textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

The overall forecast remains largely unchanged, with an upper level low slow meandering eastward across the Gulf of Alaska. Its trough extends into Southcentral, pushing a series of easterly shortwaves across the region. Warmer air pulled in from interior Canada will raise temperatures into the low to mid 70's for inland areas today and Friday, with upper 60's expected for most coastal areas. Coastal areas along the upper Cook Inlet, including Kenai and Anchorage could see temperatures dip into the low 70's on Friday as warm air is pulled south along the western edge of the trough. Clearing skies and warmer temperatures, coupled with increased instability, will allow for potential convective thunderstorm development and rain showers over the Talkeetna Mountains, as well as portions of the Alaska Range, namely Mentasta Pass and Isabel Pass, with thunderstorm chances of 10% to 20%. Another round of isolated thunderstorm potential (10-20% chance) extend into the Copper River Basin and Susitna Valley on Friday. Convective potential decreases over the weekend as westerly waves from a low in the Bering bring in cooler air.

KM

LONG TERM FORECAST (Days 4 through 7: Sunday through Wednesday)

An unsettled weather pattern will persist across much of southern Alaska through the extended forecast period as a series of weak disturbances move northward from the Gulf of Alaska while broad low pressure remains established over the Bering Sea. This pattern will support periods of showers across much of Southcentral Alaska beginning Sunday and continuing into early next week.

On Sunday, increasing moisture and several weak upper-level shortwaves lifting north across the Gulf will promote scattered to numerous showers across the Southcentral Interior, including the Copper River Basin and Susitna Valley. Modest daytime heating may allow for isolated thunderstorms to develop during the afternoon and evening hours, particularly across the Copper River Basin and portions of the Susitna Valley where instability appears most favorable. Elsewhere across Southcentral, cloud cover and cooler marine influences should help limit thunderstorm development.

By Monday, energy associated with the Bering Sea low begins shifting eastward into mainland Alaska. As a result, shower activity is expected to become more widespread across Southcentral, with periods of rain developing across portions of the Kenai Peninsula, Susitna Valley, Copper River Basin, and surrounding higher terrain. While rainfall amounts generally look light to moderate, locally heavier showers will remain possible beneath stronger convective cells.

Showery and unsettled conditions are expected to continue through Tuesday as the upper-level pattern remains progressive and weak disturbances continue moving through the region. Temperatures should remain near seasonal normals, though persistent cloud cover and precipitation may keep daytime highs slightly cooler in areas that experience more frequent rainfall. Isolated thunderstorms may remain possible across the eastern Interior portions of Southcentral, especially near the Copper River Basin during the afternoon and evening hours.

By Wednesday, guidance suggests a stronger North Pacific system moving into the Bering Sea may begin increasing southerly flow across southern Alaska. This could lead to increasing moisture transport into Southcentral and maintain chances for showers across much of the region. Confidence in specific timing and impacts remains lower this far out, but the overall signal favors continued unsettled weather with periods of rain, extensive cloud cover, and locally breezy conditions developing through favored gap wind locations and along portions of the Gulf.

Father west, a stronger North Pacific low and associated front will bring hazardous marine conditions to the western Aleutians and western Bering early next week. Sustained southeasterly gale- force winds with storm-force gusts remain possible, accompanied by periods of moderate to heavy rain. These conditions are expected to spread eastward through the Aleutian Chain, reaching Adak and Atka Monday before advancing toward Unalaska and Nikolski by Tuesday. Marine interests should continue monitoring later forecasts as confidence in a period of impactful winds and rainfall remains relatively high.

LM

AVIATION

PANC...VFR conditions will mostly persist. There is a chance for a lower cloud deck to redevelop overnight and into the morning hours tomorrow. Should this happen it could push ceilings into the MVFR range. Any lower ceilings from Thursday morning should burn off by late morning as this is not due to a large area of stratus throughout Cook Inlet, but rather from residual low level moisture locally that condenses as an inversion develops. Winds are expected to remain mostly from a westerly direction at 10 kt or less.