Area Forecast Discussion
Issued by NWS Juneau, AK
Issued by NWS Juneau, AK
861 FXAK67 PAJK 231246 AFDAJK Southeast Alaska Forecast Discussion National Weather Service Juneau AK 446 AM AKDT Sun Jun 23 2024 .SHORT TERM... Somewhat damp short range forecast for Sunday with a stacked, diminishing low off the coast of Haida Gwaii causing rain chances for the central and southern panhandle. Easterly flow and vorticity advection aloft from the aforementioned low combined with a fully saturated profile will generate just enough lift for the occasional rain shower. Chances for these showers will maximize towards the afternoon time frame with a shortwave moving along the easterly flow. Chances for rain diminish behind the shortwave with reduced influence from aloft flow. There exists some uncertainty around the central panhandle with the potential for downsloping winds prematurely drying the low levels of the atmosphere. Ultimately, either way, expect mostly cloudy skies this Sunday and Sunday night. Changes to the forecast include increasing PoPs around the Petersburg and Wrangell area and across PoW Island to better represent the weak shortwave trough moving eastward. Furthermore, reduced PoPs in the northern panhandle as the stationary front on the Canadian`s side looks to have its upward motion cut off by a growing ridge aloft. .LONG TERM... Extended forecast remains relatively unchanged for next week with lingering showers Monday diminishing into Tuesday, followed by a warming and drying trend. For the big picture, the showers to start the period are due to energy from an easterly wave mentioned above in the short term discussion. After this, a surface ridge is expected to build in over the gulf which will bring clearing skies to the inner channels and overall warmer surface temperatures due to abundant summer sunshine. Being on the downstream side of this developing ridge, the one exception to clearer skies may be the chance of a marine layer developing and pushing into coastal communities. This will also lead to generally light winds overall throughout the panhandle. Expect the highest winds with the usual sea breeze circulations in the afternoon and evening hours. Being on the downstream side of the developing ridge, the exception to otherwise clearer skies would be any marine layer potentially moving into coastal communities. As is often the case, model guidance is not in full agreement on the longevity of this blocking ridge over the gulf. However, the first indications of unsettled weather returning to the panhandle do not show up until the end of next week as of this forecast issuance. Overall shaping up to be a fairly dry, warm and not so windy week to end the month of June! && .AVIATION... Calm winds and saturated low levels has led to intermittent IFR cigs and vsbys across southern panhandle TAF sites this morning. A dissipating upper low over southeastern Gulf will continue to bring isolated to scattered rain showers across the panhandle. Anticipating pre- dominate MVFR flight conditions for Sitka over to Petersburg and southward through much of the day with CIGS AoB 5000ft. Winds are expected to remain less than 10kts through the period except this afternoon for Skagway which could see sustained winds up to 15kts. No LLWS concerns for expected at at this time. && .HYDROLOGY...The Chilkat River remains above minor flood stage today after a brief dip below flood stage yesterday afternoon. Current forecast is on track to peak around late morning today after cloud cover inhibited daytime heating and, therefore, snow melt. The stalled weak frontal feature continues to precipitate but will diminish through this morning. Aloft ridging will overwhelm the weak stationary front and begin to clear out clouds in the extreme northern panhandle. If clouds are successful in clearing through this morning, warm temperatures from solar radiation will likely yield increased snowmelt and a flood stage for Monday higher than currently advertised. && .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...None. MARINE...Small Craft Advisory for PKZ641-661. && $$ SHORT TERM...NC LONG TERM....STJ AVIATION...NM Visit us at http://www.weather.gov/Juneau