textproduct: Juneau

SYNOPSIS

Key Messages:

- Rain continues into Friday as a low passes south of the panhandle

- Chances of showers linger into the weekend with seasonably cool temperatures

- Leaning towards drier and slightly warmer conditions for early next week

LONG TERM.../Sunday through Wednesday/

Deterministic and ensemble guidance are still not in complete agreement on the details for the end of the upcoming weekend. However, the overall pattern tends to keep the jetstream in more zonal flow and south of the Gulf of Alaska. Moving down to 500 mb, models are also in relative agreement on an upper level low moving eastward from the Aleutians will phase with a shortwave trough sliding southward from over the Bering Sea. At the surface, a cold front extending from a low south of the Aleutians will progress eastward and attempt to form a closed surface circulation south of Kodiak Island by late Saturday.

With the expected lack of upper air support, any low that forms is expected to be vertically stacked almost upon inception, and struggle to produce significant hazardous weather over the region. Continuing from inherited forecast, rain seems most likely to be limited the panhandle south of the Icy Strait Corridor and once again be predominantly light in terms of total accumulations. With the expected closed circulation aloft, this system is expected to linger over the Gulf into early next week before gradually dissipating as ridging tries to build in from the south. This will however mean light onshore flow and continued shower potential, mainly for the outer coast. This will be looked at further in the coming days to see if the drying trend in model guidance continues.

With the continued onshore flow, temperatures will remain seasonably cool over the weekend with daytime highs ranging from the mid 50s in the north to mid 60s in the south. By early next week there will be some slight warming as the ridge takes over and should help clear out some of the residual cloud cover heading into midweek. Snow levels also look to remain above 4000 ft, which means many mountain tops and ridge lines should continue to see gradually retreating snow lines through the period.

AVIATION

The nearly stationary front and associated rain band across the northern and central panhandle is the main aviation concern today. Currently stretching from Gustavus down to Petersburg the rain band is producing ceilings as low as 300 ft (lowest at Gustavus, and Petersburg), and vis as low as 3 miles (lowest at Angoon, Juneau and Hoonah). That feature will be slowly drifting south through the day, reaching Wrangell and northern Prince of Wales Island by evening, before diminishing by Saturday morning with conditions gradually improving. For the rest of the area, MVFR to VFR conditions prevail and will likely persist into tonight (though some periods of lower conditions due to low clouds or shower activity is not out of the question especially this morning). Surface winds remain low with 15 kt or less of wind for most areas.

MARINE

A low S of the panhandle will slowly move E into BC through Friday. A remnant frontal band from the low will linger over the panhandle before falling apart by late Friday. A ridge begins to build over the E Gulf over the weekend, before weakening as a new low enters the Gulf and its associated front stalls offshore.

Outer Waters: Winds of 10-15 kt through the day on Friday, before flow strengthens to 15 - 20 kt out of the SE Friday night, and reaches upwards of 25 kt for the NE Gulf Coast and Northern Gulf on Saturday. Seas in the outer coastal waters of 5 to 7 ft are expected. Seas will remain 5 to 7 ft for most of the outer coast until Sunday when wave heights build back to 8 to 10 ft. The far Northern Gulf W of Yakutat Bay may see 8 ft seas begin to build back in earlier, arriving as soon as Saturday. S swell of 1-2 ft through the weekend.

Inner Waters: Winds over the inner waters will fluctuate between 10 to 15 kt through the day, with wind speeds spiking upwards as frontal bands move through. Lynn Canal and Clarence Strait will likely remain on the stronger side, with these areas in particular likely to see winds of 20 to 25 kt for locations like Lynn Canal and Clarence Strait. Winds will generally follow a diurnal cycle through Saturday, diminishing overnight before ramping back up during the daytime hours.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ012-036-641-642-644-651-652-661>664- 671-672.