Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
141 FXAK69 PAFG 032124 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 124 PM AKDT Mon Jun 3 2024 .SYNOPSIS... An active pattern persists today with a couple of new stories. A Red Flag Warning has been issued for the Yukon Delta beginning at 2 PM this afternoon for warm, dry and windy conditions. Easterly waves will continue to move through the Interior with scattered showers and thunderstorms this week. Wednesday is looking like one of the largest lightning days of the year in the Interior with widespread wetting rains possible as well. The West Coast will be chilly and windy today with isolated snow showers possible from the NW Arctic Coast to St. Lawrence Island. The strongest winds will be near Kivalina where there is a High Wind Warning through noon tomorrow. Along the North Slope and Brooks Range, expect areas of light snow, as well as some freezing drizzle and light freezing rain tonight. && .DISCUSSION... Upper Level Analysis... A 529 decameter upper low is dropping south over the Seward Peninsula providing northerly flow over the coast and east/southeast flow for much of the rest of the state. The main driver for the Interior weather has been a low in the Gulf of Alaska providing easterly flow with several shortwaves. This will continue and we currently have one of those waves located in the SE Interior. This will push northwest through the Central Interior this afternoon and evening. Tomorrow the main 500mb shortwave has lagged behind a little bit, but there is plenty of 700mb vorticity that will push through the Central and Eastern Interior with scattered showers and storms. Wednesday afternoon currently has the strongest shortwave moving across the state with numerous vorticity maximums and plenty of upper level support for storms. Surface Analysis... A strong thermal trough is in place over the Interior with a high over the Chukchi creating a strong pressure gradient over the West Coast resulting in very strong wind. A surface convergence zone remains in place from Anaktuvuk Pass to Bethel. Showers and storms will develop along that line today. Light snow and potentially freezing drizzle or freezing rain will continue at times along the North Slope. Then, there is a quick cut-off where Red Flag conditions are likely in and around Fort Yukon. Otherwise, partly to mostly cloudy skies prevail in the Interior with showers and storms developing this afternoon as a shortwave moves through. Central and Eastern Interior.. Showers and storms will be the game today for most of the Interior. The one exception will be around Fort Yukon where warm, dry and windy conditions are expected today and tomorrow during the day. Overnight, red flag conditions end as temperatures and winds drop as well as relative humidity rises. Otherwise cloudy skies may limit some convection today but some clearing is developing from Dry Creek east which will assist convective initiation. Tomorrow will be a "rinse and repeat" type of day with comparable temperatures and afternoon showers/storms. Wednesday looks like it could be one of the largest days for thunderstorms in the Interior so far. Some guidance is beginning to show Mixed Layer CAPE values near 500-1000 J/kg with a strong shortwave which would promote scattered to numerous thunderstorms. Luckily, these storms look to be wet and come with wetting rains for much of the Interior. Some spots may see as much as 0.50-1.00" of rain, especially in the most persistent thunderstorms. This still remains a couple of days out so things can change, but the potential for widespread thunderstorms in the Interior is there. Thursday looks to clear out a bit with less thunderstorm activity and temperatures in the 60s to near 70. West Coast and Western Interior... Windy and chilly for the remainder of the afternoon today with a High Wind Warning for Kivalina through noon tomorrow. A few snow showers will be around the Bering Strait through Wednesday afternoon. Temperatures away from the Strait will be gradually warming up Tuesday through Thursday as winds diminish. North Slope and Brooks Range... The North Slope remains relatively active with light snow and light freezing rain or drizzle around tonight and tomorrow. As temperatures warm into the 60s and low 70s along the southern Brooks Range tomorrow, a few showers and storms will develop which may move through the North Slope during the afternoon/evening hours. These would mostly turn into rain showers as they move through the Plains and Arctic Coast. Wednesday looks to dry out with some clearing possible as well. A warming trend then continues through the end of the week. Coastal Hazard Potential Days 3 and 4...None. && .FIRE WEATHER... A Red Flag Warning will begin at 2 PM this afternoon in the Yukon Flats and continue through 9 PM tomorrow evening. Sustained winds around Hodzana and Graphite Lake have been around 15 mph with gusts up to 30 mph. Minimum RHs are expected to be around 20-25% with temperatures in the mid to upper 70s today. Tomorrow, wind will be a bit more marginal around 10 to 15 with gusts to 25 mph in the afternoon and evening, RHs will be as low as 25% and temperatures will be in the upper 70s. Tonight and tomorrow night, winds come down, temperatures drop and RHs will rebound. Otherwise, in terms of precipitation, scattered showers and isolated storms will be around today and tomorrow with the bulk of activity remaining over the higher terrain. Fort Yukon will have a chance for widely scattered storms this evening as an easterly wave moves through. Wednesday looks like it could be a big lightning day, potentially the largest one of the year so far. Already, guidance is hinting at 500-1000 J/kg of CAPE with the NAM being bullish and showing up to 1500 J/kg in the Middle Tanana Valley. A strong shortwave is looking to move through during the afternoon and it will spark thunderstorms. There is a potential for widespread storms with frequent lightning. Luckily, these storms do look to be wet and come with heavy rain. Some localized spots may receive up to 1.00" of rain in the most persistent thunderstorms. We will be determining where exactly the thunderstorms set up, but it is beginning to look focused from Stevens Village south. The shortwave will then push west during the evening with thunderstorms possible as far northwest as Ambler Wednesday evening. && .HYDROLOGY... Warming temperatures along the North Slope this week will promote snowmelt and the potential for high water for the Sag, Colville and Kuparuk Rivers and their tributaries. The Colville has a few ice jams on it already which may result in some flooding concerns. One ice jam of note is a known seven mile long ice jam downstream of Ocean Point (on the Colville) and a smaller ice jam a few miles long at Horseshoe Bend (roughly 9 river miles up from Nuiqsut). Snowmelt will likely push out these ice jams, but expect high water upstream before the release. Water levels are expected to crest by the end of this week into the weekend. The water level in Fort Yukon will continue receding very slowly. Satellites and ground observations continue to indicate abundant snow in the Porcupine Mountains. As temperatures warm this week, snowmelt could lead to continued high water along the Porcupine and the interrelated sloughs. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...High Wind Warning for AKZ815. Red Flag Warning for AKZ933. PK...Gale Warning for PKZ801-850. Gale Warning for PKZ802-853. Small Craft Advisory for PKZ803. Small Craft Advisory for PKZ805. Gale Warning for PKZ806-810-854-856. Gale Warning for PKZ807. Brisk Wind Advisory for PKZ808-855. Brisk Wind Advisory for PKZ809. Gale Warning for PKZ811. Small Craft Advisory for PKZ812-816-817-851-857-858. Heavy Freezing Spray Warning for PKZ817. Small Craft Advisory for PKZ852. && $$ Bianco