Area Forecast Discussion
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000 FXAK67 PAJK 231519 CCB AFDAJK Southeast Alaska Forecast Discussion...CORRECTED National Weather Service Juneau AK 719 AM AKDT Fri Jun 23 2017 .SYNOPSIS...
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High pressure ridge along the panhandle Friday will weaken through the day. A low over the far SW Gulf of Alaska will continue to track northeast into the central gulf by Saturday morning. The associated weather front will move across the central gulf and push into the panhandle on Saturday.
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Most of Southeast Alaska Friday morning is sunny based on satellite imagery and web cams. Clouds are expected to spread northeast into the southern panhandle then to the coastal areas north along Baranof and Chichagof Islands later today. Light rain, may start to spread into west coast area around midnight and could spread east to the coastal mountain range Saturday morning. Winds along the coast increasing to 20-25 kt from Mt Fairweather southward for late tonight then it will lift north to the southern portion of the marine areas 51 and 52 for Saturday. Likely rain or better for early Saturday morning is shifting more showery into Sunday as the PoPs lower to 30 to 50 percent range. Light winds and sunny conditions for the panhandle...especially the northern part will see the Friday temperatures rising to the mid to upper 60s, although with a lesser pressure gradient, an afternoon sea breeze has a stronger potential of developing and that could cut the highs back a few degrees. Due to an increased cloud cover amount over the panhandle Saturday, have lowered the Saturday high temperatures 1 to 3 degrees as a first step and if one of the model solutions for the high temperatures were right may need to lower a couple more. .LONG TERM...Monday through Friday...As of 930 PM Thu...Period begins with models in fairly good agreement depicting an upper low over the central gulf drifting E across the central panhandle into Mon. As expected, there are minor differences in position and/or timing of this feature moving inland, but overall agreement minimizes impacts of these differences on the fcst. This feature is relatively weak as only the SREF mean SLP indicates a closed SFC circulation while all other guidance depicts an open wave just off S Baranof Mon Morning. Chc PoPs will persist Mon before the upper low pushes E of AOR Tue. Although the low will be inland, expect enough instability on the back side of it to see some ISOLD showers Tue over E CWA. Ridge will build over the gulf and push E over the panhandle Tue into Wed. Model solutions continue to diverge by mid week, mainly with the strength and timing of the system pushing into the W gulf. How long the ridge persists over SE will depend on this next system`s approach. Expect dry weather to continue Wed before increasing sky cover and precip chances late next week. Temps will be slightly below normal Mon then slightly above normal mid next week as supported by NAEFS low level T standard dev swinging from 1-2 below to 1-2 above normal during the first half of the week. Given model spreads in the extended it`s difficult to determine how long the ridge will maintain dry wx across SE. Therefore, elected to stay close to WPC guidance for the latter half of next week with cooling temps and increasing precip chances. Inherited forecast represented this well with very little change before trending toward WPC.
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&& .AVIATION...IMC Conditions dominate the skies above our airfields. Change groups this morning were reserved for some sea/channel breezes developing. A few spots like Skagway, Haines, and Ketchikan may experience enhanced mesoscale channel breezes this afternoon. At this time, the only appearance of the front approaching from the west is a late prob30 group for Sitka Saturday morning for MVMC conditions with light rain. && .MARINE...Winds along the incoming frontal band Friday night are roughly small craft strength and they will move across central gulf and the coastal waters late Friday night and Saturday. Think that outflow through Cross Sound will be small craft late Friday night and early Saturday before weakening. && .AJK Watches/Warnings/Advisories... PUBLIC...None. MARINE...Small Craft Advisory for PKZ022-042-043. && $$ Bezenek/BC Visit us at is the U.S. government's official web portal to all federal, state and local government web resources and services.