textproduct: Juneau

UPDATE...update for the 06Z TAF issuance

Only minor edits to the forecast this evening. The gale force low continues to push towards Haida Gwaii and is bringing gusty winds and rain to the southern panhandle through most of tonight. Dry weather with some mid to high clouds expected for the north. Did drop nighttime temperatures a few degrees, especially for Yakutat, as there may be a bit of clearing there later on. A Frost Advisory was issued for Yakutat. Patchy frost may occur along upper Haines Highway, and along the Icy Strait corridor, but confidence was not high enough for an advisory as clouds look to be a bit more expansive than last night.

PREV DISCUSSION......ISSUED AT 407 PM AKDT

SYNOPSIS...

Key Messages:

- An unseasonably strong system impacts the southern half of the panhandle through Sunday night. With bands of rain and gale force winds in Dixon Entrance, and breezy conditions for southern Prince of Wales and Annette Islands.

- Conditions improve Monday as the system departs, with clearing skies and warm daytime temperatures taking hold. Monday looks to be the nicest day of the week with daytimes temperatures reaching the mid to high 60s.

- Another front arrives into the N Panhandle by Tuesday afternoon into mid week, bringing another round of rain and wind to communities along the coast and along and north of the Icy Strait Corridor through Tuesday night.

SHORT TERM.../through Tuesday/ The panhandle this Sunday is a study in meteorological contrasts. On one hand, drier weather and sunnier skies are in abundance across the northern half of the area as NW flow becomes predominant, bringing with them warmer daytime temperatures. On the other hand, a warm front moving across the southern panhandle is bringing with it increasing rain and windy conditions which will last through Sunday night. NBM guidance is pointing towards anywhere from 0.5 to 1.5 inches of rain with this system for areas from Sumner Strait southward, with the greatest totals for the far southern panhandle. Given the easterly flow, am not too concerned with significant orographic enhancement in areas of elevated topography, though will continue to closely monitor in case the situation changes.

Winds across the southern panhandle with this system will feature gusts up to 35 mph, though occasional gusts of up to 40 mph are possible, especially for areas around Ketchikan and Annette Island. Gale force winds continue Sunday night through the Dixon Entrance, Southern Clarence Strait, and near the Sumner Strait Ocean entrance, with northerly winds of 15 to 20 kt for the central and northern inner channels.

The precipitation along with most of the winds, depart through Monday morning as the front and its parent low move into Canada. By Monday afternoon clearer skies, drier weather, and warmer temperatures will be in abundance across SE AK, barring a few isolated showers.

LONG TERM.../Tuesday night through Friday/ A weak warm front is expected to move over the panhandle from north to south, beginning Tuesday evening. This front is preceding its parent low, which is currently tracking along the Aleutians and into Bristol Bay. Guidance now suggests the low is moving slower than initially thought and will likely not cross into the Gulf of Alaska until late Wednesday night into Thursday morning. When it does arrive, it is expected to dissipate as it reaches the central Gulf due to weaker upper-level support. The movement of this low will be associated with significant southwesterly fetch and longer wave periods in our outer marine zones. Refer to the marine discussion for more information.

The front's primary impacts will be felt across the northern panhandle, bringing moderate rain showers on Wednesday. This is attributed to proper instability accompanying the frontal passage, decent low-level lapse rates, and moisture advection into the inland areas. 24-hour precipitation totals from Tuesday evening into Wednesday evening are expected to be highest inland, along the windward side of the Coast Range, and along the northeast Gulf coast. There is high confidence (80%) in total precipitation ranging from 0.65 to 1.0 inches across these areas, while other parts of the panhandle are forecasted to see 0.45 inches or less. Windier conditions are anticipated in Lynn Canal, Taiya Inlet, and Stephens Passage. Sustained winds of 20 to 25 knots are forecast to peak Tuesday night and Wednesday as the front moves through. Frederick Sound is less likely to experience a significant increase in winds due to the general north-south orientation of the pressure gradient and weak ridging over the southern panhandle and Haida Gwaii region.

Later in the week, ridging is expected to build over a greater portion of the panhandle, following the front and the dissipation of the Gulf low. This transition will lead to more zonally oriented onshore flow and relatively benign light rain. While minor warming is anticipated to begin mid week into the weekend, temperatures will still remain seasonably cooler.

AVIATION.../through Monday evening/... For areas north of Frederick Sound, VFR flight conditions dominate with mid to high clouds persisting. Winds will generally be less than 10kt for the period; except 10-15kt through Monday morning for PAHN, along with winds increasing to around 15kt for PAGY Monday afternoon.

From PASI over to PAPG and on south, rain and gusty winds will slowly diminish from north to south through Sunday night. Generally VFR flight conditions continue for the TAF terminals, however, a steadier/heavier shower could result in MVFR VIS and CIGs. Through Sunday evening, PAKT over to PAKW will see gustier winds 10-15G20-30kt. Otherwise, winds will generally become 10kt or less through the overnight into Monday. LLWS will also slowly diminish across the southern panhandle, with winds 2kft aloft 30-40kt decreasing for PAKT and PAKW by daybreak Monday. Lighter winds and clearing skies with VFR flight conditions should prevail from Monday morning onward.

MARINE... Outside: A 980mb low located 200 miles SW of Haida Gwaii continues to track E across the N Pacific this afternoon, and is forecast to track just S of Haida Gwaii tonight into early Monday morning. The associated gale force front with this system will stall over the SEAK panhandle through this evening as it occludes, keeping a predominate SE to E-ly wind regime across the S panhandle inner channels and coastal waters through the evening before eventually turning more N-ly overnight into Monday as low tracks south away from the area and off-shore conditions develop. Marine interests along coastal PoW and S Clarence should remain aware, buoys across central Gulf and near Dixon Entrance are reporting sustained winds 30 to 35 kts with gusts up to 45kts. Mariners should continue to take caution along the S Panhandle coast with Gale Warnings issued through this evening. For Monday, winds become NW along the coast between 15 to 25kts with wave heights 8 to 11 kts as low continues to track SE away from the area.

Inside: A strong front continues to push into the S Panhandle inner channels through Sunday night as a low moves towards Haida Gwaii, with reported sustained winds around 20kts and gusts up to 30 kts S of Gravina Island. As this low moves south of the Panhandle through tonight, anticipate northerly winds to build through the S inner channels along and south of Frederick Sound, likely reaching moderate to fresh breezes, especially in Chatham and Sumner. Overall inner channel winds diminish overnight into Monday morning as the low tracks south with surface high pressure moving eastward over the area. With clearing skies, anticipating typical afternoon sea breezes to develop around 10 to 15kts,with stronger winds around 20kts expected in Lynn Canal.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Frost Advisory from 2 AM to 8 AM AKDT Monday for AKZ317. MARINE...Gale Warning for PKZ641-661-662. Small Craft Advisory for PKZ012-035-036-053-642>644-651-652-663- 664-671-672.