Scientific Forecaster Discussion
000 FXAK69 PAFG 232235 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 235 PM AKDT Tue Jul 23 2019 .SYNOPSIS... Ridging over the Interior will bring warm and dry conditions over the Interior through Tuesday. Ridging will weaken on Wednesday but still remain warm over the eastern Interior. The main weather concerns for today is the growing coverage and intensity of smoke across the Interior. Additionally, thunderstorm activity will increase on Wednesday across the Interior. Slightly cooler temperatures with rain showers expected Thursday and into the weekend for the Interior. && .DISCUSSION... Aloft...A 575 dam ridge of high pressure has moved over Interior Alaska and persist through today. Ridging over the Interior will weaken and push northward on Wednesday allowing shortwaves to move up from the Gulf of Alaska. This will increase shower and thunderstorm activity over the Interior Wednesday and Thursday. A longwave trough will deepen over the Bering Strait through Wednesday. This trough will push shortwaves across the Bering Strait through Thursday. The trough will linger over the west coast through Friday. An easterly wave will move into the Eastern and Central Interior Thursday evening, bringing primarily numerous shower activity. Temperatures will reach the low to mid 80s across the Interior today, with cooling conditions through the rest of the week. Surface...A 1022 mb high over the eastern Beaufort Sea will move to the northeast as a 1023 high by tomorrow afternoon. A developing 995 mb low will be south of Wrangel Island by tomorrow. Strong easterly winds will develop over the eastern north slope on Wednesday and persist into Thursday. A thermal trough will develop over the southern Interior today then move north over the central Interior on Wednesday. Interior...Main weather concern today is smoke over the central Interior. Low visibility reported in many locations due to the smoke this afternoon. Dense smoke advisories have been extended out until noon Wednesday for the Delta Junction area and around Fort Yukon. Warm and dry condtions will continue today with temperatures in the low 80s. A thermal trough will develop south of the Alaska Range today. This setup will increase isolated thunderstorm coverage across the southern Interior today. As the high pressure slides further northeast, the thermal trough will move north over the central Interior tomorrow. As a result, thunderstorm activity will increase across the Interior on Wednesday, with widely scattered thunderstorms possible in areas around Tanana. An easterly wave will move into the Eastern and Central Interior on Thursday, bringing primarily widespread shower activity. Models differ on the exact timing of this wave but general consensus of the rain for the central Interior is late Thursday afternoon into the evening hours. Cooler temps and chances of rain will continue into the weekend. North Slope and Brooks Range...Easterly flow will persist through Thursday. Expect low ceilings and periodic low visibility to return from Utqiagvik and east. Winds will be strong as well around 25 to 40 mph along the eastern north slope. Isolated thunderstorms are possible in the central and eastern Brooks Range for the tomorrow and Thursday. West coast...Low stratus and fog expected to persist over the Bering strait today. A weather front will push east into St. Lawrence Island, with rain showers likely this evening. A strong low pressure system will move north to St. Lawrence Island by Thursday morning, pushing a strong front across the west coast bringing widespread showers on Thursday. Coastal Hazard Potential Days 3 and 4...None. && .FIRE WEATHER... Main fire weather concern today is smoke over the central Interior. Low visibility reported in many locations due to the smoke this afternoon. Dense smoke advisories have been extended out until noon Wednesday for the Delta Junction area and around Fort Yukon. A thermal trough will develop over the southern Interior today and will be the focus for isolated thunderstorms as well. The thermal trough will move north over the central Interior tomorrow. As a result, thunderstorm activity will increase across the Interior on Wednesday, with widely scattered thunderstorms possible in areas around Tanana. On Thursday, the best chance of thunderstorms willl be from Fort Yukon to the eastern Brooks range. An easterly wave will bring widespread showers into the Interior on Thursday, with increased chances for wetting rains. Temperatures expected to peak today and then decrease for the rest of the week in the Interior, with minimum RH improving. && .HYDROLOGY... Expect glacier-fed rivers to remain elevated through this week due to increasing temperatures. Otherwise, relatively dry conditions should keep rivers at their current levels. && .AFG WATCHES/WARNINGS/ADVISORIES... Dense Smoke Advisory for AKZ220-AKZ223. Small Craft Advisory for PKZ230-PKZ235-PKZ240-PKZ245.