textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

A low moving into the eastern Bering Sea is sending a series of fronts into Southcentral. Currently, a weak front is lifting through the area that will increase gap winds for early this afternoon. There is a trailing, stronger front following on its heels to reinforce those gusty, gap winds and precipitation. Stronger southeast flow with precipitation is bringing a steadier rain to the Northern Gulf coast and Prince William Sound while its interaction across the Chugach and Kenai Mountains are leading to a rainshadow effect, keeping the leeside drier. A few sprinkles are making it over the mountains though and as the front lifts through the area this afternoon, some of that precipitation could push a period of more steadier rain later in the day. Most of this diminishes though as it moves farther inland.

The parent low will start to track across Bristol Bay and Kodiak Island by Sunday morning. Weak waves of energy wrapping around this low will keep the weather pattern fairly steady state through it trek to the Gulf, but the magnitude of the wind speeds and amount of precipitation will decrease with each passing wave. Models differ in the position of the low once it settles into the Gulf Monday through midweek. This will dictate how much precipitation falls for coastal locations. Consensus overall, appears to be pointing towards a cooling trend, weaker winds, and decreasing chances of precipitation. Should precipitation linger though, it would be relatively higher for the Gulf coast and perhaps near higher elevations.

LONG TERM FORECAST (Days 4 through 7: Tuesday through Friday)

The long term period starting out on Tuesday will feature a complex trough moving over the southern Mainland and Alaska Gulf, with a surface low moving over the northeastern Gulf near Yakutat. Gusty northwest winds will likely be ongoing through gaps and passes along the coast of Southcentral, particularly near Kodiak Island and the Barrens. Out west, cool northwesterly flow extending from the Bering Strait down along the western coastline will bring seasonably cool temperatures in the 30s and 40s down into much of Southwest Alaska through midweek. A low-amplitude ridge is anticipated to be progressing across parts of the central Bering and Aleutian Chain, allowing for relatively quiet conditions to prevail initially. However, a low moving out of Kamchatka will likely reach the central/western parts of the Bering and Aleutians by Tuesday afternoon, sending gusty southeast winds and rain across the region as the low and leading frontal boundary push east with time.

Looking towards the end of next week, models diverge in regards to the progression of the low approaching the southwestern Bering earlier in the week. The deterministic 12z ECMWF is a notable outlier at this time, as it depicts the ridge over the Bering remaining much farther west through Thursday and Friday. It also attempts to dig a separate trough south from northern Kamchatka down into the AKPen and Gulf region between Tuesday and Thursday, ultimately becoming a deeper low in the southern Gulf on Friday as it interacts with another system driving up from the Pacific. In contrast, most of the other deterministic and ensemble guidance supports the Bering low and attendant upper trough remaining as as the dominant system, showing the low continue to track mainly east along the Aleutian Chain through Friday. Assuming this more favored solution plays out, gusty south to southeast winds and rain along the low's front could shift from the Bering and Southwest into Southcentral between Thursday and Friday. Most of the heavier rain would likely be focused mainly along the Gulf Coast, with most of the interior parts of Southcentral staying drier towards the second half of next week.

-AS

AVIATION

PANC...VFR conditions will persist through the TAF period. Light northerly winds are forecast through at least midday, at times becoming variable. Similarly to Friday, there is much uncertainty in whether southeasterly Turnagain Arm winds clip the terminal later this afternoon. The best chance for any southeasterly winds and gusts will be closer to 00z but surface flow is expected to remain largely down inlet, keeping any terminal interactions brief. Rain chances will be scarce with stronger southeasterly flow aloft approaching or exceeding 30 knots. Which should downslope moisture and limit any precipitation largely to light drizzle.

BL