textproduct: Juneau

UPDATE

Update to the discussion to include the 06z TAFs.

PREV DISCUSSION......ISSUED AT 352 PM AKDT Tue Apr 14

SYNOPSIS... Key Messages:

- Clear skies through Wednesday morning before clouds begin to move in preceding more precipitation Wednesday night into Thursday

- Another front reaches the northern panhandle Thursday night, continuing precipitation through Friday and into the weekend

SHORT TERM...Drier weather has spread across SE AK as a low dips south of the panhandle, bringing the arrival of spring in full force across the area. Clear skies will allow for warmer daytime high temperatures, with colder nighttime lows and patchy fog development through the early morning hours for parts of the southern and central panhandle. The primary changes made to the forecast were increases in northerly flow for the inner channels, alongside some upward adjustments to high temperatures for Wednesday. The ridge building over SE AK will keep precipitation at bay through most of Wednesday, with cloud cover steadily increasing through Wednesday evening as a shortwave manages to move over the ridge axis and into the panhandle. This shortwave will increase precipitation chances across the northern outer coast and eventually spread into the rest of the panhandle, though precipitation is expected to remain light and mostly rain. See the long term discussion for more information.

LONG TERM.../Thursday through Sunday/...Minimal changes have been made to the long term forecast, with increased confidence in a shortwave trough bringing light precipitation to the northern panhandle Wednesday night into Thursday morning. This organized band of precipitation will move into the northern outer coast overnight and spread southeast through the early morning. Overnight temperatures are still expected to get cold enough for parts of the northern panhandle, mainly Yakutat and the northern highways at higher elevations, to see snow or a rain/snow mix with the initial band of precipitation into Thursday morning. These temperatures will increase to above freezing through daytime hours, which will limit any snowfall from accumulating through Thursday. Onshore flow will push showers over the panhandle after the band moves over, continuing on and off precipitation until late Thursday night when a more organized frontal band reaches the northern outer coast and pushes inland overnight. This front is expected to mainly impact the northern and central panhandle through early Friday morning, but moist onshore flow will continue precipitation through the rest of the panhandle during this period. Higher resolution models are showing a chance for parts of the southern and central panhandle to see some breaks in weather during this showery period on Friday, but many of the medium-range models depict more consistent moisture lingering over the entire panhandle. Temperatures should stay warm enough to keep precipitation as rain into the weekend, though rainfall rates will remain on the lighter side. The only real wind issue is expected near the typical hot spots from Thursday into Friday as the front moves inland, with Lynn Canal, southern Stephens Passage near Five Finger Lighthouse, and around Point Couverden potentially seeing small craft advisories through this period.

Active weather is expected to persist over the northern panhandle, especially the northern outer coast around Yakutat, through Saturday morning before another low pressure system jumps up into the southern gulf which will bring consistent precipitation back to the rest of the panhandle. This is expected to continue through Saturday before another front moves in along the northern gulf coast, forcing the lingering precipitation to shift southeast out of the panhandle. Uncertainty still remains on the position of the low center and how strong this upcoming front will be, which will impact the timing of the previous system moving out and the next front moving in. The EC is thinking this front will move in through SUnday morning and blanket the entire panhandle, while the GFS is hanging back with the front moving in Sunday night and only reaching parts of the northern panhandle. Due to the northern location of this low, precipitation has the possibility of falling as snow overnight for northern locations such as Yakutat and the northern highways. Updates to the timing of this late weekend system will be made as the period gets closer.

AVIATION...Showers continue to move out of the area this evening as the low that was producing showers dives to the south. With this, VFR conditions are left behind with clearing skies with the exception of a band of clouds over the southern panhandle. One concern with the clearing skies is the potential development of fog during the overnight hours this evening as temperatures cool. This will need to be monitored closely as some places are borderline for fog development. But this fog could also frost out with the dropping temperatures. Heading into tomorrow, clear conditions are expected through the morning before clouds from the next approaching system move across the Gulf to the NE Gulf coast and Baranof island area. With these clouds, MVFR conditions could be possible along the outer coast as well as some potential for light precipitation for the latter half of the TAFs.

MARINE... Outer Coastal Waters: Westerly fresh to strong breezes continue across the outer coastal waters on Tuesday. Wave heights of 5 to 6 ft in the northern gulf and to 7 to 8 ft in the southern gulf will steadily decrease through Wednesday to around 4 and 6 ft, respectively. Winds will begin to turn more southeasterly as a system approaches through the northern gulf Wednesday night into Thursday.

Inner Channels: Northerly winds have strengthened above what was previously anticipated, bringing N/S oriented channels up to a fresh to strong breeze (20-25 kt) through Tuesday. Winds are expected to diminish through Tuesday evening before flipping out of the south Wednesday morning and remaining light.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ641-642-661>663.