Marine Weather and Tide Forecast for Cohoe, AK

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3: Today through Thursday afternoon)...

A few rain showers are working southward across the northern fringes of Southwest Alaska ahead of an advancing cold front in response to an upper level arctic trough digging southward over the region. The trough is clearly visible on satellite, as is a large swath of low stratus and areas of fog from persistent high pressure situated across the Bering and draped along the Bering side of the Eastern Aleutians and the Alaska Peninsula. The fog and low stratus has lingered long enough today for these areas to keep temperatures cooler for the Bristol Bay region and the Bering side of the Alaska Peninsula/Eastern Aleutians. High resolution models such as the HRRR keeps fog/low stratus going through the overnight hours, though the MOS guidance has backed off on fog for these areas for tomorrow morning. This is a challenging fog forecast for tomorrow morning considering we have seen a similar setup/pattern over the last few days, but the arctic trough driving southward should force more mixing and shearing at the top of a fog/low stratus layer. All said, the most likely outcome for tomorrow morning is a shorter duration of fog and for it not to be as widespread as today. Precipitation wise, the trend in the guidance for Tuesday morning is for the western half of Southwest Alaska to see less rain showers as the front moves southward overnight with much of the rainfall confined to the eastern half of the region (essentially from Sleetmute to Koliganek and points eastward). Expect cooler daytime high temperatures to be in the works for Tuesday across all of Southwest Alaska as cold air advection spills southward with the progression of the trough.

The global models show that the trough weakens and becomes ill defined by Tuesday afternoon as it swings over the Alaska Peninsula, which will allow for ridging over the Bering to start to build eastward. The movement of this synoptic feature will lead to warmer and drier weather for Southwest Alaska for Wednesday and Thursday. That said, fog and low stratus will persist across the Bering. Meanwhile, with the ridge moving eastward, the global models generally agree that this will pave the way for a high end small craft to gale force front to approach the Western Aleutians leading into Wednesday afternoon with rainfall. Though the high pressure is on track to move eastward across the Bering, it will still have enough of an influence that the front will essentially become blocked from progressing much farther eastward than the Western Aleutians.

Looking a bit farther out of the short term timeframe, models are honing in on the North Pacific storm track becoming more active once again as a North Pacific low begins to move northward and generally towards the Alaska Peninsula. Stay tuned.

-AM

.LONG TERM FORECAST (Days 4 through 7: Friday through Monday)...

On Friday, A weak Gulf low will generate showers to Southcentral Alaska and A high over the Kusko Delta will bring fair weather to Southwest as well as the Alaska Peninsula. Both systems will dissipate by the afternoon. A trough over the Bering will bring showers to the Aleutians Friday through Monday.

An upper level ridge over the eastern Gulf will remain nearly stationary through Sunday and then move eastward by Monday. This is important as it blocks an originating Pacific Low from going into the eastern Gulf. The combination of the anticyclonic flow aloft from the ridge and cyclonic flow from the low pressure system will enhance southerly flow ushering in warm and moist air into the northern and western Gulf coast. This is expected to bring precipitation to Southcentral Alaska, Alaska Peninsula, and Kodiak Island. There is strong model confidence that there will be periods of heavy rain for Prince William Sound and Kodiak Island Saturday into Sunday.

-SS


AVIATION

PANC...VFR conditions will persist through tonight. A front moving in from the northwest will bring potential for rain arriving at the terminal late tonight into Tuesday morning. Expect ceilings to lower as rain arrives, perhaps dipping into MVFR range by early Tuesday morning. The rain should end, with a return to VFR conditions, by late Tuesday morning.

Westerly winds this afternoon will turn northerly overnight with a return to light westerly winds Tuesday afternoon.