textproduct: Juneau

UPDATE

Forecast remains on track this evening. Made some minor adjustments to sky cover and temperatures to account for the latest trends. An update to the aviation section is included below for the 06z TAFs.

SYNOPSIS

Key Messages:

- Shower potential shifts southeastward and diminishes through Wednesday afternoon, with skies clearing behind. Northerly winds build across the inner channels Thursday. - High pressure returns through the end of the week with drier conditions, more sunshine, and high temperatures in the mid 60s to low 70s.

LONG TERM.../Saturday through Tuesday/

Still no major changes are expected in the long term forecast, as a high pressure ridge dominates the Gulf for the foreseeable future, bringing consistently dry and benign weather. Beginning Saturday morning, winds across the inner channels and coastal waters are expected to weaken and remain at or below 10 knots. Afternoon sea breezes will likely develop with daytime heating, but are not expected to cause significant impacts.

The greatest uncertainty in the long term is whether a weak disturbance will bypass the northern panhandle early next week. Model guidance generally agrees that high pressure will strengthen and block most appreciable precipitation, however, there is a small but increasing chance of light rain reaching the northern panhandle/outer coast region by midweek. Highest confidence is that most precipitation will stay over the mainland interior, though could still see widespread cloud cover move in from the north by Monday. Overall, generally dry conditions with daytime temperatures rising into the mid 60s to low 70s across most of the region, continuing to remain seasonably warm through midweek.

AVIATION...06Z TAFs

As a trough exits the southeast portion of the region, rain showers are gradually ending. However, plenty of low level moisture has been left in its wake. And, as an area of high pressure builds in behind the trough, we expect some mist and fog to develop across the panhandle, with perhaps the lowest ceilings and visibilities to affect PAPG and PAWG. As the pressure gradient increases late tonight into Thursday morning, winds will gradually increase over the northern panhandle. The strongest winds are still expected for Lynn Canal, where northerly gusts up to 30 kts are possible. Any lingering low clouds and fog will burn off by 18Z in most areas, with VFR becoming predominant Thursday afternoon and evening.

MARINE

Outer waters: Generally downward trend through the tonight period, as the front exists into southern British Columbia. Wave heights, driven by prolonged strong winds and a modest westerly swell look to diminish from 8-12 ft at 9 seconds to 4-5 ft by Friday night at around 15 seconds with very little swell influence. Expecting to see highest wave heights and wind speeds out of Chatham Strait and into Dixon Entrance from unseasonably strong northerlies, before falling off Friday morning.

Inside Waters: Main story through Friday is a transition from southerly winds to northerly tonight, strengthening through the day Thursday, and peaking overnight Thursday night into Friday. High pressure from a cold front in Canada, in combination with a shortwave trough moving down from the Yukon, look to increase northerlies in north south facing channels like Lynn Canal, Chatham Strait, and Stephens Passage. Expanded out the areas of strong breezes to exit Chatham Strait into the gulf, but notably did not increase Lynn Canal up to gale force. Pressure gradients for this area look to approach around a 7 mb difference between Whitehorse and Juneau, which has historically only caused gale force winds 20% of the time. Therefore, kept gales out of the forecast, as the more likely scenario will be Lynn Canal maximizing around 30 knots

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-013-032-033-641>644-661>664-671- 672.