textproduct: Fairbanks

SYNOPSIS

The weather will finally resemble the middle of June. Temperatures will continue to warm today across Northern Alaska with 60s/70s in the Interior Valleys, and 30s/40s on the coastline. These warming temperatures will bring us increasing thunderstorm potential this afternoon and Friday afternoon. Friday has the potential to be much more active in thunderstorm development. Sunday a low in the Gulf will bring us increasing cloud cover, cooler temperatures, and potentially moderate to heavy rainfall through early next week.

KEY WEATHER MESSAGES

Central and Eastern Interior... - A warming trend with highs in the 60s to near 70 this afternoon, then increasing into the low to upper 70s by Saturday. Saturday could be the first day we see 80 degrees in the Eastern Interior. Relative humidity will be as low as 20-25%. Warmest and driest spots will be in the valleys. - Isolated thunderstorms are possible today along the Alaska Range. Friday will be a bigger thunderstorm day, with scattered thunderstorms possible for much of the Eastern Interior, from the Alaska Range to the Brooks Range. - On Friday these thunderstorms could produce small hail, gusty winds, and frequent lightning.

- Southerly gap winds in the Alaska Range will begin to strengthen on Saturday with gusts up to 35 mph. They will continue on Sunday, and will strengthen to around 50 to 60 mph.

West Coast and Western Interior... - Temperatures will continue to rise across the Region through the weekend with 70s in the Interior and 50s/60s along the coastline.

- Gusty southwesterly winds up to 45 mph will continue today through the Bering Strait. These winds will slowly weaken throughout the day tomorrow.

- An isolated shower is possible today on the western portions of the Seward Peninsula, and western slopes of the Brooks Range.

- Isolated thunderstorms are possible this afternoon in the Upper Kuskokwim Valley. Another round of thunderstorms are possible tomorrow afternoon in the same region. - On Friday these thunderstorms could produce small hail, gusty winds, and frequent lightning.

North Slope and Brooks Range.. - Warming temperatures will continue across the region today with highs in the 50s/60s on the Arctic Plain and 40s along the coast. A brief cooldown will occur Friday/Saturday as a very weak front moves through the region.

- Isolated to scattered showers will be possible in the Brooks Range Thursday and Friday. On Friday one or two thunderstorms are possible in the Eastern Brooks Range from Atigun Pass to the AlCan border.

FORECAST ANALYSIS AND DISCUSSION

Thursday through Sunday Night. High pressure is building at the surface and at the upper levels. This high pressure will be our mainstay feature in Northern Alaska, until we get a low approach from the Gulf on Sunday. As the upper level ridge builds in over the Bering Sea and Western Canada, we will begin to see warmer 850 mb temperatures being brought into the area. These 850 mb temperatures will help to fuel the widespread warm-ups across Northern Alaska. Our warmest day in the Interior will be Saturday. 850 mb temperatures will be approaching 8C. This would help to support upper 70s and even 80 degrees in the Interior Valleys. Cloud cover could put a hamper on these temperatures and not allow for the surface to warm as much, regardless temperatures will well be in the 70s, and will be a nice summer day.

With temperatures in the 60s and 70s, we still need some upper level support to get thunderstorm initiation. That will be found with a shortwave feature currently moving east across Far Eastern Siberia. Ahead of this feature, there is a very weak shortwave that will move through the Interior this afternoon. The timing of the feature will put it over the Central Interior during peak heating, and with it being a weak shortwave, only isolated thunderstorms are anticipated. Friday however will be a much more active day. The main upper level shortwave will be moving through the Central and Eastern Interior during peak heating on Friday. Scattered thunderstorms are expected on Friday as there will be ample synoptic forcing as well as thermodynamic forcing.

Model soundings are showing good potential to see gusty winds, small hail, and frequent lightning with the thunderstorms on Friday. Looking at a sounding we have nearly 500 J/kg of Cape, a dry adiabat layer to around 800 mb, and some moisture in the Dendritic Growth Zone. While 500 J/kg of CAPE isn't impressive for most areas, it is perfectly capable to produce thunderstorms due to our terrain influences. The dry adiabat layer will not only mix winds aloft down to the surface, any precipitation thats falls into the dry layer it occupies will see gusty winds from evaporative cooling. The moisture in the DGZ and 500 J/kg of CAPE will help to establish hail cores on longer lived storms, allowing for the formation of 1/2" to 3/4" hailstones.

Looking towards the weekend a low will be moving into the northern Gulf, and will bring a series of shortwaves into the Interior. These shortwaves will be filled with nearly an inch of precipitable water (PWAT). For context an inch of PWAT is nearly a record for Fairbanks for June 14th. Model confidence will be discussed in more detail in the Extended Forecast Discussion, as this will be a multi-day storm.

FIRE WEATHER

A warming and drying trend continues over the state today as high pressure continues to build in from the Bering Sea and Western Canada. High temperatures will rise into the low to mid 70s through the rest of the week, with Saturday expected to be the warmest day so far this summer. Afternoon temperatures may reach as high as 80F possible this weekend in the Yukon Flats and Interior Valleys. Min RHs will continue to remain low with values bottoming out this afternoon to around 20-25% in the Yukon Flats, with the rest of the Interior seeing min RHs below 35% through the weekend. Scattered showers and isolated thunderstorms may develop this afternoon across portions of the Western Interior and Alaska Range as a frontal system moves east, with localized wetting rains possible. Going into Friday, scattered showers and thunderstorms are likely across much of the Interior from the Lower Kuskokwim Valley north towards the Central/Eastern Brooks Range. These storms may produce periods of frequent lightning, small hail, and gusty winds at times. Wetting rains are likely through Saturday afternoon.

Southwest winds persist through the week with periods of gusty winds possible across the Seward Peninsula this afternoon. Winds begin to shift Friday into Saturday as a low in the Gulf of Alaska moves farther north. As the low moves closer inland, winds shift towards the northeast across the Western Interior and towards the south/southeast across the Central/Eastern Interior. Winds gusting up to 45 mph are possible through Isabel Pass and near Delta Junction Saturday afternoon, creating near critical fire weather conditions. By next week, upper level southeast flow will allow for increased moisture and precipitation chances across much of Northern Alaska, in addition to continued warm summer-like temperatures.

HYDROLOGY

No updates since the previous discussion. Unless there is a significant change, the next update 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, 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 later this week with the Brooks Range only dropping into the 40s while the North Slope remains in the mid 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.

EXTENDED FORECAST DAYS 4-7

For Monday through Thursday Model guidance continues to be in good agreement on the overall pattern, with a vertically stacked low near the Aleutians becoming more of an open wave trough by mid week, individual disturbances moving along the southerly flow will ultimately determine which areas will receive the most rainfall. Regardless of the solution, guidance is tending towards the central, eastern, and parts of the northern interior for the highest likelihood for heavier rain rates Monday and Tuesday. The Yukon Flats area continue to be highlighted, as a possible area for moderate to heavy rain. While most of the interior is expected to have at least 0.8 in PWAT, with around 70- 80% confidence, the Yukon Flats area is slowly gaining more confidence for greater than 1 inch, currently around 40% chance of exceedence. While this does not directly translate into rainfall, certainly this is unusual for this time of year.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. 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.