textproduct: Fairbanks

SYNOPSIS

A warming trend continues today over most of Northern Alaska with highs reaching near/above normal. Scattered showers and isolated storms are expected from the Western AK Range to Tanana with a slight chance for a storm near Bettles. Otherwise, a much larger thunderstorm day is expected on Friday with the possibility that it's the most active lightning day of the year so far. This weekend, we will begin to see a pattern change as chinook flow brings strong winds through the Alaska Range Passes. Fire weather concerns exist in Isabel Pass and Delta Junction Saturday and Sunday afternoon. The pattern does become a bit more wet, especially away from the Southern Interior as an abundant amount of moisture moves in from the Gulf of Alaska.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Warm and dry conditions today with showers with isolated storms, especially in the Alaska Range and near Tanana/Bettles.

- More abundant storms tomorrow across the area. Any storm can come with small hail, gusty wind, lightning and heavy rain.

- Near Red Flag conditions in the Yukon Flats this afternoon through Friday afternoon. A Fire Weather Watch for this weekend in Delta and Isabel Pass.

West Coast and Western Interior... - Warm and dry with scattered showers and isolated storms, mainly near or just east of McGrath, towards the Western AK Range and points north today and tomorrow. - A few of these thunderstorms could produce small hail, gusty winds, and frequent lightning.

- Gusty southwest winds up to 45 mph from the Bering Strait northward today will weaken tomorrow.

- Warm again on Saturday with the warmest temperatures of the year likely in many spots. Expect low to mid 70s in the Interior with 50s and 60s along the coast.

- More widespread showers arrive in the Interior Sunday afternoon as a front moves in from the southeast.

North Slope and Brooks Range.. - Warm weather today with highs near or above seasonal norms. A weak front moves through tomorrow, cooling temperatures by a few degrees, otherwise, expect mild temps to continue in the Brooks Range and Arctic Plain through the weekend with near average temperatures along the coast.

- Isolated to scattered showers will be possible in the Brooks Range today and Friday. On Friday a couple of thunderstorms are possible in the Eastern Brooks Range from Atigun Pass to the AlCan border.

FORECAST ANALYSIS AND DISCUSSION

The main story will be thunderstorms today and tomorrow as a front crosses Northern Alaska from west to east. Otherwise, the pattern flips giving us chinook flow this weekend with the potential for moderate rain for portions of the Interior and Brooks Range next week.

Looking aloft at 500mb, there is predominantly west/southwest flow across Northern Alaska today. This is coming from a shortwave trough over the Chukotsk Peninsula, a 566 decameter high over St. Paul Island and a 567 decameter high over Western Canada. As we progress through tomorrow, the highs remain nearly stationary, but the shortwave trough moves over the Interior and Brooks Range. This will spark scattered to widespread thunderstorms over the Central/Eastern Interior. Current models and model soundings are showing several signs that these thunderstorms may be relatively strong. These factors include mid level dry air, steep low to mid level lapse rates at 8C-10C/km, nearly 500 J/Kg of CAPE and a shortwave trough to provide lift. Ideally for strong thunderstorms we would need more CAPE, a more saturated surface and taller swath of steep lapse rates. However, this atmosphere is capable of producing hail around 1/2" or less, and strong outflow wind gusts. If any storms can become organized along the trough, there can be 3/4" hail, but any larger than that is not supported.

Nonetheless, the trough continues to drift north and east, out of Alaska by Saturday afternoon. Mostly dry conditions are left in its wake on Saturday. As this happens, a 537 decameter low will move northward over the Alaska Peninsula. For the most part, the wind and rain will stay south of the Western Interior until Sunday, but a few showers are possible from Hooper Bay to Galena. On Sunday the main push of moisture from this low arrives in the Interior with showers blossoming during the afternoon. The bulk of the showers will be in the Northern/Eastern Interior, southern AK Range, and Brooks Range while the Southern Interior gets chinook flow. Rain showers will continue in these locations through early next week with the heaviest being in the Brooks Range. In the Southern Interior, given the chinook flow, south wind gusts will increase to around 45 mph in Isabel/Windy Pass. Min RHs will be as low as 15% to 20% Saturday afternoon in Isabel Pass and Delta Junction resulting in possible Red Flag conditions. After the initial front passes through Saturday evening, there will be a lull in the winds Saturday night before a ramp up again on Sunday. These winds look stronger, potentially up to 60 mph. There is an abundance of moisture moving from south to north which will try to push through the AK Range Passes, so higher RHs are possible on Sunday resulting in near Red Flag conditions again. Elsewhere, there aren't major concerns for fire weather and with the increase in moisture moving into Northern Alaska, this should keep the fire season at bay for now. The rain for early next week will be spoken about more in the extended discussion.

