textproduct: Juneau

SYNOPSIS

Key Messages:

- A series of fronts will push into the panhandle through the end of the work week with rounds of light precipitation expected.

- Increasing forecast confidence of drier and warmer conditions heading into the weekend.

LONG TERM.../Thursday Through Saturday/

The spring weather pattern continues unabated through the week, as high temperatures in the upper 30s and 40s remain, and a front moves across the panhandle from NW to SE Thursday through Friday. The weekend offers a respite from the rain, with the sun breaking out across much of the area.

The upper level ridge over the area will have flattened out by Thursday, allowing a system to break through and move across the panhandle. Am expecting rain to be predominant, as snow levels remain between 1000-2500 feet (with the higher snow levels for the southern panhandle). 1000-850mb thicknesses will also remain at or above 1290 decameters across SE AK. This will significantly limit chances of snow near sea level with this system, and while some snow flakes will mix in during the overnight hours for the Icy Strait Corridor northward, expect rain to remain the primary precip type. The QPF totals look to be rather limited, with NBM 75th percentiles at or below 1 inch for most locations, and so don't expect any flooding concerns with this system either.

As the system departs to the south Friday into Saturday, anticipate weak northerly outflow winds developing. Particularly during the overnight and early morning hours, winds of 20 to 25 kt will spread across Lynn Canal with gusty conditions expected for areas like Chatham Strait, and Stephen's Passage. During daytime hours, these winds will be far weaker, as the Northerly pressure gradient force clashes with diurnal heating (ocean effect sea breezes). Clearing skies are expected in the wake of the system as a ridge rebuilds, and then lasts through much of the weekend. Ensemble guidance struggles once we enter next week, with the usual difficulties in trying to time the breakdown of the ridge in the extended range.

AVIATION

The flat ridge near the northern gulf coast. Pulled back on the precip in a number of these locations. Currently expecting the precipitation to be lighter than expected, battling the dry surface air to reach the surface. Instead of making many of these areas prevailing precipitation, opted to bump this down to PROB30 to represent the reduced likelihood.

Not expecting large visibility drops in the next 12 hours below 6SM, due to dry surface conditions, but may see conditions dip below to 4-5SM overnight with the incoming light precipitation. Additionally, expecting to see predominantly light rain to begin, transitioning to more of a rain snow mix by this evening. Still not going to rule out any full snow development overnight, but not currently representing it in any TAF in the Icy Strait corridor. Consider the likelihood less than 20% at this time, with chances diminishing further by the end of this TAF issuance.

Expecting to see the windy conditions diminish in the Skagway area, due to a relaxing gradient from cooling nighttime temperatures.

MARINE

Inside (Inner Channels): Inner channel winds this afternoon remain light, with obs around the area reporting generally 10 to 15kts or less, locally higher within Lynn Canal northward to Taiya Inlet up to 20kts as thermal gradient winds have persisted. Outside of Lynn Canal, winds will continue to diminish through Tuesday evening, going largely light and variable through Tuesday night into Wednesday morning. Wave heights within Lynn will diminish through tonight, with widespread wave heights 3ft or less for the inner channels expected through Wednesday.

Outside (Gulf and coastal waters): Ridging continues across the Gulf waters as high pressure remains anchored over the N Pac with a long wave trough over the Aleutians, sending a weak front inland across the N Panhandle through this afternoon. Looking at latest surface obs and satellite imagery, SW-ly winds across the SW Gulf turn more Westerly as you move towards the SEAK coast, ranging from 20 kts over the Gulf to around 10 kts along the coast. A brief lull expected through the evening before another front tracks eastward across the Gulf overnight Tuesday into Wednesday with off-shore wave heights increasing up to 12ft by early Wednesday morning, diminishing to around 7 to 9ft along the Baranof coast through Wednesday afternoon. Further north in the Gulf, main marine hazard will be weak easterly barrier jet forming near Cape Suckling towards Yakutat as this secondary front approaches through Wednesday morning, with sustained winds Fresh to Strong Breeze with gusts up to near Gale expected and wave heights approaching 7 to 10ft by the early afternoon before the front pushes inland with winds and waves diminishing into Wednesday night.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ642>644-651-652-661>664-671-672.