733 FXAK67 PAJK 191253 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 453 AM AKDT Thu Jun 19 2025 .SHORT TERM...Not much has changed in the forecast outlook for Thursday. The weak surface low and associated broad upper level low in the southeastern gulf get pushed out by an advancing ridge in the central gulf through Thursday night. This doesn`t stop a band of showers from rotating into the northern panhandle and Icy Strait Corridor this morning, followed by the central and southern panhandle through the afternoon. The ridge will influence onshore flow which should help to clear skies for the entire panhandle by Friday, starting with the northern panhandle through Thursday and progressively getting more clear as the showers pass. Haze is still possible for the northern panhandle as the easterly flow from Canada continues. Only light to moderate rain is expected for these showers, though periods of heavier rain could blow through briefly with the influence of surface heating. Onshore flow will become more enhanced through the afternoon as a thermal gradient builds between the warm, sunny interior and the cooler gulf waters. A very small shortwave trough aided by this thermal advection has potential to spin up over the outer coast of the panhandle and move north quickly, bringing elevated winds of up to 15 to 20 kts through the inner channels Thursday afternoon into the evening. This will also bring sea breezes through the daylight hours to coastal communities Icy Strait northwards. With clearing skies allowing for maximum daytime heating as we near the summer solstice, temperatures inland away from sea breeze influence will reach the mid to upper 70s. Along higher elevations of the Haines Highway, temperatures will reach around 80 degrees Thursday afternoon. A heat advisory has been issued for these expected conditions. Convection over BC continues to flow westward over the Coast Mountains through the day, looking to be a very similar situation to yesterday. The far northern panhandle will be experiencing very warm temperatures alongside clearing skies and upper level easterly flow, which all point to potential for at least lightning-producing showers. Strong CAPE associated with a low lifted index and a similar set up to yesterday influenced the addition of a slight chance of thunderstorms through the afternoon for the forecast. While lightning may not actually make it across the border, potential will continue to be assessed throughout the day. .LONG TERM.../Friday through Monday/... Showers will begin to decrease Thursday night into Friday morning as a surface ridge approaches the panhandle from the west, pushing the weakening low to the southeast. This ridge, accompanied by an upper level ridge building over the Gulf on Friday, will help to bring drier weather, clearer skies, and some higher temperatures into this weekend. Models showing 850mb temperatures of between 10 and 12 degrees C moving into the area alongside this ridge, which will bring us some warm air advection that will also aid in bringing temperatures up. This warm air advection alongside the surface ridging will bring some areas of the panhandle to over 70 degrees for their highs this weekend, with the highest temperatures looking to be Saturday afternoon and in the southern panhandle. There are some higher (14- 15 degrees C) 850mb temperatures moving along the border with British Columbia, though this will have little impact on the panhandle outside of Dyea, which is expected to see highs above 80 for the weekend. Temperatures will also be higher due to the lack of cloud cover during Friday and the weekend, resulting in likely even higher temperatures than the models are showing due to the long sunlight hours and surface heating. However, there is likely to be a marine layer that forms along the coast and into some coastal locations (Yakutat, Elfin Cove, Sitka, and parts of western POW in particular). This will bring some overcast skies and decrease the high temperatures in these locations Friday through Sunday. There is still a lot of variability in temperatures for these areas as confidence isn`t high on the exact timing or locations of the marine layer at this time, but we expect at least some decreases in temperatures at these locations due to the coastal impacts regardless. Temperatures will then begin to decrease again Sunday into Monday through the majority of the panhandle, with only Hyder looking like it will stay warmer for longer. The higher temperatures in the Yukon Territory and British Columbia alongside their potential for some convective showers later in the week may result in some risk for wildfires, which may bring some haze in to Haines and Skagway. We have kept the haze in for the first half of the midrange forecast for just Haines and Skagway in anticipation of this, before the ridge moves more eastward and begins to change the northeasterly flow to a more northerly or northwesterly flow that might not allow smoke to flow in the direction of the panhandle. Winds look to stay on the lighter side over the region for the rest of the week into the weekend. However, the pressure gradient in the northern panhandle may tighten as the surface ridge begins to move in while a low remains over Canada to the northeast, which may bring some elevated winds to Lynn Canal on Thursday. Friday into Saturday morning there will be some elevated winds along the southern outer coast and coming out of Chatham Strait and Clarence Strait as the ridge continues to push east while a low remains over British Columbia, bringing some 15 to 25 kt winds as the gradient tightens. These winds are not expected to last however as the ridge continues to push eastward Saturday into Sunday, with winds decreasing to between 10 and 15 kt off the coast Sunday into Monday. && .AVIATION...Aviation concerns still center on the rainfall and lower ceilings from shortwaves moving in from Canada. This morning, one shortwave is over the Icy Strait and Juneau area where rain showers with ceilings down to 700 ft have been observed over night. Elsewhere this morning VFR conditions are the rule, except for Haines and Skagway where a lower 2500 ft deck has settled in. Some very isolated shallow ground fog is showing up at Yakutat, and Skagway as well this morning. Today the wave over the north will move out into the gulf this morning, while a new shortwave will move into the southern panhandle. Expect improving ceilings across the north up to VFR while the south (particularly around Petersburg south to just north of Ketchikan) will see lowering ceilings down to MVFR or even IFR in some cases through this evening. Then expect improving ceilings late tonight into Friday as the easterly wave activity diminishes. Convective situation is expected to mostly be the same as what we saw yesterday with thunderstorms developing during the afternoon in northern British Columbia that will try to be advected into the northern inner channels. Most of these storms will likely lose their intensity as they try to cross the coast mountains with the best chance of lightning right along the international border from Taku River north to White and Chilkoot Passes. Can not completely rule out a stray lightning strike or two around Haines or Skagway this afternoon or evening though. Mostly lighter winds expected through Friday through some southerly winds to 15 to 20 kt at the surface could develop this afternoon and evening near Stephens Passage and Lynn Canal. && .MARINE... Outside Waters: Variable winds turning W and increasing to moderate to fresh breezes (11 to 21 kts) through Thursday with the ridge approaching in the gulf. Dixon entrance may continue to see elevated winds through the day as the persisting low in the southern gulf continues to spin up bands of clouds and precipitation for the panhandle. Wave heights remain around 4 to 5 ft as a SW swell diminishes through Thursday evening. Inside Waters: Generally light and somewhat variable winds with calm waters for inner channels through early Thursday morning. Onshore flow will increase as a ridge approaches through the gulf through the day. Upper level easterly flow keeps bands of clouds and scattered showers in the forecast for the southern panhandle into Thursday afternoon, with some isolated thunderstorms possible for Lynn Canal Thursday afternoon. Overall winds will remain light, with light to moderate sea breezes developing in the afternoon. This thermal heating will potentially blow a quick wave of higher wind speeds up the channels this afternoon, though it will diminish quickly. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...Heat Advisory from 1 PM this afternoon to 7 PM AKDT this evening for AKZ319. MARINE...None. && $$ SHORT TERM...ZTK LONG TERM....Contino AVIATION...EAL MARINE...ZTK/STJ Visit us at http://www.weather.gov/Juneau