textproduct: Juneau

UPDATE

Aviation Discussion for 18z TAF issuance

SYNOPSIS

Key Messages:

- Onshore flow continues with persistent showers through the upcoming weekend.

- Gusty winds over land as another front pushes through Friday afternoon and into the evening.

- Isolated thunderstorms, primarily for the SE gulf Friday night on the back side of the front.

LONG TERM.../Sunday through Wednesday/

Not many changes were made to the extended forecast, with the main ones being timing and strength of the winds going into Sunday morning. Along the northern gulf coast, the E to SE winds were bumped forward a few hours and therefore diminish quicker. In the inner channels, winds were slightly increased and prolonged going into Sunday, as well as Tuesday night. The previous gale force low bringing impacts Friday into Saturday will stall in the northwestern gulf through Sunday, enhancing S to SW onshore flow and allowing for widespread shower development to push into the panhandle. Overall winds for the panhandle will steadily decrease through the end of the weekend into early next week, though showers may still bring periods of moderate to heavy rain and gusty winds as they pass over.

Shower potential will begin to diminish Monday afternoon as a fast moving system dips into the southern gulf, turning overall flow more E to SE. Rain rates for the northern panhandle significantly drop early next week, and some small breaks in the clouds may be possible as well. The associated frontal band will mainly affect areas south of the panhandle along the eastern BC coast, though it will attempt to wrap around and swing up into the southern panhandle overnight Tuesday into Wednesday. This could allow for some enhanced easterly winds, especially through gaps in terrain. Rain rates will start low and slowly pick up through the week, with less than half an inch expected in 24 hours when the system initially hits increasing to around an inch in 24 hours by Wednesday. Near gale to gale force E to SE winds (28 to 40 kts) will pick up in the southeastern gulf through the day Tuesday, and with high pressure developing in YT, the pressure gradient over the panhandle will begin to tighten and turn. This will allow for outflow winds to pick up going into Wednesday, with areas such as Lynn Canal seeing wind speeds reaching gale force for a short while Wednesday morning. This low looks to similarly stall in the gulf for a few days, potentially helping to steer showers or another system into the panhandle for next weekend. High temperatures in the mid to upper 40s will prevail through the weekend before the northern panhandle drops significantly to highs in the low 40s going into next week. Lows will be in the mid to upper 30s this weekend, with the northern panhandle following the trend and dropping down to low 30s early next week.

AVIATION

VFR conditions between showers this morning have become more few and far between as coverage has increased, with isolated thunderstorms observed along the outer coast, particularly in the vicinity of Sitka. Convective showers will persist through Saturday afternoon before a front moves through bringing widespread MVFR conditions with lowering CIGs. With this frontal passage, periods of rain along with some LLWS are expected across a majority of the southern outer coast as well as the central panhandle up to Icy Strait. Gusty surface winds will finally start to fall off later Sunday as the low in the gulf begins to weaken and eventually push northward into the gulf coast.

MARINE

Main story: Elevated winds and seas continue as another front moves into the area.

Outside Waters: Winds in the Gulf will be on an upward trend through the morning as another front sweeps across the outer waters and enters the panhandle. Sustained winds will reach 40-45 kt and waveheights of 22-27 ft are expected. Through the evening and overnight hours, winds and waves will slowly subside, diminishing to 20-30 kt and 12-15 feet respectively. Winds and waveheights will continue on a diminishing trend through Sunday, before a weak wave moves up from the south on Monday. Wave period as of early Saturday morning is 13-15 seconds with a SW swell.

Inside Waters: Winds in the inside waters will be on a strengthening trend through the day as another front moves across the panhandle. Through the afternoon hours, winds ranging from strong breezes to gale-force will be present across the inner channels, alongside elevated wave heights. Some relief is expected on Sunday, when wind speeds diminish down towards 15 - 25 kt (fresh breeze to strong breeze).

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Strong Wind from 1 PM this afternoon to 7 PM AKDT this evening for AKZ322-325. Strong Wind from 1 PM to 4 PM AKDT this afternoon for AKZ323. MARINE...Gale Warning for PKZ012-033-642>644-651-652-661>664-671-672. Small Craft Advisory for PKZ011-013-021-022-031-032-034>036-053- 641.