textproduct: Juneau

SYNOPSIS

Key Messages:

- Widespread precipitation and strong winds continue through Sunday night, with accumulating snowfall in the far northern panhandle. A winter weather advisory remains in effect for the Klondike Highway through early Monday morning.

- Diminishing trend in winds and precipitation latter half of Monday into Tuesday. Lingering showers primarily across northern panhandle.

- Another system arrives Tuesday night bringing predominantly rain and warming temperatures into midweek.

- Late week into next weekend, long range models are hinting at a weather pattern that has been known to produce heavy snow. High uncertainty at this time but worth watching closely.

LONG TERM.../through this week/

The upcoming week is looking like another cloudy and rainy week. There will be lulls between the frontal passages but the overall trend in the long term forecast is cloudy and rainy this week. But late this week into next weekend, the long range weather models and ensembles are hinting at a weather pattern that has been known to produce heavy snow.

After the midweek frontal passage, continued showery weather with on/off type rain with above normal temps.

Friday into the weekend, the overall weather pattern looks to change. The long term weather models and ensembles are hinting at a low pressure trough to develop to our north with a high pressure ridge to our south at the higher levels of the atmosphere. This kind of pattern usually allows for cold air from Canada to slide southward into SE AK while moisture streams in from the gulf at the mid to higher levels. This type of pattern is called overrunning and has been known to produce heavy snow here.

The forecast challenges will be centered around the the cold air from the north and the flow from the gulf. These two variables will be fighting each other. Too much cold/dry air from the north causes the precip amounts to be limited. Too much wind from the gulf causes the atmosphere to mix and the snow switches to rain. But where that balance sets up just right is where heavy snow is likely.

As of now, there is high uncertainty in the details but overall trend is on the snowy side of the rain/snow spectrum. Stay tuned.

AVIATION.../through Monday afternoon/

Widespread moderate to heavy rain precipitation expected through Sunday night. Snow has changed over to rain across the northern TAF sites except for PAGY, which could remain snow a touch longer before changing over to rain by Sunday evening. Generally low- end MVFR flight conditions through Sunday night with VIS and CIGs lowering to IFR under heavier precip. Flight conditions will improve slightly on Monday afternoon as precip slowly diminishes, but MVFR flight conditions likely to remain.

Winds 10-17kt with gusts to around 25kt through Sunday evening. Winds will then diminish to generally less than 10kt, starting first for PAYA Sunday night, then across much of the panhandle Monday morning. Elevated winds look to linger a bit longer into Monday afternoon for PAHN and PAGY. LLWS also expected across the region through Sunday night with winds 2kft aloft 30-45kt.

MARINE

Outer Waters: A strong gale force front is currently moving inland over the coastal land areas at time of writing. A small pocket of expected storm force winds have been observed from an ASCAT pass around 1 PM today, east of Cape St. Elias along the coastline, mainly influenced by a barrier jet. Expecting to see the cold occluded front move ENE over the panhandle, with mainly SW flow behind the front. Expect this SW flow to further enhance the SW swell, increasing heights to 8-10 ft, for a combined, relatively consistent height of around 11-13 ft through tomorrow night.

Inside waters: Wind speeds are beginning to increase from the strong gale force front moving over the panhandle. Expecting to see winds increase out of the south in the coming hours, maximizing around a strong breeze with gale force gusts. Late tonight into early tomorrow morning, expect to see a S to SW shift in winds, particularly in Cross Sound/western Icy Strait, and Frederick Sound. Beyond this timeframe, winds are somewhat likely to diminish slowly over time, to mostly light air to a gentle breeze by tomorrow night. There is some indications of some brief clearing tomorrow night, but was not confident on both clearing skies and calm enough winds for radiation fog to develop.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Weather Advisory until 3 AM AKST Monday for AKZ318. MARINE...Storm Warning for PKZ652-672. Gale Warning for PKZ642>644-651-662>664-671. Small Craft Advisory for PKZ012-013-021-022-031>036-053-641-661.