textproduct: Fairbanks

SYNOPSIS

Broad scale troughing continues over the state today situated between low pressure systems over the Arctic Ocean and Gulf of Alaska. As high pressure builds over Siberia, two cold fronts, one today and one on Sunday, will move southward into the central interior bringing widespread showers and isolated thunderstorms. This afternoon has the highest likelihood of moderate showers for the Tanana Valley with some small hail. Winds ahead of and along the front will be gusty at times before shifting towards the south/southwest behind the front. By early next week, warmer and drier conditions are expected as high pressure over Siberia and Canada build further inland.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Widespread showers and isolated thunderstorms continue across the southern Interior this afternoon ahead of and along the front. Thunderstorm coverage decreases behind the front, with the highest chances for lightning in the Upper Tanana Valley and lower Kuskokwim Valley through the weekend.

- High temperatures will remain in the low 60s through the weekend with a warming trend into the low 70s expected by Tuesday. - Localized moderate rain showers are possible for the Upper Tanana Valley and Alaska Range primarily this afternoon. Lighter rain showers are expected for similar areas this weekend.

West Coast and Western Interior... - Scattered showers and isolated thunderstorms continue across the southern Interior and lower Kuskokwim Valley this afternoon as the front moves south. Showers and thunderstorm chances decrease through the weekend as high pressure builds in from the west.

- Low clouds and fog chances will continue through the weekend along the coast, moving over the area overnight and retreating during the day. Visibilities one mile and below are possible in fog.

- Temperatures will remain in the upper 50s to low 60s through the weekend before steadily increasing to around 70F in the valleys by Tuesday.

North Slope and Brooks Range... - Temperatures are expected to increase steadily through the weekend and into Monday, reaching the . Highs may reach the upper 60s along the southern slopes of the Brooks Range by Tuesday.

- Gusty north winds through the Brooks Range passes continue today with winds gusting up to 40 mph at times. Winds will shift towards the west/southwest behind the front on Sunday with gusts up to 40 mph.

- Low clouds and patchy fog continue this morning across the North Slope, with clearer skies expected this weekend into next week as winds weaken and offshore flow sets up along the coast.

FORECAST ANALYSIS AND DISCUSSION

Through Sunday: Broad scale troughing continues still over the state today situated between low pressure systems over the Arctic Ocean and the Gulf of Alaska. Both of these lows will gradually be pushed east as high pressure builds over Siberia this weekend. A cold front, currently over the Fairbanks area, following a northeast to southwest orientation. Showers have developed along the front; however, with constant overcast skies and little surface heating, not expecting any widespread thunder chances. There is the possibility of moderate showers embedded within the lighter showers. PW values are around 0.5 inches, near normal for this time of year, and with a mostly saturated profile and CAPE values of around 300 J/kg, rain rates between 0.15 - 0.25 in/hr are possible. Additionally, weak directing flow means that any storms that do develop along the very slow front moving southward have the potential to have fast accumulating totals. Highest probability for these moderate showers are along the north side of the Alaska Range from the Tanana Valley to the upper Kuskokwim Valley, with orographic helping initiate these storms. Saturday and Sunday look weaker compared to this afternoon, with increased drying from the 700 mb layer and above by Saturday afternoon. Behind the front, north/northeast winds through the Brooks Range gradually weaken and shift towards the west/southwest by Sunday. As the pressure gradient over the state tightens on Sunday, expect southerly winds gusting up to 30 to 40 mph possible through the Alaska Range passes and across higher terrain of the Interior, with drying winds.

For the west coast, high pressure building in the Bering Sea looks to bring clearing skies and fog chances over the water and coastal areas. Fog and low stratus could move as far as Pilot Station on the YK Delta, with visibilities as low as a half mile. It is possible to have some longer lasting clearing on Sunday, as vorticity advection moving over the area may scour out clouds. Otherwise, very little precipitation is expected

FIRE WEATHER

Showers with isolated thunderstorms continue for the Interior, but should remain south of the Yukon Flats and Ray Mountains this afternoon. As an upper-level low weakens in the Gulf of Alaska, coverage for showers and thunderstorms decreases, ending in the most Southern parts of the Interior and along the Alaska Range by Saturday and Sunday. Along with the showers, temperatures and relative humidities will remain fairly moderate across the Interior and West Coast as broad scale troughing persists through Saturday. Temperatures should peak in the high 50s/low 60s and RHs should only get as low as the 30s with a slight exception; a surface high that skirts the Eastern Arctic Coast will produce northerly winds across the Brooks Range until early Saturday morning. Downslope winds will help to dry out the Northern Interior enough to see RHs in the mid 20s on Saturday. In addition to the lower RHs, winds will be gusty, particularly in the higher terrain of the Northern Interior through Saturday morning.

On Sunday, a ridge will start to start to extend over Northern Alaska. As high pressure builds at the surface, southerly winds through the Alaska Range look to briefly swell Sunday night but they don't appear strong or long lasting enough to have significant fire weather impact. Southwesterly winds will strengthen across the Interior as well Sunday afternoon. The strongest gusts look to be around 30 mph in the Dalton Highway and White Mountain summits, but most other areas will likely see occasional gusts up to 20 mph. Monday, winds will turn more westerly and have similar strength to Sunday. The ridge settles over Alaska through the middle of next week, keeping chances for precipitation low and allowing daytime high temperatures in Interior valleys to reach the mid 70s Tuesday an possibly upper 70s Wednesday. Where there are clear skies and warmer temperatures, minimum relative humidities should be in the 20s.

HYDROLOGY

Sagavanirktok River: Some overflowing is occurring; however, breakup along the Sag River has not begun yet. High temperatures are expected to increase to around the mid to upper 30s Monday and Tuesday before dropping below normal going into the late week. Near the Sag River source on the north Brook Range, high temperatures could reach the mid 50s by Monday and Tuesday, with snow levels reaching upwards of 4000 ft. Again, temperatures look to moderate going into the late week but continue to be above freezing.

Yukon River: River Watch has concluded as of 8 AM Wednesday. Ice continues to move through the channels into the mouth with relative ease and with upstream ice moving unhindered. Residents should still use caution near the banks as the ice run continues to be very dynamic and water levels can fluctuate quickly.

All Flood Watches and Warnings have expired.

Additional Information: Visit www.weather.gov/aprfc for the latest hydro information.

EXTENDED FORECAST DAYS 4-7

Monday through late week. Monday sees the Siberian ridge dominate most of Alaska, with building high pressure, warming temperatures, reducing wind speeds, and reducing precipitation chances across the area. The bigger story for the extended is how fast this ridge will break down. At this time, there are two camps. The first being an arctic trough moving down into the central interior; however, for this solutions, there is high uncertainty how far south this trough will dig. Current progs indicate anywhere between the northern and central interior before moving into Canada. Likelihood for this solution is around 70% and would moderate much of our above normal temperatures currently expected early next week. The less likely solution at around 30% sees the the ridge hold on, which would result in much warmer temperatures, even north of the Brooks Range.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. PK...None.