Area Forecast Discussion
Issued by NWS Juneau, AK
Issued by NWS Juneau, AK
424 FXAK67 PAJK 272307 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 307 PM AKDT Thu Jun 27 2024 .SHORT TERM...An upper level and surface ridge of high pressure sits over the gulf, creating a marine layer of clouds that are hanging around some coastal areas of POW and Baranof Island. At the mid-levels, high pressure is in the Yukon and there is a low developing over the SW gulf. This pattern generally leads to an easterly flow aloft, while the surface ridge causes NWLY winds, and the marine layer vs. sunshine causes enhanced sea breezes. All this to say that wind directions can be a bit tricky on an otherwise quiet weather day. The ridge over the gulf will be under-cut by the SW gulf low pressure system tonight into Friday. This will cut off the surface high pressure and push it to the northern gulf, while the low will slowly progress east toward Haida Gwaii. This change in position will affect where the marine layer pushes back inland tonight. The Yakutat area would have more potential for marine layer clouds and most models are showing it pushing a little further into other ocean entrances than it did last night. Have not expanded the mention of fog in the forecast as clouds have been off the surface, but wouldn`t rule it out. As the low approaches, it will send bands of showers and clouds into the southern panhandle. One band of vorticity that models have at 500mb looks to track northward across the the panhandle Friday afternoon and into Saturday morning. Additionally, models are showing afternoon showers developing over Canada and along the Coast Mountains, but not looking as if many will affect the panhandle. Greatest chances of showers coming in from Canada look to be over the south between Hyder and Wrangell while the southern outer coast of POW has the greatest chances with the frontal bands. Generally increased POP with the frontal band Friday night, but lowered POP across the north/central inner channels. Temperatures look to stay fairly similar or a couple degrees cooler on Friday. .LONG TERM...Ridging becomes less dominant over the eastern GULFAK and SEAK over the weekend as a weak low pressure system settled into the eastern GULFAK and a weak front moves in from the southwest. For this midrange forecast package we increased the chances for showers starting Friday night in the far south and gradually worked higher chances northward through Saturday and into the weekend. Rainfall amounts look fairly typical through the weekend so we are not expecting significant impacts from heavy rainfall. We do see temperatures moderating a bit with increased cloud cover and cooler temperatures aloft working in from the southwest. && .AVIATION...Generally VFR most locations through the early evening however we do expect to see more marine layer low clouds and fog tonight for Ketchikan, Klawock, Sitka, and Yakutat (generally 10Z- 17Z). Winds remain relatively light except in Skagway due to afternoon seabreeze enhancement this afternoon and again tomorrow afternoon. && .HYDROLOGY... && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...None. MARINE...Small Craft Advisory for PKZ641-661-662. && $$ SHORT TERM...Ferrin LONG TERM....Garmon AVIATION...Garmon HYDROLOGY...Ferrin Visit us at http://www.weather.gov/Juneau