains low.

Coastal Hazard Potential... High Surf Advisories will remain in effect for portions of the Norton Sound through Saturday morning for elevated water levels of 2 to 4 feet around the time of high tide. In general winds across much of the west coast have diminished, but there remain a large fetch of water being transported towards the Norton Sound. Highest levels will likely be near Golovin and Elim. A return to more normal tide levels is expected later in the weekend.

FIRE WEATHER

An active and increasingly wet pattern will continue across Northern Alaska through the weekend. An atmospheric river will continue to bring periods of rain to much of the Interior today into Saturday, followed by continued troughing across the Western portion of the state, bringing additional opportunities for precipitation through the week. Fairbanks NSB and west are expected to be the primary recipients of the most consistent precipitation, however areas East are expected to see some scattered showers as continued shortwave disturbances wrap around the ridge axis that remains over the southeast.

Across the Eastern Interior, the Upper Tanana Valley will remain the area of greatest concern. Warmer temperatures and relatively lower humidities keep areas east of Tanacross with RHs in the upper 30s make the Upper Tanana Valley an outlier amidst the widespread precip the rest of the interior is experiencing. However, a shortwave disturbance is expected to make its way up and over the ridge axis Saturday morning bringing chances for isolated showers through the first half of the day. Thunderstorms may develop in the afternoon as another shortwave reaches the area during peak heating. Thunderstorms are expected to remain mostly confined to the higher elevations of Fortymile Country, and will bring localized heavy rainfall and gusty outflow winds. Drier conditions then prevail through early next week, with a few scattered showers possible as lows pass to the West.

Winds are generally expected to remain light across most of the state, with the strongest winds expected along the West Coast and through the Alaska Range passes. Strong gusts through the passes bring potential for Delta Junction to see gusts up to 30 mph on Monday night into Tuesday morning, however a potential round of precip late Monday into Tuesday could raise minimum RHs to the upper 50s to low 60s helping mitigate potential wind driven fire risk.

Temperatures remain moderate, with the highest temperatures expected to in the low 70s in the Upper Tanana on Saturday before cooling back into the 60s through the week. Cloud cover is expected to continue across the state, keeping temperatures moderated into the week.

HYDROLOGY

A strong push of moisture from the West Coast to the Central Interior will wind down past Saturday. Rainfall totals through Saturday of 1 to 2 inches are expected between the Yukon Flats, Bettles, and McGrath with locally higher amounts in the Upper Kuskokwim Valley especially. Expect fairly decent rises in local streams and rivers with sandbars potentially covered, but there are no immediate concerns for the main stem rivers in the area. Average return intervals of 2 to 5 years have ben observed at some sites, and expect ARIs of 2 to 5 years to remain possible throughout much of the Central and Western Interior through the weekend. While heavier rainfall has fallen in the Chena Basin than previously forecast, river rises should still remain within banks. While rain continues through next week, anticipate that after Saturday the day to day totals will drop significantly across northern AK.

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Surf Advisory until 11 AM AKDT this morning for AKZ822- 824. MARINE...Small Craft Advisory until 1 PM AKDT this afternoon for PKZ812- 813-858. Brisk Wind Advisory until 7 PM AKDT this evening for PKZ814- 815. Small Craft Advisory until 7 PM AKDT this evening for PKZ814- 815-860. Small Craft Advisory until 7 AM AKDT this morning for PKZ857. Brisk Wind Advisory from 10 AM this morning to 4 PM AKDT this afternoon for PKZ860. Brisk Wind Advisory until 7 PM AKDT this evening for PKZ861. Small Craft Advisory until 7 PM AKDT this evening for PKZ861.