textproduct: Fairbanks

SYNOPSIS

Thunderstorms are expected today in the same spots as yesterday with an emphasis on the Central and Eastern Brooks Range where numerous thunderstorms are expected. Red Flag Warnings are in effect from the Upper Kobuk/Lower Koyukuk to the Upper Koyukuk Valley. The western most warnings are in effect for hot/dry/windy conditions while the easternmost warning is for scattered thunderstorms. These are in effect through tonight. Otherwise, thunderstorm coverage expands east tomorrow, then will be centered over the Central/Eastern Interior on Saturday. Heavy rain is becoming more likely Saturday night through Sunday across much of the Interior.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Isolated storms over the Fortymile Country this afternoon/evening as well as north and west of Manley Hot Springs. Red Flag Warning in effect for the Upper Koyukuk.

- Temperatures will be warm today, getting into the low to mid 70s across the Interior. Mid 70s to low 80s are expected tomorrow with isolated thunderstorms.

- Isolated to scattered storms expected on Saturday with temps cooling to the low 70s.

- Sunday is looking like a raw day with highs in the low 60s and periods of rain, heavy at times possible.

West Coast and Western Interior... - Red Flag Warnings in effect for the Upper Kobuk/Lower Koyukuk for hot/dry/windy conditions through 10PM Thursday night.

- Isolated to scattered thunderstorms expected from the Nulato Hills and eastern Seward Peninsula to Ruby, thunderstorms will be around the Nulato Hills tomorrow but largely shift east.

- A cooling trend arrives this weekend with a fall-like feel expected as highs remain in the 50s and 60s by Sunday. Heavy rain is possible towards the western AK Range on Sunday, this may spread into the Kuskokwim Valley and will be monitored.

North Slope and Brooks Range.. - Quiet weather on the North Slope but numerous thunderstorms are expected in the Central/Eastern Brooks Range today, then isolated storms on Friday.

- Temperatures are warm today, but a cold front arrives later this afternoon/evening bringing a chance for rain showers along the Coast as well as much colder temperatures Friday through Sunday.

- Winds will be breezy behind the front with gusts up to 25 mph from the northwest tonight through Friday morning. Winds then turn northeast and around 5 to 15 mph with higher gusts making it feel quite chilly for late June.

- Expect highs in the low to mid 30s along the Western Arctic Coast, upper 30s/low 40s east, and 50s/60s in the Brooks Range.

FORECAST ANALYSIS AND DISCUSSION

Aloft we have a 549 decameter low in the eastern Gulf of Alaska, a 537 decameter low in the Central Bering, and a 518 decameter low in the Arctic at about 80N. In the middle of all of this is a 562 decameter high over the Western Interior which has a stalled front on the east side of it.

A stationary front remains draped over Northern Alaska from Kaktovik to Holy Cross. Along and west of this front will be isolated to scattered thunderstorms. The exceptions will be the Central/Eastern Brooks Range where numerous storms are expected today. The front will continue to degrade tomorrow allowing for less thunderstorm activity in the Western Interior, but isolated storms remain probable.

The lows in the Bering and Gulf will play a major factor in our weather this weekend. A potent piece of energy will detach from the main low in the Gulf and remain wrapped up near Yakutat/Cordova while a front from the Bering Sea low pushes east, then eventually north. These two features will phase on Saturday and with a high over the Northern Pacific as well as Western Canada, it allows a path straight into Northern Alaska. There will be an abundance of moisture with as this energy moves over the Interior leading to areas of heavy rain from Saturday night through at least Sunday afternoon. There is still uncertainty with the exact placement of the heavy rain, but the probabilities for >1" of rain are starting to exceed 30% to 50% over much of the Interior and Alaska Range. It's not a lock, but becoming more and more likely that another big rain event hits the Interior.

Otherwise, as this is occurring, the Western Interior will be seeing increased chances for rain showers and much cooler temperatures. The Northwest Interior and Arctic looks fairly dry through most of the weekend but as the front continues to trek north on Sunday, there will be higher chances for showers near the active fires. The rain looks to get towards the Brooks Range Sunday or early next week but most of the North Slope remains dry and chilly.

FIRE WEATHER

Red Flag Warnings are in effect through 10 PM in the Upper Kobuk and Lower Koyukuk Valleys for hot/dry/windy conditions. There is a Red Flag Warning in the Upper Koyukuk Valley for lightning and that is out through 12 AM Friday morning. Otherwise, the bulk of the thunderstorm activity on Thursday will be in the Central/Eastern Brooks Range with isolated to scattered thunderstorms expected from the Nulato Hills east/north and isolated storms in Fortymile Country.

Moving into tomorrow, isolated thunderstorms remain over the Western Interior with scattered storms from McGrath to Grayling. There will also be an area of scattered over the AlCan Border. Storms continue to pivot east on Saturday with isolated to scattered storms over the Central and Eastern Interior. After this, moderate to heavy rain is becoming more likely Saturday night into Sunday for nearly all of the Central and Eastern Interior.

Temperatures will be warmest tomorrow as highs get into the mid to upper 70s and low 80s across the Interior. Given the saturated atmosphere, lowest min RHs will only dip into the mid 30s in the Yukon Flats and Middle Tanana Valley, though a few spotty 25-30% readings are possible in the Koyukuk/Kobuk Valleys. Saturday will come with temperatures in the 70s, warmest in the Northern Interior. Then the bottom drops out everywhere across the Interior on Sunday as highs only reach the 60s with rain in C/E Interior. The driest portion of the Interior will be the Kobuk Valley where there may only be a few showers and no guarantee for wetting rain. However, min RHs will be higher, in the 40s and maybe low 50s.

HYDROLOGY

A long-duration period of moderate rain is anticipated to start on Saturday evening and continue through Monday. This could impact a large portion of the Interior with a particular focus near Denali National Park.

Return intervals indicate this as a 1 in 5 year to a 1 in 10 year event. We are continuing to monitor and will provide updates on the evolution of this system.

Those recreating on or near rivers should expect water level increases late in the weekend and into early next week. For more specifics visit: weather.gov/afg/?story=5

EXTENDED FORECAST DAYS 4-7

Monday through Thursday.

The pattern next week will be dominated by a slow-moving upper level low tracking from the Bering Sea to the Gulf before gradually shifting east into Canada by late week. This will keep a generally unsettled pattern in place with periodic rounds of precipitation moving across the Interior. On Monday, we see a cold front associated with this system begin to lift north across the Interior through the Brooks Range bringing a band of widespread precipitation. Additional showers are then expected to wrap around the slow-moving low throughout the week, with another Bering Sea system bringing renewed precipitation into Western Alaska by midweek. High pressure remains anchored over the Gulf of Alaska while strengthening over the Arctic later in the week, helping push the departing low eastward.

Confidence is moderate in the overall pattern, but lower in the timing and placement of individual rounds of precipitation as small- scale disturbances rotate through the broad trough. These details will determine where areas of heaviest rainfall occur from day to day.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Red Flag Warning for AKZ919-928. Red Flag Warning for AKZ931. PK...Small Craft Advisory for PKZ806.