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000 FXAK67 PAJK 272226 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 226 PM AKDT Thu Apr 27 2017 .SHORT TERM.../Tonight through Saturday/ 1002 mb low spinning 60 miles WNW of Sitka is currently bringing wet and breezy conditions to many areas of the central panhandle as the second wrap of the associated front moves inland. Gusts around 25 to 30 mph have been recorded at Sitka, Angoon, and Juneau so far this afternoon. This low will gradually move inland S of Cross Sound this evening and is expected to weaken over the northern panhandle tonight. W winds of around 15 to 25 kt are present on the S side of the system and will be hitting the central outer coast for much of the night. Some of this will bleed over into the northern inner channels as well. Ended up raising winds for tonight`s forecast over what was previously there using hires nam with some inner channel areas seeing up to 25 kt out of the south at times tonight. Winds are expected to diminish as the system rapidly weakens late tonight. Showers continue through Fri night, particularly over the northern panhandle, as onshore flow in the wake of the low persists. A building ridge will gradually shut those showers off, but it will only be when offshore flow develops ahead of the next low on Sat that the showers shut off completely. The weekend is looking rather dry for the north with persistent offshore flow. Meanwhile the southern panhandle will be dealing with increasing clouds, wind, and precip as a 996 mb low moves NE toward Haida Gwaii. .LONG TERM.../Saturday to Thursday/ Ridging over the eastern gulf and panhandle expected to shift into British Columbia as an upper level trough/closed low moves into the southeastern gulf. 500 mb vort max band associated with this trough may lift northward late Saturday as ridging builds again over the central gulf and then into the eastern gulf through Sunday. Upstream a large deep upper low moves over the Aleutians and remains quasi stationary through mid week with the ridge remaining over the eastern gulf and panhandle. By the end of the week this broad upper low will likely shift east but uncertain on the exact track. At the surface on Saturday there is be a weak low in the northwest gulf with a developing low tracking south of the eastern gulf. Lots of model spread on the track of this system, and with the position of this low track differences will result in large forecast variation. Best estimate is the low will move near Haida Gwaii through Saturday and likely dissipate by early Sunday morning. Seems to be a trend of models moving the low center further south which will have more offshore flow for the northern regions, thus drier weather, compared to the south which will have greater chance for rain. Nudged winds from this system toward small craft levels in the southeast gulf. GFS/Canadian have trended further north with stronger winds than the ECMWF/NAM which also dissipate the low sooner. Decided best option was a compromise blend until we get better model resolution. Beyond the weekend models fell more in line with the next surface low near the Aleutians the the associated occluded front moving into the gulf Monday into Tuesday. Later in the week a much stronger low appears to track up from the southwest and will have more impact with respect to winds/pop/qpf. Once again the word of the long range is uncertainty, especially for the weekend. RMOP values below 30% with the weekend low. Values improve later in the week as the next systems move in and model align. Used a blend of GFS/ECMWF for Saturday even though they were not in great agreement. Did this to get a smoother wind field and moderate any very low or high wind speeds. For the rest of the long range utilized WPC for its use of ensembles. Forecast confidence is below average. && .AVIATION...Mainly MVFR conditions with low moving onshore across the central area this evening. This will continue for most central and south TAF sites into early Fri morning. Should improve to VFR during late Fri morning to early afternoon. For PAYA, trapped low level moisture will keep MVFR conditions going through the night with potential for IFR late tonight as trof moves in. They may improve to VFR Fri afternoon but for now keeping MVFR ceilings as that will depend on how much of a break in cloud cover occurs to allow heating to raise cloud bases. && .AJK Watches/Warnings/Advisories... PUBLIC...None. MARINE...Gale Warning for PKZ042. Small Craft Advisory for PKZ022-031>036-041-043. Small Craft Advisory due to Seas for PKZ051. && $$ EAL/PRB Visit us at http://www.weather.gov/Juneau

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