textproduct: Juneau

UPDATE

Aviation discussion updated with 18Z TAF issuance.

AVIATION.../through 18Z Sunday/

The forecast remains largely unchanged with fog lingering at PAJN at 18Z Saturday, anticipated to dissipate shortly. All sites remain VFR with clear skies, which is expected to continue through the period with the exception of fog development overnight. Wind across the southern panhandle has already picked up to 10-15 kts with gusts up to 20kts which is likely to persist through the day. Winds at all other locations are generally calm, with the exception of PAHN, and are expected to remain below 10kts through the rest of the day before becoming light and variable overnight.

PREV DISCUSSION......ISSUED AT

SYNOPSIS...

Key Messages:

- No major weather hazards are expected through the weekend.

- Drier trend expected going through the weekend and into next week with clear skies and widespread cooler overnight temperatures down into the mid 20s to mid 30s.

SHORT TERM.../through Monday night./... No major changes to ongoing forecast this morning, patchy fog has been touch and go, not lingering long between developing and frosting out, limiting visibilities briefly down to ~1 mile at times. As mentioned in the previous discussion, temperatures were nudged down overnight temperatures across the board, lowest into the mid 20s for communities along the Icy Strait corridor like Gustavus, Hoonah, and Juneau. By mid day, expecting high temperatures in the low 40s to low 50s before a plummet back down into the low 20s to low 30s once more Saturday night given ongoing clear skies and drier conditions with lower dew points expected.

Cloud cover increases from west to east through Sunday as a weak front moves out of Prince William Sound and dissipates pushing across the northern Gulf. Outside of the increase cloud cover, not expecting any real rainfall with a grand total of 0.10" or less along the coast near Yakutat through Monday. However, we will likely see a bit of a rebound in overnight low temperatures as a result of the increased cloud coverage Sunday night into Monday.

LONG TERM.../Tuesday through Friday/ Generally uneventful weather pattern in the extended portion of the forecast, wrapping up October neatly. A ridge of high pressure in the Gulf will be the main feature driving the weather in SE AK. Offshore flow will lead to milder weather and limited to no precipitation for much of this week. Early in the week, the feature most worthy of discussing is a small low which intensifies a bit over the southern panhandle and move further south. This will amp up the N-S pressure gradient on Tuesday into Wednesday, increasing northerly winds in Lynn Canal, and potentially other N-S inner channels to a lesser extent.

Later in the week on Friday the next considerable low and attendant fronts will be moving into the Gulf, raising rain chances yet again.

AVIATION.../Through 12z Sunday/... Widespread clear skies is the main story for Saturday as high pressure persists over the gulf, with outflow winds increasing through the day. Patchy fog development has been observed in sheltered interior passes and at some central panhandle sites this morning, but with temperatures hovering around freezing, many locations have managed to stay VFR with only a thin bank persisting near the surface. There have been periods of LIFR conditions reported overnight with thickening fog, but comparison to camera images indicates this is mainly localized to just over the ASOS/AWOS. Any lingering fog will dissipate by 15 to 18z this morning as northerly outflow winds up to 10 to 15 kts increase through the inner channels. The main locations expected to see gusts of 20 to 25 kts through midday would be PAGY and PAHN, though PAKT and PAKW have the potential to see gusts increase up to 20 kts for a short period as a low pressure system dips south of the area. Winds should begin to decrease through Saturday evening, with many locations becoming calm overnight. Some upper level clouds have the potential to ride the ridge into the northern panhandle early Sunday morning, but for the most part, skies are expected to stay relatively clear through the rest of the period.

MARINE...

Outer waters: A 1030mb high slides across the central Gulf of Alaska through Saturday while a gale force low south of Haida Gwaii. In tandem, E-ly winds across the central Gulf become more light and variable through the afternoon with NE- ly winds turning more N-NW-ly along the coast through Saturday night. Winds and seas diminish across the Gulf and coastal waters Saturday night into Sunday as the high pressure moves towards the Gulf from NW to SE as the aforementioned low departs SE towards Vancouver Island.

Winds and seas will increase early next week as this stronger area of high pressure builds back into the western Gulf and increases the gradient as low pressure develop to the south, with winds becoming fresh to possibly strong from the northwest, especially over the southern waters.

Inside Waters: Northerly off-shore winds continue this morning as a strong low continues to track south of Haida Gwaii in tandem with building high pressure over the Gulf. Made targeted forecast changes to inner channel forecast, including dropping the strength of the winds a tad this morning as the low track near Haida Gwaii is a bit further southward. However still thinking the strongest inner channel winds through early Saturday will remain around 20 to 25 kts with some brief gusts up to 30 kts near Eldred Rock within N Lynn Canal and from Midway Island to Five Finger in S Stephens Passage to Frederick Sound through early afternoon. Winds and seas lessen into Saturday evening as pressure gradient turns more parallel to the panhandle inner channels with high pressure moving across the Gulf and inner channels through Sunday. Winds and seas looks to increase again early next week with as high pressure builds back into the northern Gulf and increases the gradient as low pressure develops to the south, with northerly/easterly offshore winds possibly becoming fresh to strong.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-033-641-642-661-662.