FIRE WEATHER

Near Red Flag conditions in the Yukon Flats this afternoon and tomorrow afternoon. Temperatures will be in the low 70s with southwest wind gusts around 15 to 20 mph and min RHs as low as 15% to 20%. The other area of concern is Isabel Pass and Delta Junction Saturday and Sunday afternoons. Southerly chinook winds increase to 45 mph Saturday afternoon and 60 mph Sunday afternoon. RHs will be as low as 15 to 20% Saturday afternoon and 30% Sunday afternoon. A Red Flag Warning may be warranted for Saturday and potentially Sunday. The Western Interior will have dry and warm conditions with isolated showers and thunderstorms, mainly near the Western AK Range and north to Tanana and potentially Bettles. The Central and Eastern Interior will have more robust thunderstorm activity on Friday as a shortwave moves across the area from the afternoon through the night. Most of the area is covered by isolated to scattered thunderstorms with widespread storms expected from the White Mountains to Eagle/Chicken. This may end up being the largest lightning day of the year so far. Moving into Sunday afternoon and early next week, a wetter pattern is expected but with chinook flow, the southern Interior may remain predominantly dry while most other spots receive rain, potentially heavy wetting rain from the Eastern Interior to the Brooks Range as well as the Western Interior.

HYDROLOGY

No updates since the previous discussion. Unless there is a significant change, the next update for the rivers will come on Friday 6/12/26.

Satellite imagery indicates the Sag River has broken up close to the mouth with no updates on the Kuparuk given the lack of clear satellite imagery. The Colville has broken up near Nuiqsut and potentially farther downstream but there are 2 ice jams at Horseshoe Bend and Ocean Point. Even with the ice jams, water has remained relatively low.

Heading into the end of the week/weekend, we'll see temperatures rise into the 50s/60s in the Brooks Range and 40s/50s on the North Slope. Low temperatures will be above freezing with the Brooks Range only dropping into the 40s while the North Slope remains in the 30s. The increase in temperatures along with the recent snowfall may result in rapid river rises by this weekend but there is high uncertainty in any potential flooding impacts. On top of this, we are also monitoring the potential for heavy rain in the Brooks Range from Sunday night through Tuesday. There is a potential for over 1 inch of rain across a wide area.

EXTENDED FORECAST DAYS 4-7

Next week, the overall pattern is expected to transition toward increasing ridging across mainland Alaska as a weakening low pressure system near the Aleutians interacts with an Arctic low tracking across the northwest Arctic coast. Moisture wrapping around the departing low and periodic disturbances moving through the flow will maintain unsettled conditions through Tuesday with the greatest shower coverage focused across the Northern and Eastern Interior, Brooks Range, and portions of the North Slope. Recent guidance has trended wetter across portions of the Eastern Interior, however considerable uncertainty remains regarding how far the deeper moisture spreads and where the heaviest rainfall ultimately develops. Thunderstorm potential appears limited due to widespread cloud cover and modest instability, though an isolated storm near the Alcan border cannot be ruled out.

By midweek, strengthening high pressure building in the Bering Sea and western Canada is expected to become the dominant weather feature across much of the state. This should promote a gradual drying trend, decreasing shower coverage, and more stable conditions across the state. However, lingering moisture and weak disturbances may continue to support scattered showers across portions of the YK Delta, Brooks Range, and North Slope. Model guidance remains in good agreement regarding the development of the ridge, resulting in moderate confidence in the overall trend towards drier weather. Uncertainty remains in the strength and placement of the ridge axis and any embedded shortwaves moving around it, which will ultimately determine how quickly precipitation diminishes and whether isolated thunderstorms can redevelop over higher terrain later in the week.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Fire Weather Watch for AKZ937. PK...Small Craft Advisory for PKZ804. Small Craft Advisory for PKZ806. Brisk Wind Advisory for PKZ807. Small Craft Advisory for PKZ811. Small Craft Advisory for PKZ812. Small Craft Advisory for PKZ817. Small Craft Advisory for PKZ854. Small Craft Advisory for PKZ856.