textproduct: Juneau

SYNOPSIS

Key Messages:

- Rain rates and rain coverage decreases across the southern panhandle Monday into Tuesday.

- Slight chance of thunderstorms possible for the southern panhandle near Misty Fjords area Tuesday afternoon.

- Brief break in rain expected by Tuesday afternoon across the northern panhandle before more widespread rain returns Wednesday morning.

LONG TERM.../Thursday through Sunday/

A weak shortwave trough is expected to bring a front across the region Wednesday morning through Thursday morning, causing rain showers to move from the northwest to the southeast. This initial system is expected to be relatively light, with higher confidence in 24-hour precipitation totals along the coast ranging from 0.25 to 0.5 inches. Amplification by orographic lifting could cause windward areas to see totals on the higher end of this range. Precipitation will taper off Thursday night into Friday morning as high pressure briefly builds aloft and helps to clear skies.

Conditions are expected to deteriorate again Friday night, as a stronger front approaches from a low moving into the north-central gulf. This system will bring more significant precipitation to the gulf coast, spreading across the entire panhandle through the weekend. While guidance on the low's progression varies, high confidence exists for 24-hour totals of 0.5 to 0.75 inches, with potential for 1.25 to 1.75 inches in some models. The heaviest impacts are anticipated along the coast from Yakutat to Sitka, with significant orographic enhancement expected in the Fairweather, Chilkat, and Coast Ranges, likely increasing totals in inland areas such as Juneau, Petersburg, and Ketchikan. Additionally, as the front pushes inland Saturday, the increased pressure gradient will strengthen winds, specifically in Lynn Canal and between Cape Suckling and Cape Fairweather, where a weak barrier jet may form as the low moves further east.

Temperatures through this period will persist in the upper 50s and 60s, with potential to see upper 60s further inland on Friday, given ample clearing.

AVIATION

/through 00z Wednesday/ MVFR to VFR flight conditions across the panhandle this afternoon as a low in the N Pacific splits the panhandle vertically, with a persistent band of rain into the S Panhandle terminals with clearing across the North. Rain will continue into Monday evening, primarily for terminals from Petersburg to Kake and southward before gradually diminishing moving into late Monday night with a general widespread drying trend into Tuesday morning. By Tuesday morning, predominate MVFR to VFR flight conditions for the northern terminal TAF sites, along and north of the Icy Strait Corridor. Further south, thinking flight conditions will be a bit lower for Tuesday morning with predominate MVFR ceilings, higher confidence of IFR development by 12z, and brief periods of LIFR possible through 16z.

Sustained winds across the panhandle will remain around 10kts or less through Wednesday morning across the SEAK terminals with some isolated gusts up to 20kts through this afternoon. No significant LLWS concerns through the TAF period.

MARINE

Outer Waters: The low in the gulf is moving southward, bringing calming conditions in its wake as high pressure takes its place. The rest of Monday and Tuesday, winds are expected to be light and variable, no more than 10-15kts. Significant wave heights are not expected to exceed 5ft through Tuesday. Early Wednesday morning, another low pressure system moves into the gulf, bringing another round of wind and waves. Current thinking is that winds are not likely to exceed 20kts in the gulf, but could be gusty as the front moves across the area. NW winds along the coast could also funnel winds around prominent capes late in the day Tuesday and through the night as the low pressure center creates somewhat of a ridge between itself and the coast.

Inner Channels: High pressure looks to build over the panhandle Monday night as the low pressure center moves south of the area. This is likely to bring light and variable winds overnight and through the morning on Tuesday. Clearing across the northern panhandle on Tuesday ill allow sea breezes to prevail with Lynn Canal expected to reach 15kt SE. A low pressure center is expected to move into the gulf on Wednesday, bringing a front that is likely to bring gusty winds, especially in the northern panhandle. Wind are expected to be relatively more elevated in the northern panhandle, around 15kts, as the front will break apart across the terrain as is moves south.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...None.