textproduct: Juneau

UPDATE

Update to include the 06z TAFs.

PREV DISCUSSION......ISSUED AT 334 PM Tue Apr 28

SYNOPSIS...

Key Messages:

- Light rain and low clouds continue overnight in the northern panhandle, with clouds steadily creeping into the southern panhandle.

- A stronger system arrives on Wednesday morning, bringing widespread breezy conditions and periods of heavy rain.

SHORT TERM...On this fine Alaskan Tuesday afternoon in the worlds largest temperate rain forest, several systems were present across the North Pacific and Gulf. The first system is a shortwave trough embedded in the polar jet, with the axis currently moving north across the northern coast. Associated with this feature is a weak front, which was/is responsible for the heavy rain along the northern coast and southeasterly winds in the eastern Gulf. Peak winds were overnight near Cape St. Elias, with peak gusts of 60 knots. As the front marches northeast Tuesday night expecting winds to remain southerly but below 30 knots by and large, with light rain.

Main threat remains in a developing low near 40N 150W, which will be carried north by an additional lifting trough into Wednesday. Expect southerly winds to increase to near-gale force for much of the coast, with localized gales likely near the Fairweather grounds. This feature will also bring heavy rain back to the Panhandle into Thursday. We remain consistent in our message of 1 to 2 inches of rain at sea level from Wednesday morning into Thursday morning; heaviest rain in the central and northern Panhandle. Certainly, a wet and breezy Wednesday.

Thursday winds and rain relax across much of the region, with an additional system lifting into Prince William Sound Friday, driving gale force easterly winds along Cape St. Elias.

LONG TERM.../Friday through Tuesday/... Another weak frontal passage will be the story for this weekend, following the low pressure system moving out of the area Thursday afternoon. This system will bring rain back to the panhandle Friday night starting in the north and making its way southward through the weekend. Southerly flow associated with the low will drive mid to low level moisture into the region causing moderate precipitation rates to the outer coast and areas north and near the Icy Strait Corridor with the heaviest rainfall concentrated near Yakutat. Dynamic forcing will help keep precipitation rates elevated as the upper level jet traverses northward over the northeast gulf coast and exiting the region Sunday evening. With models continuing to be in agreement, there is confidence on QPF amounts across the region. The panhandle is expected to receive about an inch of rain over the Friday and Saturday period, nothing unreasonable to the area. However, the northeast Gulf Coast including Yakutat could receive over 2.5 inches or through the weekend.

Following the passage of this system, a transition to a drier and significantly warmer pattern is anticipated for Monday and Tuesday as a ridge aloft develops. The NBM guidance for early next week highlights the potential for temperatures in the low to mid 60s, across the central to southern panhandle. Theses warmer temperatures are coupled with clearing skies and drier lower levels.

AVIATION.../through 06z Thursday/...VFR conditions continue for most of the panhandle this evening with the exception of some MVFR and IFR conditions for the northern panhandle and NE Gulf Coast. Ceilings are expected to continue to trend down in response to the next system moving up from the south just in time for Wednesday morning. This system is expected to bring MVFR ceilings and visibilities to the Inner Channels and should persist through the evening tomorrow as we see rain spread across the area. There is the potential that some locations drop down to IFR conditions during the heavier periods of precipitation tomorrow. With the incoming system, winds could become gusty especially during the daytime hours tomorrow.

MARINE...Wind speed described using the Beaufort Wind Scale.

Outside (Gulf and Coastal Waters): As of Tuesday afternoon, Satellite and ASCAT passes show an occluding front pushing north into the northern coast, with winds of moderate to strong breezes. Highest winds were overnight Monday, with ELXA2 reporting peak gusts of violent storm. Touching on sea state, a gentleman's swell from the southwest, formed a few days ago by a hurricane force low in the Bering, was being reported by coastal buoys 46083 and 46084. WSW 14 to 16 seconds at 4 to 6 ft. Along with this wave group southerly fresh seas were present near 8 to 10 seconds. Highest seas were near 10 ft near Cape St. Elias. Expect swell and seas to trend down Tuesday night.

As a developing low lifts north Wednesday, westerly swell continues to dominate the majority of our coast, with developing fresh seas out of the southeast in response to near gale force winds. Expect significant wave heights of 10 to 13 ft from Cape Decision to the Fairweather grounds. Winds decrease and become more westerly Thursday, with a gale force system impacting the northern coast Friday, highest winds near Cape St. Elias.

Inside (Inner Channels): Tuesday afternoon winds of gentle to moderate breezes were widespread. Expect winds to increase for Chatham and Lynn, with building southerly winds of moderate to fresh breezes; highest winds likely near Eldred Rock. Winds decrease early Wednesday morning but don't let this lull trick you, southerly winds will increase through the morning, with widespread fresh to strong breezes impacting the inner channels. Of particular concern is small recreational vessels operating near Cross Sound, Southern Chatham or Sumner Strait, where a long fetch of southerly winds will help increase fresh seas to 5 to 8 ft, with 10 ft seas likely near Cross Sound.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Gale Warning for PKZ644. Small Craft Advisory for PKZ013-022-032-033-641>643-651-661>664- 671.