textproduct: Juneau

SYNOPSIS

Key Messages:

- Suicide Basin has released. Major flood stage on Mendenhall Lake and River was reached Thursday morning with a crest of 14.7 ft around 2:15pm Thursday afternoon.

- Very warm temperatures to end the work week with highs in the mid 70s to lower 80s. - The warm and dry conditions will bring elevated threat for fire starts across much of SE AK. A few small fires have been observed already over the past week.

LONG TERM.../Sunday through Wednesday/

The upper level ridge is expected to begin to dissipate Sunday as a weak trough builds over the gulf, shifting the region toward zonal flow that will bring cooler, more saturated air onshore. Temperatures are expected to follow a cooling trend, due to 850mb level temps dropping, and leading to daily highs in the mid 60s by next week, though inland and southern areas may remain warmer in the low 70s due to the residual influence of a weakening surface ridge. As surface high pressure also weakens, a series of weak frontal bands originating from a surface trough dropping into the gulf from the Alaska Peninsula will move across the panhandle, resulting in widespread overcast skies and moisture advection in the low to mid levels. The northeast gulf coast, particularly near Yakutat, will be the primary focus for precipitation, with the most significant activity expected between Monday and Tuesday. While deterministic models show some spread still, the highest forecaster confidence results in 24 hour rainfall accumulations of 0.75 to 1.25 with this disturbance. The remainder of the week is expected to stay showery with lighter, intermittent rain and cooler temperatures across the panhandle, offering relief from the recent dry spell.

MARINE

Outside: High pressure over the Gulf keeps a tighter gradient over the eastern waters. Moderate to fresh breezes for the outer coastal waters through tonight. Winds will gradually diminish on Friday, becoming a gentle to moderate breeze that will remain into the weekend as the high weakens and gradient relaxes. Wave heights of 4 to 6 ft will diminish slightly through the weekend. Seas will diminish about a foot by Friday and continue into the weekend. Main marine concern for outer and coastal waters will be nightly return of marine layer, with fog and low stratus offshore. Winds and seas look to trend back upward by early next week as a change in weather pattern brings a low and front into the Gulf.

Inside: Weakening high pressure out in the Gulf will allow for moderate to fresh N to NWly to trend downward as the gradient weakens across the panhandle. Winds will become light to gentle and more N to NEly by Friday low pressure sitting south of the panhandle and troughing drifting west. Lynn Canal will likely see moderate to fresh northernly with the tightened N-S gradient remaining. Light to gentle winds should continue into the weekend with occasional moderate winds for Lynn Canal. Winds will become more onshore through the weekend as the high pressure builds east towards the panhandle. Slight chances remain for isolated thunderstorm development from Canada moving into the southern panhandle this evening, but especially on Friday and Saturday Friday afternoon/evening, primarily near Misty Fjords and Clarence Strait. Gusty winds and lightning would be possible if any thunderstorms make it into the area.

HYDROLOGY

The Mendenhall River crested around 2:15pm this afternoon with a height of 14.7 ft. The river will continue to drop through the afternoon and evening tonight before exiting flood stage during the overnight. Levels in Suicide Basin could still continue to fall somewhat even though the release has stopped but should come to a steady here eventually. The water in the Mendenhall river basin will continue to drain out but will take some time to move from the lake down to below Brotherhood bridge.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Heat Advisory until 7 PM AKDT Friday for AKZ318-319-321-325-328- 330>332. MARINE...None.