textproduct: Juneau

LONG TERM

Cold, stable, and predominantly dry weather pattern is currently expected through Saturday night with higher confidence. The arctic air mass situated over the Yukon, further amplified by a strong upper-level ridge will dictate much of the weather going into the weekend. The northern channels, including Haines and Klondike Highway will experience the coldest conditions, with daytime highs likely remaining in the single digits, and overnight temperatures dipping below zero near White Pass and Haines Customs. The low pressure currently lingering near the NE gulf coast finally looks to dip south on Friday, bringing changes of snow showers for the outer coast mainly. Not expecting these snow showers to move into the inner channels as much, due to dry and cold air filtering in from the north.

This pattern begins to shift on Sunday as upper level forcing drives a low pressure system towards the northern coast. The main source of uncertainty for this incoming system is the interaction with the high pressure in the Yukon. The EPS is definitely the most aggressive in breaking down this high pressure, with the GEFS and GEPS keeping the high pressure from breaking down as much in the means. One interesting point is the currently non operational HGEFS show an in between solution in the means, which would still keep most of the panhandle cold enough for snow. While not included in the current analysis, it more points to the unknowns for how this energy will interact with the cold, dry air in Canada. While there is high uncertainty in this part of the forecast, what can be said is moisture is highly likely (>80%) to stream back into the panhandle bringing more precipitation. The main question going forward is where will get the most precipitation, and what weather type (rain, snow, exc) could fall at each location.

AVIATION

/ through Thursday afternoon / Key features today is the surface low south of the Yakutat area which is spinning showers about this low. The showers are moving across the coast and Yakutat. Some of the showers have been heavier in nature so will have to account for those overnight.

Related to the low are the showers moving into the northern portion of the panhandle. Snow for the Haines and Skagway areas, but the north central has had some rain in the Juneau and possibly the Gustavus area. So IFR for northern portion with vis and ceilings / 1/2 mile or less and ceiling up to 1500 feet. / There higher ceiling of 2500 to 5000 for the southern panhandle overnight and this could continue into Thursday.

MARINE

Outside (Gulf/Coastal Waters): Current wind analysis along the central and eastern gulf shows strong breezes out of the S-SW for the Chichagof/Baranof/PoW coast, with northeasterly fresh breezes along the coast; localized areas of gales out of major inlets/bays like Dangerous River and Lituya. Sea state is dominated by SW seas, with significant heights 10 to 15 ft, highest seas from the Fairweather grounds to Cape Decision. A 10 to 12 second period is masking the underlying shorter period SW wind chop and northeasterly outflow. As the southerly winds diminish today southwest seas will begin to trend down, with outflow winds generating easterly seas out of major entrances and gaps in terrain. Most of our coast should be below 10ft significant wave heights by late Wednesday night. Main threat continues to be major inlets/rivers like Dangerous River and Cross Sound for NE outflow winds bringing higher seas of 8 to 10ft. Favoring the coast will help limit wave growth due to limited fetch potential.

Inside (Inner Channels): The tale of two regimes continues this afternoon; warm blustery winds along/south of Icy Strait-Portland Island, with cool outflow winds continuing in Lynn Canal and the northern inlets of Glacier Bay. Expect a brief respite in winds this afternoon for the north before the pressure gradient between the Gulf of Alaska and Canada builds, with our N to NE outflow wind regime dominating most of the inner channels. Regarding wind strength, expect many channels to switch between near-gale force to gale force conditions over the next several days. As cold arctic air infiltrates the Panhandle, freezing spray will become more of a threat, Eldred Rock to Taiya Inlet will likely see moderate to heavy freezing spray. Caution is advised for gale force E-NE winds around the four corners area (Taku Inlet).

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Storm Warning until 9 AM AKST Thursday for AKZ317. Winter Weather Advisory until midnight AKST tonight for AKZ318. Winter Storm Warning until midnight AKST tonight for AKZ319. MARINE...Gale Warning for PKZ012-013-651. Small Craft Advisory for PKZ011-022-031-032-053-641>644-652- 661>664-671-672.