Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
351 FXAK68 PAFC 091323 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 523 AM AKDT Thu May 9 2024 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)... Areas of showers that developed along and ahead of a now weakening shortwave trough lifting into northern Southcentral this morning managed to change over to mostly snow across parts of Anchorage overnight. Half an inch to an inch or more was able to accumulate on elevated surfaces, with 0.7 inches recorded at the official observation site at the Anchorage forecast office. This brings us solidly into 2nd place for the snowiest season on record in Anchorage, with our total for the 2023 to 2024 snow year now sitting at 133.3" as of 5 AM this morning. While it probably won`t be much, we might be able to add a touch more to this total today. A secondary, weaker trough showing up well near 700 mb is now lifting into the Kenai Peninsula from the Gulf this morning. This feature is helping to focus bands of snow showers across the Kenai Peninsula and up into Anchorage, though precipitation is staying quite a bit lighter thus far in the band of snow set up near and just west of Anchorage compare to what moved through yesterday evening. This second shortwave should continue to shift north towards the Talkeetnas today as another push of cooler air follows in tow behind it up the Cook Inlet, helping additional areas of light rain/snow develop across the Kenai Peninsula and Anchorage initially. This activity will shift north towards the Mat-Su as the cooler and drier air rushes in behind this next trough moving past. Confidence for precipitation type is very low through this evening due to the combination of seasonably cool low level temperatures and long daylight hours, so have generally stuck with a rain/snow mix for most of the western Kenai up into Anchorage for remaining precipitation potential through this evening. Meanwhile, a low moving near the AKPen will move northeast past Kodiak Island as it becomes and open wave in the upper levels today. This stronger resulting trough axis will swing north into Southcentral by tonight, solidly ending the threat for lingering snow/rain for interior locations once the trough axis nears the Alaska Range early Friday morning. A shortwave ridge will move into much of the region behind this stronger trough passage, yielding drier and perhaps even a bit sunnier conditions for at least the first half of the day for some. By Friday afternoon, a stronger low moving up along the AKPen will extend it`s front into the Gulf as strong southeasterly flow begins to pick up out ahead of this feature. Gusty south to southeast winds will spread from Kodiak Island back into the remainder of Southcentral through Saturday as the front slowly lifts north and the parent low shifts into the western Gulf. Steady low elevation rain and mountain snow will primarily be focused along the coast and across Prince William Sound, while strong cross-barrier flow keeps most of the inland portions of Southcentral mostly dry. Temperatures will remain cool, but will begin to rebound closer to seasonal norms in the low 50s over interior valleys by Saturday afternoon. -AS && .SHORT TERM FORECAST SOUTHWEST ALASKA, THE SEA AND THE ALEUTIANS (Days 1 through 3)... A compact polar low moves up the Alaska Peninsula Thursday morning. Gusty winds and snow showers continue through the day but dissipate as the low weakens by the afternoon. A larger low advances eastward over the western Aleutians, pushing a broad front of widespread precipitation and gale force winds. Warm air along the front should raise temperatures above freezing along the chain, and change precipitation over to rain. The low reaches the Southwest mainland by Friday morning before a new low consolidates south of Shemya Saturday morning. && .LONG TERM FORECAST (Days 4 through 7: Sunday through Wednesday)... The Alaska weather map shows a very broad upper level trough stretching from the Western Bering to the Canadian border. A number of occasionally vigorous troughs work through the pattern, picking up energy from the North Pacific and helps relax the overall amplitude of the trough into a more or less zonal flow through midweek. A couple of weakening low centers slip across from Bristol Bay along the North Gulf Coast through Wednesday, with most of the active weather production in their tracks. A moderate ridge over the Russian Far East flattens out with help from troughs moving out of Siberia late Monday into Tuesday. A surface low near the Shumagin Islands with its front extending into the Gulf of Alaska pushes most of its precipitation ahead of the front. Locally heavy rainfall is expected from the Eastern Kenai Peninsula, and diminishes over Prince William Sound to the Canadian Border through Monday. Lesser amounts will occur further inland to the Alaska Range. A well developed low near Kodiak Island and its front spreads another period of rainfall across Southcentral Alaska through Wednesday. A moderately strong trough drags another area of precipitation across the Aleutians and Alaska Peninsula Sunday and Monday. A new front out of Russia enters the Western Aleutians and Bering Tuesday, moving across the Central Aleutians by Wednesday. A third weather producer out of Russia approaches the Western portions for Wednesday. - Kutz && .AVIATION... PANC...Predominantly MVFR ceilings and visibilities with intermittent periods of IFR ceilings are expected to diminish and lift by the early afternoon. Rain/snow showers over the area possible, however will become increasingly sparse by the early afternoon, but could make a resurgence by the mid-to-late afternoon. Gusty southerly winds over the terminal early this morning will weaken, becoming variable by noon, then shifting back southerly by the late afternoon. && $$