textproduct: Juneau

SYNOPSIS

Key Messages:

- Outflow winds continue for northern channels and NE gulf coast through Friday.

- Multiple systems pushing into the southern panhandle will bring rounds of wintry precipitation to Ketchikan, Annette, and Prince of Wales Island.

- Potential for a weak front to move in Monday.

LONG TERM.../Sunday through Tuesday/

The long term forecast continues to be relatively uneventful, with only a few changes made. The northern panhandle is expected to stay mostly dry through the weekend and into early next week. Sunday looks to be more of a break day for the south, allowing the whole panhandle the chance to see breaks in the clouds as residual showers from the previous deteriorating low taper off. An upper level trough over the panhandle persists through the period with the southernmost tip largely remaining south of the panhandle, steering the bulk of the active weather into British Columbia and away from SE AK. A 500 mb low moves along the deepest part of the trough Sunday into Monday, preceded by an upper level shortwave in the northern gulf. The surface inflection associated with the shortwave may bring light precipitation along the outer gulf coast of the panhandle through Monday, though this doesn't seem to have enough energy to make it too far inland.

A surface low following the upper level trough jumps into the southeastern gulf Monday afternoon, though this looks to be too far south for the resulting frontal band to make it to the panhandle. There is potential for the initial warm front to combine with the latter half of the shortwave band, which would bring a more organized band of precipitation through the southern and part of the central panhandle Monday night through Tuesday morning. Cold temperatures aloft (-8 to -10 degrees C) would keep most of this precipitation as snow, with the chance to mix into rain through midday as daytime temperatures rise. Daytime highs in the upper 30s to low 40s, combined with the increased sun angle, will make it so most snowfall does not accumulate until the evening or nighttime hours when temperatures decrease.

This low is not expected to stick around for long, dipping south Tuesday night into Wednesday. Uncertainty remains for the exact impacts through the early week, as model guidance is still very split on the position of the low and resulting front. The EC is favoring the front sweeping all the way through the panhandle, while the GFS is keeping it more offshore. Went with a compromise, with more certainty on the front at least reaching the southern panhandle. Guidance does agree on the exiting of the low, increasing confidence on cutting down on PoPs Tuesday afternoon. Southerly winds will briefly increase going up through the inner channels with the frontal band, though they aren't expected to be very strong. Both before and after the low moves through, light outflow looks to develop with the pressure gradient tightening over Lynn Canal. This is only expected to reach up to 25 kts through Lynn Canal and Stephens Passage, as well as around Point Couverden and out of Cross Sound. This will help to keep skies clear through the northern panhandle and extending down through the central panhandle into the early week, potential clouding up more by Tuesday with the weak frontal band.

AVIATION

The northern panhandle remains mostly clear with continuing VFR conditions throughout the TAF period. The main impact continues to be increased winds of 10 to 15 kts with gusts around 25 kts over Skagway and Haines. Some variations in winds will occur throughout the day as the low to the south of the panhandle weakens, but the high pressure to the north slightly increases. Then for the Juneau area, winds have greatly decreased but LLWS is still possible with winds aloft, from 1500 to 2000 ft, around 25 to 30 kts. This wind shear will be diminishing through the morning hours.

A different story continues across the southern panhandle as the low pressure system near Price of Wales Island continues to send showers over the area. These showers are bringing variable ceiling and visibilities. Heaviest showers have and can create IFR conditions with ceilings slightly below 1000 ft and visibilities below 2 SM. Otherwise prevailing MVFR conditions, and times of VFR, continue with broken ceilings AoA 2500 ft and visibilities between 4 to 6 SM. Variable conditions will continue throughout the day as a couple of more organized bands of preciptiation move northward. Prince of Wales Island, Annette Island, and Ketchikan will continue to be the main areas affected, but snow will continue to push as far north as Petersburg, Wrangell, and Kake. Sitka is less likely to see these bands of showers, but short times of lowered ceilings and precipitation are possible. Conditions for the southern panhandle will begin to improve late Friday into Saturday morning.

MARINE

Inner Channels...Outflow winds in the northern channels remain the main concern for marine interests this morning. Currently 25 to 30 kt winds are blowing down Lynn Canal, out of Taku Inlet, and down Stephens Passage. Those winds are expected to diminish by tonight with only Lynn Canal retaining 25 kt winds into Saturday morning. Freezing spray remains a possibility for many of the those northern channels especially at night. Other wise most areas will be 20 kt or less mainly out of the north or east. Clarence Strait is the exception with mainly SE winds today and this evening before starting to switch to a NW winds late tonight. The higher seas in the inner channels are still mainly focused on the outflow areas, especially the longer fetch areas of Lynn Canal and Stephens Passage where high winds blowing down the long linear channels has built seas to 7 to 10 ft. Those seas are expected to subside tonight as winds diminish.

Gulf Waters...Fairly quiet across the gulf with only a low near Prince of Wales Island producing any winds over 20 kt right now (25 kt max near that low). That is expected to persist today before weakening tonight as the low weakens. Otherwise mostly N to NW 20 kt or less winds expected through Saturday across the gulf. Seas are generally low with 3 to 8 ft seas being the norm (S swell of 3 to 5 ft). Diminishing trend expected for seas as winds and swell subside. Most areas should be 5 ft or less by tonight and lasting into Saturday or Sunday at least.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Weather Advisory until 10 AM AKDT this morning for AKZ327. Winter Weather Advisory until 10 AM AKDT Saturday for AKZ328-330- 332. MARINE...Gale Warning for PKZ012-013. Small Craft Advisory for PKZ031-032-034-641>643-661>664.