textproduct: Juneau

SYNOPSIS

Key Messages:

-No major weather concerns expected through the early week, however marine layer low clouds will persist over the eastern Gulf.

-Mainly dry and mild weather expected through Sunday night, before precipitation chances return to the northern Gulf Coast by Monday. No heavy rainfall is expected.

-High pressure over the eastern Gulf of Alaska will keep the southern panhandle dry through at least mid week.

LONG TERM

The surface ridge of high pressure over the eastern Gulf of Alaska looks to persist through the extended forecast period. This will keep the heavy rain threat on the west side of the ridge axis and outside of our forecast area. However, marine layer clouds will likely be held under that ridge over the gulf and along the outer coast. As a mid-level trough passes over the marine layer Tuesday night thru Wednesday the PVA will be just enough lift to have a chance/slight chance of rain (more likely drizzle) along the northern and central outer coast and into the Icy Strait corridor. The ridge will periodically flatten some (dirty ridge) and allow moisture/clouds to stream in, namely for the Yakutat area. Meanwhile, areas on the lee side of the ridge axis (Chatham Strait to Clarence Strait) will have NWLY (downslope) flow and mostly clear skies for majority of the next week.

Most models were in lock-step today on keeping the ridge offshore for the work week and sharper as well. The GFS represented these wind directions well with NWLY flow along the southern outer coast and southern inner channels to Dixon Entrance as well as stronger wind speeds. These speeds were raised in the forecast to about 15- 20kt, but some areas of 25kt are possible in vicinity of Cape Decision to Dixon Entrance and will be monitored over the coming days.

AVIATION

/through 00z Monday/ Early Saturday afternoon, VFR continues to expand across the north, with pockets of MVFR in the central Panhandle, and MVFR in the south. Overnight the marine layer returns, bringing widespread MVFR to IFR across Southeast, similar to conditions we experienced Saturday morning. For the central and southern Panhandle that saw light rain and/or drizzle Saturday, if high clouds can clear out late tonight areas of Dense Fog will likely form in the morning. Expect FG and MVFR/IFR to improve to VFR for most of the Panhandle Sunday afternoon, with sea breezes impacting the area.

MARINE

Outside (Gulf and Coastal Waters): Classic summer day out and about this Saturday, with a surface high pressure dominating the Gulf, bringing a low mariner layer to much of the coast. Current SITREP as of 1400 Saturday afternoon is NW winds of moderate breezes. Sea state is currently dominated by southerly swell 15 seconds at 3 ft, with a NW wind wave on top. This afternoon winds continue to build to moderate to fresh breezes with increasing wind waves out of the NW burying the southerly swell, driving significant wave heights of 4 to 5 ft.

Sunday the marine layer continues to bring low clouds to much of the coast, with NW winds of moderate to fresh breezes. Southerly swell dominates overnight, with wind waves once again burying the southerly swell Sunday afternoon. Significant wave heights of 4 to 5 ft continue.

Inside: Primary threat over the next 36 hours is sea breezes of fresh to strong breezes impacting favored areas (like Icy Strait, Northern Lynn Canal etc.) in the afternoon/evening hours of Saturday and also Sunday. Expect the marine layer to form again overnight Sunday, with the lowest cloud layers along the coast. If more extensive cloud cover can clear out this evening in the central and southern Panhandle, we could see areas of Dense Fog in Frederick Sound and Sumner Strait. If you wake up Sunday and you are socked in with fog, it will clear by 0900-1100 AKDT Sunday morning.

Sea breezes of 15 to 20 knots will likely impact Icy Strait and Lynn Canal both Saturday afternoon and Sunday afternoon. Mariners planning to operate through both Inian Passes in western Icy Strait should be aware of higher than forecasted seas, as westerly wind collide with the outgoing tide. Our marine wave forecast does not take into consideration the combined tide/wind impacts.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...None.