textproduct: Anchorage

SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)

Widespread moderate to heavy rainfall is currently falling over the Susitna Valley as a strong trough from an upper low in the Gulf moves through Southcentral. Lighter rainfall is falling over the Matanuska Valley with more scattered rain over Anchorage, Kenai Peninsula, and the Copper River Basin due to downslope drying. Rainfall will slowly diminish through Wednesday. The shortwaves from the low are causing ridging over the Chugach Mountains, which is promoting gusty gap winds in South Anchorage, Palmer, and the Copper River Basin. Winds will diminish by tonight over the aforementioned areas and will remain relatively light (5 to 10 mph) through the end of the week. Winds will be light for the rest of Southcentral as well. Temperatures today will be in the 50s and 60s due to the cloud cover and rainfall.

Easterly waves from the upper low will continue after the main wave from today dissipates on Wednesday, but there won't be enough lift to trigger convection on Thursday except for maybe along the Wrangells. Temperatures will slowly warm through the week as rain diminishes and cloud cover breaks. By Friday, warming temperatures and clearing skies will allow for scattered showers and isolated thunderstorms across the Susitna Valley and the Copper River Basin. There is some uncertainty on the full potential of thunderstorms for Friday with the possibility of more or less thunderstorms depending on how much instability arises and the coverage of lingering cloud cover.

-JAR

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

The long-term pattern continues to look unsettled across the Bering Sea, Aleutian Chain, and across the Southern Mainland. A low in the Bering Sea spreads showers along the Aleutian Chain to the Southern Alaska Peninsula Saturday and Sunday. This system also brings showery conditions to Southwest Alaska by Sunday afternoon. At the same time, weak upper-level shortwaves lift northward from the Gulf of Alaska and across Southcentral Alaska. This will help produce showers across the Southcentral Interior Saturday and Sunday; namely the Copper River Basin and Susitna Valley. There could be enough instability in place Saturday and Sunday afternoon across the Copper River Basin and Susitna Valley to produce a few lightning strikes in more robust showery activity. There airmass across Southwest Alaska looks to be more stable than that across portions of Southcentral, therefore, lightning strikes are less of a threat there.

For Monday, the Bering low that brought showers across the Bering Sea, Aleutians, and Mainland Southwest Saturday through Monday, now sends it energy into Southcentral by Monday evening. Therefore, expect showery conditions to continue across much of Southcentral Monday evening through much of Tuesday.

Back to the west, a stronger North Pacific low and front push sustained southeasterly gale-force winds with storm-force gusts into the Western Aleutians and western Bering by Monday morning. Also accompanying this system will be moderate to heavy rain at times. Rain and gusty winds move to Adak/Atka by Monday afternoon and evening and to Unalaska/Nikolski by Tuesday morning.

AVIATION

PANC...VFR conditions are expected to persist in spite of the rain; which should taper off late this evening. Southeasterly Turnagain Arm winds will increase again this afternoon through evening, with gusts reaching up to 25 kts.