textproduct: Juneau

UPDATE

Issued several new small crafts and a marine weather statement regarding a gust front moving northward. At time of writing, it is currently approaching the Eldred Rock area. Highest uncertainty is if winds will extend into the Glacier Bay area, or if lack of heating due to dusk will reduce the thermal gradient enough to be non impactful. Leaned towards it moving into the Glacier Bay area. Gusts associated with this front may reach up to 30 knots.

AVIATION...00z TAFs

Showers are expected to largely be on the downward trend, with gusty winds diminishing going into the overnight timeframe. In the wake of the second front that moved through the central and southern panhandle, mostly VFR to MVFR conditions with the occasional convective shower. No longer expecting any lightning to be associated with any of these showers, the area of lift looks to be too low to provide any significant ice for lightning development. Going into tomorrow morning, a front does approach from the southwest, once again bring down CIGs AOB 2500 ft with a slight increase in winds and additional rain showers.

PREV DISCUSSION...

SYNOPSIS...

Key Messages:

- An organized band of stronger showers is over Baranof and Prince of Wales Island and will continue to move inland Tuesday evening

- A slight chance of isolated thunderstorms will be possible, with potentially gusty outflows from the stronger cells

- Active weather continues midweek as shower potential continues Wednesday and another front moves into the central and southern panhandle through the evening

SHORT TERM.../ through Thursday night / The with the inner frontal band wraps spinning showers along the coast line of Baranof Island to Cape Edgecumbe and then westward into the gulf. Some of the showers are stronger with locally gusty winds, the Low will drift ESE into the southern panhandle overnight before falling apart. Mid level support and orographic lifting may allow stronger convection sufficient to spark a few isolated thunderstorm for the southern portion of the panhandle this evening and perhaps Wednesday afternoon towards the Misty Fjords area of the panhandle.

Should see showers tapering off over the south, but the next incoming trough across the southern gulf to the southern panhandle Wednesday evening/night. The northern gulf and panhandle is looking drier and the front is sweeping to the area, but not over the northeast gulf.

LONG TERM.../Friday through Sunday/...After the low pressure on Thursday brings a front across the southern half of the panhandle, this low will move southeastward and dissipate quickly as it gets near Haida Gwaii overnight into Friday morning. The remnants of this low will keep some precipitation chances into the morning for the far southern panhandle Friday. As for the northern panhandle, a low to the NE of the panhandle in Canada will bring a band of showers southeastward Friday. The timing and extent of this easterly wave is still uncertain at this time, associated with some disagreement on the timing of a shortwave and upper level band of vorticity moving through the area around the upper level low in Canada, and the overall presence of the upper level low into the end of the week as some ridging attempts to build over the interior and Yukon. The confidence as of now is for the wave to push through the northern panhandle from Skagway and Haines down Lynn Canal through Friday morning, into the central panhandle by the afternoon hours, before just grazing the coastal mountains of the southern panhandle by the evening.

This uncertain pattern continues into the weekend as the possibility of some weak easterly waves impacting the panhandle lasts through Sunday night with this main low sitting to the NE. None of these waves appear to have as much confidence past Friday's shortwave, but with the ridging building over the Gulf and panhandle into this weekend, the chances for drier weather and breaks in the cloud cover is higher for this weekend across much of the panhandle as this more benign pattern sets in.

AVIATION...Active pattern from an aviation standpoint for the southern half of the panhandle while a line of showers work their way eastward towards Prince of Wales Island. Looking at NUCAPS soundings out ahead of the front, there is some evidence of less than expected lapse rates between 850-500 mb, with good confidence, however, this may change with the 0z Annette sounding. Regardless, embedded thunderstorm development, particularly in southern PoW and southern Clarence Strait including Ketchikan is possible due to orographic lift. Guidance does indicate that CAPE values greater than 300 J/kg are possible ahead of this system, partly with assistance of daytime heating around the Ketchikan area. Any thunderstorms that do develop are expected to be associated with wind gusts up to 35 knots, CIGs AoB 2000 ft, and moderate rain showers with visibilities less than 4 SM. Behind this convective system, unstable conditions will still be present without a clear lifting mechanism; however, it is possible to see some occasional rain showers.

MARINE... Inside (Inner Channels): Winds across the inside waters mainly remain southeasterly around or below 10 kts with the exception of Clarence Strait and Taiya Inlet. These areas have seen southerly winds increase to around 20 kts late this morning into this afternoon. Along with this, a slight chance of thunderstorms continues into this evening for southern areas. The main impact will be erratic gusty winds that can quickly increase. Todays higher winds will remain into tonight before the overall wind trend is diminishing winds. The next front starts to make its way through the gulf tomorrow. This will once again increase winds. Again the main areas, with strongest winds, are most likely to be over N Lynn Canal and Clarence Strait. Those areas could see winds increase to 15 to 20 kts. Winds and seas will then diminish once again Thursday.

Outside (Gulf and Coastal Waters): An area of low pressure remains just west of Baranof Island slowly moving southeasterly. Due to this low, areas from Baranof Island southward will continue to see south to southwesterly winds around 20 kts into this evening. There continues to be a slight chance of thunderstorms along the coast, south of Baranof Island into tonight. The main impact from any thunderstorm development will be gusty winds. There may also be a few lightning strikes possible. Later winds will then begin to diminish into Wednesday. The next front will then move across the gulf Wednesday afternoon and evening. This will once again increase winds to around 20 kts from the southeast. We may see some of these increased winds last into Thursday before a broad ridge enters the gulf decreasing winds. This ridge will also change wind direction to become more northwesterly.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ011>013-021-031.