Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
973 FXAK68 PAFC 081330 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 530 AM AKDT Mon Jul 8 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today through Wednesday)... Southcentral is sandwiched in between an elongated low stretching into the region from well south of the Gulf to the Kenai and Chugach Mountains. At the same time, a weak 500 mb trough is in the Susitna Valley and will be moving eastward through the area today. This setup is causing a persistent band of rain to have developed over the northern part of Knik Arm and the Matanuska Valley this morning. This rain may persist through much of the morning until the 500 mb trough passes to the east. By late Monday night, the low in the Gulf will push a front to the northern Gulf and bring widespread rainfall along the coastal areas late tonight into Tuesday. This rainfall is not expected to push very far inland as the increasing pressure gradient increases southerly gap winds in the typical locations and there will be enough downsloping to keep inland areas with less chance of rain than today. While the pesky and persistent upper level low that has been along the northern coast of the state moves eastward late today, on Tuesday, another upper level low will dig southward from the Arctic Ocean into the Bering Sea. At this time it looks like the bulk of the rainfall from this system will occur over Southwest Alaska for Tuesday and Wednesday. However, most of Southcentral will remain in this cool, damp, and cloudy pattern through the middle of the week.If one is looking for a respite from this August-like pattern, the one area that may see some break in the cloud cover is the Copper River Basin from Tuesday night into Wednesday morning. && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3)... A blocking low located over the Gulf of Alaska will budge little over the coming days. Immediately to its northwest, weak high pressure is persisting over Southwest Alaska. Meanwhile, a compact low north of the Central Aleutians has transitioned into an open wave trough and will cross over the Aleutians into the North Pacific through tonight. Dry conditions and light southerly winds will start the day across Southwest Alaska, though low stratus and areas of fog have been observed on satellite beneath high pressure aloft. High pressure will break down over the second half of the day as a shortwave trough, evident on water vapor imagery over the Bering Strait, dips across the region later this evening. Increasing rain showers are forecast to expand into the Kuskokwim Delta and the Lower Kuskokwim Valley. The trough`s eastward movement and a broader front sagging across all the way into the southern Bering will see widespread showers by Tuesday across Southwest Alaska, along with developing gusty southwesterly winds ahead of the trough and front. Further west, isolated to scattered showers will be possible as the aforementioned open wave trough crosses the Aleutians on its way into the North Pacific. However, conditions should dry out by this afternoon and evening as temporary high pressure resumes across the southern Bering. The next shortwave trough tracks into the Western Aleutian on Tuesday in concert with a broad front extending across the southern Bering and into Southwest Alaska. Thus, late Tuesday will likely see rain showers spanning the Aleutians and much of Southwest Alaska. Shower activity continues across the Western and Central Aleutians on Wednesday with yet another trough into the region. The rest of the Aleutians dry out as the previously mentioned front continues southeastward into the Pacific and western Bering. High pressure lingering over the Western Alaska Range on Wednesday will see the bulk of shower activity for Southwest Alaska confined to the Kuskokwim Delta and Bristol Bay regions. -BL && .LONG TERM FORECAST (Days 4 through 7) Thursday through Sunday... The upper level Alaska Weather map opens with a closed low over the Northwest Bering that will shift towards the Western Alaska coast by the end of the forecast period. A weakening low near Kodiak Island is absorbed into this low, and results in a broad low that stretches from the Russian Far East into the Western Alaska Mainland by Sunday. A weak ridge holds across the Eastern Interior of the state, supporting surface thermal troughs and local convection through the weekend. Forecast model spread is reduced through the period. Southcentral Alaska is sustained with considerable moisture and areas of rain from the Alaska Range South. Some areas may experience briefly heavier rains through Sunday. A well developed surface frontal system brings locally heavy rains over the Aleutians and Bering through Saturday. An increasing area of heavier rains sets up from Nunivak Island and the West Coast Late Friday, and spreads inland and across the Alaska Peninsula by Saturday. Heavier rains move over Kodiak Island and the Southern Kenai Peninsula late Saturday and Sunday. This area of heavier rains continues across the Southcentral Coastal zones beyond the end of forecast period. - Kutz .AVIATION... PANC...MVFR or low VFR ceilings will persist through this afternoon and into this evening. A weak Turnagain Arm wind will persist over the terminal through Monday evening. && $$